U.S. patent application number 12/272523 was filed with the patent office on 2009-05-28 for method for producing organic acid.
This patent application is currently assigned to MITSUBISHI CHEMICAL CORPORATION. Invention is credited to Atsushi ISOTANI.
Application Number | 20090137843 12/272523 |
Document ID | / |
Family ID | 29424660 |
Filed Date | 2009-05-28 |
United States Patent
Application |
20090137843 |
Kind Code |
A1 |
ISOTANI; Atsushi |
May 28, 2009 |
METHOD FOR PRODUCING ORGANIC ACID
Abstract
A novel method is provided whereby a free organic acid can be
produced particularly from an ammonium salt of an organic acid
having a high melting point obtainable by bioconversion of a carbon
source in the presence of a neutralizing agent, efficiently at a
low cost, and the used material for reaction and a byproduct can be
recycled for reuse without being disposed. An ammonium salt of
organic acid A such as a dicarboxylic acid, a tricarboxylic acid or
an amino acid is subjected to reactive crystallization by means of
acid B such as a monocarboxylic acid satisfying the following
formula (1), to separate free organic acid A in solid form:
pKa(A).ltoreq.pKa(B) (1) where pKa(A) and pKa(B) represent
ionization indices of organic acid A and acid B, respectively,
provided that when they have plural values, they represent the
minimum pKa among them. The crystallization mother liquor after
precipitating and separating organic acid A is, after separating
acid B and then an ammonium salt of acid B, recycled for use in the
reactive crystallization step. The ammonium salt of acid B is
decomposed into acid B and ammonia, which are recycled for use in
the reactive crystallization step and as a neutralizing agent in
the bioconversion step, respectively.
Inventors: |
ISOTANI; Atsushi; (Mie,
JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
MITSUBISHI CHEMICAL
CORPORATION
Tokyo
JP
|
Family ID: |
29424660 |
Appl. No.: |
12/272523 |
Filed: |
November 17, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11688647 |
Mar 20, 2007 |
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12272523 |
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10976822 |
Nov 1, 2004 |
7217837 |
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11688647 |
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PCT/JP03/05826 |
May 9, 2003 |
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10976822 |
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Current U.S.
Class: |
562/608 ;
562/400; 562/606; 564/192 |
Current CPC
Class: |
C07C 51/48 20130101;
C07C 51/412 20130101; C07C 51/02 20130101; C07C 51/43 20130101;
C07C 51/50 20130101; C07C 51/02 20130101; C07C 55/14 20130101; C07C
51/02 20130101; C07C 55/02 20130101; C07C 51/02 20130101; C07C
55/10 20130101; C07C 51/50 20130101; C07C 55/10 20130101; C07C
51/50 20130101; C07C 55/14 20130101; C07C 51/50 20130101; C07C
55/20 20130101; C07C 51/50 20130101; C07C 53/122 20130101; C07C
51/412 20130101; C07C 53/122 20130101; C07C 51/412 20130101; C07C
53/10 20130101; C07C 51/412 20130101; C07C 53/124 20130101; C07C
51/43 20130101; C07C 55/10 20130101; C07C 51/48 20130101; C07C
55/10 20130101 |
Class at
Publication: |
562/608 ;
562/400; 562/606; 564/192 |
International
Class: |
C07C 51/64 20060101
C07C051/64; C07C 231/00 20060101 C07C231/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 10, 2002 |
JP |
2002-135656 |
Aug 8, 2002 |
JP |
2002-231740 |
Aug 8, 2002 |
JP |
2002-231741 |
Oct 21, 2002 |
JP |
2002-305989 |
Claims
1. In a process for separating and recovering an acid B and ammonia
by decomposing an ammonium salt of acid B to the acid B and
ammonia, a method for decomposing the ammonium salt of acid B,
wherein said method comprises: heating a liquid comprising water,
the ammonium salt of acid B, and a metal salt of acid B, by
supplying the liquid to a site of a distillation column having at
least two plates as the real number of plates to produce a gas of a
basic aqueous solution and a remaining liquid, wherein the
temperature of the site of the distillation column is not higher
than the melting point of the ammonium salt of acid B, and wherein
the metal of the metal salt of acid B is one or more metals
selected from the group consisting of Na, K, Ca and Mg; and
withdrawing the gas of the basic aqueous solution from the top of
the distillation column.
2. The method according to claim 1, wherein the acid B is at least
one acid selected from the group consisting of formic acid, acetic
acid, propionic acid and butyric acid.
3. The method according to claim 1, wherein said method further
comprises recovering the acid B by subjecting the remaining liquid,
after said withdrawing, to a temperature of at least 125.degree. C.
under reduced pressure or atmospheric pressure, and separating the
acid B from a residual liquid.
4. The method according to claim 3, wherein said method further
comprises mixing the residual liquid, after said separating, with
an aqueous system to hydrolyze an amide compound formed as a
byproduct in said heating and said separating; and recycling the
residual liquid, after said mixing, to said heating.
5. The method according to claim 1, wherein said method further
comprises withdrawing the gas of the basic aqueous solution from
the remaining liquid.
6. The method according to claim 1, wherein said method further
comprises subjecting the gas of the basic aqueous solution, either
directly or after condensation, to a gas separation carried out at
a temperature of not higher than the melting point of the ammonium
salt of acid B, wherein said gas separation is selected from the
group consisting of a gas/liquid separation, a gas/solid separation
and a gas/liquid/solid separation.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S. patent
application Ser. No. 11/688,647, filed on Mar. 20, 2007, which is a
divisional of U.S. patent application Ser. No. 10/976,822, filed on
Nov. 1, 2004, which is a continuation of International patent
application PCT/JP03/05826, filed on May 9, 2003, which claims
priority to Japanese patent application JP 2002-305989, filed on
Oct. 21, 2002, Japanese patent application JP 2002-231741, filed on
Aug. 8, 2002, Japanese patent application JP 2002-231740, filed on
Aug. 8, 2002, and Japanese patent application JP 2002-135656, filed
on May 10, 2002, the contents of which are hereby incorporated by
reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to method for producing an
organic acid having a high melting point such as a dicarboxylic
acid, a tricarboxylic acid or an amino acid (hereinafter sometimes
generally referred to as organic acid A). More particularly, it
relates to a method for producing an organic acid comprising a
novel separation/purification step of an organic acid, which is
useful in a case where a biogenic material such as glucose,
fructose or cellulose, is produced by bioconversion.
BACKGROUND ART
[0003] A carboxylic acid such as succinic acid or its derivative is
widely used as a material for a polymer such as a polyester or a
polyamide, particularly as a material for a biodegradable
polyester, or as a material for food products, pharmaceuticals and
cosmetics. Further, a tricarboxylic acid such as citric acid is
widely used as a food additive, etc. In recent years, particularly
succinic acid is expected to be a material for a biodegradable
polymer, together with lactic acid.
[0004] Succinic acid has heretofore been industrially obtained by
hydrogenation of maleic acid, and the maleic acid is a material
derived from petroleum. Accordingly, as a technique to produce an
organic acid such as succinic acid, malic acid, tartaric acid or
citric acid from a material derived from a plant, a technique to
utilize a fermentation operation has been studied. Further, an
amino acid has already been produced by a fermentation method, but
separation and purification of an amino acid have been carried out
usually by isoelectric point precipitation employing sulfuric
acid.
[0005] Further, such an organic acid as a dicarboxylic acid or a
tricarboxylic acid has at least two carboxyl groups, or carboxyl
groups and an amino group, as functional groups. Due to such
hydrogen bonds, its melting point is usually high (usually at least
120.degree. C.), and in its production process, a distillation
operation as a common separation/purification method, can not be
employed. Further, in the production of such an organic acid by
fermentation, neutralization is usually required, since a
microorganism such as fungus or mold to be used for the
fermentation does not show an adequate activity usually under a low
pH condition. Accordingly, an organic acid obtainable from a
fermenter, is usually in the form of a salt with an alkali used for
the neutralization. This is a factor which makes the
separation/purification of such an organic acid more difficult.
[0006] Heretofore, a method employing electrodialysis
(JP-A-2-283289) is available as a common separation/purification
method for a salt of an organic acid formed by fermentation.
However, the electrodialysis has a problem that since the apparatus
is large in proportion to production scale, and the scale merit is
small even by production on an industrial scale, and consequently
the cost tends to be high.
[0007] Further, a method of employing an ion exchange resin has
been proposed (U.S. Pat. No. 6,284,904). However, in this method, a
salt of a strong acid and strong base (such as NaCl) will be formed
at the time of regenerating the ion exchange resin, and eventually,
this salt is required to be disposed or to be treated by
electrodialysis.
[0008] Further, a method of decomposing calcium succinate with
sulfuric acid has been proposed (JP-A-3-030685). However, in this
method, calcium sulfate will be formed in a large amount as a
byproduct, and its treatment is problematic.
[0009] Further, as an effective method, a method of carrying out
reactive crystallization by an exchange reaction of a salt by means
of sulfuric acid has been proposed (JP-A-2001-514900, U.S. Pat. No.
5,958,744). Namely, this is a method for precipitating and
separating an organic acid by carrying out reactive crystallization
by adding sulfuric acid to an ammonium salt of an organic acid.
[0010] In this method, a soluble amount of the ammonium salt of the
organic acid will remain in the crystallization mother liquor after
separating the organic acid by crystallization, and ammonium
sulfate will also be contained in this crystallization mother
liquor. In order to increase the recovery rate of the entire
process, it is necessary to recover such an ammonium salt of the
organic acid remaining in the crystallization mother liquor, but
even if a crystallization operation is further applied to this
crystallization mother liquor, it is extremely difficult to
separate ammonium sulfate in solid form, while permitting the
ammonium salt of the organic acid to remain in the liquid.
Otherwise, even if it is attempted to carry out separation by a
gas/liquid separation operation such as distillation, the ammonium
salt of the organic acid and ammonium sulfate have very high
melting points, and under such a high temperature condition as to
vaporize these compounds, the ammonium salt of the organic acid
will undergo a dehydration reaction, and it would be impossible to
recover the organic acid. Further, by this method, a special
installation has been required to carry out pyrolysis of ammonium
sulfate at a temperature of at least 300.degree. C. in order to
recover and reuse sulfuric acid from ammonium sulfate.
[0011] It is an object of the present invention to solve such
conventional problems and to provide a novel method for producing
organic acid A having a high purity by separating and purifying
free organic acid A from a salt of organic acid A formed by a
fermentation method by bioconversion of a carbon source in the
presence of a neutralizing agent.
[0012] Another object of the present invention is to provide a
method for producing organic acid A efficiently at a low cost with
a low level of waste in consideration of environment, by
decomposing and reusing a byproduct salt formed in the
above-mentioned novel method for producing organic acid A.
DISCLOSURE OF THE INVENTION
[0013] As a result of an extensive research on the above problems,
the present inventor has paid particular attention to
characteristics of organic acid A to be obtained in the present
invention such that its solubility in a monocarboxylic acid
(hereinafter sometimes referred to as acid B) being a weak acid
such as acetic acid or propionic acid, is generally low and its
temperature dependency is high, and an ammonium salt of organic
acid A has a high solubility in acid B. It has been found that by
utilizing such characteristics, it is possible to separate the
ammonium salt of organic acid A which should be hardly decomposable
when judged solely from pKa (Ka: dissociation constant,
pKa=log.sub.10Ka), in the form of an acid, by reactive
crystallization by means of acid B, and it is possible to decompose
an ammonium salt of acid B formed as a byproduct, under a
relatively mild heating condition, and it is possible to reuse
ammonia obtained by the decomposition.
[0014] In the present invention, "an ammonium salt" means a mono-,
di- and/or tri-ammonium salt, unless otherwise defined.
[0015] It is a well known fact that in general, a salt of a weak
acid can be decomposed by a strong acid by means of an exchange
reaction of the salt to produce a salt of the strong acid as a
byproduct and to obtain the weak acid. This is the above-mentioned
conventional method for carrying out an exchange reaction of a salt
by means of sulfuric acid (U.S. Pat. No. 5,958,744). Further, also
in the method of employing an ion exchange resin, the ion exchange
resin is required to be an acid stronger than a dicarboxylic acid
or a tricarboxylic acid. However, as mentioned above, in such a
method, a salt of an acid stronger than the desired organic acid
will be formed as a byproduct.
[0016] When comparison is made with respect to pKa as an index for
the acid intensity in an acid/base exchange reaction, for example,
pKa of succinic acid and acetic acid is as shown below, and it is
evident that diammonium succinate (secondary kPa) is capable of an
acid/base exchange reaction with acetic acid, but monoammonium
succinate is hardly capable of such an acid/base exchange reaction
with acetic acid.
[0017] Succinic acid primary pKa: 4.21
[0018] Succinic acid secondary pKa: 5.64
[0019] Acetic acid pKa: 4.76
[0020] Accordingly, as mentioned above, it has been common to
employ a method of using a strong acid or an ion exchange resin
having a strong acidity. As shown in JP-A-2001-514900, in the
crystallization employing an inorganic acid, it is usually required
to have a high recovery rate by a single stage of crystallization,
since an ammonium salt of the inorganic acid is usually
non-volatile. Accordingly, in the case of succinic acid, primary
pKa is 4.21, whereby the pH must be smaller than 2.1 in order to
obtain a sufficient recovery rate. Thus, in JP-A-2001-514900,
sulfuric acid is used for the reactive crystallization. In this
method, the pH is required to be from 1.5 to 1.8.
[0021] Whereas, the present inventor has discovered that organic
acid A which is difficult to obtain solely by an acid/base
reaction, can be easily separated and purified by reactive
crystallization by means of acid B such as a monocarboxylic acid,
which is an acid weaker than the desired organic acid A.
[0022] Namely, paying an attention to the fact that organic acid A
obtainable as a result of bioconversion in the presence of a
neutralizing agent, has a high solubility as an ammonium salt of
organic acid A and a low solubility as ammonia free organic acid A,
in acid B as a weak acid, the present inventor has found a fact
that there is a region wherein it is soluble as an ammonium salt of
organic acid A, but insoluble as ammonia free organic acid A, in
acid B.
[0023] On the other hand, acid B functions as a proton source,
whereby by permitting a sufficient amount of acid B to be
coexistent, to lower the pH, it is possible to convert the ammonium
salt of organic acid A to ammonia free organic acid A by an
acid/base reaction with acid B. If such ammonia free organic acid A
is present beyond the solubility, the ammonia free organic acid A
precipitates. At that time organic acid A in the form of ammonium
salt has a sufficiently high solubility in acid B and will not
precipitate at the same time.
[0024] On the basis of such discoveries, the present inventor has
succeeded in separating organic acid A which used to be difficult
to obtain solely by an acid/base reaction, in solid form, by
reactive crystallization by means of acid B which is a weaker acid
than organic acid A.
[0025] On the other hand, in such a case, there may be a case where
the recovery per stage tends to be poor as compared with
conventional crystallization employing a strong acid. Therefore, it
is preferred that the ammonium salt of acid B formed as a byproduct
and the ammonium salt of organic acid A, contained in the mother
liquor, are separated and recovered from the mother liquor and
recycled, for industrial operation. Further, if the salt of acid B
formed as a byproduct, is disposed, a problem of a disposed waste
will be created like the conventional technique, and accordingly,
it is preferred to decompose and reuse the ammonium salt of acid B
formed as a byproduct.
[0026] The present inventor has found that ammonia constituting the
ammonium salt of organic acid A is a volatile base, and in a case
where a volatile acid, preferably a saturated monocarboxylic acid
having a low boiling point such as acetic acid or propionic acid is
used as acid B, it is possible to vaporize the ammonium salt of
acid B. By this operation, they have succeeded in recovering
organic acid A from the mother liquor obtained by reactive
crystallization.
[0027] Thus, the present invention is characterized by having the
following features.
1. A method for producing organic acid A, which comprises
subjecting an ammonium salt of organic acid A to reactive
crystallization by means of acid B satisfying the following formula
(1), to separate organic acid A in solid form:
pKa(A).ltoreq.pKa(B) (1)
where pKa(A) and pKa(B) represent ionization indices of organic
acid A and acid B, respectively, provided that when they have
plural values, they represent the minimum pKa among them. 2. The
method according to Item 1, wherein acid B is volatile. 3. The
method according to Item 1 or 2, wherein organic acid A is an
organic acid having a melting point of at least 120.degree. C. 4.
The method according to Item 1 or 2, wherein organic acid A is a
C.sub.4-12 dicarboxylic or tricarboxylic acid, or a C.sub.4-12
amino acid. 5. The method according to any one of Items 1 to 4,
wherein acid B is a monocarboxylic acid. 6. The method according to
any one of Items 1 to 4, wherein acid B is acetic acid or propionic
acid. 7. The method according to any one of Items 1 to 6, wherein
the reactive crystallization is carried out in a single stage or
multi-stages, and the pH is from 2.1 to 6.5 at least in one stage.
8. The method according to any one of Items 1 to 7, wherein the
ammonium salt of organic acid A is one obtained via a bioconversion
step in which a carbon source is converted by a microorganism in
the presence of at least one neutralizing agent selected from the
group consisting of ammonia, ammonium carbonate and urea. 9. The
method according to any one of Items 1 to 7, wherein the ammonium
salt of organic acid A is one obtained in the form of an aqueous
solution of the ammonium salt of organic acid A in such a manner
that a reaction solution containing an alkali metal and/or alkaline
earth metal salt of organic acid A is obtained via a bioconversion
step in which a carbon source is converted by a microorganism in
the presence of at least one neutralizing agent selected from the
group consisting of an alkali metal hydroxide, an alkaline earth
metal hydroxide, an alkali metal carbonate and an alkaline earth
metal carbonate; ammonia and carbon dioxide, and/or ammonium
carbonate, is added to said reaction solution containing an alkali
metal and/or alkaline earth metal salt of organic acid A to carry
out reactive crystallization to precipitate an alkali metal and/or
alkaline earth metal carbonate (Solvay process step); and the
precipitated carbonate is separated. 10. The method according to
Item 8 or 9, which includes a concentration step of concentrating
the reaction solution obtained in the bioconversion step, and
wherein a concentrate obtained in the concentration step is
subjected to the reactive crystallization. 11. The method according
to any one of Items 1 to 7, wherein the ammonium salt of organic
acid A is one formed in a chemical process. 12. The method
according to any one of Items 1 to 11, wherein organic acid A
precipitated by the reactive crystallization is separated; after
the separation, an ammonium salt of acid B in the crystallization
mother liquor is decomposed by a decomposition step to obtain acid
B; and the obtained acid B is recycled for use as a solvent for the
reactive crystallization. 13. The method according to Item 12,
wherein organic acid A precipitated by the reactive crystallization
is separated; after the separation, the crystallization mother
liquor is concentrated by vaporizing acid B therefrom; and then,
the acid B and its ammonium salt are decomposed/vaporized in order
to recover organic acid A and its ammonium salt. 14. The method
according to Item 13, wherein the vaporization of acid B is carried
out at a temperature of not higher than the melting point of the
ammonium salt of acid B. 15. The method according to Item 13 or 14,
wherein the decomposition/vaporization of the acid B and its
ammonium salt are carried out by heating under a reduced pressure
of from 0.001 mmHg to 200 mmHg. 16. The method according to any one
of Items 12 to 15, wherein the decomposition step comprises a
heating step of heating a liquid comprising the ammonium salt of
acid B, an alkali metal and/or alkaline earth metal salt of acid B,
and water, and withdrawing a gas of a basic aqueous solution, and a
step of subjecting the basic aqueous solution withdrawn from the
heating step, directly or after condensation, to gas/liquid
separation, gas/solid separation or gas/liquid/solid separation at
a temperature of not higher than the melting point of the ammonium
salt of acid B. 17. The method according to any one of Items 12 to
15, wherein the decomposition step comprises a heating step of
supplying a liquid comprising the ammonium salt of acid B, an
alkali metal and/or alkaline earth metal salt of acid B, and water,
to a distillation column having at least two plates as the real
number of plates, and withdrawing a gas of a basic aqueous solution
from the top of the distillation column. 18. The method according
to Item 17, wherein in the heating step, the liquid comprising the
ammonium salt of acid B, an alkali metal and/or alkaline earth
metal salt of acid B, and water, is supplied to a site of the
distillation column having at least two plates as the real number
of plates, where the temperature is not higher than the melting
point of the ammonium salt of acid B. 19. The method according to
any one of Items 16 to 18, wherein the alkali metal and/or alkaline
earth metal constituting the alkali metal and/or alkaline earth
metal salt of acid B, is at least one member selected from the
group consisting of Na, K, Ca and Mg. 20. The method according to
any one of Items 16 to 18, wherein the liquid after withdrawing the
gas of a basic aqueous solution in the heating step, is subjected
to a separation step which is carried out under reduced pressure or
atmospheric pressure at a temperature of at least 125.degree. C.,
to separate and recover acid B. 21. The method according to Item
20, wherein the residual liquid after the separation step is mixed
with a system containing water to hydrolyze an amide compound
formed as a byproduct in the heating step and the separation step
and then recycled to the heating step. 22. The method according to
any one of Items 1 to 10 and 12 to 21, wherein the ammonium salt of
organic acid A is one obtained as a reaction solution containing
the ammonium salt of organic acid A via a bioconversion step in
which conversion is carried out by a microorganism by means of
ammonia as a neutralizing agent; organic acid A precipitated by the
reactive crystallization carried out by adding acid B, is
separated; after the separation, the ammonium salt of acid B in the
crystallization mother liquor, is decomposed to obtain ammonia; and
the ammonia is used as a neutralizing agent for the bioconversion
step. 23. The method according to any one of Items 1 to 10 and 12
to 21, wherein the ammonium salt of organic acid A is one obtained
in the form of an aqueous solution of the ammonium salt of organic
acid A in such a manner that a reaction solution containing an
alkali metal and/or alkaline earth metal salt of organic acid A is
obtained via a bioconversion step in which a carbon source is
converted by a microorganism in the presence of at least one
neutralizing agent selected from the group consisting of an alkali
metal hydroxide, an alkaline earth metal hydroxide, an alkali metal
carbonate and an alkaline earth metal carbonate; ammonia and carbon
dioxide, and/or ammonium carbonate, is added to said reaction
solution containing an alkali metal and/or alkaline earth metal
salt of organic acid A to carry out reactive crystallization to
precipitate an alkali metal and/or alkaline earth metal carbonate
(Solvay process step); and the precipitated carbonate is separated;
organic acid A precipitated by the reactive crystallization carried
out by adding acid B, is separated; after the separation, the
ammonium salt of acid B in the crystallization mother liquor, is
decomposed to obtain ammonia; and the ammonia is used as an ammonia
source for the Solvay process step. 24. The method according to any
one of Items 1 to 23, wherein the reactive crystallization is
carried out in multi-stages, and in reactive crystallization in the
second or subsequent stage, the crystallization mother liquor after
separating the precipitated organic acid A is, directly or after
concentrating the ammonium salt of acid B by vaporization of the
reactive crystallization solvent containing acid B, or after
separating organic acid A or its salt dissolved in the mother
liquor, recycled to a crystallizer for reactive crystallization in
a preceding stage. 25. In a process for separating and recovering
acid B and ammonia by decomposing an ammonium salt of acid B to
acid B and ammonia, a method for decomposing the ammonium salt of
acid B, which comprises a heating step of heating a liquid
comprising the ammonium salt of acid B, an alkali metal and/or
alkaline earth metal salt of acid B, and water, and withdrawing a
gas of a basic aqueous solution, and a step of subjecting the basic
aqueous solution withdrawn from the heating step, directly or after
condensation, to gas/liquid separation, gas/solid separation or
gas/liquid/solid separation at a temperature of not higher than the
melting point of the ammonium salt of acid B. 26. In a process for
separating and recovering acid B and ammonia by decomposing an
ammonium salt of acid B to acid B and ammonia, a method for
decomposing the ammonium salt of acid B, which comprises a heating
step of supplying a liquid comprising the ammonium salt of acid B,
an alkali metal and/or alkaline earth metal salt of acid B, and
water, to a site of a distillation column having at least two
plates as the real number of plates, where the temperature is not
higher than the melting point of the ammonium salt of acid B, and
withdrawing a gas of a basic aqueous solution from the top of the
distillation column. 27. The method according to Item 25 or 26,
wherein the alkali metal and/or alkaline earth metal constituting
the alkali metal and/or alkaline earth metal salt of acid B, is at
least one member selected from the group consisting of Na, K, Ca
and Mg. 28. The method according to any one of Items 25 to 27,
wherein acid B is at least one member selected from the group
consisting of formic acid, acetic acid, propionic acid and butyric
acid. 29. The method according to any one of Items 25 to 28, which
comprises a step of recovering acid B, wherein the liquid after
withdrawing the gas of a basic aqueous solution in the heating
step, is subjected to a separation step which is carried out under
reduced pressure or atmospheric pressure at a temperature of at
least 125.degree. C., to separate and recover acid B. 30. The
method according to any one of Items 25 to 29, wherein the residual
liquid after the separation step is mixed with a system containing
water to hydrolyze an amide compound formed as a byproduct in the
heating step and the separation step and then recycled to the
heating step. 31. Organic acid A produced by a method as defined in
any one of Items 1 to 24. 32. A polymer prepared by using, as a
material, organic acid A produced by a method as defined in any one
of Items 1 to 24.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 is a schematic flowchart showing the construction of
an apparatus suitable for carrying out the method for decomposition
of an ammonium salt of acid B of the present invention.
