U.S. patent application number 10/573327 was filed with the patent office on 2008-11-06 for method for producing cyclododecanone.
This patent application is currently assigned to BASF Aktiengesellschaft. Invention is credited to Thomas Genger, Rolf Pinkos, Thomas Preiss, Beatrice Rossler, Joaquim Henrique Teles.
Application Number | 20080275276 10/573327 |
Document ID | / |
Family ID | 34384285 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080275276 |
Kind Code |
A1 |
Teles; Joaquim Henrique ; et
al. |
November 6, 2008 |
Method for Producing Cyclododecanone
Abstract
A process for preparing cyclododecanone by reacting
cyclododecene with dinitrogen monoxide, comprising in particular
steps (I) and (II): (I) preparing cyclododecene by partially
hydrogenating cyclododecatriene; (II) reacting cyclododecene
obtained in (I) with dinitrogen monoxide to obtain
cyclododecanone.
Inventors: |
Teles; Joaquim Henrique;
(Otterstadt, DE) ; Rossler; Beatrice; (Bad
Durkheim, DE) ; Pinkos; Rolf; (Bad Durkheim, DE)
; Genger; Thomas; (Lambsheim, DE) ; Preiss;
Thomas; (Weisenheim am Sand, DE) |
Correspondence
Address: |
CONNOLLY BOVE LODGE & HUTZ, LLP
P O BOX 2207
WILMINGTON
DE
19899
US
|
Assignee: |
BASF Aktiengesellschaft
Ludwigshafen
DE
|
Family ID: |
34384285 |
Appl. No.: |
10/573327 |
Filed: |
September 23, 2004 |
PCT Filed: |
September 23, 2004 |
PCT NO: |
PCT/EP2004/010680 |
371 Date: |
July 16, 2008 |
Current U.S.
Class: |
568/363 |
Current CPC
Class: |
C07C 2601/20 20170501;
C07C 45/28 20130101; C07C 45/28 20130101; C07C 49/413 20130101 |
Class at
Publication: |
568/363 |
International
Class: |
C07C 45/28 20060101
C07C045/28 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2003 |
DE |
103 44 594.3 |
Claims
1. A process for preparing cyclododecanone by reacting
cyclododecene with dinitrogen monoxide.
2. A process as claimed in claim 1, wherein the dinitrogen monoxide
source is at least one dinitrogen monoxide-containing offgas of at
least one industrial process.
3. A process as claimed in claim 2, wherein the dinitrogen monoxide
source is the offgas of an adipic acid plant and/or of a
dodecanedioic acid plant and/or of a hydroxylamine plant and/or of
a nitric acid plant operated with the offgas of an adipic acid
plant and/or of a dodecanedioic acid plant and/or of a
hydroxylamine plant.
4. A process as claimed in any of claims 1 to 3, wherein
cyclododecene is reacted with a gas mixture containing from 20 to
99.9% by weight of dinitrogen monoxide, based on the total weight
of the gas mixture.
5. A process as claimed in any of claims 1 to 4, wherein dinitrogen
monoxide or the gas mixture containing dinitrogen monoxide is used
in liquid form.
6. A process as claimed in any of claims 1 to 5, wherein the
reaction is carried out continuously in at least one tubular
reactor at a temperature in the range from 140 to 350.degree.
C.
7. A process as claimed in any of claims 1 to 6, wherein a mixture
comprising cis-cyclododecene and trans-cyclododecene is reacted
with dinitrogen monoxide in two stages.
8. A process as claimed in claim 7, wherein the reaction in the
first stage is carried out at a temperature in the range from 140
to 300.degree. C. and the reaction in the second stage at a
temperature in the range from 165 to 325.degree. C., the
temperature in the first stage being lower than the temperature in
the second stage.
9. A process as claimed in any of claims 1 to 8, wherein the
cyclododecene is obtained from the catalytic hydrogenation of at
least one cyclododecatriene.
10. A process as claimed in claim 9, wherein cyclododecatriene is
hydrogenated to cyclododecene and cyclododecene is converted to
cyclododecanone using dinitrogen monoxide in the presence of the
same catalyst.
11. A process as claimed in claim 10, wherein the reactant used for
the reaction with dinitrogen monoxide is a mixture which results
from the hydrogenation of cyclododecatriene to cyclododecene in the
presence of a homogeneous catalyst and comprises cyclododecene and
homogeneous catalysts.
12. A process for preparing cyclododecanone, which comprises steps
(I) and (II): (I) preparing cyclododecene by partially
hydrogenating cyclododecatriene; (II) reacting cyclododecene
obtained in (I) with dinitrogen monoxide to obtain
cyclododecanone.
13. A process as claimed in claim 12, wherein the source used for
the dinitrogen monoxide used in (II) is at least one offgas
comprising dinitrogen monoxide from at least one industrial
process.
14. A process as claimed in claim 13, wherein the dinitrogen
monoxide source is the offgas of an adipic acid plant and/or of a
dodecanedioic acid plant and/or of a hydroxylamine plant and/or of
a nitric acid plant operated with the offgas of an adipic acid
plant and/or of a dodecanedioic acid plant and/or of a
hydroxylamine plant.
15. A process as claimed in any of claims 12 to 14, wherein
cyclododecene is reacted in (II) with a gas mixture containing from
20 to 99.9% by weight of dinitrogen monoxide, based on the total
weight of the gas mixture.
16. A process as claimed in any of claims 12 to 15, wherein the
dinitrogen monoxide or the gas mixture containing dinitrogen
monoxide is used in liquid form.
17. A process as claimed in any of claims 12 to 16, wherein the
reaction is carried out in (II) continuously in at least one
tubular reactor at a temperature in the range from 140 to
350.degree. C.
18. A process as claimed in any of claims 12 to 17, wherein a
mixture comprising cis-cyclododecene and trans-cyclododecene is
reacted in (II) with dinitrogen monoxide in two stages.
19. A process as claimed in claim 18, wherein the reaction in the
first stage is carried out at a temperature in the range from 140
to 300.degree. C. and the reaction in the second stage at a
temperature in the range from 165 to 325.degree. C., the
temperature in the first stage being lower than the temperature in
the second stage.
20. A process as claimed in any of claims 12 to 19, wherein
cyclododecatriene is partially hydrogenated to cyclododecene in (I)
and cyclododecene is converted to cyclododecanone using dinitrogen
monoxide in (II) in the presence of the same catalyst.
21. A process as claimed in claim 20, wherein the reactant used for
the reaction with dinitrogen monoxide in (II) is a mixture which
results from the partial hydrogenation of cyclododecatriene to
cyclododecene in the presence of a homogeneous catalyst in (I) and
comprises cyclododecene and homogeneous catalyst.
Description
[0001] The present invention relates to a process for preparing
cyclododecanone from cyclododecene, wherein cyclododecene is
oxidized to cyclododecanone by reacting with dinitrogen monoxide.
In a preferred embodiment, the present invention relates to a
two-stage process, wherein cyclododecatriene is converted to
cyclododecene by partial hydrogenation and the resulting
cyclododecene is oxidized to cyclododecanone by reacting with
dinitrogen monoxide.
[0002] Cyclododecanone is an important intermediate for the
preparation of, for example, laurolactam, dodecanedioic acid and
polyamides derived therefrom, for example nylon-12 or
nylon-6,12.
[0003] Cyclododecanone is prepared in the common industrial process
by air oxidation of cyclododecane in the presence of boric acid to
give cyclododecyl borate, hydrolysis of the borate to give
cyclododecanol and subsequent de hydrogenation of the
cyclododecanol. Cyclododecane itself is also obtained by fully
hydrogenating cyclododecatriene (CDT). One description of this
industrial process for synthesizing cyclododecanone can be found in
T. Schiffer, G. Oenbrink, "Cyclododecanol, Cyclododecanone and
Laurolactam" in Ullmann's Encyclopedia of Industrial Chemistry, 6th
Edition, 2000, Electronic Release, Wiley VCH.
[0004] However, the industrial process mentioned has a series of
disadvantages.
[0005] First, the oxidation of cyclododecane with oxygen only
ensures acceptable selectivity at low conversions. Even with the
addition of boric acid, which protects the cyclododecanol formed
from further oxidation in the form of boric ester, the
cyclododecane conversion must not be above 30%. After the
oxidation, the boric esters have to be hydrolyzed in a separate
step, and both the boric acid and the unconverted cyclododecane
have to be recycled into the oxidation. Additionally, boron
containing waste products are formed, which are difficult to
dispose. The main products formed are cyclododecanol and
cyclododecanone in a ratio of 10:1.
[0006] Secondly, the mixture of cyclododecanol and cyclododecanone
which is formed has to be separated by distillation and the
cyclododecanol has to be converted to cyclododecanone by
dehydrogenation. This dehydrogenation is endothermic and likewise
affords only partial conversion. The unconverted cyclododecanol
then in turn has to be removed by distillation and recycled into
the process.
