U.S. patent application number 10/424982 was filed with the patent office on 2005-06-02 for fluorobutene derivatives and process for producing same.
This patent application is currently assigned to Central Glass Company, Limited. Invention is credited to Alty, Adam C., Du Boisson, Richard A..
Application Number | 20050119512 10/424982 |
Document ID | / |
Family ID | 33415908 |
Filed Date | 2005-06-02 |
United States Patent
Application |
20050119512 |
Kind Code |
A1 |
Du Boisson, Richard A. ; et
al. |
June 2, 2005 |
Fluorobutene derivatives and process for producing same
Abstract
The present invention provides novel compounds
2,4,4,4-tetrafluoro-1-buten- e and (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes. Furthermore, the present
invention provides the following novel first and second processes
for producing 2,4,4,4-tetrafluoro-1-butene and (E)- and
Z-1,1,1,3-tetrafluoro-2-butenes. The first process is a process for
producing 2,4,4,4-tetrafluoro-1-butene by heating
1,1,1,3,3-pentafluorobu- tane at from about 200.degree. C. to about
700.degree. C. The second process is a process for producing (E)-
and (Z)-1,1,1,3-tetrafluoro-2-but- enes by bringing
1,1,1,3,3-pentafluorobutane with a base. By the first and second
processes, it is possible to obtain respective target fluorobutenes
with high selectivity.
Inventors: |
Du Boisson, Richard A.;
(Gainesville, FL) ; Alty, Adam C.; (Gainesville,
FL) |
Correspondence
Address: |
CROWELL & MORING LLP
INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
Central Glass Company,
Limited
Yamaguchi
JP
|
Family ID: |
33415908 |
Appl. No.: |
10/424982 |
Filed: |
April 29, 2003 |
Current U.S.
Class: |
570/136 |
Current CPC
Class: |
Y02P 20/584 20151101;
C07C 21/18 20130101; C07C 17/25 20130101; C07C 17/25 20130101; C07C
17/25 20130101; C07C 21/20 20130101; C07C 21/18 20130101; C07C
21/20 20130101 |
Class at
Publication: |
570/136 |
International
Class: |
C07C 021/18 |
Claims
1. 2,4,4,4-tetrafluoro-1-butene.
2. (E)- and (Z)-1,1,1,3-tetrafluoro-2-butenes.
3. (E)- or (Z)-1,1,1,3-tetrafluoro-2-butene.
4. A process for producing 2,4,4,4-tetrafluoro-1-butene,
characterized in that 1,1,1,3,3-pentafluorobutane is heated at from
about 200.degree. C. to about 700.degree. C.
5. A process for producing 2,4,4,4-tetrafluoro-1-butene according
to claim 4, characterized in that the heating of claim 4 is
conducted under a condition that is substantially free of a
base.
6. A process for producing 2,4,4,4-tetrafluoro-1-butene according
to claim 4, characterized in that the heating is conducted by
passing 1,1,1,3,3-pentafluorobutane through a reaction tube heated
at from about 200.degree. C. to about 700.degree. C.
7. A process for producing 2,4,4,4-tetrafluoro-1-butene according
to claim 5, characterized in that the heating is conducted by
passing 1,1,1,3,3-pentafluorobutane through a reaction tube heated
at from about 200.degree. C. to about 700.degree. C.
8. A process for producing 2,4,4,4-tetrafluoro-1-butene,
characterized in that 1,1,1,3,3-pentafluorobutane is passed through
a reaction tube heated at 400.degree. C.-500.degree. C. under a
condition that is substantially free of a base.
9. A process for producing 2,4,4,4-tetrafluoro-1-butene according
to claim 8, characterized in that the passing of the
1,1,1,3,3-pentafluorobutane to the reaction tube according to claim
8 is conducted with an input raw material standard contact time of
18-40 seconds.
10. A process for producing and isolating
2,4,4,4-tetrafluoro-1-butene, characterized in that a mixture
containing 2,4,4,4-tetrafluoro-1-butene is obtained by a process of
claim 4, and then the mixture is subjected to a distillation.
11. A process for producing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes, characterized in that
1,1,1,3,3-pentafluorobutane is heated at from about 200.degree. C.
to about 700.degree. C.
12. A process for producing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes, characterized in that
1,1,1,3,3-pentafluorobutane is brought into contact with a
base.
13. A process for producing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes according to claim 12,
characterized in that the contact of the
1,1,1,3,3-pentafluorobutane with the base is conducted at from 0 to
300.degree. C.
14. A process for producing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes according to claim 12,
characterized in that the base is a base selected from alkali metal
hydroxides, alkali earth metal hydroxides and tertiary amines.
15. A process for producing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes according to claim 13,
characterized in that the base is a base selected from alkali metal
hydroxides, alkali earth metal hydroxides, and tertiary amines.