[0029] FIG. 2 is a schematic flowchart showing the construction of
another apparatus suitable for carrying out the method for
decomposition of an ammonium salt of acid B of the present
invention.
[0030] FIG. 3 is a schematic flowchart showing the construction of
another apparatus suitable for carrying out the method for
decomposition of an ammonium salt of acid B of the present
invention.
[0031] FIG. 4 is a schematic flowchart showing the construction of
another apparatus suitable for carrying out the method for
decomposition of an ammonium salt of acid B of the present
invention.
[0032] FIG. 5 is a schematic flowchart showing the construction of
another apparatus suitable for carrying out the method for
decomposition of an ammonium salt of acid B of the present
invention.
[0033] FIG. 6 is a flowchart showing the construction of the
apparatus employed in Test Examples 2-2 and 2-3.
MEANING OF SYMBOLS
[0034] 1, 1A, 1B: Distillation columns [0035] 2: Vaporizer [0036]
3: Acetamide decomposition vessel [0037] 4: Thin film evaporator
[0038] 5: Flash drum [0039] 10: Distillation column [0040] 12: Oil
bath [0041] 13: Flask [0042] 16: Feed material vessel [0043] 17:
Preheater
EMBODIMENTS OF THE INVENTION
[0044] Now, embodiments of the method for producing an organic acid
according to the present invention, will be described in
detail.
Formation of an Ammonium Salt of Organic Acid A
[0045] Organic acid A to be produced by the present invention may,
for example, be one having a melting point which is preferably at
least 120.degree. C. Its carbon number is preferably from 4 to 12,
and it is preferably one having a straight chain form. A
dicarboxylic acid or a tricarboxylic acid may, for example, be
mentioned as a typical example. Preferred is one having two or
three carboxyl groups bonded to a saturated or unsaturated
aliphatic hydrocarbon, and it may have a branched chain or cyclic
structure, and it may have a substituent. Further, organic acid A
includes an amino acid having a melting point which is preferably
at least 120.degree. C.
[0046] Specifically, organic acid A may, for example, be succinic
acid, fumaric acid, maleic acid, malic acid, tartaric acid,
asparaginic acid, glutaric acid, glutamic acid, adipic acid,
suberic acid, citric acid, itaconic acid, terephthalic acid,
phenylalanine, tryptophan, asparagine, glutamine, valine,
isoleucine, leucine, histidine, methionine or tyrosine. These acids
may be a mixture of two or more of them. Among them, preferred as
organic acid A is, for example, succinic acid, adipic acid,
glutamic acid, suberic acid, tartaric acid or citric acid.
Particularly preferred is succinic acid, adipic acid, glutamic acid
or suberic acid. Such organic acid A may be formed, for example, by
bioconversion using a carbon source as the starting material. As
the carbon source, a fermentable carbohydrate, such as a
carbohydrate such as galactose, lactose, glucose, fructose,
glycerol, sucrose, saccharose, starch or cellulose, or a
polyalcohol such as glycerine, mannitol, xylitol or ribitol, may,
for example, be used. Among them, glucose, fructose or glycerol is
preferred. Particularly preferred is glucose. As a broader
plant-derived material, cellulose as the main component for paper,
is preferred. Further, a starch-succharized liquid or treacle
containing the above-mentioned fermentable carbohydrate, may also
be used. Such fermentable carbohydrates may be used alone or in
combination as a mixture of two or more of them.
[0047] The microorganism to be used for such bioconversion is not
particularly limited so long as it has an ability to produce
organic acid A. For example, anaerobic bacteria such as genus
Anaerobiospirillum (U.S. Pat. No. 5,143,833), facultative anaerobic
bacteria such as genus Actinobacillus (U.S. Pat. No. 5,504,004) or
genus Escherichia (U.S. Pat. No. 5,770,435), or aerobic bacteria
such as genus Corynebacterium (JP 11113588) may, for example, be
used. The reaction conditions such as the reaction temperature,
pressure, etc., in the bioconversion, depend upon the activities of
the fungus, mold, etc. to be selected, but suitable conditions to
obtain the corresponding organic acid A may be suitably selected
depending upon the respective cases.
[0048] In the above bioconversion, if the pH becomes low, the
metabolic activities of the microorganism tend to be low, or the
microorganism tends to stop its activities, whereby the production
yield is likely to deteriorate, or the microorganism is likely to
die. Therefore, a neutralizing agent is used. Usually, the pH in
the reaction system is measured by a pH sensor, and the pH is
adjusted to be within a prescribed pH range, every time when a
neutralizing agent is added. In the present invention, the method
for adding a neutralizing agent is not particularly limited, and it
may be continuous addition or intermittent addition.
[0049] The neutralizing agent may, for example, be ammonia,
ammonium carbonate, urea, an alkali metal hydroxide, an alkaline
earth metal hydroxide, an alkali metal carbonate or an alkaline
earth metal carbonate. Preferred is ammonia, ammonium carbonate or
urea. Namely, as mentioned above, in a case where an alkali metal
or alkaline earth metal hydroxide or an alkali metal or an alkaline
earth metal carbonate is employed, an alkali metal or alkaline
earth metal salt of acid B will be formed as a byproduct in the
reactive crystallization by means of acid B, and the alkali metal
or alkaline earth metal used for neutralization can not directly be
recovered. Accordingly, in the Solvay process step, a step of
obtaining an ammonia salt of organic acid A will be required.
Further, the alkali metal or alkaline earth metal hydroxide may,
for example, be NaOH, KOH, Ca(OH).sub.2, Mg(OH).sub.2, or a mixture
thereof. The alkali metal or alkaline earth metal carbonate may,
for example, be Na.sub.2CO.sub.3, K.sub.2CO.sub.3, CaCO.sub.3,
MgCO.sub.3, NaKCO.sub.3 or a mixture thereof.
[0050] The pH value to be adjusted by such a neutralizing agent, is
adjusted depending upon the type of the fungus or mold to be used,
within a range where its activities are most effectively obtained.
Usually, the pH is within a range of from 4 to 10, preferably from
6 to 9.
[0051] The ammonium salt of organic acid A to be the starting
material for organic acid A to be produced by the present
invention, is not necessarily limited to one obtained by the
above-mentioned bioconversion, but may be one produced or produced
as a byproduct from a petrochemical process or from other various
processes.
Reactive Crystallization
[0052] In general, crystallization refers to an operation to
precipitate the necessary component in a state where unnecessary
components are dissolved in a solvent. Whereas, in the present
invention, "reactive crystallization" means an operation whereby a
necessary component is obtained by a reaction and at the same time
crystallization is carried out. Namely, it is meant for an
operation in which crystallization of the desired product is
carried out while carrying out a reaction to obtain the desired
product to be crystallized. In the present invention, separation
and purification of such organic acid A is carried out by reactive
crystallization employing acid B which is a weaker acid than
organic acid A, as mentioned above. Acid B to be used, is required
to satisfy the following formula (1):
pKa(A).ltoreq.pKa(B) (1)
[0053] Here, in the formula (1), Ka(A) and Ka(B) represent the
dissociation constants of organic acid A and acid B, respectively,
and in a case where they have plural values, they represent the
minimum pKa among them. Although it may depend substantially on the
functional groups of organic acid A, pKa(B) is preferably larger by
from 0 to 3 than pKa(A) while satisfying the above formula (1).
[0054] As an example of acid B, a preferably C.sub.16, particularly
preferably C.sub.1-4, monocarboxylic acid, is preferred.
Specifically, at least one member selected from formic acid, acetic
acid, propionic acid, n-butyric acid and isobutyric acid, may be
mentioned. Among them, acetic acid or propionic acid is preferred
from the viewpoint of the low corrosiveness to the material of the
apparatus and the evaporation latent heat. More preferably, it is
an acid produced as a byproduct by the fungus to be used for
bioconversion. For example, in the case of the fungus disclosed in
JP-A-11-206385 or JP2002-34826, acetic acid is preferred. Further,
acid B must be volatile, so that it can be separated from the
alkali metal salt. Further, it is preferably stable against heat.
Not preferred is one which has a carbon-carbon double bond or
triple bond and which undergoes polymerization or decomposition
under a condition of not higher than 200.degree. C. in the presence
of an alkali metal or alkaline earth metal, or one which has a
peroxide as a functional group and which undergoes self
decomposition under a condition of not higher than 200.degree. C.
in the presence of an alkali metal or alkaline earth metal, or one
which has plural functional groups in one molecule such as lactic
acid, tartaric acid or an amino acid and which forms a polymer
(such as a polyester or polyamide).
[0055] As mentioned above, organic acid A is obtained from a
fermenter as a dilute aqueous solution in the form of a salt with
the neutralizing agent employed in the bioconversion. Accordingly,
organic acid A is separated and purified from the reaction solution
discharged from this fermenter, whereby organic acid A as a
commercial product can be produced. Here, a case will be described
in which at least one member selected from the group consisting of
ammonia, ammonium carbonate and urea is used as a neutralizing
agent (hereinafter sometimes referred to as an ammonia type
neutralizing agent).
[0056] In such a case, the reaction solution from the fermenter
containing an ammonium salt of organic acid A is usually a dilute
aqueous solution, and this reaction solution is preferably
concentrated. The method for concentration is not particularly
limited, and, for example, evaporation, crystallization by means of
an alcohol or the like, membrane separation utilizing reverse
osmosis, or electrodialysis by means of an ion exchange membrane,
may be mentioned. Among them, electrodialysis has a difficulty such
that a scale merit can not be obtained, and the cost for the
apparatus or operation is high, as mentioned above. In the
crystallization by means of an alcohol or the like, an
extradistillation apparatus to recover the alcohol will be
required. From such a viewpoint and from the viewpoint of the cost,
distillation is preferred, and preferably, distillation by means of
a multi-effect evaporator may be mentioned.
[0057] With respect to the degree for concentration of the reaction
solution, even in the case of an aqueous solution having a high
concentration, for example, a highly concentrated aqueous solution
in which the concentration of an ammonium salt of organic acid A is
at least 40 wt %, concentration may be carried out until the
ammonium salt of organic acid A precipitates in solid form. In the
case of a highly concentrated aqueous solution, there is a merit
such that dissolution into acid B is easy, and the operation is
easy as compared with a slurry or solid. On the other hand, in a
case where the ammonium salt of organic acid A is made into solid
form, mixing of water and acid B can be avoided, and there is a
merit such that even if excess ammonia or an ammonium salt of acid
B formed as byproduct, is present, such ammonia or an ammonium salt
can be removed by vaporization in the drying/evaporation step, for
example, by means of a thin film evaporator. The degree for
concentration is suitably determined so that the entire process
including the reaction conditions for bioconversion which are
influential over the types and amounts of impurities, can be
optimized.
[0058] Depending upon the type of organic acid A or the type of
acid B, the reactive crystallization may be carried out in a single
stage or in multiple stages (a plurality of stages). It is usually
carried out in multi-stages from restrictions such as initial
investment, operational conditions or recovery rate, and it is
particularly preferably carried out in from 2 to 4 stages in many
cases. Further, in a case where multi-stage crystallization is
carried out, one having a pH of not higher than 7, corresponds to
the reactive crystallization in the present invention. When the pH
is not higher than 7, for example, if organic acid A is succinic
acid, a monoammonium salt of succinic acid can be obtained from a
diammonium salt of succinic acid, whereby in the subsequent
reactive crystallization, succinic acid can be obtained at a higher
recovery rate.
[0059] Thus, this corresponds to the reactive crystallization. In
the final stage of the reactive crystallization (in the single
stage when the reactive crystallization is carried out in a single
stage), the amount of acid B to be added to the reaction solution
may be an amount such that organic acid A will precipitate by the
addition of acid B, i.e. an amount which is sufficient for
formation of organic acid A by an acid/base reaction of acid B with
an ammonium salt of organic acid A and which is sufficient to
precipitate formed organic acid A without dissolution. The amount
of acid B varies depending upon the type and pKa of acid B, the
type and pKa of organic acid A, the degree of concentration of the
fermentation reaction solution, etc., and is not particularly
limited. From the viewpoint of the operation efficiency,
precipitation efficiency, etc., the amount of acid B to be added is
from about 1 to 100 times by mol, preferably from 1.5 to 30 times
by mol, more preferably from 2 to 20 times by mol, to the ammonium
salt of organic acid A, when the concentrate is in solid form.
[0060] Further, the system in which the above organic acid A
precipitates, may contain water. Especially under a condition where
ammonia is present in a large amount, in order to dissolve an
ammonium salt of acid B to be formed as a byproduct, it may be
desirable for the system to contain water in many cases, and water
may be added also when the amount of acid B to be used is
small.
[0061] There is no particular limitation to the conditions for the
reactive crystallization of organic acid A by the addition of acid
B. However, usually, acid B may be added to the concentrate of the
above-mentioned reaction solution, followed by heating and then the
mixture is left to cool. Otherwise, water may be added to dissolve
the ammonium salt of organic acid A, and then acid B is added for
crystallization. The latter method is effective for organic acid A
which has a low solubility in water in the form of an acid and will
have a high solubility when formed into a salt, so that the
difference in solubility is remarkable, like glutamic acid.
[0062] The heating temperature, the heating time and the cooling
temperature at the time of crystallization may vary depending also
on the type of organic acid A in the concentrate, the type and the
amount to be added of acid B, etc. However, it is usually preferred
that it is completely dissolved at a temperature of from 60 to
130.degree. C., and then left to cool at a temperature of at most
50.degree. C., preferably at most 40.degree. C. and at least
0.degree. C., preferably at least 10.degree. C.
[0063] In a case where acetic acid is employed as acid B, its
melting point is 16.degree. C., but the cooling temperature may be
lowered to close to 10.degree. C. by an influence of lowering of
the solidification point. For a practical process, the cooling
temperature is preferably at least 15.degree. C. as a safe
condition to avoid solidification of acid B. Especially in the case
of a continuous process, it is preferred that the temperature of
utility (cooling medium) of a heat exchanger has a temperature
difference by about 10.degree. C. from the objective temperature,
whereby the cooling temperature is more preferably at least
20.degree. C. when acid B is acetic acid.
[0064] The reactive crystallization in the present invention can be
carried out in accordance with a usual method by means of a
commonly employed crystallizing apparatus. However, with some
organic acid A, particularly with succinic acid, the
crystallization speed is slow, and accordingly, it is preferred to
employ some measure to improve the amount of crystallization, such
as circulating seed crystals or taking a long retention time.
[0065] By carrying out the reactive crystallization, organic acid A
having a low solubility in acid B will form and precipitate by an
acid/base reaction of acid B and an ammonium salt of organic acid A
obtained by the bioconversion employing an ammonia type
neutralizing agent. Accordingly, by separating the precipitate from
this crystallization solution by e.g. filtration, organic acid A
having a high purity can be recovered as the desired product. The
obtained organic acid A may be purified, for example, by
recrystallization employing e.g. acid B, as the case requires, to
obtain a final product.
[0066] Further, in the production of organic acid A by
bioconversion, depending upon the microorganism, the productivity
may be changed by the neutralizing agent. Therefore, there may be a
case where it is preferred to use an alkali metal and/or alkaline
earth metal hydroxide or carbonate (hereinafter sometimes referred
to as an alkali metal or alkaline earth metal type neutralizing
agent) rather than the above ammonia type neutralizing agent, as
the neutralizing agent. In a case where an alkali metal or alkaline
earth metal type neutralizing agent is employed, organic acid A by
bioconversion will be formed in the form of an alkali metal or
alkaline earth metal salt, but the alkali metal or alkaline earth
metal is not volatile, whereby it is difficult to separate organic
acid A and the alkali metal or alkaline earth metal salt of acid B
from the mother liquor comprising organic acid A and the alkali
metal or alkaline earth metal salt of acid B formed as a byproduct
by this reactive crystallization.
[0067] Therefore, in a case where an alkali metal or alkaline earth
metal type neutralizing agent is employed, a Solvay method is
employed as the first reactive crystallization step, wherein
exchange of the bases is carried out to obtain an ammonium salt of
organic acid A, and this ammonium salt of organic acid A is
subjected to reactive crystallization by means of acid B in the
second reactive crystallization step to obtain organic acid A. Also
in this case, it is preferred to supply the reaction solution
obtained in the bioconversion step to the first reaction
crystallization step after concentrating it.
[0068] In the first reactive crystallization step, firstly, ammonia
and carbon dioxide and/or ammonium carbonate is added to the
concentrate obtained in the concentration step, to precipitate an
alkali metal or alkaline earth metal carbonate from an aqueous
solution of an alkali metal or alkaline earth metal salt of organic
acid A. In this first reactive crystallization step, the amount of
ammonia and carbon dioxide and/or ammonium carbonate to be added,
is not particularly limited so long as it is an amount sufficient
to precipitate the alkali metal or alkaline earth metal
carbonate.
[0069] By this first reactive crystallization step, from the alkali
metal or alkaline earth metal salt of organic acid A, an alkali
metal or alkaline earth metal carbonate will precipitate, and an
ammonium salt of organic acid A will form. From the ammonium salt
of organic acid A formed in the first reactive crystallization
step, in the next second reactive crystallization step, organic
acid A can be precipitated by reactive crystallization by means of
acid B in the same manner as in the reactive crystallization step
in the case where the above-mentioned ammonia type neutralizing
agent is employed.
Separation, Recovery and Recycling of Acid B, Organic Acid a and
Ammonium Salts Thereof in the Separated Mother Liquor
[0070] The separated mother liquor (hereinafter sometimes referred
to as "the crystallization mother liquor" or "the mother liquor")
after separating organic acid A from the reactive crystallization
solution, contains an ammonium salt of organic acid A, an ammonium
salt of acid B formed by an acid/base reaction therewith, excess
acid B and residual organic acid A. In the present invention, acid
B and its ammonium salt are efficiently separated from such a
separated mother liquor by the following method, whereby the
ammonium salt of organic acid A, and organic acid A, can be
recovered. Further, the separated ammonium salt of acid B is
decomposed, and acid B and ammonia thereby obtained, are
reused.