[0007] As a consequence of the incomplete conversion, the
conventional process includes several large recycle streams and a
series of technically costly and inconvenient distillative
separations.
[0008] It is an object of the present invention to provide a novel
process for preparing cyclododecanone.
[0009] We have found that this object is achieved by a process in
which cyclododecene is converted to cyclododecanone using
dinitrogen monoxide as an oxidant. In particular, we have found
that this object is achieved by a process in which cyclododecene is
prepared from cyclododecatriene in one step by partial
hydrogenation and cyclododecene is converted to cyclododecanone in
a further step using dinitrogen monoxide as an oxidant. In the
process according to the invention, pure cyclododecene or a mixture
comprising cyclododecene, and pure dinitrogen monoxide or a mixture
comprising dinitrogen monoxide may be used. Moreover, cyclododecene
may be present as the cis-isomer or as the trans-isomer or as a
mixture of cis- and trans-isomer.
[0010] The oxidation of an olefinic compound to an aldehyde or a
ketone by means of dinitrogen monoxide is described, for example,
in GB 649,680 or in the equivalent U.S. Pat. No. 2,636,898.
However, the cyclic olefinic compounds described there are only
cyclopentene, cyclohexene and cyclooctene. In both documents, it is
quite generally disclosed that the oxidation may in principle
proceed in the presence of a suitable oxidation catalyst.
[0011] The more recent scientific articles of G. L. Panov et al.,
"Non-Catalytic Liquid Phase Oxidation of Alkenes with Nitrous
Oxide. 1. Oxidation of Cyclohexene to Cyclohexanone", React. Kinet.
Catal. Lett. Vol. 76, No. 2 (2002) p. 401-405, and K. A. Dubkov et
al., "Non-Catalytic Liquid Phase Oxidation of Alkenes with Nitrous
Oxide. 2. Oxidation of Cyclopentene to Cyclopentanone", React.
Kinet. Catal. Lett. Vol. 77, No. 1 (2002) p. 197-205 likewise
describes oxidations of olefinic compounds with dinitrogen
monoxide. However, the disclosures on this subject are restricted
exclusively to cyclopentene and cyclohexene.
[0012] Also, the scientific article "Liquid Phase Oxidation of
Alkenes with Nitrous Oxide to Carbonate Compounds" of E. V.
Starokon et al. in "Advanced Synthetic Catalysis" 2004, 346,
268-274 gives a mechanistic study of the oxidation of alkenes with
dinitrogen monoxide in the liquid phase.
[0013] The present invention therefore relates to a process for
preparing cyclododecanone by reacting cyclododecene with dinitrogen
monoxide.
[0014] The dinitrogen monoxide used for the reaction may in
principle be used in pure form or in the form of a suitable gas
mixture comprising dinitrogen monoxide. Moreover, the dinitrogen
monoxide may in principle stem from any desired source.
[0015] The term "gas mixture" as used in the context of the present
invention refers to a mixture of two or more compounds which are in
the gaseous state at ambient pressure and ambient temperature. The
gas mixture can also have another aggregation with varying
temperature or varying pressure, for example a liquid or
hypercritic condition, preferably liquid, and is still classified
as a gas mixture in the context of the present invention.
[0016] When a gas mixture is used, its dinitrogen monoxide content
is essentially arbitrary, as long as it is ensured that the
reaction according to the invention is possible.
[0017] In a preferred embodiment of the process according to the
invention, a gas mixture containing at least 10% by volume of
dinitrogen monoxide is used, and the dinitrogen monoxide content in
the mixtures is preferably in the range from 20 to 99.9% by volume,
more preferably in the range from 40 to 99.5% by volume, more
preferably in the range from 60 to 99.5% by volume and especially
preferably in the range from 80 to 99.5% by volume.
[0018] In the context of the present invention the composition of
the gas mixtures is given in volume percent. All values given refer
to the composition of the gas mixture at ambient pressure and
ambient temperature.
[0019] The term "gas mixture" as used in the context of the present
invention also refers to gas mixtures which, in addition to
dinitrogen monoxide, contain at least one further component,
preferably one further gas. The component can also be a gas which
is for example liquid under the conditions chosen. In this context,
essentially all gases are conceivable, as long as it is ensured
that the reaction of cyclododecene with dinitrogen monoxide is
possible. Preference is accordingly given in particular to gas
mixtures which, in addition to dinitrogen monoxide, contain at
least one inert gas. The term "inert gas" as used in the context of
the present invention refers to a gas which behaves inertly with
regard to the reaction of dinitrogen monoxide with cyclododecene.
Useful inert gases are, for example, nitrogen, carbon dioxide,
carbon monoxide, hydrogen, water, argon, methane, ethane and
propane.
[0020] Equally, the gas mixture may also include components,
preferably gases which do not behave as inert components,
preferably as inert gases in the reaction of N.sub.2O with
cyclododecene. Useful such gases include NO.sub.x or, for example,
oxygen. The term "NO.sub.x" as used in the context of the present
invention relates to all compounds N.sub.aO.sub.b except N.sub.2O,
wherein a is 1 or 2 and b is a number from 1 to 6. Instead of the
term "NO.sub.x", the term "nitrogen oxides" is also used in the
context of the present invention. In such a case, preference is
given to using those gas mixtures whose content of these gases is
in the range from 0 to 0.5% by volume, based on the total volume of
the gas mixture.
[0021] Accordingly, the present invention also describes a process
as described above, wherein the gas mixture contains from 0 to 0.5%
by volume of oxygen or from 0 to 0.5% by volume of nitrogen oxides
or both from 0 to 0.5% by volume of oxygen and from 0 to 0.5% by
volume of nitrogen oxides, based in each case on the total volume
of the gas mixture. In this context, a value of, for example, 0.5%
by volume relates to a total content of all possible nitrogen
oxides apart from N.sub.2O of 0.5% by volume.
[0022] In principle, the composition of the gas mixture can be
determined for every method known to the person skilled in the art
in the context of the present invention. In the context of the
present invention, the composition of the gas mixtures is
preferably determined by gas chromatography. It can also be
determined by UV-spectroscopy, IR-spectroscopy or by chemical
methods.
[0023] According to the present invention, dinitrogen monoxide or
the gas mixture containing dinitrogen monoxide can be used in every
form, in particular as a gas or in liquid form. Dinitrogen monoxide
or the gas mixture containing dinitrogen, monoxide can be
liquidified by all methods known to the person skilled in the art,
preferably by choosing a suitable pressure and a suitable
temperature.
[0024] According to the present invention, it is also possible that
dinitrogen monoxide or the gas mixture containing dinitrogen
monoxide is first absorbed in a suitable solvent and then added to
the reaction.
[0025] In a preferred embodiment of the present invention, the
dinitrogen monoxide source is at least one dinitrogen
monoxide-containing offgas of a chemical process. The scope of the
present invention also includes embodiments in which the dinitrogen
monoxide source used is at least two dinitrogen monoxide-containing
offgases of a single plant. Likewise included are embodiments in
which the dinitrogen monoxide source used is at least one
dinitrogen monoxide-containing offgas of one plant and at least one
further dinitrogen monoxide-containing offgas of at least one
further plant.
[0026] The present invention also relates to a process as described
above, wherein the dinitrogen monoxide source used is at least one
dinitrogen monoxide-containing offgas of at least one industrial
process.
[0027] In the context of the present invention, it is also possible
that dinitrogen monoxide used in the process according to the
invention is prepared for the process. Preference is given to the
preparation by thermal decomposition of NH.sub.4NO.sub.3 as
disclosed, for example, in U.S. Pat. No. 3,656,899 whose contents
on this subject is fully incorporated by reference into the context
of the present application. Likewise preferred is a preparation by
catalytic oxidation of ammonia, as disclosed for example in U.S.
Pat. No. 5,849,257 or in WO 98/25698, whose contents on this
subject are fully incorporated by reference into the context of the
present application.
[0028] In the context of the present invention, the term
"dinitrogen monoxide source" relates both to embodiments in which
the offgas mentioned is used in unmodified form in the inventive
conversion of cyclododecene, and embodiments in which at least one
of the offgases mentioned is subjected to a modification.
[0029] The term "modification" as used in this context within the
scope of the present invention relates to any suitable process by
which the chemical composition of an offgas is changed.
Accordingly, the term "modification" relates, among other
embodiments, to those in which a dinitrogen monoxide-containing
offgas is concentrated with respect to the dinitrogen monoxide
content in at least one suitable process. Such processes are
described, for example, in DE-A 27 32 267, EP 1 076 217 A2 or WO
00/73202 A1, whose contents on this subject are fully incorporated
by reference into the context of the present application.
[0030] In the context of the present invention, the gas mixture can
also be the subject of a modification to reduce the concentration
of inert or non-inert compounds in the gas mixture.