16. A process for producing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes according to claim 12,
characterized in that the contact of the
1,1,1,3,3-pentafluorobutane with the base in claim 12 is conducted
under a coexistence with water, an ether, a halogen solvent, or a
phase transfer catalyst.
17. A process for producing and isolating
(E)-1-1-1,3-tetrafluoro-2-butene- , characterized in that a
reaction mixture containing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes is obtained by the contact with
the base in claim 12, and then the mixture is subjected to a
distillation.
18. A process for producing and isolating
(Z)-1,1,1,3-tetrafluoro-2-butene- , characterized in that a
reaction mixture containing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes is obtained by the contact with
the base in claim 12, and then the mixture is subjected to a
distillation.
Description
CROSS REFERENCE TO RELATED DOCUMENTS
[0001] This specification contains subject matter in common with
Disclosure Document No. 492915 entitled "Thermal
Dehydrofluorination of HFC's" submitted by Adam C. Alty and Richard
A. Du Boisson to the United States Patent and Trademark Office on
May 1, 2001, and hereby claims all benefits legally available from
said disclosure document. In addition, the contents of said
disclosure documents are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to novel fluorobutenes.
Furthermore, it relates to a process for producing a fluorobutene
by a dehydrofluorination with a raw material of a
polyfluorobutane.
[0003] Fluorobutenes are useful as monomers for fluorine-containing
polymers, synthesized intermediates/building blocks for producing
fluorine-containing intermediates, and raw materials for producing
hydrofluorocarbons.
[0004] Thermal dehydrofluorination is a well-known process for
synthesizing olefins. Dehydrochlorination is widely used for
forming a carbon-carbon multiple bond. Furthermore, there are
several examples of thermal dehydrochlorination process used for
producing fluoroolefins. On the other hand, almost all of thermal
dehydrofluorinations are impractical based on a general knowledge
due to their low conversion and low selectivity.
[0005] As its theoretical background, there is provided that the
energy necessary for severing a C--F bond is close to that
necessary for severing a carbon-carbon bond since the
carbon-fluorine bond is very strong. In general, the temperature
necessary for releasing hydrogen fluoride (HF) is far higher than
the temperature for dehydrochlorination of an analogous substance
containing chlorine atom instead at the defluorination site. Under
a high temperature condition necessary for conducting the
dehydrofluorination, molecular decomposition reactions and
rearrangement reactions compete, thereby lowering selectivity. U.S.
Pat. No. 2,480,560 describes that non-catalytic
dehydrofluorinations of five different hydrofluorocarbons give
fluoroolefins with low selectivity.
[0006] Even in the examination process in relation to the present
invention of the present inventors, when
1,1,1,4,4,4-hexafluorobutane (HFC-356mf) had been added to a nickel
reaction tube at 630.degree. C., it mainly gave trifluoromethane
and 3,3,3-trifluoropropene with a conversion of 56%, and it was not
possible to obtain 1,1,4,4,4-pentafluoro-1-butene, which is
considered to be formed by dehydrofluorination (Comparative Example
1). Furthermore, when 2-trifluoromethyl-1,1,1-trifluoropropane was
similarly treated at 660.degree. C., it mainly gave
trifluoromethane and 3,3,3-trifluoropropene, and it was not
possible to obtain 2-trifluoromethyl-1,1-difluoropropene, which is
considered to be formed by dehydrofluorination (Comparative Example
2).
[0007] In order to overcome such problems and to efficiently
produce fluoroolefins, much effort has been made in the development
of catalytic dehydrofluorination. By catalytic process, it may be
possible that hydrogen fluoride is released at a temperature lower
than that at which the above side reactions become noticeable,
thereby causing an expectation for improving selectivity. U.S. Pat.
No. 2,599,631 describes both of thermal (non-catalytic) and
catalytic processes for producing vinyl fluoride by
dehydrofluorination of 1,1-difluoroethane and shows that the
catalytic process is more useful. However, one of big problems of
the catalytic dehydrofluorination process is a rapid deactivation
of the catalyst due to by-products and polymerization products.
[0008] Another means for producing fluoroolefins by
dehydrofluorination is a process by contact with a base. However,
in general, a base-used dehydrofluorination gives in many cases
isomers that are different from products obtained by a thermal
dehydrofluorination process, and therefore it has been difficult to
say that it is an efficient production process of necessary
fluoroolefins.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to provide
2,4,4,4-tetrafluoro-1-butene and (E)- and
(Z)-1,1,1,3-tetrafluoro-2-buten- es, which are novel fluoroolefins.
It is another object of the present invention to provide an
industrially achievable process for producing these compounds.