[0071] In the present invention, firstly, acid B is vaporized and
removed from the crystallization mother liquor, followed by further
heating to vaporize the ammonium salt of acid B. The vaporization
of acid B from the crystallization mother liquor is preferably
carried out at a temperature of not higher than the melting point
of the ammonium salt of acid B, and it can be carried out by means
of e.g. a kettle type evaporator, a thin film evaporator, a flashed
drum having a heating section, a combination of a heat exchanger
and a flash drum, or a combination thereof. In a case where one
having a distillation column form is employed, if the interior of
the column is not higher than the melting point of the ammonium
salt of acid B, the crystallization mother liquor may be supplied
to any position, such as a condenser section, a reflux line, etc.
The specification and the form of the apparatus may be any so long
as they are under such a condition that acid B can be vaporized at
a temperature of not higher than the melting point of the ammonium
salt of acid B.
[0072] The temperature range for vaporization of acid B is
preferably at least 20.degree. C. and at most the melting point of
the ammonium salt of acid B. The melting point of ammonium acetate
as a typical example of the ammonium salt of acid B in the present
invention, is 114.degree. C. The melting point has a specific
meaning in the motion of the molecule, and if ammonium acetate
exceeds the melting point, it will be vaporized while being
pyrolized. A boiling point of the ammonium salt of acid B is
theoretically necessarily present, and a phenomenon such as
sublimation is also involved. It is difficult to strictly divide
one due to the pyrolysis and contribution of evaporation or
sublimation. Accordingly, vaporization of the ammonium salt of acid
B may sometimes be called as "decomposition/vaporization" in the
present invention, On the other hand, ammonium propionate has
strong deliquescence, and its melting point is not known. However,
taking into consideration the similarity to ammonium acetate, it is
difficult to simply consider that the difference in the melting
point between acetic acid and propionic acid will be the difference
in the melting point of their ammonium salts. However, a
temperature slightly lower than 114.degree. C., i.e. about
100.degree. C., is assumed to be the melting point of ammonium
propionate.
[0073] Melting point of acetic acid: 16.6.degree. C.
[0074] Melting point of ammonium acetate: 114.degree. C.
[0075] Melting point of propionic acid: -20.8.degree. C.
[0076] Thus, the temperature for vaporization of acid B varies also
depending upon the type of acid B (i.e. the type of the ammonium
salt of acid B), but it is usually preferably within a range of
from 40 to 100.degree. C. At the time of vaporizing acid B at such
a temperature, the operation conditions other than the temperature
are not particularly limited. However, with respect to the pressure
condition, reduced pressure or atmospheric pressure is preferred,
since corrosion of the material of the apparatus will be vigorous
if the pressure is elevated. Particularly preferred is a reduced
pressure condition of from 10 to 400 mmHg, more preferably, from 40
to 200 mmHg.
[0077] At the time of vaporization of such acid B, substances
having melting points lower than acid B contained in the
crystallization mother liquor, such as water, etc., will also be
vaporized.
[0078] Thus, acid B in the crystallization mother liquor is
vaporized and recovered, but from the viewpoint of the subsequent
operations, i.e. vaporization of the ammonium salt of acid B,
recovery of the residual ammonium salt of organic acid A, or
organic acid A, etc., the amount of acid B to be vaporized and
removed from the crystallization mother liquor may vary also
depending upon the amounts of acid B and other components in the
crystallization mother liquor, but the degree of vaporization may
be to such an extent that the mother liquor will be a slurry. If
the vaporization is proceeded to obtain solid, in a usual method by
the second vaporization apparatus, the thermal conductivity tends
to deteriorate (e.g. a thin film evaporator), such being
undesirable. As an index, the solubility of organic acid A will be
saturated at the temperature for vaporization. The saturated
solubility is determined by the amount of the ammonium salt of acid
B corresponding to the amount of ammonia to be removed and the
dissolved amount of organic acid A. In the following, the
crystallization mother liquor after vaporizing acid B will
sometimes be referred to as "the first residual liquid".
[0079] At the time of vaporization of the ammonium salt of acid B
after vaporizing acid B, the retention time will be important.
Namely, as will be evident from the results of the Test Examples
given hereinafter, the amidation reaction will be rapidly
accelerated by heating at a temperature of about 120.degree. C. On
the other hand, in order to separate the ammonium salt of acid B
from organic acid A and its ammonium salt, a higher temperature is
required, and a temperature of at least the melting point of the
ammonium salt of acid B is particularly preferred.
[0080] Accordingly, as a method for vaporizing the ammonium salt of
acid B, one having a short heating time is preferred in order to
prevent a side reaction such as amidation under such a high
temperature condition. Further, it is preferred to carry out the
vaporization in a super heated state, i.e. to set the process fluid
under a reduced pressure condition, to heat it with a heat source
having a sufficiently high temperature. As such a heat source,
steam or heating oil may, for example, be usually considered. In
such a case, the heating temperature is considered to be preferably
at most 200.degree. C., taking into consideration e.g. corrosion by
acid B. Otherwise, the temperature may be raised rapidly, for
example, by imparting molecular vibration by means of
electromagnetic waves. However, the heating temperature may be at
least the melting point, and the retention time may not have the
upper limit, so long as it is sufficiently short.
[0081] Accordingly, with respect to the process fluid, the operable
range is at least 0.001 mmHg (0.133 Pa) and at most 200 mmHg (26.7
kPa), more preferably at most 100 mmHg (13.3 kPa). More preferably,
it is from 20 mmHg (2.67 kPa) to 90 mmHg (12.0 kPa).
[0082] As an apparatus satisfying such a condition, a thin film
evaporator may be mentioned which is usually suitable for heating
under reduced pressure for a short period of time. Further, a
heater having a spraying function or an evaporator having a
temperature difference between a utility and the process fluid of
at least 20.degree. C., may, for example, be mentioned. The heating
method is not particularly limited, and it may be a rapidly heating
method by imparting molecular vibration by means of electromagnetic
waves in the same principle as for a microwave oven. Any other
operation may be employed so long as it satisfies the reduced
pressure condition and the high temperature condition, and there is
no particular restriction as to the apparatus, the principle or its
structure, so long as the heating time is short, and a sufficient
heat can be provided.
[0083] The heating temperature may vary also depending upon the
type of the ammonium salt of acid B or the pressure condition.
However, in the case of ammonium acetate, it is preferably from 115
to 180.degree. C., more preferably from 120 to 160.degree. C., and
in the case of ammonium propionate, it is preferably from 100 to
180.degree. C.
[0084] The liquid or slurry (hereinafter sometimes referred to as
"the second residual liquid") obtained by vaporizing the ammonium
salt of acid B from the first residual liquid in such a manner,
contains organic acid A and its ammonium salt, and residual acid B
and its ammonium salt, and it may be circulated to and treated in
the reactive crystallization step to further recover organic acid
A.
[0085] In the present invention, acid B separated by vaporization
from the crystallization mother liquor after precipitating and
separating organic acid A in the reactive crystallization of the
ammonium salt of organic acid A and acid B, is preferably recycled
to and reused in the reactive crystallization step. This acid B may
contain water and other substances. Recovered acid B is usually
purified and then reused as a solvent for crystallization. However,
depending upon the type and amount of the impurity, it may be used
as it is as a solvent for crystallization without carrying out the
purification.
Decomposition of the Ammonium Salt of Acid B
[0086] The ammonium salt of acid B separated by vaporization from
the crystallization mother liquor, is decomposed into acid B and
ammonia. The method for decomposing the ammonium salt of acid B
will be described below, but it is not limited to the ammonium salt
of acid B obtained from the separated mother liquor of organic acid
A, and it is similarly applicable to an ammonium salt of acid B
obtained from another process.
[0087] In the method for decomposing the ammonium salt of acid B in
the present invention, in a heating step, a liquid containing the
ammonium salt of acid B, an alkali metal or alkaline earth metal,
and water, preferably a liquid having an alkali metal or alkaline
earth metal salt of acid B added to a mixed liquid comprising the
ammonium salt of acid B and water (hereinafter sometimes referred
to as "feed material liquid") is heated to withdraw a gas of a
basic aqueous solution. Hereinafter, this step of heating will be
referred to as "the heating step", and the operation at that time
may sometimes be referred to as "the heating operation".
[0088] When the temperature of the gas of a basic aqueous solution
withdrawn in the heating step is higher than the melting point of
the ammonium salt of acid B, acid B may partially be withdrawn
together. Therefore, the withdrawn gas of a basic aqueous solution
is subjected to gas/liquid separation, gas/solid separation or
gas/liquid/solid separation of the ammonium salt of acid B at a
temperature of not higher than the melting point of the ammonium
salt of acid B under reduced pressure or atmospheric pressure,
directly or after condensation. This separating step will be
hereinafter referred to as "the separation step", and its operation
may sometimes be referred to as "the separating operation".
[0089] The alkali metal and/or alkaline earth metal to form the
alkali metal salt and/or alkaline earth metal salt of acid B is
preferably at least one member selected from the group consisting
of Na, K, Ca and Mg. Particularly preferred is Na or K.
[0090] The apparatus to be used for this heating step may be any
apparatus so long as it is one capable of heating operation and
capable of separating a gas phase and a liquid phase. The heating
and the gas/liquid separation may be carried out in separate
apparatus or by a combination of a heat exchanger and a flash drum.
In the case of a kettle type heat exchanger, the heating and the
gas/liquid separation can be carried out in one apparatus. Further,
the heating mechanism is not particularly limited, and it may, for
example, be a flash drum provided with a jacket or a heat
conductive coil.
[0091] In order to carry out both the heating and the gas/liquid
separation efficiently, a distillation column is most preferred.
The distillation column may be either a packed column or a plate
column, and there is no particular restriction also with respect to
the structure. However, to secure the retention time as described
hereinafter, a plate column is preferred. Further, the reboiler may
be built-in or externally attached. When an external reboiler is
employed, it may be a forcibly circulating type reboiler, a
thermo-siphon type reboiler or a kettle type reboiler, but it is
not limited thereto. In the present invention, an operation carried
out by a combination of a distillation column and a reboiler, is
regarded as a heating operation.
[0092] There is no restriction as to the presence or absence of a
condenser, and a condenser is not one which constitutes a part of
the heating operation. Theoretically, a kettle type heat exchanger
or a flash drum equipped with a heating device may be regarded as a
single plate distillation column.
[0093] The gas withdrawn in the heating step, contains ammonia and
necessarily has a pH of higher than 7. Accordingly, in this
invention, this is referred to as the heating step for withdrawing
a gas of a basic aqueous solution.
[0094] Among apparatus to carry out such a heating operation to
withdraw the gas of such a basic aqueous solution, most preferred
is a distillation column. Accordingly, the following description
will be made with respect to a case where a distillation column is
mainly employed.
[0095] In order to obtain the effect for separating acid B and
water by a salt effect and at the same time to decompose the
ammonium salt of acid B, a distillation column is suitable. Ammonia
is considered to be not in usual gas/liquid equilibrium
(evaporation and condensation are in the same amount) but be
substantially influenced by the retention time and the size of the
gas/liquid interface area, and accordingly, in order to carry out
the heating step more efficiently, secure hold up of the liquid or
a longer retention time becomes important. For this purpose, as the
distillation column, a plate (tray) column is preferred. Even with
a packed column, hold up of a liquid may be obtained to some
extent, but with a plate (tray) column rather than a packed column,
the effect for separating acid B and water by a salt effect, and
the effect for decomposing the ammonia salt of acid B can be
simultaneously obtained more certainly.
[0096] With respect to the tray type of the plate column, when the
operation range at the time of the start up or shut down is taken
into consideration, a sieve tray is practically inferior, as
weeping is likely to take place. Even if the operation rate is low
or 0, a tray whereby a liquid is certainly held on the tray and
weeping scarcely occurs, is preferred. As such a tray, a bubble
tray may be mentioned as one example of a fixed tray. With a bubble
tray, in order to improve the gas/liquid contact on the tray, in
addition to a weir for downcomer, a weir is present also at gas
holes on the tray from the construction of the bubble portion,
whereby the depth of liquid can be maintained. Further, like a
valve cap tray, a tray of the type wherein holes on the tray may be
closed by a movable cap, scarcely undergoes weeping and is thus
preferably applied to the present invention.
[0097] However, when the temperature profile in the interior of the
column is taken into consideration, if the temperature becomes high
in a state where water is little, amidation take place, and
therefore, it is preferred to shorten the retention time at the
lower portion of the column where stripping of water is carried
out. Therefore, it is preferred that the upper portion of the
column is a plate column, and the lower portion is a packed column.
Their ratio or the plate number varies depending upon the
temperature or the pressure and may suitably be optimized.
[0098] In order to obtain the effect for separating acid B and
water by a salt effect by the entire apparatus, in the case of a
distillation column, it is preferred to supply the feed material
from the top of the column, i.e. to carry out the separation in the
form of so-called extraction distillation. However, the plate where
the feed material is supplied is not particularly limited.
[0099] The pressure of the column is not particularly limited, but
for efficient decomposition of the ammonium salt of acid B, it must
be a pressure such that at least the column bottom temperature will
be at least 80.degree. C., preferably from 115 to 180.degree. C.
Further, if the column top is at a temperature lower than whichever
is higher between the melting point of the ammonium salt of acid B
and the boiling point of acid B, the column top portion can be
regarded as a gas/liquid separation apparatus in the separation
step after the heating step, whereby it becomes possible to carry
out the heating step and the separation step in one apparatus, and
the number of apparatus can be reduced, such being desirable from
the viewpoint of the investment cost. The temperature condition at
the column top in such a case is not higher than 114.degree. C.
(the melting point of ammonium acetate) in a case where the
ammonium salt of acid B is ammonium acetate, or not higher than
141.degree. C. (the boiling point of propionic acid) in the case of
ammonium propionate.
[0100] The pressure condition to satisfy the conditions of the
column top varies depending upon e.g. the type and the amount of
acid B or the alkali metal or alkaline earth metal, the amount of
water and the desired degree for separation of water/acid B, but it
is usually at most 2.0 atm (0.2 MPa), preferably at most
atmospheric pressure (1 atm (0.1 MPa)). Further, the pressure
condition satisfying the conditions of the above-mentioned column
bottom likewise varies depending upon e.g. the type and the amount
of acid B or the alkali metal or alkaline earth metal, the amount
of water, the desired degree for separation of water/acid B, and
the pressure loss due to trays or packing material, but it is
usually at least 80 mmHg (10.6 kPa), preferably at least 200 mmHg
(26.7 kPa).
[0101] When the feed material is supplied to the column top
portion, acid B or its salt may sometimes be distilled off by a
stripping effect or entrainment (inclusion of splash). In such a
case, even if the conditions for the heating operation and the
separating operation can be satisfied solely by a distillation
column, it may be necessary to take some measure such as to lower
the supply plate or to additionally install a gas/liquid separation
apparatus corresponding to the separating operation for the purpose
of removing the salt by stripping.
[0102] Whereas, in a case where a distillation column as one of
heating apparatus and a gas/liquid separating apparatus are
separated, the gas of a basic aqueous solution withdrawn from the
column top of the distillation column may once be condensed by a
condenser and then supplied to a gas/liquid, gas/liquid/solid or
gas/solid separating apparatus. Otherwise, as the case requires, a
pressure adjustor may be installed in the withdrawing line from the
column top, so that the condenser may be made to be a gas/liquid,
gas/liquid/solid or gas/solid separating apparatus. In the former
case, the supply to the gas/liquid separating apparatus will be
mainly a liquid, but it may be supplied as gas/liquid. In the
latter case, the supply to the gas/liquid separating apparatus may
accompany entrainment (inclusion of splash) but is mostly a
gas.
[0103] The liquid, solid or slurry withdrawn from the gas/liquid,
gas/liquid/solid or gas/solid separating apparatus, is mainly one
having the ammonium salt of acid B distilled by the stripping
effect, concentrated. This concentrate may be returned to the
heating apparatus to carry out the heating step, or mixed to an
aqueous solution of an ammonium salt of acid B to be supplied
afresh, or to an aqueous solution of acid B, and subjected to
recycling treatment until it is decomposed.
[0104] Either in a case where the distillation column for the
heating step and the gas/liquid, gas/liquid/solid or gas/solid
separating apparatus for the separation step are unitary or in a
case where they are separate apparatus, the liquid withdrawn from
the bottom of the column is separated into acid B and the alkali
metal or alkaline earth metal salt of acid B by a usual method such
as one by means of an evaporator or a thin film evaporator.
Otherwise, gas withdrawal may be carried out from a recovery
portion (a recovery plate) of the distillation column as a
heater.
[0105] Having been subjected to a heat history by the process up to
this stage, the ammonium salt of acid B has been partially
amidated. Such an amide compound has a high boiling point, and the
majority takes a behavior similar to an alkali metal or alkaline
earth metal salt of acid B. The boiling point of acetamide as a
typical amide compound is 222.degree. C. and will not substantially
be included. Even if such an amide compound is included slightly in
acid B, for example, by entrainment, it can readily be separated by
a usual method such as distillation.
[0106] Such an amide compound will be hydrolyzed by the presence of
an alkali metal or an alkaline earth metal, when water is added,
followed by heating. Namely, the alkali metal or alkaline earth
metal salt of acid B is recovered for recycling, and before it is
supplied to a heating step i.e. to a heating apparatus provided
separately from a separating apparatus or to a distillation column
as a heating apparatus, or to a distillation apparatus, as mixed to
an aqueous solution of an ammonium salt of acid B or an aqueous
solution of acid B to be supplied afresh, it may be preheated, or
it may be heated in the heating apparatus or the distillation
apparatus, whereby the amide compound can be hydrolyzed and
removed.
[0107] In the present invention, the type of the alkali metal or
alkaline earth metal is not particularly restricted, and one type
may be used alone, or two or more types may be used in combination.
As between the alkali metal and the alkaline earth metal, the
alkaline earth metal is likely to take a crosslinked structure and
thus has a drawback such that it is likely to bring about a problem
of high viscosity or crystallization. Accordingly, an alkali metal
is preferred. Among alkali metals, sodium or potassium is
particularly preferred in a case where the product to which this
process is applied, is a food additive or a pharmaceutical, or when
economical efficiency or handling efficiency is taken into
consideration. Further, they may be used as mixed.
[0108] The ammonium salt of acid B is heated at a temperature of at
least 80.degree. C., preferably from 100 to 160.degree. C., under a
condition of at least pH 6.5, preferably from pH 7 to pH 10
together with an alkali metal salt (such as a sodium salt or a
potassium salt) and/or an alkaline earth metal salt (such as a
magnesium salt or a calcium salt) of acid B in the presence of a
proper amount e.g. from 0.3 to 10 times by weight, preferably from
0.5 to 5 times by weight, to the ammonium salt of acid B, of water,
whereby ammonia can be vaporized.
[0109] Especially when a reactive distillation apparatus is
employed, the column top portion is at least pH 7, and the column
bottom portion is at most pH 7. With respect to such conditions,
the ammonium salt of acid B can be decomposed by using from 0.3 to
5 times by weight, preferably from 0.5 to 3 times by weight, of
water, and from 0.2 to 2 times by weight, preferably from 0.5 to
1.5 times by weight, of an alkali metal salt (such as a sodium salt
or a potassium salt) and/or an alkaline earth metal salt (such as a
magnesium salt or a calcium salt) of acid B, to the ammonium salt
of acid B.
[0110] The smaller the amount of water, the smaller the consumption
of energy, but amidation is more likely to take place. Accordingly,
it is suitably controlled depending upon the type of acid B, the
type and amount of the alkali metal or alkaline earth metal, the
structure of the apparatus, the retention time distribution,
etc.
[0111] Further, the method of the present invention can be used
also as an economically effective method for separating an
industrially important aqueous acetic acid solution, by mixing
ammonia to e.g. an aqueous acetic acid solution to obtain an
aqueous ammonium acetate solution. In such a case, the withdrawn
aqueous ammonia or a vapor containing ammonia is separated into
pure water and concentrated aqueous ammonia by a usual method such
as distillation, and the concentrated aqueous ammonia or ammonia
gas is returned to an aqueous acetic acid solution to be supplied
afresh and recycled for use. Thus, this method is particularly
effective for purification of water having a small acetic acid
content.
[0112] Further, in the present invention, the liquid after
withdrawing the gas of a basic aqueous solution in the heating
step, contains mainly free acid B obtained by decomposition of the
alkali metal or alkaline earth metal salt of acid B and a
non-decomposed ammonium salt of acid B. This liquid may be heated
under reduced pressure or atmospheric pressure, preferably under
reduced pressure, more preferably at most 100 mmHg, particularly
preferably at most 75 mmHg at a temperature of at least 125.degree.
C., preferably at least 135.degree. C., more preferably at least
160.degree. C., particularly preferably from 180 to 220.degree. C.,
whereby acid B can be separated and recovered. Acid B thus
recovered, can be reused in the above-mentioned reactive
crystallization step. If the operation is carried out under
sufficiently reduced pressure (at most 100 mmHg) at a high
temperature (at least 180.degree. C.), an acid B amide compound and
the non-reacted ammonium salt of acid B will be vaporized together
with acid B. They are separated by a usual method (such as
distillation), whereby acid B having a higher purity can be
obtained.
[0113] Further, the residue after separating and recovering acid B
as described above, contains an alkali metal or alkaline earth
metal, a non-decomposed ammonium salt of acid B, and an amide
compound of acid B as a byproduct, and such residue can be recycled
for use as an alkali metal or alkaline earth metal source. In such
a case, this residue contains an amide compound of acid B as a
byproduct. This amide compound can easily be hydrolyzed in the
presence of an alkali metal and water. After adding water or a
liquid containing acid B and water to the above residue, the amide
compound of acid B as a byproduct, can be hydrolyzed at a
temperature of at least 125.degree. C., preferably at least
140.degree. C., more preferably at least 150.degree. C.