[0031] According to the present invention, this modification can
for example be an absorption of the gas mixture in a suitable
solvent and subsequent desorption to purify the gas mixture from
inert components. A suitable solvent for the absorption is, for
example, water, as disclosed in DT 20 40 219.
[0032] According to the present invention, the modification of the
gas mixture can also comprise a further purification step, for
example a step for separating of NO.sub.x from the gas mixture.
Suitable processes for separating of NO.sub.x are in principle
known from the state of the art. According to the present
invention, all processes for separating of NO.sub.x known to the
person skilled in the art can be used.
[0033] According to the invention, it is preferred that the
offgases are subjected to treatment comprising the absorption in a
suitable solvent and subsequent desorption to remove inert
compounds. A suitable solvent is, for example, water, as disclosed
in DT 20 40 219.
[0034] In an example of a preferred embodiment of the process
according to the invention, it is possible to concentrate the
abovementioned dinitrogen monoxide-containing offgas by feeding it
to at least one adsorption column and dissolving the dinitrogen
monoxide in at least one organic solvent. An example of a suitable
solvent for this purpose is cyclododecene. This inventive process
variant offers the advantage that the resulting solution of
dinitrogen monoxide in cyclododecene can be fed without further
workup to the conversion according to the invention. This solution
of dinitrogen monoxide in cyclododecene may contain dinitrogen
monoxide in all conceivable concentrations up to saturation. In
other embodiments, at least one further solvent or a mixture of
cyclododecene and at least one further solvent may be used for
adsorption. Such further solvents are, for example, all suitable
common organic solvents. Preferred solvents include
N-methylpyrrolidone, dimethylformamide, dimethyl sulfoxide,
propylene carbonate, sulfolane and N,N-dimethylacetamide. When at
least one further solvent or a mixture of cyclododecene and at
least one further solvent is used, a further preferred embodiment
involves at least partly preferably substantially fully obtaining
the dinitrogen monoxide from the solution enriched with dinitrogen
monoxide in at least one suitable desorption step, and feeding it
to the conversion according to the invention.
[0035] In a further embodiment, the chemical composition of an
offgas may also be changed by adding pure dinitrogen monoxide to
the offgas.
[0036] In a further preferred embodiment of the present invention,
the at least one dinitrogen monoxide-containing offgas stems from
an adipic acid plant, a dodecanedioic acid plant, a hydroxylamine
plant and/or a nitric acid plant, in which case the latter is in
turn preferably operated with at least one offgas of an adipic acid
plant, of a dodecanedioic acid plant or of a hydroxylamine
plant.
[0037] In a preferred embodiment, the offgas stream used is from an
adipic acid plant in which oxidation of cyclohexanol/cyclohexanone
mixtures with nitric acid generally forms from 0.8 to 1.0 mol of
N.sub.2O per mole of adipic acid formed. As described, for example,
in A. K. Uriarte et al., Stud. Surf. Sci. Catal. 130 (2000) p.
743-748, the offgases of adipic acid plants also contain, in
varying concentrations, further constituents including nitrogen,
oxygen, carbon dioxide, carbon monoxide, nitrogen oxides, water and
volatile organic compounds.
[0038] The abovementioned dodecanedioic acid plant is of a
substantially identical type of plant.
[0039] An example of a typical composition of an offgas of an
adipic acid plant or of a dodecanedioic acid plant is reproduced in
the following table:
TABLE-US-00001 Component Concentrations/% by weight NO.sub.x 19-25
N.sub.2O 20-28 N.sub.2 30-40 O.sub.2 7-10 CO.sub.2 2-3 H.sub.2O
~7
[0040] The offgas stream of an adipic acid plant or of a
dodecanedioic acid plant may be used directly in the process
according to the invention. Preference is given to cleaning the
offgas stream of the adipic acid plant or a dodecanedioic acid
plant before use for converting the cyclododecene. For example, it
is advantageous to adjust the oxygen and/or nitrogen oxide content
of the offgas stream to contents in the range of in each case from
0 to 0.5% by volume. The above-cited document of A. K. Uriarte et
al. discloses various possibilities of how such an offgas stream
can be cleaned for use in catalytic benzene hydroxylation. The
document describes absorption processes, for example pressure swing
absorption, membrane separation processes, low temperature
distillation or a combination of selective catalytic reduction with
ammonia followed by catalytic removal of oxygen. All of these
cleaning methods can also be applied in order to clean the
dinitrogen monoxide-containing offgas stream of an industrial
plant, for example of an adipic acid plant or of a dodecanedioic
acid plant or of a nitric acid plant. Very particular preference is
given to the distillative cleaning and therefore distillative
concentration of the offgas stream of an adipic acid plant or of a
dodecanedioic acid plant or of a nitric acid plant.
[0041] Particular preference is given in the context of the present
invention to purifying the offgas stream of an adipic acid plant or
of a dodecanedioic acid plant in the case that it contains in each
case more than 0.5% by volume of oxygen and/or nitrogen oxides.
[0042] Accordingly, the present invention also describes a process
as described above, wherein the cyclododecene is converted using
the offgas stream of an adipic acid plant or of a dodecanedioic
acid plant.
[0043] Accordingly, the present invention further describes a
process as described above, wherein the offgas stream, which has
preferably been distillatively cleaned if necessary, of the adipic
acid plant or of a dodecanedioic acid plant contains oxygen and/or
nitrogen oxides in the range of in each case from 0 to 0.5% by
volume.
[0044] In a likewise preferred embodiment, the offgas stream used
is of a nitric acid plant which is supplied, entirely or partly,
with offgases comprising dinitrogen monoxide and nitrogen oxides
from other processes. In such nitric acid plants, nitrogen oxides
are adsorbed and converted for the most part to nitric acid,
whereas dinitrogen monoxide is not converted. For example, such a
nitric acid plant may be supplied by nitrogen oxides which are
prepared by selective combustion of ammonia, and by offgases of an
adipic acid plant and/or by offgases of a dodecanedioic acid plant.
It is equally possible to supply such a nitric acid plant solely by
offgases of an adipic acid plant and/or by offgases of a
dodecanedioic acid plant.
[0045] The offgases of such nitric acid plants always contain
different concentrations of further constituents including
nitrogen, oxygen, carbon dioxide, carbon monoxide, nitrogen oxides,
water and volatile organic compounds.
[0046] An example of a typical composition of an offgas of such a
nitric acid plant is reproduced in the table which follows:
TABLE-US-00002 Component Concentrations/% by wt. NO.sub.x <0.1
N.sub.2O 8-36 N.sub.2 57-86 O.sub.2 3-9 CO.sub.2 1-4 H.sub.2O
~0.6
[0047] The offgas stream of a nitric acid plant may be used
directly in the process according to the invention. Preference is
given to purifying the offgas stream of the nitric acid plant
before using it to convert the cyclododecene. For example, it is
advantageous to adjust the content of oxygen and/or nitrogen oxides
in the offgas stream to contents in the range of in each case from
0 to 0.5% by volume. Suitable processes by which these values can
be attained are described above in the context of the adipic acid
plant and dodecanedioic acid plant. Very particular preference is
also given in the context of the offgases of the nitric acid plant
to distillatively purifying and therefore to distillatively
concentrating.
[0048] Particular preference is given in the context of the present
invention to purifying the offgas stream of a nitric acid plant in
the case that it contains in each case more than 0.5% by volume of
oxygen and/or nitrogen oxides.
[0049] The present invention accordingly also relates to a process
as described above, wherein the cyclododecene is converted using
the dinitrogen monoxide-containing offgas stream of a nitric acid
plant.
[0050] The present invention accordingly further relates to a
process as described above, wherein the offgas stream of the nitric
acid plant, which is preferably purified by distillation if
necessary, contains oxygen and/or nitrogen oxides in a range from 0
to 0.5% by volume.
[0051] In a likewise preferred embodiment of the process according
to the invention, the offgas stream of a hydroxylamine plant is
used, in which, for example, ammonia is initially oxidized with air
or oxygen to NO and small amounts of dinitrogen monoxide are
by-produced. The NO is subsequently hydrogenated with hydrogen to
give hydroxylamine. Since dinitrogen monoxide is inert under the
hydrogenation conditions, it accumulates in the hydrogen circuit.
In preferred process versions, the purge stream of a hydroxylamine
plant contains dinitrogen monoxide in the range from 9 to 13% by
volume in hydrogen. This purge stream may be used as such for the
conversion according to the invention. It is equally possible to
suitably concentrate this stream with respect to the dinitrogen
monoxide content as described above.
[0052] The present invention accordingly also relates to a process
as described above, wherein the dinitrogen monoxide source is the
offgas of an adipic acid plant and/or of a dodecanedioic acid plant
and/or of a hydroxylamine plant and/or of a nitric acid plant
operated with the offgas of an adipic acid plant and/or of a
dodecanedioic acid plant and/or of a hydroxylamine plant.