[0114] Now, with reference to the drawings, specific constructions
of apparatus suitable for carrying out the method for decomposing
the ammonium salt of acid B, will be described. However, it should
be understood that the present invention is by no means restricted
to the methods shown in the drawings. Further, in the following,
ammonium acetate is exemplified as an ammonium salt of acid B, and
sodium is exemplified as an alkali metal or alkaline earth metal.
However, it is needless to say that the present invention is not
limited to ammonium acetate and sodium, but is applicable to other
ammonium salts of acid B and other alkali metals or alkaline earth
metals.
[0115] In the method of FIG. 1, ammonium acetate and water are
supplied to a distillation column 1 via an acetamide decomposition
vessel 3. To this acetamide decomposition vessel 3, a residue
(containing sodium acetate, acetamide as byproduct and
non-decomposed ammonium acetate) from a thin film evaporator 4 of a
later stage, is recycled, and this residue is mixed with an aqueous
ammonium acetate solution and sent to the distillation column 1 and
introduced to the upper portion of the distillation column 1. As
mentioned above, in this acetamide decomposition vessel 3,
acetamide is mixed with water, whereby hydrolysis of acetamide is
carried out.
[0116] The mixed liquid from the acetamide decomposition vessel 3
is subjected to the heating operation and the separating operation
under the above-described distillation conditions in the
distillation column 1, whereby a gas of a basic aqueous solution
containing ammonia, water and a small amount of ammonium acetate,
will be distilled from the top of the distillation column 1. This
gas of a basic aqueous solution is subjected to gas/liquid
separation at a temperature of not higher than the melting point of
ammonium acetate in a vaporizer 2, whereby water and ammonia are
separated. Residual ammonium acetate is supplied to the acetamide
decomposition vessel 3 and subjected to recycling treatment.
[0117] The bottom liquid from the bottom of the distillation column
1, contains acetic acid, non-decomposed ammonium acetate, acetamide
as a byproduct and sodium acetate. In a thin film evaporator 4,
acetic acid is separated, and the residue is recycled to the
acetamide decomposition vessel 3.
[0118] The method shown in FIG. 2, is different from the method
shown in FIG. 1 in that the ammonium acetate distillate from the
vaporizer 2 is returned to the distillation column 1, but the
heating operation and the separating operation are carried out in
the same manner as in FIG. 1.
[0119] The method shown in FIG. 3 is different from the method
shown in FIG. 1 in that in the distillation column 1A, vaporization
and distillation are carried out to omit the vaporizer 2, but the
heating operation and the separating operation are carried out in
the same manner as in FIG. 1. Further, in this method, the mixed
liquid from the acetamide decomposition vessel 3 may be introduced
to the vaporizing section or to the upper portion of the distilling
section in the distillation column 1A.
[0120] The method shown in FIG. 4 is different from the method
shown in FIG. 1 in that in the distillation column 1B, acetic acid
is withdrawn from an intermediate plate to carry out also
separation of acetic acid thereby to omit a thin film evaporator 4,
but the heating and separating operations are carried out in the
same manner as in FIG. 1.
[0121] The method shown in FIG. 5 is different from the method
shown in FIG. 1 in that a flash drum 5 is employed instead of the
distillation column, but the heating and separating operations are
carried out in the same manner as in FIG. 1.
[0122] In any one of these methods, by the presence of an alkali
metal or an alkaline earth metal, and ammonia, in the heating step
such as in the distillation column or flash drum, the reflux ratio
will be small, and it is possible to substantially reduce the
energy consumed in the heating and separating operations.
Recycling of Separated Mother Liquor
[0123] In the present invention, in a case where the reactive
crystallization is carried out in multi stages, a mother liquor in
a later stage reactive crystallization is mixed with an ammonium
salt of organic acid A to be supplied afresh, as a recycling liquid
as shown in the following (1) to (3).
[0124] (1) The later stage mother liquor is recycled as it is and
mixed with an ammonium salt of organic acid A to be supplied
afresh. In this later stage mother liquor, acid B and its ammonium
salt, and organic acid A and its ammonium salt, are contained.
Among them, acid B will be reacted with the ammonium salt of
organic acid A to be supplied, thereby to be converted to an
ammonium salt of acid B and to precipitate organic acid A
monoammonium salt, and in the next vaporization step, it will be is
removed together with the ammonium salt of acid B in the later
stage mother liquor. Whereas, organic acid A and its ammonium salt
will be separated as organic acid A and/or its monoammonium salt in
the reactive crystallization together with the ammonium salt of
organic acid A to be supplied afresh.
[0125] (2) From the later stage mother liquor, acid B is vaporized,
separated and recovered, and then the residue is recycled and mixed
with an ammonium salt of organic acid A to be supplied afresh.
[0126] In this case, it is preferable to retain acid B in the
residue to such an extent that the residue after vaporization and
separation will maintain a liquid phase. Namely, it is necessary
that in the recycled liquid, acid B is present in such an amount
that the ammonium salt of acid B, organic acid A and its ammonium
salt can sufficiently be dissolved therein.
[0127] Also in this case, as in the case of (1), acid B in the
recycled liquid will be reacted with the ammonium salt of organic
acid A to be supplied afresh, and converted to an ammonium salt of
acid B, which will be removed in the next vaporization step
together with the ammonium salt of acid B in the later stage mother
liquor. Whereas, organic acid A and its ammonium salt are separated
as organic acid A and/or its monoammonium salt in the reactive
crystallization together with an ammonium salt of organic acid A to
be supplied afresh.
[0128] (3) From the separated mother liquor, acid B is vaporized,
separated and recovered, and then the ammonium salt of acid B is
vaporized and separated from organic acid A and its ammonium salt,
and the distillate of the ammonium salt of acid B is recycled and
mixed with an ammonium salt of organic acid A to be supplied
afresh.
[0129] In this case, it is necessary that in the distillate of the
ammonium salt of acid B, acid B is contained to such an extent that
this distillate will maintain a liquid phase. Namely, it is
necessary that in the recycled liquid, acid B is present in such an
amount that the ammonium salt of acid B can sufficiently be
dissolved therein.
[0130] Also in this case, as in the case of (1), acid B in the
recycled liquid, will be reacted with an ammonium salt of organic
acid A to be supplied afresh, and converted to an ammonium salt of
acid B, which will be removed in the next vaporization step
together with the ammonium salt of acid B in the crystallization
mother liquor.
[0131] Further, the condition for vaporizing acid B from the
crystallization mother liquor, is the same as in the case of the
above (2). Further, to vaporize the ammonium salt of acid B to
separate it from organic acid A and its ammonium salt, it is
preferred to employ the same operational condition as in the
after-mentioned vaporization step. Organic acid A and its ammonium
salt separated by this method, are recycled and treated in the
reactive crystallization step to recover organic acid A. The
condition for mixing the recycled liquid of the above (1) to (3)
with the ammonium salt of organic acid A to be supplied afresh, is
not particularly limited, the mixing can be carried out by stirring
in a mixing vessel at a temperature of from 20 to 140.degree. C.,
preferably from 40 to 110.degree. C.
Applications of Organic Acid A
[0132] Organic acid A as the desired product obtained by the method
of the present invention is useful for various applications. Among
them, dicarboxylic acids are useful as raw materials for polyesters
or polyamides.
[0133] For example, oxalic acid, succinic acid, itaconic acid,
glutaric acid, adipic acid, sebacic acid, dodecanoic acid, or lower
alcohol esters thereof, succinic anhydride, adipic anhydride, etc.,
as dicarboxylic acids to be produced by the present invention, are
raw materials for high molecular weight polyesters. Particularly
from the aspect of the physical properties of the polymer, succinic
acid, adipic acid, sebacic acid or an anhydride thereof, is
preferred, and such an acid can be produced by the present
invention without giving a burden to the environment by a microbial
fermentation method from a natural carbon source.
[0134] Further, a diol to be used for e.g. production of a
polyester copolymer, such as 1,4-butanediol, 1,5-pentanediol,
1,6-hexanediol, 1,4-cyclohexanediol or 1,6-cyclohexanedimethanol,
may also be obtained by hydrogenating the above-mentioned organic
acid A produced by the present invention.
SPECIFIC PREFERRED EMBODIMENTS
[0135] Specific preferred embodiments of the present invention are
as follows.
1. A method for producing a dicarboxylic acid and/or tricarboxylic
acid by bioconversion of a carbon source, which comprises:
[0136] a bioconversion step in which a carbon source is converted
by a microorganism in the presence of at least one neutralizing
agent selected from the group consisting of ammonia, ammonium
carbonate and urea, to obtain a reaction solution containing an
ammonium salt of a dicarboxylic acid and/or tricarboxylic acid;
[0137] a reactive crystallization step in which reactive
crystallization is carried out by adding a monocarboxylic acid to
the ammonium salt of a dicarboxylic acid and/or tricarboxylic acid
obtained in the bioconversion step, to precipitate the desired
dicarboxylic acid and/or tricarboxylic acid; and
[0138] a separation step in which the dicarboxylic acid and/or
tricarboxylic acid precipitated in the reactive crystallization
step, is separated.
2. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to Item 1, which includes a
concentration step of concentrating the reaction solution obtained
in the bioconversion step, and wherein the concentrate obtained in
the concentration step is supplied to the reactive crystallization
step. 3. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to Item 1 or 2, which includes an
ammonia recovery step in which the monocarboxylic acid is vaporized
and removed from the liquid after separating the dicarboxylic acid
and/or tricarboxylic acid in the separation step, then an ammonium
salt of the monocarboxylic acid in the liquid is vaporized and
collected, the ammonium salt of the monocarboxylic acid is mixed
with water and an alkali metal and/or alkaline earth metal salt of
the monocarboxylic acid, followed by heating to vaporize and
recover ammonia; and
[0139] a recycling step in which the ammonia recovered in the
ammonia recovery step, is used as a neutralizing agent in the above
bioconversion step.
4. A method for producing a dicarboxylic acid and/or tricarboxylic
acid by bioconversion of a carbon source, which comprises:
[0140] a bioconversion step in which a carbon source is converted
by a microorganism in the presence of at least one neutralizing
agent selected from the group consisting of an alkali metal
hydroxide, an alkaline earth metal hydroxide, an alkali metal
carbonate and an alkaline earth metal carbonate, to obtain a
reaction solution containing an alkali metal and/or alkaline earth
metal salt of a dicarboxylic acid and/or tricarboxylic acid;
[0141] a first reactive crystallization step in which reactive
crystallization is carried out by adding ammonia and carbon
dioxide, and/or ammonium carbonate, to the alkali metal and/or
alkaline earth metal salt of a dicarboxylic acid and/or
tricarboxylic acid obtained in the bioconversion step, to
precipitate a carbonate of the alkali metal and/or alkaline earth
metal, and the carbonate is separated to obtain an aqueous solution
of an ammonium salt of the dicarboxylic acid and/or tricarboxylic
acid;
[0142] a second reactive crystallization step in which reactive
crystallization is carried out by adding a monocarboxylic acid to
the liquid after removing the carbonate of the alkali metal and/or
alkaline earth metal precipitated in the first reactive
crystallization step, to precipitate the desired dicarboxylic acid
and/or tricarboxylic acid; and
[0143] a separation step in which the dicarboxylic acid and/or
tricarboxylic acid precipitated in the second reactive
crystallization step, is separated.
5. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to Item 4, which includes a
concentration step of concentrating the reaction solution obtained
in the bioconversion step, and wherein the concentrate obtained in
the concentration step is supplied to the first reactive
crystallization step. 6. The method for producing a dicarboxylic
acid and/or tricarboxylic acid according to Item 4 or 5, which
includes an ammonia recovery step in which the monocarboxylic acid
is vaporized and removed from the liquid after separating the
dicarboxylic acid and/or tricarboxylic acid in the separation step,
then an ammonium salt of the monocarboxylic acid in the liquid is
vaporized and collected, the ammonium salt of the monocarboxylic
acid is mixed with water and an alkali metal and/or alkaline earth
metal salt of the monocarboxylic acid, followed by heating to
vaporize and recover ammonia; and
[0144] a recycling step in which the ammonia recovered in the
ammonia recovery step, is used as an ammonia source in the above
first reactive crystallization step.
7. A method for producing a dicarboxylic acid and/or tricarboxylic
acid wherein a dicarboxylic acid and/or tricarboxylic acid is
obtained from an ammonium salt of a dicarboxylic acid and/or
tricarboxylic acid, which comprises:
[0145] a reactive crystallization step in which reactive
crystallization is carried out by adding a monocarboxylic acid to
the ammonium salt of a dicarboxylic acid and/or tricarboxylic acid,
to precipitate the dicarboxylic acid and/or tricarboxylic acid;
[0146] a separation step in which the dicarboxylic acid and/or
tricarboxylic acid precipitated in the reactive crystallization
step, is separated;
[0147] a step for recovering ammonia and the monocarboxylic acid,
in which an ammonium salt of the monocarboxylic acid is separated
from the liquid containing the ammonium salt of the monocarboxylic
acid after separating the dicarboxylic acid and/or tricarboxylic
acid in the separation step, and then, an alkali metal and/or
alkaline earth metal salt of the monocarboxylic acid is added to
this separated ammonium salt of the monocarboxylic acid to obtain
the monocarboxylic acid and ammonia; and
[0148] a recycling step in which the ammonia and monocarboxylic
acid recovered in the step for recovering ammonia and the
monocarboxylic acid, are used as an ammonia source for the ammonium
salt of the dicarboxylic acid and/or tricarboxylic acid and as the
monocarboxylic acid in the above reactive crystallization step,
respectively.
8. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to Item 7, wherein the ammonium salt
of the dicarboxylic acid and/or tricarboxylic acid is obtained by
bioconversion of a carbon source employing, as a neutralizing
agent, at least one member selected from the group consisting of
ammonia, ammonium carbonate and urea. 9. The method for producing a
dicarboxylic acid and/or tricarboxylic acid according to Item 7,
wherein the ammonium salt of the dicarboxylic acid and/or
tricarboxylic acid, is obtained by a Solvay method in which the
ammonium salt of the dicarboxylic acid and/or tricarboxylic acid is
obtained from an alkali metal and/or alkaline earth metal salt of
the dicarboxylic acid and/or tricarboxylic acid obtained by
bioconversion of a carbon source employing, as a neutralizing
agent, at least one member selected from the group consisting of an
alkali metal hydroxide, an alkaline earth metal hydroxide, an
alkali metal carbonate and an alkaline earth metal carbonate. 10.
The method for producing a dicarboxylic acid and/or tricarboxylic
acid according to any one of Items 1 to 9, wherein the carbon
number of the dicarboxylic acid and/or tricarboxylic acid is from 4
to 12. 11. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to Item 10, wherein the dicarboxylic
acid and/or tricarboxylic acid is at least one member selected from
the group consisting of succinic acid, adipic acid, malic acid,
tartaric acid, fumaric acid, maleic acid, citric acid, asparaginic
acid and glutamic acid. 12. The method for producing a dicarboxylic
acid and/or tricarboxylic acid according to any one of Items 1 to
11, wherein the carbon number of the monocarboxylic acid is from 1
to 6. 13. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to Item 12, wherein the monocarboxylic
acid is acetic acid and/or propionic acid. 14. A method for
producing a dicarboxylic acid and/or tricarboxylic acid in which a
dicarboxylic acid and/or tricarboxylic acid is obtained from an
ammonium salt of the dicarboxylic acid and/or tricarboxylic acid,
which comprises:
[0149] a reactive crystallization step in which reactive
crystallization is carried out by adding a monocarboxylic acid to
the ammonium salt of the dicarboxylic acid and/or tricarboxylic
acid, to precipitate the dicarboxylic acid and/or tricarboxylic
acid;
[0150] a separation step in which the dicarboxylic acid and/or
tricarboxylic acid precipitated in the reactive crystallization
step, is separated;
[0151] a first vaporization step in which the monocarboxylic acid
is further vaporized from the crystallization mother liquor after
separating the dicarboxylic acid and/or tricarboxylic acid in the
separation step;
[0152] a second vaporization step in which an ammonium
monocarboxylate is vaporized from the crystallization mother liquor
after the first vaporization step.
15. The method for producing a dicarboxylic acid and/or a
tricarboxylic acid according to Item 14, wherein the is first
vaporization step is a step of vaporizing the monocarboxylic acid
from the crystallization mother liquor at a temperature of not
higher than the melting point of the ammonium monocarboxylate. 16.
The method for producing a dicarboxylic acid and/or tricarboxylic
acid according to Item 14 or 15, wherein the second vaporization
step is a step of vaporizing the ammonium monocarboxylate by
heating the above crystallization mother liquor under a reduced
pressure of from 0.001 mmHg (0.133 Pa) to 200 mmHg (26.7 kPa). 17.
The method for producing a dicarboxylic acid and/or tricarboxylic
acid according to any one of Items 14 to 16, in which the carbon
number of the dicarboxylic acid and/or tricarboxylic acid is from 4
to 12. 18. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to Item 17, wherein the dicarboxylic
acid and/or tricarboxylic acid is at least one member selected from
the group consisting of succinic acid, adipic acid, malic acid,
tartaric acid, fumaric acid, maleic acid, citric acid, asparaginic
acid, glutaric acid and glutamic acid. 19. The method for producing
a dicarboxylic acid and/or tricarboxylic acid according to any one
of Items 14 to 18, wherein the carbon number of the monocarboxylic
acid is from 1 to 6. 20. The method for producing a dicarboxylic
acid and/or tricarboxylic acid according to Item 19, wherein the
monocarboxylic acid is acetic acid and/or propionic acid. 21. A
method for producing a dicarboxylic acid and/or tricarboxylic acid
in which a dicarboxylic acid and/or tricarboxylic acid is obtained
from an ammonium salt of the dicarboxylic acid and/or tricarboxylic
acid, which comprises:
[0153] a reactive crystallization step in which reactive
crystallization is carried out by adding a monocarboxylic acid to
the ammonium salt of the dicarboxylic acid and/or tricarboxylic
acid, to precipitate the dicarboxylic acid and/or tricarboxylic
acid;
[0154] a supplying step in which the ammonium salt of the
dicarboxylic acid and/or tricarboxylic acid is supplied to the
reactive crystallization step; and
[0155] a separation step in which the dicarboxylic acid and/or
tricarboxylic acid precipitated in the reactive crystallization
step, is separated; and which includes:
[0156] a recycling step in which the crystallization mother liquor
after separating the dicarboxylic acid and/or tricarboxylic acid in
the separation step, is recycled to the above supplying step;
[0157] a mixing step in which the recycled liquid in the recycling
step is mixed with an ammonium salt of the dicarboxylic acid and/or
tricarboxylic acid supplied afresh in the supplying step; and
[0158] a vaporization step in which an ammonium salt of the
monocarboxylic acid is vaporized from the mixture obtained in the
mixing step, wherein the residue after vaporizing and removing the
ammonium salt of the monocarboxylic acid in the vaporization step,
is supplied to the above reactive crystallization step.
22. A method for producing a dicarboxylic acid and/or tricarboxylic
acid in which a dicarboxylic acid and/or tricarboxylic acid is
obtained from an ammonium salt of the dicarboxylic acid and/or
tricarboxylic acid, which comprises:
[0159] a reactive crystallization step in which reactive
crystallization is carried out by adding a monocarboxylic acid to
the ammonium salt of the dicarboxylic acid and/or tricarboxylic
acid, to precipitate the dicarboxylic acid and/or tricarboxylic
acid;
[0160] a supplying step in which the ammonium salt of the
dicarboxylic acid and/or tricarboxylic acid is supplied to the
reactive crystallization step; and
[0161] a separation step in which the dicarboxylic acid and/or
tricarboxylic acid precipitated in the reactive crystallization
step, is separated; and which includes:
[0162] a monocarboxylic acid recovery step in which the
monocarboxylic acid is vaporized and separated from the
crystallization mother liquor after separating the dicarboxylic
acid and/or tricarboxylic acid in the separation step;
[0163] a recycling step in which the residual liquid after removing
the monocarboxylic acid in the monocarboxylic acid recovery step,
is recycled to the above supplying step;
[0164] a mixing step in which the recycled liquid in the recycling
step, is mixed with an ammonium salt of the dicarboxylic acid
and/or tricarboxylic acid supplied afresh in the supplying step;
and
[0165] a vaporization step in which the ammonium salt of the
monocarboxylic acid is vaporized from the mixture obtained in the
mixing step, in which a residue after vaporizing and removing the
ammonium salt of the monocarboxylic acid in the vaporization step,
is supplied to the above reactive crystallization step.
23. A method for producing a dicarboxylic acid and/or tricarboxylic
acid in which a dicarboxylic acid and/or tricarboxylic acid is
obtained from an ammonium salt of the dicarboxylic acid and/or
tricarboxylic acid, which comprises:
[0166] a reactive crystallization step in which reactive
crystallization is carried out by adding a monocarboxylic acid to
the ammonium salt of the dicarboxylic acid and/or tricarboxylic
acid, to precipitate the dicarboxylic acid and/or tricarboxylic
acid;
[0167] a supplying step in which the ammonium salt of the
dicarboxylic acid and/or tricarboxylic acid is supplied to the
reactive crystallization step; and
[0168] a separation step in which the dicarboxylic acid and/or
tricarboxylic acid precipitated in the reactive crystallization
step, is separated, and which includes:
[0169] a first recovery step in which the monocarboxylic acid is
vaporized and separated from the crystallization mother liquor
after separating the dicarboxylic acid and/or tricarboxylic acid in
the separation step;
[0170] a second recovery step in which the dicarboxylic acid and/or
tricarboxylic acid, and its ammonium salt, are separated from the
residual liquid after removing the monocarboxylic acid in the first
recovery step;
[0171] a recycling step in which the residual liquid after
separating the dicarboxylic acid and/or tricarboxylic acid, and its
ammonium salt in the second recovery step, is recycled to the above
supplying step;
[0172] a mixing step in which the recycled liquid in the recycling
step, is mixed with an ammonium salt of the dicarboxylic acid
and/or tricarboxylic acid supplied afresh in the supplying step;
and
[0173] a vaporization step in which the ammonium salt of the
monocarboxylic acid is vaporized from the mixture obtained in the
mixing step, in which the residue after vaporizing and removing the
ammonium salt of the monocarboxylic acid in the vaporization step,
is supplied to the above reactive crystallization step.
24. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to any one of Items 21 to 23, wherein
the mols of the monocarboxylic acid in the recycled liquid to the
mols of the dicarboxylic acid and/or tricarboxylic acid supplied
afresh in the above mixing step, are at most 30 times. 25. The
method for producing a dicarboxylic acid and/or tricarboxylic acid
according to any one of Items 21 to 24, wherein the vaporization
step is a step of vaporizing the ammonium salt of the
monocarboxylic acid by heating the above mixture under a reduced
pressure of from 0.001 mmHg (0.133 Pa) to 200 mmHg (26.7 kPa). 26.
The method for producing a dicarboxylic acid and/or tricarboxylic
acid according to any one of Items 21 to 25, wherein the carbon
number of the dicarboxylic acid and/or tricarboxylic acid is from 4
to 12. 27. The method for producing a dicarboxylic acid and/or
tricarboxylic acid according to Item 26, wherein the dicarboxylic
acid and/or tricarboxylic acid is at least one member selected from
the group consisting of succinic acid, adipic acid, malic acid,
tartaric acid, fumaric acid, maleic acid, citric acid, asparaginic
acid, glutaric acid and glutamic acid. 28. The method for producing
a dicarboxylic acid and/or tricarboxylic acid according to any one
of Items 21 to 27, wherein the carbon number of the monocarboxylic
acid is from 1 to 6. 29. The method for producing a dicarboxylic
acid and/or tricarboxylic acid according to Item 28, wherein the
monocarboxylic acid is acetic acid and/or propionic acid. 30. A
method for decomposing an ammonium salt of a monocarboxylic acid to
separate and recover a monocarboxylic acid and ammonia, which
comprises a heating step in which a liquid containing an ammonium
salt of a monocarboxylic acid, an alkali metal and/or alkaline
earth metal and water, is heated to withdraw a gas of a basic
aqueous solution, and a separation step in which the gas of a basic
aqueous solution withdrawn from the heating step is, directly or
after condensation, subjected to gas/liquid separation, gas/solid
separation or gas/liquid/solid separation at a temperature of not
higher than the melting point of the ammonium salt of the
monocarboxylic acid. 31. The method for decomposing an ammonium
salt of a monocarboxylic acid according to Item 30, in which a
liquid containing the ammonium salt of a monocarboxylic acid, an
alkali metal salt and/or alkaline earth metal salt of the
monocarboxylic acid, or ions derived therefrom, and water, is
supplied to a distillation column, and the gas of a basic aqueous
solution, is withdrawn from the top of the distillation column. 32.
The method for decomposing an ammonium salt of a monocarboxylic
acid according to Item 30 or 31, wherein the alkali metal and/or
alkaline earth metal is at least one member selected from the
consisting of Na, K, Ca and Mg. 33. The method for decomposing an
ammonium salt of a monocarboxylic acid according to any one of
Items 30 to 32, wherein the monocarboxylic acid is at least one
member selected from the group consisting of acetic acid, propionic
acid and butyric acid. 34. The method for decomposing an ammonium
salt of a monocarboxylic acid according to any one of Items 30 to
33, which includes a monocarboxylic acid recovery step in which a
liquid after withdrawing the gas of a basic aqueous solution in the
heating step, is heated at a temperature of at least 125.degree. C.
under reduced pressure or atmospheric pressure, to separate and
recover the monocarboxylic acid. 35. The method for decomposing an
ammonium salt of a monocarboxylic acid according to Item 34,
wherein an ammonium salt of a monocarboxylic acid and water are
mixed to the residue after separating the monocarboxylic acid in
the monocarboxylic acid recovery step, and the mixture is recycled
to the above heating step. 36. The method for decomposing an
ammonium salt of a monocarboxylic acid according to Item 35,
wherein an ammonium salt of a monocarboxylic acid and water are
mixed to the above residue, and then the mixture is preheated at a
temperature of at least 90.degree. C. and then recycled to the
above heating step.
EXAMPLES
[0174] Now, the present invention will be described in further
detail with reference to Examples.
TABLE-US-00001 TABLE 1 Iso- Solubility Pyne elec- at Organic tric
25.degree. C. Chemistry point g/100 MW m.p. pKa1 pKa2 pKa3 pI g
H.sub.2O Asparagine 132.12 236 2.02 5.41 3.11 Aspartic acid 133.1
269 2.1 3.86 2.98 0.5 Glutamic acid 147.13 247 2.1 4.07 3.08 0.843
Glutamine 146.15 186 2.17 5.7 3.6 Histidine 155.16 287 1.77 7.64
4.29 Isoleucine 131.18 284 2.32 6.04 4.117 Leucine 131.18 337 2.33
6.04 2.19 Methionine 149.21 283 2.28 5.74 3.35 Phenylalanine 165.19
283 2.58 5.91 2.965 Tryptophan 204.23 289 2.38 5.88 1.14 Tyrosine
181.19 344 2.2 5.66 0.045 Valine 117.15 315 2.29 6 8.85 Fumaric
acid 116.07 299.5 3.03 4.44 Tartaric acid 150.09 205 3.04 4.37
Succinic acid 118.09 188 4.21 5.64 Maleic acid 116.07 141 1.83 6.07
Malic acid 134.09 132 3.40 5.11 o-Phthalic acid 166.13 210 2.95
5.41 Glutaric acid 147.13 -- 4.31 5.41 Adipic acid 146.14 153.4
4.43 5.41 Citric acid 192.13 153 3.13 4.76 6.4 Suberic acid 174.2
142.1 4.52 Terephthalic 166.13 3.51 4.82 acid Acetic acid pKa 4.76
Propionic acid pKa 4.86
[0175] pKa of dicarboxylic acids and of propionic acid: Handbook of
Chemistry and Physics
[0176] In the following Example 1-1, diammonium succinate
(manufactured by Wako Pure Chemical Industries, Ltd.) was used as a
substitute material for a concentrate obtained by concentrating, in
the concentration step, the ammonium salt of organic acid A
obtained from a bioconversion step. Further, as acid B, acetic acid
(manufactured by Wako Pure Chemical Industries, Ltd.) or propionic
acid (manufactured by Wako Pure Chemical Industries, Ltd.) was
used.
Example 1-1
[0177] 180 g of diammonium succinate (succinic acid: 78 wt %,
ammonia: 22 wt %) was dissolved in 720 g of water to prepare 900 g
of a 20 wt % ammonium succinate solution.
[0178] This aqueous solution was evaporated and concentrated in an
oil bath of 140.degree. C. (the interior of the evaporator:
100.degree. C.) to a level of 256.5 g. 249 g was taken therefrom,
and 173 g of acetic acid was added to succinic acid, followed by
thorough stirring. The mixture (415.5 g charge) was put into a
crystallization apparatus and maintained at 100.degree. C. for 10
minutes, and then maintained at 40.degree. C. for 18 hours with
stirring.
[0179] Then, vacuum filtration was carried out, and then the solid
content was taken out. The filtrate was 296.6 g, and the solid
content was 93.4 g. The obtained solid content was analyzed for
organic substances by liquid chromatography and for ammonia by ion
chromatography, whereby acetic acid was 28.4 wt %, succinic acid
was 58.3 wt %, and ammonia was 10.4 wt %. The total was not 100%,
and this is believed attributable to a measurement error, as
ammonia and organic substances were analyzed separately. Likewise,
the mother liquor was found to comprise 59.9 wt % of acetic acid,
25.3 wt % of succinic acid and 6.7 wt % of ammonia.
[0180] It is hardly believed that the mother liquor contained such
a large amount of acetic acid, and it is believed that a
substantial amount of ammonium acetate was coprecipitated.
Therefore, the molar ratios (on the assumption of 100 g) were
calculated and found to be as follows. [0181] Acetic acid:
28.4/60=0.473 Carboxylic acid: 47 mol [0182] Succinic acid:
58.3/118=0.494 Carboxylic acid: 98 mol (49.times.2) [0183] Ammonia
10.4/17=0.611 Ammonia: 61 mol
[0184] If it is assumed that 60% of acetic acid is in the form of
ammonium acetate (28 mol), ammonia is 33 mol to 98 mol of
carboxylic acid of succinic acid, whereby 16 mol (1/3 of the
obtained solid) is already succinic acid itself formed by the salt
decomposition, and the rest is a monoammonium salt of succinic
acid. In reality, the mother liquor also contained ammonia, and it
is believed that the salt decomposition proceeded more by the
reactive crystallization.
[0185] Further, 90 g of the obtained solid was dissolved in 80 g of
acetic acid at a temperature of about 80.degree. C., and the
solution (165 g) was put into a crystallizing apparatus and
maintained at 80.degree. C. for 10 minutes, and then maintained at
40.degree. C. for 7 hours with stirring.
[0186] Then, vacuum filtration was carried out, and then, a solid
content was taken out. The filtrate was 129.6 g, and the solid
content was 16.2 g. The obtained solid content was analyzed for
organic substances by liquid chromatography and for ammonia by ion
chromatography, whereby acetic acid was 10.9 wt %, succinic acid
was 87.4 wt % and ammonia was 2.8 wt %. Likewise, the mother liquor
was found to comprise 90.2 wt % of acetic acid, 25.2 wt % of
succinic acid and 6.0 wt % of ammonia. [0187] Acetic acid:
10.9/60=0.182 Carboxylic acid: 18 mol [0188] Succinic acid:
87.4/118=0.741 Carboxylic acid: 148 mol (74.times.2) [0189] Ammonia
2.8/17=0.165 Ammonia: 16 mol
[0190] In this Example, it was possible to obtain succinic acid
from ammonium succinate without employing electrodialysis or an
inorganic acid, whereby it was confirmed that decomposition to
succinic acid was carried out solely by reactive
crystallization.
Example 1-2
[0191] Using a 100 ml reagent bottle, 15.2 g (0.1 mol) of
diammonium succinate was mixed to 15.2 g (0.25 mol) of acetic acid
and 6 g of water under heating and dissolved at 90.degree. C. This
solution was left for 12 hours in a water bath (40.degree. C.).
White solid thereby precipitated was collected by filtration. The
recovered solid was 6.1 g, and as a result of the analysis,
succinic acid was 69 wt %, and ammonia was 12.8 wt %.
[0192] 3.1 g of this solid was again put into a 100 ml reagent
bottle and mixed with 5.4 g of acetic acid under heating and
dissolved at 75.degree. C. This solution was left to stand for 8
hours in a water bath (40.degree. C.). White solid precipitated,
was collected by filtration. The recovered solid was 0.5 g, and as
a result of the analysis, succinic acid was 97 wt %, and ammonia
was 1.6 wt %.
Example 1-3
[0193] Using a 100 ml reagent bottle, 15 g (0.1 mol) of diammonium
succinate was mixed with 35 g (0.58 mol) of acetic acid and 10 g of
water under heating and dissolved at 95.degree. C. This solution
was left to stand for 12 hours in a water bath (40.degree. C.).
White solid precipitated, was collected by filtration. The
recovered solid was 4.3 g.
[0194] 4 g of this solid was again put into a 100 ml reagent bottle
and added to 16 g of acetic acid under heating and dissolved at
70.degree. C. This solution was left to stand at room temperature
(about 15.degree. C.) for 8 hours. White solid precipitated was
collected by filtration. The recovered solid was 2.2 g, and as a
result of the analysis, succinic acid was 90 wt %, and ammonia was
0.8 wt %.
[0195] From the foregoing results, it is evident that it was
possible to recover succinic acid of high purity by reactive
crystallization by means of acetic acid.
Example 1-4
[0196] 50.35 g of diammonium succinate and 269.72 g of acetic acid
were put into a crystallizing apparatus, dissolved at 85.degree. C.
and maintained for 10 minutes, and then cooled to 15.degree. C.
with stirring. Upon expiration of 22 minutes after cooling to
15.degree. C., 1.03 g of reagent succinic acid (manufactured by
Wako Pure Chemical Industries, Ltd.) was put as seed crystals, and
the mixture was maintained for 4 hours.
[0197] A filtrate was 299.8 g, and a solid was recovered in an
amount of 13.1 g. The obtained solid content was analyzed for
organic substances by liquid chromatography and for ammonia by ion
chromatography, whereby acetic acid was 19.5 wt %, succinic acid
was 82.4 wt %, and ammonia was 1.1 wt %. Likewise, the mother
liquor was found to comprise 80.7 wt % of acetic acid, 9.9 wt % of
succinic acid and 4.0 wt % of ammonia. [0198] Recovery rate of
succinic acid: (13.1.times.0.824)/(50.35.times.118/152)=0.276
(27.6% recovery) [0199] Solid molar composition: [0200] Succinic
acid 13.1.times.0.824/118=0.0915 [0201] Acetic acid
13.1.times.0.195/60=0.0425 [0202] Ammonia
13.1.times.0.011/17=0.0084
Example 1-5
[0203] 50.46 g of diammonium adipate (manufactured by Wako Pure
Chemical Industries, Ltd.) and 269.83 g of acetic acid were put
into a crystallizing apparatus, dissolved at 85.degree. C. and
maintained for 10 minutes, and then cooled to 15.degree. C. with
stirring. Precipitation started immediately, and the system was
left to stand for 4 hours and 23 minutes.
[0204] A filtrate was 253.4 g, and a solid was recovered in an
amount of 55.4 g. The obtained solid content was analyzed for
organic substances by liquid chromatography and for ammonia by ion
chromatography, whereby acetic acid was 47.1 wt %, adipic acid was
61.8 wt % and ammonia was 2.0 wt %. Likewise, the mother liquor was
found to comprise 85.0 wt % of acetic acid, 5.1 wt % of adipic acid
and 3.7 wt % of ammonia. [0205] Recovery rate of adipic acid:
(55.4.times.0.618)/(50.465.times.150.1/184.2)=0.832 (83.2%
recovery) [0206] Solid molar composition: [0207] Adipic acid
55.4.times.0.618/150.1=0.228 [0208] Acetic acid
55.4.times.0.471/60=0.434 [0209] Ammonia
55.4.times.0.02/17=0.065
[0210] 50.21 g of the obtained solid content was washed at
16.degree. C. for 30 minutes by using 149.78 g of acetic acid,
followed by filtration. The obtained solid was 25.9 g, and the
rinsing liquid was 169.5 g. The solid was analyzed, whereby acetic
acid was 11.6 wt %, adipic acid was 80.3 wt % and ammonia was 0.2
wt %. Likewise, the rinsing liquid was found to comprise 89.4 wt %
of acetic acid, 3.9 wt % of adipic acid and 0.5 wt % of ammonia.
[0211] Recovery rate of adipic acid:
(25.9.times.0.803)/(50.46.times.150.1/184.2)=0.505 (50.5% recovery)
[0212] Solid molar composition: [0213] Adipic acid
25.9.times.0.803/150.1=0.139 [0214] Acetic acid
25.9.times.0.116/60=0.050 [0215] Ammonia
25.9.times.0.002/17=0.003
Example 1-6
[0216] 6.08 g of monoammonium glutamate (manufactured by Sigma Co.)
was dissolved in 10.08 g of water. 399.69 g of acetic acid was put
into a crystallizing apparatus and maintained at 60.degree. C., and
15.72 g of the aqueous monoammonium glutamate solution was
introduced thereinto. Turbidity started immediately, and the system
was cooled to 16.degree. C. with stirring. The system was left to
stand at 16.degree. C. for 4 hours and 18 minutes.
[0217] A filtrate was 387.1 g, and a solid was recovered in an
amount of 19.3 g. The obtained solid content was analyzed for
organic substances by liquid chromatography and for ammonia by ion
chromatography, whereby acetic acid was 68.2 wt %, glutamic acid
was 24.7 wt % and ammonia was 0.15 wt %. Likewise, the mother
liquor was found to comprise 92.3 wt % of acetic acid, no glutamic
acid detected and 1.4 wt % of ammonia. The rest of the mother
liquor is assumed to be water. [0218] Recovery rate of glutamic
acid:
(19.3.times.0.247)/(6.08.times.197.1/214.2.times.15.72/16.16)=0.876
(87.6% recovery) [0219] Solid molar composition: [0220] Glutamic
acid 19.3.times.0.247/197.1=0.0247 [0221] Acetic acid
19.3.times.0.682/60=0.224 [0222] Ammonia
19.3.times.0.0015/17=0.0017
Example 1-7
[0223] Using a 100 ml reagent bottle, 50.42 g of 28% aqueous
ammonia (manufactured by Kanto Kagaku K.K.) (0.83 mol of ammonia)
was added to 15 g (0.086 mol) of suberic acid (manufactured by
Acros Organics Co.) for dissolution. This solution was dried at
80.degree. C. under reduced pressure to obtain a salt. Upon the
analysis, suberic acid was 77 wt %, and ammonia was 9.2 wt %, and
it was found that 62% of the carboxyl group of suberic acid became
an ammonium salt.
[0224] 5.01 g of this ammonium salt of suberic acid was dissolved
in 25.05 g of acetic acid under heating, and this solution was left
to stand in a constant temperature vessel at 15.degree. C. for 18
hours. White solid precipitated, was collected by filtration. The
recovered solid was is 0.46 g, and as a result of the analysis,
suberic acid was 55 wt %, acetic acid was 40 wt % and ammonia was
0.2 wt %. The mother liquor was 29.60 g, and as a result of the
analysis, suberic acid was 2.6 wt %, acetic acid was 93 wt % and
ammonia was 1.3 wt %. [0225] Recovery rate of suberic acid:
(0.46.times.0.55)/(5.01.times.0.62)=0.081 (8.1% recovery) [0226]
Solid molar composition:
TABLE-US-00002 [0226] Suberic acid 0.46 .times. 0.55/174 = 0.00145
Acetic acid 0.46 .times. 0.40/60 = 0.00307 Ammonia 0.46 .times.
0.002/17 = 0.00005
Example 1-8
[0227] 50.20 g of diammonium adipate (manufactured by Wako Pure
Chemical Industries, Ltd.) and 399.29 g of acetic acid were put
into a crystallizing apparatus, dissolved at 95.degree. C. and
maintained for 10 minutes, and then cooled to 15.degree. C. with
stirring. Upon expiration of 55 minutes after the temperature
became 15.degree. C., 0.5 g of adipic acid (manufactured by Wako
Pure Chemical Industries, Ltd.) was added as seed crystals. The
system was left to stand for 3 hours and then subjected to
filtration.
[0228] The mother liquor (the filtrate) was 420.5 g, and a solid
was recovered in an amount of 25.65 g. The obtained solid content
was analyzed for organic substances by liquid chromatography and
for ammonia by ion chromatography, whereby propionic acid was 35.3
wt %, adipic acid was 56.8 wt %, and ammonia was 5.5 wt %.
Likewise, the mother liquor was found to comprise 90.6 wt % of
propionic acid, 6.2 wt % of adipic acid and 2.2 wt % of ammonia.
[0229] Recovery rate of adipic acid:
(25.65.times.0.568)/(50.20.times.150.1/184.2)=0.356 (35.6%
recovery) [0230] Solid molar composition:
TABLE-US-00003 [0230] Adipic acid 25.65 .times. 0.568/150.1 = 0.097
Propionic acid 25.65 .times. 0.353/74 = 0.127 Ammonia 25.65 .times.
0.055/17 = 0.086
[0231] 25.2 g of the obtained solid content was dissolved at
95.degree. C. by using 99.99 g of propionic acid and then cooled to
15.degree. C. Precipitation started immediately. The system was
left to stand for 3 hours and 53 minutes and then subjected to
filtration. The obtained solid was 16.48 g, and the mother liquor
was 104.4 g. The solid was analyzed, whereby propionic acid was
28.2 wt %, adipic acid was 69.0 wt % and ammonia was 0.4 wt %.
Likewise, the mother liquor was found to comprise 94.4 wt % of
propionic acid, 3.3 wt % of adipic acid and 1.1 wt % of ammonia.
[0232] Recovery rate of adipic acid:
(16.48.times.0.568)/(25.2.times.0.690)=0.794 (79.4% recovery)
[0233] Solid molar composition:
TABLE-US-00004 [0233] Adipic acid 16.48 .times. 0.690/150.1 = 0.076
Propionic acid 16.48 .times. 0.282/74 = 0.063 Ammonia 16.48 .times.
0.004/17 = 0.004
Example 2
[0234] Now, a test for distillation of a monocarboxylic acid and an
ammonium salt of the monocarboxylic acid, will be described.
Preparation of Model Mother Liquors
[0235] {circle around (1)} Preparation of Model Mother Liquor 1
[0236] The composition of the mother liquor after reactive
crystallization will be influenced by the amount of the solvent in
the reactive crystallization and the purity of the solvent at the
time of recycling and will be determined by the optimum operational
condition by such a condition as utility. To see the difference in
separation performance based on the melting point of the ammonium
salt of a monocarboxylic acid, as the monocarboxylic acid, acetic
acid was selected, which is considered to be preferred among those
having from 1 to 6 carbon atoms, as disclosed in JP-A-2002-135656.