[0053] The present invention likewise relates to an integrated
process for preparing cyclododecanone, which comprises at least the
following steps (i) and (ii): [0054] (i) providing a dinitrogen
monoxide-containing gas mixture containing in each case from 0 to
0.5% by volume of oxygen and/or nitrogen oxides and based on at
least one offgas stream of at least one adipic acid plant and/or of
at least one dodecanedioic acid plant and/or of at least one
hydroxylamine plant and/or of at least one nitric acid plant
operated with the offgas of an adipic acid plant and/or of a
dodecanedioic acid plant and/or of a hydroxylamine plant; [0055]
(ii) reacting cyclododecene with the gas mixture provided in (i) to
obtain cyclododecanone.
[0056] It is equally possible in the context of the process
according to the invention to selectively prepare dinitrogen
monoxide for use in the process. Preference is given, inter alia,
to the preparation via the thermal decomposition of
NH.sub.4NO.sub.3, as described, for example, in U.S. Pat. No.
3,656,899, whose contents on this subject are fully incorporated by
reference into the context of the present application. Preference
is likewise also given to the preparation via the catalytic
oxidation of ammonia, as described, for example, in U.S. Pat. No.
5,849,257 or in WO 98/25698, whose contents on this subject are
fully incorporated by reference into the context of the present
application.
[0057] In the context of the inventive reaction of cyclododecene
with dinitrogen monoxide, at least one suitable solvent or diluent
may be used. These include cyclododecane or cyclododecanone,
although substantially all common solvents and/or diluents are
suitable, with the proviso that they have neither a C--C double
bond nor a C--C triple bond nor an aldehyde group.
[0058] In general, it is not necessary to add a solvent or diluent
in the inventive reaction with dinitrogen monoxide.
[0059] The reaction of cyclododecene with dinitrogen monoxide may
be carried out continuously or in batch mode, and combinations of
continuous and batch mode are also possible. Preference is given to
the continuous process version.
[0060] Useful reactors are all suitable reactors. For example, the
reaction of cyclododecene with dinitrogen monoxide or a dinitrogen
monoxide-containing gas mixture may be carried out in at least one
CSTR (Continuous Stirred Tank Reactor) having internal or external
heat exchanger, in at least one tubular reactor, in at least one
loop reactor or a combination of at least two of these reactors. It
is equally possible to configure at least one of these reactors in
such a way that it has at least two different zones. Such zones may
differ, for example, in reaction conditions, for example the
temperature or the pressure and/or in the geometry of the zone, for
example the volume or the cross section. Also conceivable is an
axial temperature profile which can be realized, for example, by
concurrent cooling and appropriate adjustment of the amount of
coolant.
[0061] Particular preference is given to carrying out the oxidation
of cyclododecene in at least one tubular reactor.
[0062] The present invention accordingly also relates to a process
as described above, wherein the reaction of cyclododecene with
dinitrogen monoxide is carried out in at least one tubular
reactor.
[0063] The conversion of cyclododecene is effected preferably at a
temperature in the range from 140 to 350.degree. C., more
preferably in the range from 200 to 325.degree. C. and most
preferably in the range from 225 to 300.degree. C.
[0064] The present invention accordingly also relates to a process
as described above, wherein the reaction is carried out
continuously in at least one tubular reactor at a temperature in
the range from 140 to 350.degree. C.
[0065] The pressure in the reaction vessel, preferably in at least
one tubular reactor, is generally at values which are greater than
or equal to, preferably greater than, the autogenous pressure of
the reactant mixture or of the product mixture at the selected
reaction temperature or the selected reaction temperatures in the
reaction vessel. In general, the reaction pressures are in the
range from 1 to 14,000 bar, preferably in the range from autogenous
pressure to 3000 bar, more preferably in the range from autogenous
pressure to 1000 bar and especially preferably in the range from
autogenous pressure to 500 bar.
[0066] The residence time of the reactants in the reactor is
generally up to 30 h, preferably in the range from 0.1 to 30 h,
more preferably in the range from 0.25 to 25 h, more preferably in
the range from 0.3 to 20 h and especially preferably in the range
from 0.5 to 20 h.
[0067] The molar ratio of the reactants, dinitrogen monoxide
cyclododecene, is generally up to 5:1, preferably in the range from
1:1 to 4:1, more preferably in the range from 1:1 to 3:1 and
particularly preferably in the range from 1.01:1 to 2:1. According
to an alternative embodiment of the present invention, the molar
ratio is for example in the range from 0.5 to 5, particularly from
0.07 to 2, preferably from 0.1 to 2, especially preferably from 0.1
to 1.
[0068] Particular preference is given to selecting the reaction
conditions in such a way that the conversion of cyclododecene is in
the range from 30 to 95%, more preferably in the range from 40 to
85% and especially preferably in the range from 50 to 80%.
According to an alternative embodiment of the present invention,
the reaction conditions are selected in a way that the conversion
of cyclododecene is in the range from 5 to 95%, preferably in the
range from 7 to 80%, in particular from 10 to 50%.
[0069] The term "conversion" as used above refers to the overall
conversion of cyclododecene. When the reactant used is exclusively
cis-cyclododecene or exclusively trans-cyclododecene, the overall
conversion corresponds to the conversion of the particular isomer.
When the reactant used is a mixture of cis- and trans-isomer,
comprising x mol % of cis-isomer and y mol % of trans-isomer, and m
% of the cis-isomer and n % of the trans-isomer are converted, the
overall conversion is calculated as the sum mx+ny.
[0070] In the case that the reactant used is an isomer mixture,
preference is given in the context of the present invention to
carrying out the reaction with dinitrogen monoxide in at least two
steps, more preferably in two or three steps and most preferably in
two steps.
[0071] In a first step, a temperature is selected which is
preferably in the range from 140 to 300.degree. C., more preferably
in the range from 180 to 290.degree. C. and especially preferably
in the range from 225 to 275.degree. C. In this first step, it is
mainly the trans-isomer which is oxidized to cyclododecanone. In a
second step, an increased temperature is selected in comparison
with the first step and is preferably in the range from 165 to
350.degree. C., more preferably in the range from 225 to
325.degree. C. and especially preferably in the range from 275 to
310.degree. C. In this second step, the cis-isomer is oxidized to
cyclododecanone.
[0072] The present invention accordingly also relates to a process
as described above, wherein a mixture comprising cis-cyclododecene
and trans-cyclododecene is reacted with dinitrogen monoxide in two
stages.
[0073] The present invention likewise also relates to a process as
described above, wherein the reaction in the first stage is carried
out at a temperature in the range from 140 to 300.degree. C. and
the reaction in the second stage is carried out at a temperature in
the range from 165 to 350.degree. C., the temperature in the first
stage being lower than the temperature in the second stage.
[0074] As far as the further reaction parameters, for example
pressure, residence time or reaction vessel, of the two stages of
the abovementioned preferred two-stage process are concerned,
reference is made in this regard to the general and preferred
embodiments of the above-described one-stage process.
[0075] The above-described two-stage process may be realized by all
suitable process versions. For example, the two-stage process may
be carried out in at least two reactors, the lower temperature
being set in at least one reactor and the higher temperature being
set in at least one further reactor. It is equally possible to
realize the different temperatures in a single reactor which has at
least two zones of different temperature. When a reactor is used
which has at least two zones of different temperature, the
transition between the two temperatures may be continuous or
discontinuous. For example, particular preference is given in this
context to a tubular reactor having an axial temperature profile
which can be realized, for example, as described above.
[0076] When at least two different reactors are used in the context
of the two-stage process, at least one intermediate treatment of
the reactant may be effected between at least two of these
reactors. Possible intermediate treatments are, for example: [0077]
heating of the reactants; [0078] changing the pressure which the
reactants are under. Preference is given in this context, for
example, to increasing the pressure using, for example, at least
one pump and/or at least one compressor; [0079] metering in at
least one reactant. In particular, dinitrogen monoxide and/or
cyclododecene may be metered in. In the case of cyclododecene, it
may be fresh reactant and/or cyclododecene which is not converted
in the second stage and is removed from the product stream by at
least one suitable measure and recycled into the process; [0080]
removing cyclododecanone formed by at least one suitable measure,
for example and with preference by at least one distillative
step.
[0081] In a further preferred embodiment of the process according
to the invention, in the case that the reactant used is a mixture
of cis- and trans-cyclododecene, at least one catalyst is added
which is capable under the reaction conditions which are selected
for the conversion of cyclododecene of catalyzing the establishment
of the equilibrium between cis- and trans-isomer.
[0082] For this purpose, all suitable catalysts may in principle be
used. For this purpose, particular preference is given in the
process according to the invention to using at least one catalyst
as also used for hydrogenations, for example of olefins or
polyenes. Particular preference is given in the process according
to the invention to using those isomerization catalysts which
contain at least one transition metal such as, inter alia,
preferably Ru.