The type of the di/tricarboxylic acid gives no influence on the
separation of the monocarboxylic acid and the ammonium salt of the
monocarboxylic acid, although its influence over the boiling point
slightly differs. In the present Test Examples, as the
di/tricarboxylic acid, succinic acid was selected as a standard
substance.
[0237] The solubility of ammonium succinate in acetic acid was
confirmed to be such that it dissolved up to a concentration of 33
wt % at 100.degree. C. and up to 10 wt % at 16.degree. C.
Therefore, on the assumption that the temperature of industrial
water is about 20.degree. C., the crystallization temperature was
assumed to be from about 30 to 50.degree. C., and it was assumed
that it would remain at a concentration of about 20 wt % in the
crystallization mother liquor after the crystallizing operation.
Therefore, assuming a crystallization mother liquor obtained by
separating succinic acid precipitated by reactive crystallization
by means of acetic acid, about 120 g of acetic acid manufactured by
Wako Pure Chemical Industries, Ltd. and about 30 g of ammonium
succinate manufactured by Wako Pure Chemical Industries, Ltd. were
mixed, heated and completely dissolved to obtain a solution having
an ammonium succinate concentration of about 20 wt %, which was
designated as "model mother liquor 1". As mentioned above:
[0238] Succinic acid primary pKa: 4.21
[0239] Succinic acid secondary pKa: 5.64
[0240] Acetic acid pKa: 4.76.
[0241] Accordingly, it is considered that while this model mother
liquor 1 comprises:
[0242] Charge: Acetic acid 120 g (2 mol) [0243] Diammonium
succinate 30.4 g (0.2 mol, about 20 wt %), the diammonium succinate
is reacted with acetic acid to have approximately the following
composition:
[0244] Dissolved liquid: Acetic acid 108 g (1.8 mol) [0245]
Monoammonium succinate 27 g (0.2 mol) [0246] Ammonium acetate 15.4
g (0.2 mol) {circle around (2)} Preparation of Model Mother
Liquor
[0247] Propionic acid manufactured by Wako Pure Chemical
Industries, Ltd., diammonium succinate manufactured by Wako Pure
Chemical Industries, Ltd. and 28% aqueous ammonia manufactured by
Wako Pure Chemical Industries, Ltd. were mixed in the following
ratio, heated and completely dissolved to obtain a solution, which
was designated as "model mother liquor 2".
[0248] Charge: Propionic acid 98.75 g (1.33 mol) [0249] Diammonium
succinate 20.29 g (0.133 mol) [0250] 28% aqueous ammonia 13.32 g
(0.22 mol: ammonia)
[0251] This model mother liquor 2 comprises:
[0252] Succinic acid primary pKa: 4.21
[0253] Succinic acid secondary pKa: 5.64
[0254] Propionic acid pKa: 4.67.
[0255] Accordingly, it is considered that the diammonium succinate
is reacted with propionic acid to have approximately the following
composition:
[0256] Dissolved liquid: Propionic acid 1.2 mol (88.8 g) [0257]
Monoammonium succinate 0.133 mol [0258] Ammonium propionate 0.35
mol (0.22 mol+0.133 mol) [0259] Water 9.6 g (7.2 wt %)
Distillation Tests
Test Example 2-1
The Lower Limit Temperature
[0260] Model mother liquor 1 (acetic acid: 120.00 g, diammonium
succinate: 30.42 g) was prepared, and then this mother liquor was
put into a 200 ml eggplant type flask, installed in a simple
distillation apparatus and subjected to simple distillation at 10
mmHg. A condenser of water-cooling type was employed. A very small
amount of nitrogen gas was constantly circulated in the simple
distillation apparatus for the purpose of preventing bumping and
for the purpose of increasing the distillation efficiency.
[0261] When the temperature in the flask became 36.degree. C.,
distillation started, and when it became 69.degree. C., no
substantial distillate was observed, and the distillation was
terminated. In the flask, precipitation occurred and solidification
was observed.
[0262] The distilled amount was 40 ml (45.65 g). The amount of the
content in the flask was 64.78 g from deduction of the tare of the
flask and the balance between before and after the test. It is
believed that the rest was not sufficiently condensed in the
condenser and was released from the reduced pressure line to a
draft, since the temperature of the cooling water of the condenser
was high as compared with the degree of reduced pressure.
Test Example 2-2
Upper Limit Temperature
[0263] Model mother liquor 1 (acetic acid: 120.18 g, diammonium
succinate: 30.40 g) was prepared, then put into a 200 ml eggplant
type flask, installed in a simple distillation apparatus and
subjected to simple distillation at 150 mmHg. A condenser of water
cooling type was used. A very small amount of nitrogen gas was
constantly circulated to the simple distillation apparatus for the
purpose of preventing bumping and for the purpose of increasing the
distillation efficiency.
[0264] When the temperature in the flask became 85.degree. C.,
distillation started, and after the temperature of an oil bath
became 105.degree. C., distillation was continued while reducing
the pressure by 10 mmHg each time. Upon expiration of 1 hour and 45
minutes, the distilled amount reached 40 ml. Here, the first
distillate sample was recovered. At that time, the temperature in
the flask was 89.degree. C., and the pressure was 120 mmHg.
[0265] Thereafter, an operation of reducing the pressure when the
distillation stopped, was repeated, so that the temperature of the
flask would not exceed 100.degree. C. The temperature of the oil
bath was controlled not to exceed the melting point (114.degree.
C.) taking into consideration a fluctuation or error of the
thermometer, and 109.degree. C. was the maximum. Upon expiration of
1 hour and 47 minutes from the first sampling, a sample was
collected when 40 ml was distilled. At that time, the temperature
in the flask was 95.degree. C., and the pressure was 60 mmHg.
[0266] The pressure was returned to atmospheric pressure, 2.55 g of
the bottom sample was collected. The amount of the content in the
flask was 64.96 g from deduction of the tare of the flask and the
balance between before and after the test. No precipitation of
crystals was observed throughout the period of the simple
distillation.
Test Example 2-3
Excess Temperature
[0267] Model mother liquor 1 (acetic acid: 120.03 g, diammonium
succinate: 30.41 g) was prepared, then put into a 200 ml eggplant
type flask, installed in a simple distillation apparatus and
subjected to simple distillation at 380 mmHg. A condenser of water
cooling type was used. A very small amount of nitrogen gas was
constantly circulated to the simple distillation apparatus for the
purpose of preventing bumping and for the purpose of increasing the
distillation efficiency.
[0268] When the temperature in the flask became 110.degree. C.,
distillation started, and in about 1 hour, the temperature reached
114.degree. C. Thereafter, the distillation rate did not increase,
and in further 45 minutes, the distilled amount reached 40 ml
(corresponding to Test Example 2-1). Here, the first distillate
sample was recovered. At that time, the temperature was 118.degree.
C. When further 40 ml was distilled, (132.degree. C.; upon
expiration of 1 hour and 10 minutes from the first sampling), the
pressure was once returned to atmospheric pressure, and the second
distillate sample and 2.55 g of the bottom sample were collected.
The pressure was again reduced to 380 mmHg, and when 2.97 g was
distilled, the distillation was terminated. The amount of the
content in the flask was 54.47 g from deduction of the tare of the
flask and the balance between before and after the test. No
precipitation of crystals was observed throughout the period of the
simple distillation.
Test Example 2-4
Effect of Water
[0269] In the same manner as for model mother liquor 1, 30.40 g of
succinic acid was used. Instead of 120 g of acetic acid in model
mother liquor 1, 72.02 g of acetic acid and 48.01 g of water were
used to dissolve the succinic acid.
[0270] The solution was put into a 200 ml eggplant type flask,
installed in a simple distillation apparatus and subjected to
simple distillation at atmospheric pressure. A condenser of water
cooling type was used. A very small amount of nitrogen gas was
constantly circulated to the simple distillation apparatus for the
purpose of preventing bumping and for the purpose of increasing the
distillation efficiency.
[0271] When the temperature in the flask became 132.degree. C. (oil
bath temperature: 158.degree. C.), distillation started, and in 20
minutes, 40 ml (42.64 g) was distilled, and a sample was collected.
Further, over a period of 34 minutes, 40 ml (41.88 g) was distilled
(the temperature in the flask: 150.degree. C., oil bath:
180.degree. C.), and a sample was collected. At that time, from the
bottom, 2.71 g was sampled. Further, heating was continued, and
when 20 ml (22.08 g) was distilled (the temperature in the flask:
169.degree. C., oil bath: 206.degree. C.), the distillation was
terminated, and the distillate and the bottom were, respectively,
sampled. The bottom was 39.27 g from deduction of the tare of the
flask and the balance between before and after the test.
Test Example 2-5
In the Case of Propionic Acid
[0272] Model mother liquor 2 was put into a 200 ml eggplant type
flask and installed in a simple distillation apparatus. After
reducing the pressure to 100 mmHg, heating was initiated. A
condenser of water cooling type was used. A very small amount of
nitrogen gas was constantly circulated to the simple distillation
apparatus for the purpose of preventing bumping and for the purpose
of increasing the distillation efficiency.
[0273] When the temperature in the flask became 72.degree. C.,
distillation started. When the temperature in the flask became
83.degree. C., the pressure was reduced to maintain the
temperature, and thus the pressure was reduced to 50 mmHg.
Subsequently, when the temperature became 90.degree. C. and upon
expiration of 55 minutes from the initiation of the distillation,
the distillate was sampled. At the at that time, the temperature of
the oil bath was 100.degree. C. Upon expiration of 1 hour from the
initiation of the distillation, distillation was continued for 20
minutes by raising the temperature to 105.degree. C. and further
for 20 minutes by raising the temperature to 108.degree. C.,
whereupon the bottom and the distillate were sampled. The
temperature in the flask upon completion of the distillation was
95.degree. C.
[0274] The first distillate recovered was 37.0 g, the second
distillate was 15.25 g, and the bottom was 79.7 g.
[0275] In Test Example 2-5, on the same basis as for the analysis,
i.e. on the assumption that the acid and the base are separately
present, the charge comprised:
TABLE-US-00005 Propionic acid 98.75 g Ammonia 20.29 .times. 34/152
+ 13.32 .times. 0.28 = 8.27 g Succinic acid 20.29 .times. 118/152 +
15.75 g Water 13.32 .times. 0.72 = 9.59 g.
Test Example 2-6
The Minimum Temperature for Vaporization of Ammonium Acetate
[0276] Taking into consideration, the results of Test Examples 2-1
and 2-2, vaporization of ammonium acetate in an acetic
acid-succinic acid system was investigated by means of the
following model solution.
[0277] 29.99 g of acetic acid, 15.19 g of ammonium succinate and
further 7.69 g of ammonium acetate in order to more accurately
grasp the vaporization of ammonium acetate, were put into a 200 ml
eggplant type flask and installed in a rotary evaporator. The
pressure was reduced to 30 mmHg, and the flask was immersed in an
oil bath heated to 108.degree. C. and heated for 27 minutes.
[0278] At a condenser portion, white solid was precipitated and
deposited. The bottom was white solid which was precipitated and
solidified, and its amount was 27.93 g.
[0279] On the same basis as for the analysis, i.e. on the
assumption that the acid and the base are present separately, the
charge comprised:
TABLE-US-00006 Acetic acid 29.99 + 7.69 .times. 60/77 = 35.98 g
Ammonia 15.19 .times. 34/152 + 7.69 .times. 17/77 = 5.10 g Succinic
acid 15.19 .times. 118/152 = 11.79 g.
Test Example 2-7
Maximum Temperature for Vaporization of Ammonium Acetate
[0280] On the basis of the results of Test Examples 2-1 and 2-2 and
further in consideration of an idea that it may be advantageous to
add water under a high temperature condition in view of Test
Examples 2-3 and 2-4, vaporization of ammonium acetate in an acetic
acid-succinic acid system was investigated by means of the
following model solution.
[0281] 24.00 g of acetic acid, 15.20 g of ammonium succinate, 6.11
g of deionized water and further 7.68 g of ammonium acetate in
order to more accurately grasp the vaporization of ammonium
acetate, were put into a 200 ml eggplant type flask and installed
in a rotary evaporator. The pressure was reduced to 150 mmHg, and
the flask was immersed in an oil bath heated to 150.degree. C.,
whereupon the oil bath was heated to 178.degree. C. The
distillation rate became slow immediately, but in consideration of
comparison to Test Example 2-6, heating was continued for 30
minutes.
[0282] At a condenser portion, white solid was precipitated and
deposited. The bottom was white solid which was precipitated and
solidified, and its amount was 16.07 g.
[0283] On the same basis as for the analysis, i.e. on the
assumption that the acid and the base are present separately, the
charge comprised:
TABLE-US-00007 Acetic acid 24.00 + 7.68 .times. 60/77 = 35.98 g
Ammonia 15.20 .times. 34/152 + 7.68 .times. 17/77 = 5.10 g Succinic
acid 15.20 .times. 118/152 = 11.80 g.
Test Example 2-8
[0284] 30.00 g of acetic acid, 15.18 g of ammonium succinate and
further, 7.71 g of ammonium acetate in order to more accurately
grasp the vaporization of ammonium acetate, were put into a 200 ml
eggplant type flask and installed in a rotary evaporator. The
pressure was reduced to 50 mmHg, and the flask was immersed in an
oil bath heated to 100.degree. C. When the temperature of the oil
bath became 132.degree. C., distillation started, and 25 minutes
later, the bottom underwent precipitation and solidification at
139.degree. C., and the distillation was terminated. The amount of
the bottom was 22.71 g. At a condenser portion, white solid was
precipitated and deposited.
[0285] On the same basis as for the analysis, i.e. on the
assumption that the acid and the base are separately present, the
charge comprised:
TABLE-US-00008 Acetic acid 30.00 + 7.71 .times. 60/77 = 36.01 g
Ammonia 15.18 .times. 34/152 + 7.71 .times. 17/77 = 5.10 g Succinic
acid 15.18 .times. 118/152 = 11.78 g.
Test Example 2-9
Effects of Water
[0286] On the basis of the results of Test Examples 2-1 and 2-2 and
in consideration of an idea that it may be advantageous to add
water in view of Test Example 2-3 and 2-4, the vaporization of
ammonium acetate in an acetic acid-succinic acid system was
investigated by means of the following model solution on the
assumption that water is added or to be added to the
crystallization solvent.
[0287] 7.50 g of acetic acid, 15.23 g of ammonium succinate, 35.99
g of deionized water and further, 7.68 g of ammonium acetate in
order to more accurately grasp the vaporization of ammonium
acetate, were put into a 200 ml eggplant type flask and installed
in a rotary evaporator. The pressure was reduced to 50 mmHg, and
the flask was immersed in an oil bath heated to 137.degree. C.
During the test, the temperature of the oil bath changed within a
range of from 137 to 138.degree. C.
[0288] The distillation was complete in 17 minutes, and the bottom
was white solid which was precipitated and solidified, and its
amount was 27.96 g. At a condenser portion, white solid was
precipitated and deposited.
[0289] On the same basis as for the analysis, i.e. on the
assumption that the acid and the base are separately present, the
charge comprised:
TABLE-US-00009 Acetic acid 7.50 + 7.68 .times. 60/77 = 13.48 g
Ammonia 15.23 .times. 34/152 + 7.68 .times. 17/77 = 5.10 g Succinic
acid 15.23 .times. 118/152 = 11.82 g.
Test Example 2-10
Vaporization of Ammonium Propionate
[0290] Ammonium propionate is not commercially available.
Therefore, 39.99 g of propionic acid, 15.23 g of ammonium succinate
and 15.16 g of 28% aqueous ammonia manufactured by Wako Pure
Chemical Industries, Ltd. were used as a model solution.
[0291] This model solution was put into an eggplant type flask and
installed in a rotary evaporator. The pressure was reduced to 40
mmHg, and the flask was immersed in an oil bath heated to
157.degree. C. The temperature was 160.degree. C. during the test.
In this state, distillation was carried out for 25 minutes.
[0292] At a condenser portion, white solid was precipitated and
deposited. The bottom was white solid which was precipitated and
solidified, and its amount was 25.38 g.
[0293] On the same basis as for the analysis, i.e. on the
assumption that acid and base are separately present, the charge
comprised:
TABLE-US-00010 Propionic acid 39.99 g Ammonia 15.20 .times. 34/152
+ 15.16 .times. 0.28 = 3.41 g Succinic acid 15.23 .times. 118/152 =
11.82 g.
Results
[0294] The results of the foregoing distillation tests are shown in
Tables 2-1 to 2-4.
TABLE-US-00011 TABLE 2-1 Simple distillation: Corresponding to a
kettle type evaporator Maximum Maximum temp. liquid in the temp.
Charged oil in the acetic Charged Charged Charged Pressure bath
flask Overall acid ammonia succinic water (mmHg) (.degree. C.)
(.degree. C.) time (g) (g) acid (g) (g) Ex. 1 Distillate 10 77 69 2
hr Bottom 10 77 69 2 hr Balance 120.00 6.80 23.62 0.00 Ex. 2
Distillate 1 150-60 105 89 1 hr 45 min Distillate 2 150-60 109 95 3
hr 19 min Bottom 150-60 109 95 3 hr 19 min Balance 120.18 6.80
23.60 0.00 Ex. 3 Distillate 1 380 134 118 1 hr 40 min Distillate 2
380 149 132 3 hr 47 min Bottom 1 380 149 132 3 hr 47 min Bottom 2
380 160 132 4 hr 25 min Balance 120.03 6.80 23.61 0.00 (bottom 1)
Ex. 4 Distillate 1 760 142 116 53 min Distillate 2 760 160 139 2 hr
36 min Distillate 3 760 175 156 3 hr 48 min Bottom 1 760 160 139 2
hr 36 min Bottom 2 760 175 156 3 hr 48 min Balance 72.02 6.80 23.60
48.01 (bottom 1) Ex. 5 Distillate 1 100-50 97-100 72-90 55 min
Distillate 2 100-50 100-108 90-95 1 hr 40 min Bottom 100-50 97-108
72-95 1 hr 40 min Balance *98.75 8.27 15.75 9.59 *Propionic
acid
TABLE-US-00012 TABLE 2-2 Simple distillation: Corresponding to a
kettle type evaporator Acetic Total Ammonia acid Ammonia Succinic
Amide Amidated Distilled in (g) (g) acid (g) (g) ammonia ammonia
bottle 1 Ex. 1 Distillate 46.69 0.03 0.00 0.00 Bottom 33.87 6.71
23.14 0.00 0.00 0.00 0.39 mol Balance 80.56** 6.73 23.14 0.00 0.00
0.00 1.00 mol fraction Ex. 2 Distillate 1 42.14 0.15 0.00 0.00
Distillate 2 42.76 0.05 0.00 0.00 Bottom 34.97 6.35 21.99 1.21 0.01
0.01 0.37 mol Balance 119.88 6.54 21.99 1.21 0.03 0.03 0.94 mol
fraction Ex. 3 Distillate 1 41.72 0.05 0.00 0.00 Distillate 2 40.36
0.01 0.00 0.00 Bottom 1 29.58 3.67 10.81 11.88 0.11 0.00 0.22 mol
Bottom 2 25.32 2.99 8.57 13.07 0.32 0.01 0.66 mol fraction Balance
111.66 3.74 10.81 11.88 (bottom 1) Ex. 4 Distillate 1 16.48 0.01
0.00 0.00 Distillate 2 21.47 0.02 0.00 0.00 Distillate 3 11.28 0.05
0.00 0.00 Bottom 1 31.90 4.52 14.67 9.30 0.08 0.00 0.27 mol Bottom
2 14.66 1.66 5.69 15.58 0.23 0.01 0.75 mol fraction Balance 69.86
4.56 14.67 9.30 (bottom 1) Ex. 5 Distillate 1 *26.20 0.28 0.00 0.00
Distillate 2 13.70 0.56 0.00 0.00 Bottom 54.29 7.34 14.50 0.20 0.00
0.05 0.43 mol Balance 94.19 8.18 14.50 0.20 0.00 0.10 0.89 mol
fraction *Propionic acid **(Partly leaked without being
condensed)
TABLE-US-00013 TABLE 2-3 Rotary evaporator: Corresponding to a thin
film type evaporator Maximum Maximum temp. liquid in the temp.
Charged oil in the acetic Charged Charged Charged Pressure bath
flask Overall acid ammonia succinic water (mmHg) (.degree. C.)
(.degree. C.) time (g) (g) acid (g) (g) Ex. 6 Distillate 30 108-110
UM 27 min Bottom 30 108-110 UM 27 min Balance 35.98 5.10 11.79 0.00
Ex. 7 Distillate 150 150-178 UM 30 min Bottom 150 150-178 UM 30 min
Balance 29.98 5.10 11.80 6.11 Ex. 8 Distillate 50 132-139 UM 25 min
Bottom 50 132-139 UM 25 min Balance 36.01 5.10 11.78 0.00 Ex. 9
Distillate 50 137-138 UM 17 min Bottom 50 137-138 UM 17 min Balance
13.48 5.10 11.82 35.99 Ex. 10 Distillate 40 157-160 UM 25 min
Bottom 40 157-160 UM 25 min Balance *39.99 3.41 11.82 0.00 UM:
Unmeasurable *Propionic acid
TABLE-US-00014 TABLE 2-4 Rotary evaporator: Corresponding to a thin
film type evaporator Acetic Total Ammonia acid Ammonia Succinic
Amide Amidated Distilled in (g) (g) acid (g) (g) ammonia ammonia
bottle Ex. 6 Distillate 4.32 0.08 0.00 0.00 (Calculated value)
Bottom 12.68 3.50 11.69 0.07 0.0006 0.09 0.21 mol Balance 17.00***
3.59 11.69 0.07 0.00 0.31 0.69 mol fraction Ex. 7 Distillate 15.05
1.45 0.00 0.00 (Calculated value) Bottom 2.37 1.52 9.56 2.28 0.0197
0.19 0.09 mol Balance 17.43*** 2.98 9.56 2.28 0.07 0.64 0.30 mol
fraction Ex. 8 Distillate 5.64 0.14 0.00 0.00 (Calculated value)
Bottom 7.60 2.88 12.25 0.16 0.0014 0.13 0.17 mol Balance 14.44***
3.02 12.25 0.16 0.00 0.43 0.57 mol fraction Ex. 9 Distillate 0.51
0.04 0.00 0.00 (Calculated value) Bottom 10.39 4.28 11.79 0.00
0.0000 0.05 0.25 mol Balance 10.90*** 4.32 11.79 0.00 0.00 0.16
0.84 mol fraction Ex. 10 Distillate *13.60 2.54 0.00 0.00
(Calculated value) Bottom 2.77 1.30 10.45 1.20 0.0103 0.11 0.08 mol
Balance 16.37*** 3.84 10.45 1.20 0.05 0.57 0.38 mol fraction
*Propionic acid ***(Solid precipitated in the condenser)
Discussion
[0295] In a succinic acid-acetic acid system, an ammonium salt of
acid B is meant for ammonium acetate, and its melting point is
known to be 114.degree. C. In Test Example 2-3, the oil bath was
from 134.degree. C. to 149.degree. C., and the liquid temperature
in the flask exceeded 114.degree. C., and the maximum was
132.degree. C. The elapsed time was about 2 hours. At that time,
acetamide was formed as much as 7.4 wt %, and further, succinic
acid amide, etc. were formed. Succinic acid introduced, was 30.4 g
(corresponding to 0.2 mol) as ammonium succinate, and succinic acid
remaining in the bottom decreased to a level of 0.09 mol. Whereas,
in Test Example 2-2, the temperature of the oil bath i.e. the wall
temperature of the flask was 109.degree. C., the liquid temperature
in the flask was 95.degree. C., and the elapsed time was as much as
3.3 hours. Nevertheless, acetamide was formed only at a level of
0.4 wt %, and likewise, succinic acid was 30.4 g (corresponding to
0.2 mol) as ammonium succinate, and it corresponds to 0.186 mol in
such a state that it is not detected in the distillate. Thus, the
difference is distinct.
[0296] From such results, the present inventor considered that
there must be a temperature which is specifically influential over
the reaction for amidation of ammonium carboxylate at a level of
around 120.degree. C. as an average temperature during the
operation, which is higher than the liquid temperature of
95.degree. C. in Test Example 2-2 and which is not higher than the
liquid temperature of 132.degree. C. in Test Example 2-3.
[0297] The melting point of ammonium acetate is 114.degree. C., and
as mentioned above, the melting point of ammonium propionate is
considered to be about 100.degree. C.
[0298] In these tests, the operation temperature is assumed to be
about the melting point or slightly higher than the melting point.
Accordingly, especially in the distillate 2, it is considered that
ammonia is slightly evaporated by pyrolysis. However, during the
majority of the elapsed time, the temperature in the flask is not
higher than 95.degree. C., amidation is observed to be not
extremely advanced. In the case of acetic acid in Test Example 2-2,
the retention time exceeded 3 hours, and the temperature was at
least 90.degree. C. for about 1 hour and a half. In the case of
Test Example 2-5, taking into consideration the retention of about
40 minutes, the amidation ratio may be regarded as substantially
the same within a range of analytical error.
[0299] It is important that acetic acid or propionic acid as acid B
is taken out in a state where it contains no ammonia, and organic
acid A and its ammonium salt are concentrated while avoiding
amidation or imidation. For such a purpose, it is necessary to take
as a threshold whichever is lower, about 110.degree. C. as the
reaction singular point or the melting point of acid B.
Accordingly, in the case of acetic acid, the reaction singular
point is unclear in a strict sense and substantially the same
temperature as the melting point, and accordingly, an operational
condition is adjusted at a temperature not higher than 114.degree.
C. as the melting point of acetic acid. In the case of propionic
acid, the melting point of propionic acid is unclear, and in the
Test Example, the evaporated amount of ammonia is not higher than
1/10 of the charged amount in spite of such a long retention time
as 1 hour and 40 minutes, and such is considered to be practically
within an allowable range, and therefore, a temperature of the
level in this Test Example is considered to be the upper limit
temperature. Namely, it is 110.degree. C. in consideration of the
temperature of the wall surface (the temperature of the oil bath).
The temperature of the wall surface is not usually measured, and
therefore, 110.degree. C. as the temperature of the utility to be
used for heating will be the upper limit. This corresponds to a
liquid temperature of 100.degree. C., which may be considered as
corresponding to the melting point of ammonium propionate.
Accordingly, in the case where propionic acid is employed, the
temperature of the process fluid being at most 100.degree. C. will
be the operational condition. It is only required that the
operational condition of either the utility or the process fluid is
satisfied.
[0300] Further, as Comparative Examples, Test Examples 2-3 and 2-4
were carried out. This is based on an idea that the amidation or
imidation reaction may be suppressed when water is contained. Under
the conditions of Test Examples 2-1 and 2-2, amidation or imidation
is slight, and no significant difference can be observed within a
range of analytical error. Accordingly, the investigation is made
intentionally under a condition where amidation or imidation takes
place. From the results, a significant difference is distinctly
observed. Thus, it can be said that it is advisable that water is
present to some extent during the vaporization of acid B.
[0301] In a test on a method of vaporizing an ammonium salt of acid
B after vaporization of acid B from the crystallization mother
liquor, not negligible is the retention time. As mentioned above,
the reaction for amidation becomes rapid at a temperature of about
120.degree. C. On the other hand, a higher temperature is required
to separate the ammonium salt of acid B from organic acid A and its
ammonium salt, since a temperature of at least the melting point of
the ammonium salt of acid B is ideal.
[0302] In the case of a simple distillation apparatus, a connecting
portion from the flask as the heating portion to a condenser
portion, is exposed to the outside air, whereby the outside air and
the process undergo heat exchange to cause an internal reflux.
Consequently, unless the difference between the heat release at the
connecting portion and the heating at the flask portion is
substantially large, the retention time increases. In Test Example
2-3, the temperature of the oil bath was rapidly raised, and the
heating calorie was large. Nevertheless, the retention time was
long, because the temperature difference between the process and
the outside air became also large, and the heat release at the
connecting portion became likewise large.
[0303] Therefore, the present inventor conducted a test in which a
rotary evaporator was used. In the rotary evaporator, the flask is
installed obliquely to the oil bath and is rotated so that the
flask can be uniformly heated to a portion close to the connecting
portion. Besides, a portion from the connecting portion of the
flask to the condenser is shielded from the outside air by a
driving portion, whereby heat exchange with the outside air is
substantially minimized. As a result, the internal reflux is
minimum, and the retention time can be shortened.
[0304] However, the liquid temperature in the rotating flask can
not be measured. Namely, in order to shorten the retention time,
the amount of charge is intentionally reduced as compared with the
size of the flask, whereby even if a thermometer may be inserted,
the liquid temperature can not be constantly measured, since the
liquid surface is always in the vicinity of the inner wall of the
flask. Further, the flask is in rotation, and at the final stage of
evaporation, organic acid A and its ammonium salt will solidify,
whereby it is difficult to measure the temperature in the
flask.
[0305] The ammonium salt of acid B undergoes pyrolysis, whereby it
is difficult to measure the physical property such as the boiling
point accurately. However, the present inventor considered that
theoretically, a boiling point is necessarily present, and a
phenomenon such as sublimation takes place, whereby it may simply
be that one due to pyrolysis can not be distinguished from the
contribution of vaporization or sublimation. Therefore, a test was
carried out in which the ammonium salt of acid B was evaporated in
a reduced pressure system by shortening the retention time. Test
Examples 2-6, 2-7 and 2-8 are tests in which a rotary evaporator
was used.
[0306] In Test Example 2-6, it has been found that by sufficiently
reducing the pressure and using an oil bath i.e. a heat source of
about 110.degree. C., ammonium acetate can be vaporized. This is a
phenomenon at a temperature of not higher than the melting point,
and it is assumed that sublimation took place. In Test Example 2-7,
ammonium acetate was adequately vaporized even under a relatively
mild reduced pressure condition at a level of 150 mmHg. In a
practical process, the retention time can be shortened, and it has
been proved that a design can be made under this condition.
However, in this test, for the purpose of comparison, the retention
time was prolonged to correspond to Test Example 2-6 while the oil
bath i.e. the heat source was set at 180.degree. C., whereby
amidation took place to some extent. This indicates that if the
temperature of the heat source is made high, the retention time
must be shortened correspondingly.
[0307] In Test Example 2-9, water evaporated quickly, whereby it
was difficult to determine the factor for the suppression of
amidation i.e. whether it was due to a short time or it was due to
suppression of dehydration reaction by the presence of water.
However, it has been confirmed that both effects contributed
substantially and that amidation can be lowered by the presence of
water.
[0308] Accordingly, as a method for vaporizing acid B after
concentrating the crystallization mother liquor, one having a short
heating time is preferred. Further, it is preferred to vaporize
under a superheated state i.e. to heat the process fluid under a
reduced pressure condition by a sufficiently high temperature heat
source.
Example 3
Test Example 3-1
Test to Confirm the Presence of Ammonium Acetate (Separation by a
Rotary Evaporator)
[0309] 6.0 g of acetic acid manufactured by Wako Pure Chemical
Industries, Ltd., 15.18 g of ammonium succinate manufactured by
Wako Pure Chemical Industries, Ltd. and 20 g of water were put into
a 200 ml eggplant type flask and installed in a rotary evaporator.
The pressure was reduced to 50 mmHg, and the flask was heated by
immersing it in an oil bath heated to 140.degree. C. The
distillation time was 5 minutes. At a condenser portion, white
solid was precipitated and deposited. The bottom was 20.8 g. The
composition of this solid was 56.1 wt % (0.099 mol) of succinic
acid, 19.6 wt % (0.068 mol) of acetic acid and 15.4 wt % (0.189
mol) of ammonia.
Test Example 3-2
Reactive Crystallization
[0310] Using a 100 ml reagent bottle, 4.5 g (0.03 mol) of
diammonium succinate was mixed with 30 g (0.5 mol) of acetic acid
under heating and dissolved at 80.degree. C. This solution was left
to stand at room temperature (17.degree. C.) for 2 hours. White
solid precipitated, and this solid was collected by filtration. The
recovered solid was 1.92 g, and as a result of the analysis, it was
confirmed to comprise 96 wt % of acetic acid and 1 wt % of
ammonia.
Test Example 3-3
Gas/Liquid Separation and Concentration after Crystallization
[0311] 120 g of acetic acid manufactured by Wako Pure Chemical
Industries, Ltd. and 30 g of ammonium succinate manufactured by
Wako Pure Chemical Industries, Ltd. were mixed, heated and
completely dissolved to obtain a solution, which was designated as
a crystallization mother liquor. Further,
[0312] Succinic acid primary pKa: 4.21
[0313] Succinic acid secondary pKa: 5.64
[0314] Acetic acid pKa: 4.76.
Accordingly, it is considered that while
[0315] Charge: Acetic acid 120 g 2 mol [0316] Diammonium succinate
30.4 g 0.2 mol (about 20 wt %), the diammonium succinate is reacted
with acetic acid to form approximately the following composition
(as ammonia: 2 wt %).
[0317] Dissolved liquid:
TABLE-US-00015 Acetic acid 108 g 1.8 mol Monoammonium succinate 27
g 0.2 mol Ammonium acetate 15.4 g 0.2 mol
[0318] This solution was put into a 200 ml eggplant type flask,
installed in a simple distillation apparatus and subjected to
simple distillation at 150 mmHg. A condenser of water cooling type
was used. A very small amount of nitrogen gas was constantly
circulated to the simple distillation apparatus for the purpose of
preventing bumping and for the purpose of increasing the
distillation efficiency.
[0319] When the temperature in the flask became 85.degree. C.,
distillation started, and after the temperature of the oil bath
became 105.degree. C., distillation was carried out while reducing
the pressure by 10 mmHg each time. For 1 hour and 45 minutes, the
distilled amount became 40 ml. Here, the first distillate sample
was recovered. The temperature in the flask at that time was
89.degree. C., and the pressure was 120 mmHg.
[0320] Thereafter, an operation of reducing the pressure when the
distillation stopped, was repeated so that the temperature in the
flask would not exceed 100.degree. C. The operation was carried out
so that the temperature of the oil bath would not exceed the
melting point (114.degree. C.) taking into consideration a
fluctuation or error of the thermometer, and 109.degree. C. was the
maximum. Over a period of 1 hour and 34 minutes from the first
sampling (overall time: 3 hours and 19 minutes), 40 ml was
distilled, whereupon a sample was collected. The temperature in the
flask at that time was 95.degree. C., and the pressure was 60
mmHg.
[0321] The pressure was returned to atmospheric pressure, and the
bottom sample was collected. The amount of the content of the flask
was 64.96 g from deduction of the tare of the flask and the balance
between before and after the test. No precipitation of crystals was
observed throughout the period of the simple distillation.
[0322] In the composition of the first distillate, acetic is acid
was 102% (exceeded 100% due to an analytical error); in the
composition of the second distillate, acetic acid was 103%
(exceeded 100% due to an analytical error), and in the composition
of the final bottom, acetic acid was 54%, acetamide 0.4%, succinic
acid 34%, succinic acid monoamide 1.8%, and ammonia 9.8%.
Test Example 3-4
Gas/Liquid or Gas/Solid Separation to Obtain a Di/Tricarboxylic
Acid and its Ammonium Salt
[0323] Vaporization of ammonium acetate in an acetic acid-succinic
acid system was investigated by means of the following model
solution.
[0324] 30.00 g of acetic acid manufactured by Wako Pure Chemical
Industries, Ltd., 15.18 g of ammonium succinate manufactured by
Wako Pure Chemical Industries, Ltd. and further 7.71 g of ammonium
acetate in order to more accurately grasp the vaporization of
ammonium acetate manufactured by Wako Pure Chemical Industries,
Ltd., were put into a 200 ml eggplant type flask, and installed in
a rotary evaporator. The pressure was reduced to 50 mmHg, and the
flask was immersed in an oil bath heated to 100.degree. C.,
whereupon the oil bath was heated to 140.degree. C. When the oil
bath reached 132.degree. C., distillation started. The distillation
time was 17 minutes.
[0325] At a condenser portion, white solid was precipitated and
deposited. The bottom was 22.71 g.
[0326] The composition of the bottom was 34% of acetic acid, 0.3%
of acetamide, 54% of succinic acid, 0.7% of succinic acid monoamide
and 12.7% of ammonia.
Test Example 3-5
Conditions for Amidation
[0327] 120 g of acetic acid manufactured by Wako Pure Chemical
Industries, Ltd. and 30 g of ammonium succinate manufactured by
Wako Pure Chemical Industries, Ltd. were mixed, heated and
completely dissolved to obtain a solution, which was designated as
a crystallization mother liquor. Further,
[0328] Succinic acid primary pKa: 4.21
[0329] Succinic acid secondary pKa: 5.64
[0330] Acetic acid pKa: 4.76. Accordingly, it is considered that
while
[0331] Charge: Acetic acid 120 g 2 mol [0332] Diammonium succinate
30.4 g 0.2 mol (about 20 wt %), the diammonium succinate is reacted
with acetic acid to form approximately the following
composition:
[0333] Dissolved liquid:
TABLE-US-00016 Acetic acid 108 g 1.8 mol Monoammonium succinate 27
g 0.2 mol Ammonium acetate 15.4 g 0.2 mol
[0334] This solution was put into a 200 ml eggplant type flask,
installed in a simple distillation apparatus and subjected to
simple distillation at 380 mmHg. A condenser of water cooling type
was used. A very small amount of nitrogen gas was constantly
circulated to the simple distillation apparatus for the purpose of
preventing bumping and for the purpose of increasing the
distillation efficiency.
[0335] When the temperature in the flask reached 110.degree. C.,
the first one drop was distilled, but thereafter, due to internal
reflux by heat release, the distillation decreased remarkably. Over
a period of 1 hour and 40 minutes from the first one drop, the
distilled amount became 40 ml (which corresponds to Test Example
3-1). Here, a first distillate sample was recovered. The
temperature at that time was 118.degree. C. When further 40 ml was
distilled (132.degree. C.; overall time: 3 hours and 47 minutes),
the pressure was once returned to atmospheric pressure, whereupon a
second distillate sample and 2.55 g of a bottom sample were
collected. Further, the pressure was reduced to 380 mmHg once
again, and when 2.97 g was distilled, the distillation was
terminated. The amount of the content in the flask was 54.47 g from
deduction of the tare of the flask and the balance between before
and after the test. No precipitation of crystals was observed
throughout the period of the simple distillation.
[0336] In the composition of the first distillate, acetic acid was
100%; in the composition of the second distillate, acetic acid was
97% (substantially 100% within an error range), and in the
composition of the bottom at the time of sampling the second
distillate, was 49% of acetic acid, 7.3% of acetamide, 18% of
succinic acid, 16% of succinic acid monoamide and 6.1% of
ammonia.
Example 4
[0337] In the following, for ammonium acetate, sodium acetate and
potassium acetate, high grade reagents manufactured by Wako Pure
Chemical Industries, Ltd. were used.
Test Example 4-1
[0338] 15.22 g (0.198 mol) of ammonium acetate, 20.01 g of
deionized water and 5.20 g of 28% aqueous ammonia, manufactured by
Wako Pure Chemical Industries, Ltd. (0.086 mol as ammonia) were put
into a 200 ml flask and installed in a simple distillation
apparatus. The pressure was reduced to 150 mmHg, and the flask was
immersed in an oil bath heated to 90.degree. C. When the liquid
temperature in the flask became 62.degree. C., distillation
started. When the liquid temperature in the flask became 75.degree.
C., the distillate was sampled. The distillate was sampled. The
amount was 15.79 g. Then, the pressure was reduced to 100 mmHg, to
obtain 3.35 g of a distillate and 18.54 g of a bottom.
[0339] Acetic acid contained in the first distillate was 0.34 wt %,
the acetic acid contained in the second distillate was 0.72 wt %,
and acetic acid contained in the bottom was 62.4 wt % (0.193 mol).
Ammonia in the bottom was 13.9 wt % (0.152 mol).
[0340] From this result, it has been proved that acetic acid is
present in the form of ammonium acetate, which is not substantially
vaporized at a temperature of not higher than the melting point
(114.degree. C.) of ammonium acetate, whereby aqueous ammonia can
be separated.
Test Example 4-2
[0341] A test was carried out by a test apparatus shown in FIG.
6.
[0342] As a distillation column 10, an Oldarshow distillation
column having 20 plates, was used. In order to improve the liquid
hold and the distillation efficiency, an inert gas from a steel
bottle 11 was circulated to this distillation column 10 via column
bottom flask 13 immersed in an oil bath 12, and a non-condensed gas
was discharged into a draft from a gas purge line 15 via a
condenser 14.
[0343] The charge was 249.9 g of ammonium acetate, 150.0 g of
sodium acetate and 250.0 g of deionized water and was preliminarily
heated to 90.degree. C. in a feed material tank 16 equipped with a
temperature-keeping means. The capacity of the flask 13 at the
column bottom was 500 ml, and for startup, 30.06 g of ammonium
acetate, 20.27 g of sodium acetate and 70.16 g of acetic acid were
charged.
[0344] When the inner temperature of the column bottom flask 13
became 120.degree. C., the feed material in the feed material tank
16 was supplied at a flow rate of 165 cc/hr from the top of the
distillation column 10 via a preheater 17. At that time, the
temperature of the preheater 17 was 110.degree. C.
[0345] After an operation for 51 minutes from the initiation of the
supply of the feed material, 63.6 g of the distillate and 120.5 g
of the bottom in the flask were withdrawn as the first withdrawal.
After an operation for further 37 minutes, 43.9 g of the distillate
and 71.1 g of the bottom in the flask were withdrawn as the second
withdrawal.
[0346] Thereafter, a steady state was assumed.
[0347] Further, after an operation for 36 minutes, 44.5 g of the
distillate and 60.3 g of the bottom in the flask were taken out as
the first analytical samples. After an operation for further 36
hours, 46.3 g of the distillate and 74.5 g of the bottom in the
flask were taken out as the second analytical samples.
[0348] The compositions of the respective analytical samples were
as shown in Table 4-1.
TABLE-US-00017 TABLE 4-1 Composition (wt %) Analytical Acetic
samples acid Ammonia Acetamide Na Water First Distillate 0.5 7.9
Rest (44.5 g) Bottom 71.8 3.8 9.1 9.9 5.4 (60.3 g) (calculated
value) Second Distillate 0.5 8.2 Rest (46.3 g) Bottom 72.6 4.0 8.1
10.1 5.2 (74.5 g) (calculated value)
[0349] As is apparent from Table 4-1, there is no substantial
difference in the composition between the first and second
analytical samples, and thus, the operation can be regarded as
substantially steady. On the basis that the operation was
substantially in a steady state, if the composition of the supplied
feed material and the composition of the second analytical samples
are compared, the mass balance will be as shown in the following
Table 4-2. Here, the supplied material of 165 cc/hr was converted
to a unit of g/hr by using the specific gravity of the feed
material being 1.14.