[0083] The isomerization catalysts used to establish the
equilibrium between cis- and trans-isomer may either be homogeneous
or heterogeneous catalysts. It is equally possible to use at least
one homogeneous and at least one heterogeneous catalyst. The
heterogeneous catalysts may be used in this context as a suspension
or as a fixed bed catalyst. It is equally possible to use either at
least one heterogeneous suspension catalyst or at least one
heterogeneous fixed bed catalyst, optionally in addition to at
least one homogeneous catalyst. Particular preference is given to
using at least one homogeneous catalyst.
[0084] While all suitable homogeneous catalysts may in principle be
used, preference is given to using those which contain Ru as the
active metal. Particular preference is further given to catalysts
as described in U.S. Pat. No. 5,180,870, U.S. Pat. No. 5,321,176,
U.S. Pat. No. 5,177,278, U.S. Pat. No. 3,804,914, U.S. Pat. No.
5,210,349 U.S. Pat. No. 5,128,296, US B 316,917 and in D. R. Fahey
in J. Org. Chem. 38 (1973) p. 80-87, whose disclosure content on
this subject is fully incorporated into the context of the present
application. Such catalysts are, for instance,
(TPP).sub.2(CO).sub.3Ru, [Ru(CO).sub.4].sub.3,
(TPP).sub.2Ru(CO).sub.2Cl.sub.2, (TPP).sub.3(CO)RuH.sub.2,
(TPP).sub.2(CO).sub.2RuH.sub.2, (TPP).sub.2(CO).sub.2RuClH, or
(TPP).sub.3(CO)RuCl.sub.2.
[0085] A catalyst used with very particular preference is
(TPP).sub.2(CO).sub.2RuCl.sub.2 or a corresponding Cl-free variant,
for example (TPP).sub.2(CO).sub.2RuH.sub.2, where TPP is
triphenylphosphine.
[0086] In a more preferred embodiment, the catalyst used is
prepared in situ in the process according to the invention. The
starting materials in this preparation in situ are, for example,
preferably the compounds ruthenium chloride, ruthenium acetate,
ruthenium acetylacetonate or other Ru compounds.
[0087] In general, additionally added to the oxidation apart from
the at least one Ru component is at least one of the compounds
NR.sub.3, PR.sub.3, AsR.sub.3 or SbR.sub.3 where R is an alkyl,
aralkyl, alkaryl or aryl radical having preferably from 1 to 20
carbon atoms. Particular preference is given in the context of the
present invention to triphenylphosphine.
[0088] In the context of a further embodiment, the oxidation is
carried out in the presence of at least one carboxylic acid, as
described in DE 198 56 862 A1, the contents on this subject are
fully incorporated by reference into the context of the present
application.
[0089] The carboxylic acid used may be, for example, aliphatic,
cycloaliphatic, aromatic or araliphatic carboxylic acids.
Preference is given to using those which are soluble in the
reaction system under the reaction conditions. Examples are
C.sub.1-C.sub.20 monocarboxylic acids, C.sub.2-C.sub.6 dicarboxylic
acids, cyclohexanecarboxylic acids, benzoic acid, terephthalic
acid, phthalic acid or phenylacetic acid. Particularly preferred
acids are aliphatic mono- and dicarboxylic acids, in particular
acetic acid, propionic acid and also C.sub.12-C.sub.20 fatty acids,
succinic acid and adipic acid.
[0090] In the in situ preparation of the catalyst, particular
preference is given to also adding at least one CO source. This may
be CO itself. Further possible CO sources are, for example,
formaldehyde, methanol, ethanol or other suitable primary alcohols,
for example benzyl alcohol, or diols or polyols having at least one
primary alcohol group, for example ethylene glycol, propylene
glycol or glycerol.
[0091] The inventive oxidation of cyclododecene generally results
in a product mixture. This product mixture preferably contains
cyclododecanone in the range from 30 to 95% by weight, more
preferably from 40 to 90% by weight and especially preferably from
50 to 80% by weight, based in each case on the total weight of the
product mixture after cooling to 20.degree. C. and decompression to
atmospheric pressure. According to an alternative embodiment, the
product mixture contains for example from 5 to 95% by weight of
cyclododecanone, preferably from 7 to 80% by weight, particularly
from 10 to 50% by weight.
[0092] Further constituents present in the product mixture are any
catalyst which has been used before the oxidation stage and has not
been removed, unconverted cyclododecene and any compounds which
have been introduced into the oxidation with the reactant and any
compounds which have also been converted in the reaction with
dinitrogen monoxide, for example cyclododecane, as described
below.
[0093] The isomerization catalyst used for the reaction may
subsequently be recycled into the process, discarded or be worked
up, for example in order to recover at least one metal present in
the catalyst. When the catalyst is recycled into the process, it
may either be recycled into the process stage of the reaction with
dinitrogen monoxide or into any other step which the process
according to the invention may additionally have. In a particularly
preferred embodiment which is described below, such an additional
step of the process according to the invention may be the partial
hydrogenation of at least one cyclododecatriene, in which case the
partial hydrogenation mentioned may more preferably proceed in the
presence of the same catalyst which is used as the isomerization
catalyst to establish the equilibrium between cis- and trans-isomer
of cyclododecene. Accordingly, the catalyst removed may also be fed
to this partial hydrogenation, in which case the catalyst may be
subjected to a suitable regeneration step before the feeding.
[0094] The cyclododecene used as a reactant, which may be used
either as the cis-isomer or as the trans-isomer or as a mixture of
cis- and trans-isomer, may in principle stem from any desired
source.
[0095] Very particular preference is given in the context of the
present invention to preparing cyclododecene by partially
hydrogenating at least one cyclododecatriene, preferably by
partially hydrogenating at least one 1,5,9-cyclododecatriene, for
example cis,trans,trans-1,5,9-cyclododecatriene or
cis,cis,trans-1,5,9-cyclododecatriene or
all-trans-1,5,9-cyclododecatriene and in particular from
cis,trans,trans-1,5,9-cyclododecatriene.
[0096] These preferred compounds may be prepared, for example, by
trimerizing pure 1,3-butadiene, as described, for example, in T.
Schiffer, G. Oenbrink, "Cyclodecatriene, Cyclooctadiene, and
4-Vinylcyclohexene", Ullmann's Encyclopedia of Industrial
Chemistry, 6th Edition (2000), Electronic Release, Wiley VCH. In
the case of trimerization in the presence of Ziegler catalysts,
this process results, for example, in
cis,trans,trans-1,5,9-cyclododecatriene,
cis,cis,trans-1,5,9-cyclododecatriene and
all-trans-1,5,9-cyclododecatriene, as described, for example, in H.
Weber et al. "Zur Bildungsweise von
cis,trans,trans-Cyclododecatrien-(1.5.9) mittels titanhaltiger
Katalysatoren" in: Liebigs Ann. Chem. 681 (1965) p. 10-20. While
all of these cyclododecatrienes may be partially hydrogenated in
the context of the process according to the invention, particular
preference is given in the context of the present process according
to the invention, as described above, to converting
cis,trans,trans-1,5,9-cyclododecatriene. This
cis,trans,trans-1,5,9-cyclododecatriene is more preferably prepared
in accordance with the abovementioned article by Weber et al.,
whose contents on this subject are fully incorporated by reference
into the context of the present application.
[0097] The present invention accordingly also relates to a process
as described above, wherein the cyclododecatriene is prepared by
trimerizing 1,3-butadiene using titanium catalysts.
[0098] While all suitable titanium catalysts may in principle be
used for trimerization, particular preference is given to the
titanium tetrachloride/ethylaluminum sesquichloride catalysts
described in the article by Weber et al.
[0099] The butadiene used for the trimerization especially
preferably has a degree of purity determined by gas chromatography
of at least 99.6% and more preferably of at least 99.65%.
Especially preferably, the 1,3-butadiene used, within the precision
of detection, contains no 1,2-butadiene and no 2-butyne.
[0100] This preferred trimerization generally results in mixtures
which contain at least 95% by weight, preferably at least 96% by
weight and more preferably at least 97% by weight, of
cis,trans,trans-1,5,9-cyclododecatriene. For example, the mixtures
especially preferably contain about 98% by weight of
cis,trans,trans-1,5,9-cyclododecatriene.
[0101] The present invention therefore also relates to a process
for preparing cyclododecanone which comprises the steps (I) and
(II): [0102] (I) preparing cyclododecene by partially hydrogenating
cyclododecatriene; [0103] (II) reacting cyclododecene obtained in
(I) with dinitrogen monoxide to obtain cyclododecanone.
[0104] The present invention likewise also relates to a process for
preparing cyclododecanone which comprises the steps (I) and (II),
wherein the cyclododecatriene used in step (I) is prepared by
trimerizing 1,3-butadiene.