[0350] Further, the amount of the acetamidated ammonia was obtained
by calculation as follows. Namely, as shown in Table 4-1, acetamide
in the bottom was 8.1 wt %, which was calculated as ammonia by
molar amount, which is then converted to a weight amount to obtain
1.7 g.
TABLE-US-00018 TABLE 4-2 Distillate Bottom (excluding (withdrawn
non- from the Supplied condensed column amount gas) bottom)
Acetamidated Components (g/hr) (g/hr) (g/hr) ammonia Acetic 50.3
0.2 54.1 -- acid Water 43.9 42.3 3.9 -- Ammonia 9.7 3.8 3.0 1.7 Na
7.4 0.0 7.5 --
[0351] As is apparent from Table 4-2, the total of the analytical
values of ammonia is 8.5 g/hr (=3.8+3.0+1.7), which is
substantially different from the supplied amount of 9.7 g/hr, and
the difference is remarkable as compared with other substances.
This is attributable mainly to the fact that a part of ammonia was
lost into a draft together with a non-condensed gas, and it was
evaporated during the sampling or during the preparation of the
standard solution for the analysis.
[0352] When it is considered that ammonium acetate and acetamide
remaining in the bottom (withdrawn from the column bottom) were not
decomposed and distilled, it is apparent that 51.3% of ammonia
supplied as ammonium acetate was distilled off or separated as a
non-condensed gas, and at the same time, it was possible to obtain
acetic acid having an unbelievably low water content and aqueous
ammonia containing no acetic acid, by a distillation column having
only 20 plates.
Test Example 4-3
[0353] Using the test apparatus as shown in FIG. 6, a test was
carried out in the same manner as in Test Example 4-2 except that
as the feed material, ammonium acetate, sodium acetate and
potassium acetate were used, and the amount of the charge of the
feed material and the operation conditions were changed.
[0354] The charge was 250 g of ammonium acetate, 150.0 g of
potassium acetate and 250.0 g of deionized water, and it was
preheated to 90.degree. C. To the column bottom flask, for startup,
30.04 g of ammonium acetate, 20.28 g of potassium acetate and 70.27
g of acetic acid were charged.
[0355] When the internal temperature of the column bottom flask
became 120.degree. C., the feed material was supplied from the
column top at a flow rate of 150 cc/hr. At that time, the
temperature of the preheater was 110.degree. C.
[0356] After an operation for 59 minutes from the initiation of the
supply of the feed material, 65.7 g of the distillate and 133.4 g
of the bottom in the flask were taken out as the first withdrawal.
After an operation for further 40 minutes, 43.5 g of the distillate
and 76.2 g of the bottom in the flask were taken out as the second
withdrawal.
[0357] Thereafter, a steady state was assumed.
[0358] Further, after an operation for 40 minutes, 42.6 g of the
distillate and 68.5 g of the bottom in the flask were taken out as
the first analytical samples. After an operation for further 40
minutes, 43.5 g of the distillate and 68.1 g of the bottom in the
flask were taken out as the second analytical samples.
[0359] The compositions of the respective analytical samples were
as shown in Table 4-3.
TABLE-US-00019 TABLE 4-3 Composition (wt %) Analytical Acetic
samples acid Ammonia Acetamide K Water First Distillate 0.3 7.1
Rest (42.6 g) Bottom 69.6 2.1 5.3 17.7 5.5 (68.5 g) (calculated
value) Second Distillate 0.3 8.7 Rest (43.5 g) Bottom 68.3 2.1 5.0
17.5 7.1 (68.1 g) (calculated value)
[0360] As is apparent from Table 4-3, there is no substantial
difference in the composition between the first and second
analytical samples, and the operation can be regarded as
substantially steady. On the basis that the operation is
substantially in a steady state, if the composition of the supplied
feed material and the composition of the second analytical samples
are compared, the mass balance will be as shown in the following
Table 4-4. Here, the supplied material of 150 cc/hr was converted
to a unit of g/hr by using the specific gravity of the feed
material being 1.14.
[0361] Further, the amount of the acetamidated ammonia was obtained
by calculation as follows. Namely, as shown in Table 4-3, acetamide
in the bottom was 5.0 wt %, which was calculated as ammonia by
molar amount, which was converted to a weight to obtain 1.0 g.
TABLE-US-00020 TABLE 4-4 Distillate Bottom (excluding (withdrawn
non- from the Supplied condensed column amount gas) bottom)
Acetamidated Components (g/hr) (g/hr) (g/hr) ammonia Acetic 50.6
0.1 46.5 -- acid Water 44.2 39.7 4.8 -- Ammonia 9.7 3.8 1.4 1.0 K
8.0 0.0 11.9 --
[0362] As is apparent from Table 4-4, the total of the analytical
values of ammonia is 6.2 g/hr (=3.8+1.4+1.0), which is
substantially different from the supplied amount of 9.7 g/hr. Like
in the case of Test Example 4-2, this is attributable mainly to the
fact that a part of ammonia was lost into a draft together with a
non-condensable gas, and it was evaporated during the sampling or
during the preparation of the standard solution for the analysis.
The reason for the substantial difference in the amount of
potassium is not clear.
[0363] When it is considered that ammonium acetate and acetamide
remaining in the bottom (withdrawn from the column bottom) were not
decomposed and distilled, it is apparent that 75.4% of ammonia
supplied as ammonium acetate was distilled off or separated as a
non-condensable gas, and at the same time, it was possible to
obtain acetic acid having an unbelievably low water content and
aqueous ammonia containing no acetic acid by a distillation column
having only 20 plates.
Test Example 4-4
[0364] Using the test apparatus as shown in FIG. 6, a test was
carried out in the same manner as in Test Example 4-2 except that
as the feed material, ammonium acetate and potassium acetate were
used, and the amount of the charge of the feed material and the
operation conditions were changed.
[0365] The charge was 250.1 g of ammonium acetate, 150.1 g of
potassium acetate and 160.0 g of deionized water, and it was
preheated to 90.degree. C. To the column bottom flask, for startup,
30.1 g of ammonium acetate, 20.1 g of potassium acetate and 70.0 g
of acetic acid were charged.
[0366] When the internal temperature of the column bottom flask
became 138.4.degree. C., the feed material was supplied from the
column top at a flow rate of 174 cc/hr. At that time, the
temperature of the preheater was 109.5.degree. C.
[0367] After an operation for 22 minutes from the initiation of the
supply of the feed material, 19.1 g of the distillate and 95.0 g of
the bottom in the flask were taken out as the first withdrawal.
After an operation for further 37 minutes, 32.0 g of the distillate
and 90.4 g of the bottom in the flask were taken out as the second
withdrawal.
[0368] Thereafter, a steady state was assumed.
[0369] Further, after an operation for 35 minutes, 22.8 g of the
distillate and 74.6 g of the bottom in the flask were taken out as
the first analytical samples. After an operation for further 34
minutes, 28.4 g of the distillate and 77.7 g of the bottom in the
flask were taken out as the second analytical samples.
[0370] The compositions of the respective analytical samples were
as shown in Table 4-5.
TABLE-US-00021 TABLE 4-5 Composition (wt %) Analytical Acetic
samples acid Ammonia Acetamide K Water First Distillate 1.3 5.8 0.0
93.0 (22.8 g) Bottom 68.5 2.6 4.2 16.6 8.1 (74.6 g) Second
Distillate 1.1 7.5 0.0 91.4 (28.4 g) Bottom 68.8 2.2 3.2 18.6 7.1
(77.7 g)
[0371] As is apparent from Table 4-5, there is no substantial
difference in the composition between the first and second
analytical samples, and the operation can be regarded as
substantially steady. On the basis that the operation was
substantially in a steady state, if the composition of the supplied
feed material and the composition of the second analytical samples
are compared, the mass balance will be as shown in the following
Table 4-6. Here, the supplied material of 174 cc/hr was converted
to a unit of g/hr by using the specific gravity of the feed
material being 1.18.
[0372] Further, the amount of the acetamidated ammonia was obtained
by calculation as follows. Namely, as shown in Table 4-5, acetamide
in the bottom was 2.2 wt %, which was calculated as ammonia by
molar amount, which was converted to a weight to obtain 0.72 g.
TABLE-US-00022 TABLE 4-6 Distillate Bottom (excluding (withdrawn
non- from the Supplied condensed column amount gas) bottom)
Acetamidated Components (g/hr) (g/hr) (g/hr) ammonia Acetic 59.4
0.32 53.5 acid Water 33.1 25.9 5.5 Ammonia 11.4 2.1 1.7 0.72 K 9.2
0.0 14.4
[0373] As is apparent from Table 4-6, the total of the analytical
values of ammonia is 4.5 g/hr (=2.1+1.7+0.7), which is
substantially different from the supplied amount of 11.4 g/hr. Like
in Test Example 4-2, this is attributable mainly to the fact that a
part of ammonia was lost into a draft together with a
non-condensable gas, and it was evaporated during the sampling or
during the preparation of the standard solution for the analysis.
The reason for the large difference in the amount of potassium is
unclear.
[0374] When it is considered that ammonium acetate and acetamide
remaining in the bottom (withdrawn from the column bottom) were not
decomposed and distilled, it is apparent that 78.7% of ammonia
supplied as ammonium acetate, was distilled off or separated as a
non-condensable gas, and at the same time, it was possible to
obtain acetic acid having an unbelievably low water content and
aqueous ammonia containing no acetic acid by a distillation column
having only 20 plates.
Test Example 4-5
[0375] Using the test apparatus as shown in FIG. 6, a test was
carried out in the same manner as in Test Example 4-2 except that
as the feed material, ammonium acetate and potassium acetate were
used, and the amount of the charge of the feed material and the
operation conditions were changed.
[0376] The charge was 250.1 g of ammonium acetate, 150.1 g of
potassium acetate and 150.0 g of deionized water, and it was
preheated to 90.degree. C. In the column bottom flask, for startup,
30.1 g of ammonium acetate, 20.0 g of potassium acetate and 70.1 g
of acetic acid were charged.
[0377] Upon expiration of 21 minutes from the initiation of the
temperature raising, the feed material was supplied from the column
top at a flow rate of 160.0 cc/hr. 11 Minutes later, the first
distillate was obtained, and the internal temperature of the column
bottom flask at that time was 137.2.degree. C., and the temperature
of the preheater was 108.5.degree. C.
[0378] After an operation for 19 minutes from the initiation of the
supply of the feed material, 10.7 g of the distillate and 102.8 g
of the bottom in the flask were taken out as the first withdrawal.
After an operation for further 30 minutes, 31.1 g of the distillate
and 79.8 g of the bottom in the flask were taken out as the second
withdrawal.
[0379] Thereafter, a steady state was assumed.
[0380] Further, after an operation for 37 minutes, 31.8 g of the
distillate and 76.9 g of the bottom in the flask were taken out as
the first analytical samples. After an operation for further 38
minutes, 31.1 g of the distillate and 79.4 g of the bottom in the
flask were taken out as the second analytical samples.
[0381] The compositions of the respective analytical samples were
as shown in Table 4-7.
TABLE-US-00023 TABLE 4-7 Composition (wt %) Analytical Acetic
samples acid Ammonia Acetamide K Water First Distillate 1.2 9.3 0.0
89.5 (31.8 g) Bottom 70.0 3.2 4.8 16.0 6.0 (76.9 g) Second
Distillate 1.1 8.3 0.0 90.6 (31.1 g) Bottom 69.2 2.7 4.6 17.5 6.0
(79.4 g)
[0382] As is apparent from Table 4-7, there is no substantial
difference in the composition between the first and second
analytical samples, and the operation can be regarded as
substantially steady. On the basis that the operation was
substantially in a steady state, if the composition of the supplied
feed material and the composition of the second analytical samples
are compared, the mass balance will be as shown in the following
Table 4-8. Here, the supplied feed material of 160.0 cc/hr was
converted to a unit of g/hr by using the specific gravity of the
feed material being 1.20.
[0383] Further, the amount of the acetamidated ammonia was obtained
by calculation as follows. Namely, as shown in Table 4-7, acetamide
in the bottom was 2.2 wt %, which was calculated as ammonia by
molar amount, which was converted to a weight to obtain 1.05 g.
TABLE-US-00024 TABLE 4-8 Distillate Bottom (excluding (withdrawn
non- from the Supplied condensed column amount gas) bottom)
Acetamidated Components (g/hr) (g/hr) (g/hr) ammonia Acetic 61.0
0.35 55.0 acid Water 31.9 28.2 4.7 Ammonia 11.7 2.6 2.1 1.05 K 9.3
0.0 13.9
[0384] As is apparent from Table 4-8, the total of the analytical
values of ammonia is 5.6 g/hr (=2.6+2.1+1.1), which is
substantially different from the supplied amount of 11.7 g/hr. Like
in the case of Test Example 4-2, this is attributable mainly to the
fact that a part of ammonia was lost into a draft together with a
non-condensable gas, and it was evaporated during the sampling or
during the preparation of the standard solution for the analysis.
The reason for the large difference in the amount of potassium is
unclear.
[0385] When it is considered that ammonium acetate and acetamide
remaining in the bottom (withdrawn from the column bottom) were not
decomposed and distilled, it is apparent that 72.8% of ammonia
supplied as ammonium acetate was distilled off or separated as a
non-condensable gas, and at the same time, it was possible to
obtain acetic acid having an unbelievably low water content and
aqueous ammonia containing no acetic acid by a distillation column
having only 20 plates.
Comparative Test Example 4-1
[0386] 15.23 g (0.198 mol) of ammonium acetate, 15.21 g (0.185 mol)
of sodium acetate, 5.02 g (0.051 mol) of potassium acetate and
50.01 g of deionized water, were put into a 200 ml flask and
installed in a simple distillation apparatus. This was immersed in
an oil bath heated to 180.degree. C. When the liquid temperature in
the flask became 180.degree. C., distillation started. When the
liquid temperature in the flask became 150.degree. C., heating was
stopped, and the distillate and the bottom were sampled. The
distillation time was 63 minutes. The amount of the distillate was
53.18 g, and the amount of the bottom was 30.28 g. Precipitation
started in about 30 minute from the first distillation, whereby it
was impossible to measure the pH.
[0387] Acetic acid contained in the distillate was 5.47 wt % (0.049
mol), and ammonia was 2.98 wt % (0.093 mol). Acetic acid contained
in the bottom was 79.32 wt % (0.400 mol), and ammonia was 0.64 wt
%.
[0388] If acetic acid present in the form of an alkali metal salt
(0.236 mol; from the charged amount) is excluded, it will be 0.164
mol, which indicates that acetic acid in an amount of 24.7% of the
ammonium acetate (0.198 mol; from the charged amount) which should
be decomposed, was distilled off. A part of ammonia was discharged
without being condensed, which is the reason for the unbalance.
Comparative Test Example 4-2
[0389] 15.22 g (0.198 mol) of ammonium acetate, 10.00 g (0.102 mol)
of potassium acetate and 50.05 g of deionized water were put into a
200 ml flask and installed in a simple distillation apparatus. This
was immersed in an oil bath heated to 180.degree. C. When the
liquid temperature in the flask became 106.degree. C., distillation
started. When the liquid temperature in the flask became
150.degree. C., heating was stopped, and the distillate and the
bottom were sampled. The distillation time was 51 minutes. The
amount of the distillate was 53.19 g, and the amount of the bottom
was 20.26 g. Precipitation started immediately after the sampling,
whereby it was impossible to measure the pH.
[0390] Acetic acid contained in the distillate was 5.05 wt % (0.045
mol), and ammonia was 3.22 wt % (0.101 mol). Acetic acid contained
in the bottom was 76.51 wt % (0.258 mol), and ammonia was not
detected.
[0391] If acetic acid present in the form of an alkali metal salt
(0.102 mol; from the charged amount) is excluded, it will be 0.156
mol, which indicates that acetic acid in an amount of 22.7% of the
ammonium acetate (0.198 mol; from the charged amount) which should
be decomposed, was distilled. A part of ammonia was discharged
without being condensed, which is the reason for the unbalance.
Comparative Test Example 4-3
[0392] 15.20 g (0.197 mol) of ammonium acetate, 5.00 g (0.061 mol)
of sodium acetate, 15.00 g (0.153 mol) of potassium acetate and
50.04 g of deionized water, were put into a 200 ml flask and
installed in a simple distillation apparatus. This was immersed in
an oil bath heated to 180.degree. C. When the liquid temperature in
the flask became 108.degree. C., distillation started. When the
liquid temperature in the flask became 150.degree. C., heating was
stopped, and the distillate and the bottom were sampled. The
distillation time was 41 minutes. The amount of the distillate was
52.32 g, and the amount of the bottom was 31.32 g. Precipitation
started immediately after the sampling, whereby it was impossible
to measure the pH.
[0393] Acetic acid contained in the distillate was 5.72 wt % (0.050
mol), and ammonia was 3.68 wt % (0.113 mol). Acetic acid contained
in the bottom was 72.21 wt % (0.377 mol), and ammonia was not
detected.
[0394] If acetic acid present in the form of an alkali metal salt
(0.214 mol; from the charged amount) is excluded, it will be 0.163
mol, which indicates that acetic acid in an amount of 25.4% of the
ammonium acetate (0.197 mol; from the charged amount) which should
be decomposed, was distilled. A part of ammonia was discharged
without being condensed, which is the reason for the unbalance.
Comparative Test Example 4-4
[0395] 15.20 g (0.197 mol) of ammonium acetate, 10.02 g (0.102 mol)
of potassium acetate and 15.27 g of deionized water were put into a
200 ml flask and installed in a simple distillation apparatus. This
was immersed in an oil bath heated to 180.degree. C. When the
liquid temperature in the flask became 116.degree. C., distillation
started. When the liquid temperature in the flask became
150.degree. C., heating was stopped, and the distillate and the
bottom were sampled. The distillation time was 23 minutes. The
amount of the distillate was 16.65 g, and the amount of the bottom
was 21.76 g. Precipitation started immediately after the sampling,
whereby it was impossible to measure the pH.
[0396] Acetic acid contained in the distillate was 8.43 wt % (0.023
mol), and ammonia was 7.00 wt % (0.069 mol). Acetic acid contained
in the bottom was 75.62 wt % (0.274 mol), and ammonia was 2.13 wt %
(0.027 mol).
[0397] If acetic acid present in the form of an alkali metal salt
(0.102 mol; from the charged amount) is excluded, it will be 0.172
mol, which indicates that acetic acid in an amount of 11.7% of the
ammonium acetate (0.197 mol; from the charged amount) which should
be decomposed, was distilled. A part of ammonia was discharged
without being condensed, which is the reason for the unbalance.
Comparative Test Example 4-5
[0398] 15.20 g (0.197 mol) of ammonium acetate, 10.01 g (0.122 mol)
of potassium acetate and 15.19 g of deionized water were put into a
200 ml flask and installed in a simple distillation apparatus. This
was immersed in an oil bath heated to 180.degree. C. When the
liquid temperature in the flask became 116.degree. C., distillation
started. When the liquid temperature in the flask became
135.degree. C., precipitation of solid was observed. When the
liquid temperature in the flask became 150.degree. C., heating was
stopped, and the distillate and the bottom were sampled. The
distillation time was 23 minutes. The amount of the distillate was
17.17 g, and the amount of the bottom was 21.25 g. Precipitation
started, whereby it was impossible to measure the pH.
[0399] Acetic acid contained in the distillate was 11.33 wt %
(0.0.32 mol), and ammonia was 6.02 wt % (0.061 mol). Acetic acid
contained in the bottom was 83.97 wt % (0.297 mol), and ammonia was
2.13 wt % (0.027 mol).
[0400] If acetic acid present in the form of an alkali metal salt
(0.122 mol; from the charged amount) is excluded, it will be 0.175
mol, which indicates that acetic acid in an amount of 16.2% of the
ammonium acetate (0.197 mol; from the charged amount) which should
be decomposed, was distilled. A part of ammonia was discharged
without being condensed, which is the reason for the unbalance.
INDUSTRIAL APPLICABILITY
[0401] According to the present invention, as is unexpected from
the conventional acid/base reaction, it is possible to obtain free
organic acid A in solid form, from an ammonium salt of organic acid
A having a high melting point, such as a dicarboxylic acid, a
tricarboxylic acid or an amino acid, produced by bioconversion of a
biogenic carbon source, by reactive precipitation utilizing an
acid/base reaction employing weak acid B such as a monocarboxylic
acid which is a weaker acid than the organic acid A.
[0402] Further, it is possible to recover organic acid A and its
ammonium salt by vaporizing and efficiently separating acid B such
as a monocarboxylic acid and an ammonium salt of acid B such as an
ammonium salt of a monocarboxylic acid, from the crystallization
mother liquor after precipitating and separating organic acid A by
reactive crystallization. It is possible to increase the efficiency
for separation and recovery of the respective substances by
preventing side reactions in this vaporization operation. It is
possible to recycle and reuse the separated acid B, organic acid A
and its ammonium salt, without requiring a cumbersome
operation.
[0403] Further, a method is presented wherein the separated
ammonium salt of acid B such as an ammonium salt of a
monocarboxylic acid, is decomposed into acid B such as a
monocarboxylic acid and ammonia by means of an alkali metal or
alkaline earth metal salt. At that time, it is possible to readily
separate water present in the reaction system and acid B such as a
monocarboxylic acid and to efficiently recover acid B having a low
water content and aqueous ammonia containing no such acid.
[0404] The entire disclosures of Japanese Patent Application No.
2002-135656 filed on May 10, 2002, Japanese Patent Application No.
2002-231740 filed on Aug. 8, 2002, Japanese Patent Application No.
2002-231741 filed on Aug. 8, 2002 and Japanese Patent Application
No. 2002-305989 filed on Oct. 21, 2002 including specifications,
claims, drawings and summaries are incorporated herein by reference
in their entireties.
* * * * *