[0105] In particular, the present invention also relates to a
process for preparing cyclododecanone which comprises the steps (I)
and (II), by preparing the cyclododecatriene used in step (I) by
trimerizing 1,3-butadiene, wherein the trimerization is effected in
the presence of a titanium catalyst and the cyclododecatriene is
cis,trans,trans-1,5,9-cyclododecatriene.
[0106] The present invention likewise also relates to a process as
described above, wherein the cyclododecene is obtained from the
catalytic partial hydrogenation of cyclododecatriene.
[0107] The present invention further also relates to an integrated
process for preparing cyclododecanone which comprises at least the
following steps (a) and (b) and also (i) and (ii): [0108] (a)
preparing cyclododecatriene from 1,3-butadiene; [0109] (b)
partially hydrogenating the cyclododecatriene to obtain
cyclododecene; [0110] (i) providing a dinitrogen
monoxide-containing gas mixture containing in each case from 0 to
0.5% by volume of oxygen and/or nitrogen oxides, based on at least
one offgas stream of an adipic acid plant and/or of a nitric acid
plant and/or of a hydroxylamine plant and/or of a nitric acid plant
operated with the offgas of an adipic acid plant and/or of a
dodecanedioic acid plant and/or of a hydroxylamine plant; [0111]
(ii) reacting cyclododecene obtained in (b) with the gas mixture
provided in (i) to obtain cyclododecanone.
[0112] Processes for catalytically partially hydrogenating
cyclododecatriene are described in the literature. It is generally
essential that the yield in this reaction is very high, since the
low mass and polarity differences of the reactants and products
only allow them to be separated by distillation with very great
difficulty, if at all. The cyclododecatriene conversion therefore
has to be substantially quantitative.
[0113] Hydrogenation of polyenes to monoenes over homogeneous Ru
catalysts with the addition of water is described, for example, in
U.S. Pat. No. 5,180,870. In Example 2 of this document, a
cyclododecatriene conversion of 98.4% is achieved with the addition
of water after a reaction time of 4 h. It is not stated which
cyclododecene yield is obtained. In Example 1 of this document, an
only unsatisfactory conversion of 85.8% is achieved after a
reaction time of 8 h with the addition of a little less water than
in Example 2.
[0114] U.S. Pat. No. 5,321,176 describes the addition of amines for
homogeneously catalyzed hydrogenation.
[0115] In U.S. Pat. No. 5,177,278, the cyclododecatriene
hydrogenation is carried out with homogeneous Ru catalysts in the
presence of solvents such as ethers or esters. According to the
examples of this document, the best cyclododecene selectivities are
96-98%. However, quantitative conversion is not achieved in any
case, so that the workup poses a separation problem.
[0116] In U.S. Pat. No. 3,925,494, operation is likewise effected
in solvents. The maximum cyclododecene yield is described as
approx. 95%. However, the conversion here too is not
quantitative.
[0117] In J. Org. Chem. 38 (1973) p 80-87, D. R. Fahey describes
the hydrogenation of cyclododecatriene over various homogeneous Ru
catalysts. In all the examples, operation is effected in the
presence of large amounts of solvent. Cyclododecene yields of
approx. 98% are described. However, the use amount of Ru described,
based on cyclododecatriene, is very high.
[0118] DE 198 56 862 A1 describes the hydrogenation of
cyclododecatriene over homogeneous Ru catalysts in the presence of
carboxylic acids. Cyclododecene yields of 98% can be achieved in
this case.
[0119] In the context of the present invention, the catalytic
partial hydrogenation of cyclododecatriene to cyclododecene may be
effected by all suitable methods.
[0120] In particular, the catalytic partial hydrogenation may be
carried out with homogeneous or heterogeneous catalysts, and the
heterogeneous catalysts may be used as a suspension or as a fixed
bed.
[0121] The heterogeneous catalyst systems used are preferably those
which contain at least one of the elements Pd, Pt, Ru, Ir, Ni and
Rh as the active hydrogenating metal.
[0122] In a particularly preferred embodiment, cyclododecatriene is
partially hydrogenated to cyclododecene in the process according to
the invention in the presence of at least one homogeneous
hydrogenation catalyst.
[0123] While all suitable homogeneous catalysts may be used in
principle, preference is given to using those which contain Ru as
the active hydrogenating metal. Particular preference is further
given to using catalysts as described in U.S. Pat. No. 5,180,870,
U.S. Pat. No. 5,321,176, U.S. Pat. No. 5,177,278, U.S. Pat. No.
3,804,914, U.S. Pat. No. 5,210,349, U.S. Pat. No. 5,128,296, US B
316,917 and in D. R. Fahey in J. Org. Chem. 38 (1973) p. 80-87,
whose disclosure content on this subject is fully incorporated by
reference into the context of the present application. Such
catalysts are, for instance, (TPP).sub.2(CO).sub.3Ru,
[Ru(CO).sub.4].sub.3, (TPP).sub.2Ru(CO).sub.2Cl.sub.2,
(TPP).sub.3(CO)RuH.sub.2, (TPP).sub.2(CO).sub.2RuH.sub.2,
(TPP).sub.2(CO).sub.2RuClH or (TPP).sub.3(CO)RuCl.sub.2.
[0124] A catalyst used with very particular preference is
(TPP).sub.2(CO).sub.2RuCl.sub.2 or a corresponding Cl-free variant,
for example (TPP).sub.2(CO).sub.2RuH.sub.2, where TPP is
triphenylphosphine.
[0125] In a further preferred embodiment, the catalyst used for
partial hydrogenation is prepared in situ in the process according
to the invention. This preparation in situ starts, for example,
preferably from the compounds ruthenium chloride, ruthenium
acetate, ruthenium acetylacetonate or other Ru compounds.
[0126] In general, additionally added to the hydrogenation
reaction, apart from the at least one Ru component, is at least one
of the compounds NR.sub.3, PR.sub.3, AsR.sub.3 or SbR.sub.3 where R
is an alkyl, aralkyl, alkaryl or aryl radical having preferably
from 1 to 20 carbon atoms. Particular preference is given in the
context of the present invention to triphenylphosphine.
[0127] Based on 1 kg of cyclododecatriene, calculated as the metal,
generally from 0.1 to 2000 mg of active hydrogenating metal, more
preferably Ru, are used in the process according to the invention.
Preference is given to using from 1 to 1000 mg and particular
preference to using from 10 to 200 mg.
[0128] In one embodiment of the process according to the invention,
the catalyst is removed from the reactants on completion of partial
hydrogenation. In a further embodiment of the present invention,
the catalyst removed is fed to any process and very particular
preference is given to recycling it into the process according to
the invention. According to the invention, the catalyst is more
preferably removed in at least one distillation, by removing the
product of the partial hydrogenation, cyclododecene, via the top,
and the catalyst, in some cases with fractions of cyclododecene,
via the bottom.
[0129] As a consequence of the very small amounts of catalyst
material as described above and therefore very low costs for the
catalyst, it is generally not necessary in the process according to
the invention to remove the catalyst from the reaction mixture
after the partial hydrogenation and recycle it into the
process.
[0130] In a further embodiment, the partial hydrogenation is
carried out in the presence of at least one carboxylic acid, as
described in DE 198 56 862 A1, whose contents on this subject are
fully incorporated by reference into the context of the present
application.
[0131] The carboxylic acid used may be, for example, an aliphatic,
cycloaliphatic, aromatic or araliphatic carboxylic acid. Preference
is given to using those which are soluble in the reaction system
under the reaction conditions. Examples are C.sub.1-C.sub.20
monocarboxylic acids, C.sub.2-C.sub.6 dicarboxylic acids,
cyclohexanecarboxylic acid, benzoic acid, terephthalic acid,
phthalic acid or phenyl acetic acid. Particularly preferred acids
are aliphatic mono- and dicarboxylic acids, in particular acetic
acid, propionic acid and C.sub.12-C.sub.20 fatty acids, succinic
acid and adipic acid.
[0132] The amount of acid added per kg of cyclododecatriene is
generally from 0.001 to 100 g, preferably from 0.01 to 50 g and
more preferably from 0.05 to 25 g.
[0133] In the in situ preparation of the catalyst, particular
preference is given to also using at least one CO source. This may
be CO itself. Further possible CO sources are, for example,
formaldehyde, methanol, ethanol or other suitable primary alcohols,
for example benzyl alcohol or diols or polyols having at least one
primary alcohol group, for example ethylene glycol, propylene
glycol or glycerol.
[0134] In the process according to the invention, the partial
hydrogenation generally takes place at temperatures in the range
from 50 to 300.degree. C., preferably in the range from 80 to
250.degree. C. and more preferably in the range from 100 to
200.degree. C. The reaction pressures are in the range from 1 to
300 bar, preferably in the range from 1 to 200 bar and more
preferably in the range from 1 to 100 bar.
[0135] The reaction times per batch in batch mode, or the residence
times in the case of the continuous process version, are generally
in the range from 0.5 to 48 h. They are determined substantially by
the batch sizes and the possibilities of supplying and removing
energy. The above-described carboxylic acid addition makes it
uncritical if the reaction batch is handled under reaction
conditions for longer than necessary. This makes possible
considerably simplified reaction control and reaction
monitoring.
[0136] The preferred process version of the partial hydrogenation
is the continuous mode. Examples of preferred reactors are stirred
reactors or reactors having mixing by pumps, in which the
introduction of water should be very efficient. This may be
achieved, for example, by baffles in stirred systems or in
general.
[0137] In one preferred embodiment of the present invention, at the
location where the hydrogenation takes place, the heat released is
removed and used, for example, to generate steam. This process
version is, for example, preferably carried out in at least one
tube bundle reactor. When tubular reactor systems are used, it is
advantageous, for example by suitable internals, to accelerate the
mixing-in of hydrogen, as is customary, for example, in packed
bubble columns.
[0138] To complete the conversion, it is possible in the context of
the present invention to operate at least two reactors in series.
For example, a first reactor may have vigorous mixing, which may be
achieved, for example, by product recycling by means of a pump,
while a second and optionally a third reactor are merely flowed
through, and hydrogen may optionally be added. In a preferred
embodiment of the specific process version, a conversion in the
range from 80 to 98% is achieved in the first reactor, while the
postreactor or postreactors ensure the remaining conversion.
[0139] When starting up the hydrogenation, particular preference is
given to not initially charging the cyclododecatriene reactant, or
to not initially charging it pure together with catalyst and/or
catalyst precursor, since this may result in undesired exothermic
reactions. In general, at least one suitable solvent or diluent may
be added. Useful such solvents or diluents are, for instance,
cyclododecane, cyclododecene, saturated aliphatic hydrocarbons,
aromatic hydrocarbons or mixtures of two or more thereof. In a
preferred embodiment, cyclododecene or cyclododecane or a mixture
of cyclododecene and cyclododecane or a mixture of cyclododecene
and cyclododecatriene or a mixture of cyclododecane and
cyclododecatriene or a mixture of cyclododecene, cyclododecane and
cyclododecatriene is initially charged. While the cyclododecatriene
content of the corresponding mixtures is generally uncritical, in
the continuous process it is preferably in the range of up to 30%
by weight, more preferably up to 25% by weight and especially
preferably up to 20% by weight.
[0140] The present invention accordingly also relates to a process
as described above, wherein the partial hydrogenation is started up
by initially charging a mixture of cyclododecane and/or
cyclododecene together with cyclododecatriene, the
cyclododecatriene content of this mixture being in the range of up
to 30% by weight.
[0141] The product which is obtained from the partial hydrogenation
according to the invention is generally a mixture. In a preferred
embodiment, this mixture contains cyclododecene in the range from
90 to 99.9% by weight, for example in the range from 92 to 99.9% by
weight or in the range from 91 to 99% by weight, more preferably in
the range from 92 to 98% by weight, more preferably in the range
from 94 to 99% by weight and especially preferably in the range
from 96 to 98% by weight, based in each case on the total weight of
the product mixture.
[0142] In general, cyclododecene is obtained as a mixture of cis-
and trans-isomer. In general, the molar ratio of cis-isomer to
trans-isomer is in the range from 0.35:1 to 2.0:1, preferably in
the range from 0.4:1 to 2.0:1.
[0143] In addition to cyclododecene, the product mixture generally
contains cyclododecane in the range from 0.1 to 8% by weight,
preferably in the range from 0.3 to 7% by weight, for example from
0.3 to 5% by weight or in a range from 0.5 to 6.5% by weight and
more preferably in the range from 0.5 to 3% by weight, based in
each case on the total weight of the product mixture.
[0144] In addition to cyclododecene and cyclododecane, the product
mixture may contain traces of cyclododecadienes and/or unconverted
cyclododecatriene and/or catalysts. The process according to the
invention may in principle be conducted in such a way that the
cyclododecatriene used is fully converted to cyclododecene. In
general, the product mixture contains the unconverted
cyclododecatriene reactant in an amount of less than 0.5% by
weight, preferably of less than 0.25% by weight and especially
preferably of less than 0.1% by weight, based in each case on the
total weight of the product mixture.
[0145] If desired, unconverted cyclododecatriene may be removed
from the product mixture by at least one suitable method, for
example and with preference at least one distillative measure, and
recycled into the process. As a consequence of the very high
conversion of cyclododecatriene, particular preference is given in
the process according to the invention to not removing it from the
product mixture from the partial hydrogenation and feeding traces
of cyclododecatriene together with the cyclododecene to the
oxidation with dinitrogen monoxide.
[0146] In a preferred embodiment of the process according to the
invention, the at least one catalyst used for the partial
hydrogenation may be removed from the product mixture of the
partial hydrogenation. This removal may be effected by any suitable
process depending on the catalyst used.
[0147] When the catalyst used in the partial hydrogenation is, for
example, a heterogeneous catalyst as a suspension catalyst,
preference is given in the context of the present invention to
removing it by at least one filtration step. The catalyst removed
in this way may subsequently either be recycled into the process or
be used in another process, discarded or worked up, for example in
order to recover at least one metal present in the catalyst.
[0148] When the catalyst used in the partial hydrogenation is, for
example, a homogeneous catalyst, preference is given in the context
of the present invention to removing it by at least one
distillation step. In this distillation, one or two or more
distillation columns may be used.
[0149] In the at least one distillation column, the product mixture
from the partial hydrogenation is separated into at least 2
fractions. The high boiler fraction comprises substantially the
entire amount of the homogeneous hydrogenation catalyst used. The
catalyst removed in this way may, optionally after at least one
suitable regeneration step, subsequently either be recycled into
the process, discarded or worked up, for example in order to
recover at least one metal present in the catalyst. It is also
possible to use the catalyst removed in another process.
[0150] In a particularly preferred embodiment of the process
according to the invention, a portion of the homogeneous
hydrogenation catalyst removed in this way may be recycled into the
process and the remainder of the catalyst removed discharged from
the process.
[0151] The main fraction from the abovementioned distillative
workup of the product mixture from the partial hydrogenation
comprises substantially cyclododecene, with small traces of
cyclododecane and in some cases traces of cyclododecadienes, as has
already been described above.
[0152] In a preferred embodiment of the process according to the
invention, this main fraction is fed to the oxidation with
dinitrogen monoxide.
[0153] It is equally possible to remove low boilers from the main
fraction in at least one suitable distillation step before feeding
to the oxidation.
[0154] In a further preferred embodiment of the process according
to the invention, the at least one catalyst used for the partial
hydrogenation is not removed from the product mixture of the
partial hydrogenation. Particular preference is given to this
embodiment when a homogeneous catalyst is used for the
hydrogenation. Preference is also given in this case to not working
up the product mixture from the partial hydrogenation and feeding
it directly to the oxidation with dinitrogen monoxide.
[0155] As already described above, in a preferred embodiment of the
oxidation of cyclododecene with dinitrogen monoxide, a suitable
catalyst is used which is capable of catalyzing the establishment
of equilibrium between cis- and trans-isomer of cyclododecene.
[0156] In a particularly preferred embodiment, the catalyst used
for this establishment of equilibrium is the same catalyst as for
the partial hydrogenation of cyclododecatriene.
[0157] The present invention accordingly also relates to a process
as described above, wherein the hydrogenation of cyclododecatriene
to cyclododecene and the conversion of cyclododecene to
cyclododecanone with dinitrogen monoxide are effected in the
presence of the same catalyst.
[0158] A considerable process technology advantage of the process
according to the invention is the fact that when the same
homogeneous catalyst is used in partial hydrogenation and oxidation
with dinitrogen monoxide, the catalyst does riot have to be removed
from the product mixture of the partial hydrogenation, and that
this mixture may be fed directly to the oxidation with dinitrogen
monoxide without costly and inconvenient distillative workup.
[0159] The present invention accordingly also relates to a process
as described above, wherein a mixture resulting from the
hydrogenation of cyclododecatriene to cyclododecene in the presence
of a homogeneous catalyst, comprising cyclododecene and homogeneous
catalyst, may be used as a reactant for the reaction with
dinitrogen monoxide.
[0160] In the context of the present invention, it is also possible
to remove only a portion of the catalyst from the product mixture
of the partial hydrogenation and to feed the resulting mixture,
comprising cyclododecene and the remaining portion of the catalyst,
to the oxidation with dinitrogen monoxide. In this case, at least
one further catalyst may optionally be added in the oxidation with
dinitrogen monoxide. It is also possible not to remove the catalyst
from the product mixture of the partial hydrogenation and to add
the same and/or at least one further catalyst in the oxidation with
dinitrogen monoxide.
[0161] One advantage of the above-described process according to
the invention for preparing cyclododecanone is that cyclododecanone
is obtained in few steps and simultaneously with high selectivity.
A further considerable advantage is the fact that the reactant used
for the process according to the invention may be dinitrogen
monoxide-containing offgases from preferably industrial plants
which firstly are available without great cost and secondly enable
the integration of the process according to the invention into an
existing integrated plant system, which allows the transport path
for the reactant to be kept to a minimum, and which also, as
potential greenhouse gases, do not have to be fed to a special
treatment for disposal, but rather flow directly into a product of
value.
[0162] The cyclododecanone prepared in accordance with the
invention may more preferably, for example, be used to prepare
dodecanedicarboxylic acid and/or laurolactam and/or polymers
derived therefrom, for example polyamides such as nylon-12 or
nylon-6,12.
[0163] The present invention is illustrated by FIG. 1 described
below and by the examples which follow.
[0164] In the context of the present invention, FIG. 1 describes
one preferred continuous hydrogenation of cyclododecatriene to
cyclododecene by means of a homogeneous catalyst, as described, for
example in Example 2. In this process, cyclododecatriene reactant
(8) is conducted via a pump (11) while mixing in hydrogen (7) into
a first continuous reactor (1) where a first hydrogenation step
takes place. The reaction effluent from the reactor (1) is pumped
out via pump (12) and split, and one portion of the reaction
effluent is recycled into the reactor (1) for dilution and the
other portion of the reaction effluent is conducted as feed into a
second, likewise continuous reactor (2), the postreactor. The
reaction effluent from the reactor (2) is separated in a separator
(9) into a liquid phase and a gas phase, and the offgas (5) is
removed from the separator (9). After leaving the separator (9),
the liquid phase is decompressed to ambient pressure and fed to a
thin-film evaporator (3) driven by a motor (6). The distillate
obtained from the removal in the thin-film evaporator (3) is the
cyclododecene product (4) and the bottom product (10) is a liquid
phase which is recycled into the reactor (1) via pump (13). This
liquid phase contains the homogeneous hydrogenation catalyst and a
portion of the product (4) as a solvent for the catalyst.
EXAMPLES
Example 1
Batchwise Hydrogenation of Cyclododecatriene to Cyclododecene
[0165] A 2.5 l stirred autoclave was charged with 1 kg of
trans,trans,cis-cyclododeca-1,5,9-triene, 150 mg of
RuCl.sub.3.H.sub.2O, 20 g of triphenylphosphine, 12.5 g of 37%
aqueous formaldehyde, 25 ml of ethanol and 2.5 g of acetic acid.
After the reactor had been flushed with nitrogen and hydrogen, 15
bar of hydrogen were injected. The reactor was then heated with
stirring. At a temperature of approx. 130.degree. C., the reactor
pressure reduced noticeably. The temperature was subsequently
increased to 140 and 150.degree. C.; the pressure was kept at 20
bar by injecting more hydrogen. On completion of hydrogen
absorption, gas chromatography analysis showed a cyclododecene
yield of 98.1% and a cyclododecane yield of 1.8% in the reaction
effluent.
Example 2
Continuous Hydrogenation of Cyclododecatriene to Cyclododecene
[0166] 1 kg of cyclododecene, 150 mg of RuCl.sub.3.H.sub.2O, 20 g
of triphenylphosphine, 12.5 g of 37% aqueous formaldehyde, 25 ml of
ethanol and 2 g of adipic acid were charged into the first reactor
(capacity approx. 1 liter) of an experimental apparatus according
to FIG. 1. After heating the reactor system to 100.degree. C., the
circulation pump was switched on, the pressure was brought to 20
bar by means of hydrogen and a feed of 200 g of cyclododecatriene
was established. The reaction temperature in both the first and the
second reactor (capacity approx. 0.6 liter) was set to approx
140.degree. C. After decompression to ambient pressure, the
reaction effluent was separated in a thin-film evaporator in such a
way that approx. 10 g/h of bottom product and 190 g/h of distillate
were obtained. The bottom product was pumped back into the first
reactor by means of a pump. After an operating time of 24 h, the
distillate contained approx. 97% of cyclododecene, 2.6% of
cyclododecane and some further products in insignificant
amounts.
Example 3
Reaction of Cyclododecene with N.sub.2O
[0167] A 250 ml autoclave was initially charged with 0.5 mol of
cyclododecene (as a mixture having 64% trans- and 33% cis content,
product from Example 2). The autoclave was then sealed and flushed
with N.sub.2. Subsequently, N.sub.2O was injected into the
autoclave up to 50 bar. The temperature was then increased to
250.degree. C. (maximum pressure during the reaction: 84 bar).
After a reaction time of 20 h, the autoclave was cooled and
decompressed. Some of the contents of the autoclave had already
crystallized. In order to analyze the product, the contents were
melted at 60.degree. C. and a homogeneous sample was taken. After
dilution with toluene, the sample was analyzed by means of
quantitative GC. The conversion of trans-cyclododecene was 98%. The
conversion of cis-cyclododecene was 24%. The overall conversion of
cyclododecene was 71%. The selectivity for cyclododecanone was more
than 95%. The only by-products which could be detected by GC-MS
were traces of cyclododecene epoxide and 11-dodecanal.
Example 4
Reaction of Cyclododecene with N.sub.2O
[0168] A 250 ml autoclave was initially charged with 0.52 mol of
cyclododecene (as a mixture having 64% trans- and 33% cis content,
product from Example 2). The autoclave was then sealed and flushed
with N.sub.2. Subsequently, N.sub.2O was injected into the
autoclave up to 50 bar. The temperature was then increased to
275.degree. C. (maximum pressure during the reaction: 122 bar).
After a reaction time of 10 h, the autoclave was cooled and
decompressed. Some of the contents of the autoclave had already
crystallized. In order to analyze the product, the contents were
melted at 60.degree. C. and a homogeneous sample was taken. After
dilution with toluene, the sample was analyzed by means of
quantitative GC. The conversion of trans-cyclododecene was 99%. The
conversion of cis-cyclododecene was 36%. The overall conversion of
cyclododecene was 76%. The selectivity for cyclododecanone was more
than 95%.
Example 5
Reaction of Cyclododecene with N.sub.2O without Removing the
Catalyst from the Partial Hydrogenation
[0169] A 250 ml autoclave was initially charged with 0.5 mol of
cyclododecene (product mixture from Example 1 which still contained
Ru catalyst). The autoclave was then sealed and flushed with
N.sub.2. Subsequently, N.sub.2O was injected into the autoclave up
to 50 bar. The temperature was then increased to 250.degree. C.
(maximum pressure during the reaction: 79 bar). After a reaction
time of 10 h, the autoclave was cooled and decompressed. Some of
the contents of the autoclave had already crystallized. In order to
analyze the product, the contents were melted at 60.degree. C. and
a homogeneous sample was taken. After dilution with toluene, the
sample was analyzed by means of quantitative GC. The conversion of
trans-cyclododecene was 75%. The conversion of cis-cyclododecene
was 21%. The selectivity for cyclododecanone was more than 95%.
Example 6
Reaction of Cyclododecene with N.sub.2O with Removal of the
Catalyst from the Partial Hydrogenation
[0170] Example 5 was repeated except that the product mixture from
the partial hydrogenation, comprising cyclododecene, was first
freed of Ru catalyst by distillation. The conversion of
trans-cyclododecene in this case was 75%. However, the conversion
of cis-cyclododecene was less than 1% (instead of 21% in Example
5). The selectivity of cyclododecanone was more than 95%.
Example 7
Two-stage Reaction of Cyclododecene with N.sub.2O without Removing
the Catalyst from the Partial Hydrogenation
[0171] The product obtained in Example 5 without further treatment
was compressed again with N.sub.2O to a final pressure of 50 bar,
and the mixture was stirred at 295.degree. C. for 20 hours (maximum
pressure during the reaction: 245 bar). Subsequently, the autoclave
was cooled and decompressed. In order to analyze the product, the
contents were melted at 60.degree. C. and a homogeneous sample was
taken. After dilution with toluene, the sample was analyzed by
means of quantitative GC. The conversion of trans-cyclododecene was
99%. The conversion of cis-cyclododecene was 32%. The selectivity
for cyclododecanone was more than 95%.
REFERENCE NUMERAL LIST
[0172] 1 Reactor 1 [0173] 2 Reactor 2 [0174] 3 Thin-film evaporator
[0175] 4 Cyclododecene [0176] 5 Offgas [0177] 6 Driving motor of
the thin-film evaporator [0178] 7 Hydrogen [0179] 8
Cyclododecatriene [0180] 9 Separator [0181] 10 Bottom product
[0182] 11 Pump [0183] 12 Pump [0184] 13 Pump
* * * * *