[0010] In order to solve the above problems, the inventors have
eagerly conducted an examination on reaction systems applicable to
thermal (non-catalytic) dehydrofluorinations. As a result, it was
surprisingly found that 1,1,1,3,3-pentafluorobutane gives
2,4,4,4-tetrafluoro-1-butene- , which is a novel
fluorine-containing compound and becomes a raw material for useful
fluorine-containing synthesis intermediates, highly selectively
with high conversion by a thermal, non-catalytic
dehydrofluorination. It was also found that conversion and
selectivity of the reaction particularly improve under a specific
condition such as passing through a heated reaction tube ("a first
process").
[0011] The present inventors further found that (E)- and
(Z)-1,1;1,3-tetrafluoro-2-butenes, which are novel compounds, are
given by heating 1,1,1,3,3-pentafluorobutane and that selectivity
of (E)- and (Z)-1,1,1,3-tetrafluoro-2-butenes particularly improves
by bringing 1,1,1,3,3-pentafluorobutane with a base ("a second
process"), thereby completing the present invention.
[0012] That is, the present invention provides
2,4,4,4-tetrafluoro-1-buten- e and (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes, which are useful novel compounds
as fluorine-containing intermediates, using a low-price
polyfluorobutane as the raw material and using a thermal
(non-catalytic) dehydrofluorination and a base-contact
dehydrofluorination. Furthermore, the present invention provides
processes for producing these 2,4,4,4-tetrafluoro-1-butene and (E)-
and (Z)-1,1,1,3-tetrafluoro-2-buten- es, which can be conducted in
an industrial scale.
[0013] The first process and the second process of the present
invention are respectively summarized as the following formulas 1
and formula 2. 1
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] In the following, the present invention is explained in
detail. Firstly, the first process of the present invention, a
production of 2,4,4,4-tetrafluoro-1-butene by a thermal,
non-catalytic dehydrofluorination of 1,1,1,3,3-pentafluorobutane,
is described. This butene is a novel substance, its production has
not been described up to now, and it is a synthesis raw material of
fluorine-containing intermediates useful in the fields of medicines
and agricultural chemicals.
[0015] This first process is achieved by heating
1,1,1,3,3-pentafluorobuta- ne, which is industrially available as
365mfc, at from about 200.degree. C. to about 700.degree. C. As to
the temperature of this dehydrofluorination, it can generally be
conducted in a range of about 200.degree. C. to about 700.degree.
C., preferably 300.degree. C.-600.degree. C. It is effective to
maintain the reaction temperature in a range of 400.degree.
C.-550.degree. C. in order to obtain the optimum conversion and
selectivity.
[0016] It is preferable to conduct the first process under a
substantially base-free condition (i.e., under an acid or neutral
condition). Herein, "base" refers to a substance known as a basic
substance. For example, a compound showing a pH of 8 or higher,
when dissolved in water to a have a concentration of 0.1 mol
dm.sup.-3, corresponds thereto. Even when the reaction is conducted
under a condition under which such base is not coexistent, the
cleavage of a carbon-carbon bond is prevented, and it is possible
to obtain 2,4,4,4-tetrafluoro-1-butene with high selectivity.
[0017] The reaction manner of the first process is either flow type
or batch type. In many cases, it is possible in the reaction to
obtain a preferable selectivity by subjecting
1,1,1,3,3-pentafluorobutane to a high-temperature treatment for a
relatively short time. Therefore, flow type is more preferable. It
becomes necessary in general to have pressurization in the reaction
of batch type. In contrast, the reaction of flow type proceeds
sufficiently under normal pressure. Therefore, flow type is
advantageous from the viewpoint of operability.
[0018] In the case of batch type, there is considered a process in
which 1,1,1,3,3-pentafluorobutane is introduced into a reactor that
is resistant against the pressurization condition and against the
contact with hydrogen fluoride, followed by sealing and heating
with stirring. Upon this, it is desirable that the inside sample is
occasionally sampled, that the analysis is conducted by a method
such as gas chromatography, and that the reaction step is
terminated at the time when the raw material has sufficiently been
consumed and converted into the product.
[0019] In contrast with this, the flow-type reaction is achieved by
heating and vaporizing 1,1,1,3,3-pentafluorobutane and by allowing
it to flow through a thermal reaction tube. The thermal reaction
tube must be constructed from a material that is resistant against
the contact with hydrogen fluoride even at high reaction
temperature. In some cases, this is filled with a filler that has
resistance against hydrogen fluoride, in order to improve the
mixing effect and the thermal contact, and that is preferable in
general. For example, although it is possible to use a nickel alloy
for the reaction tube and Monel.cndot.Pro-pack for the filler, it
is not limited to this.
[0020] In the following, in the present specification the term "raw
material input standard contact time" is defined as follows. That
is, "the value obtained by subtracting the solid phase volume
occupied by the filler from the inside volume of the reaction tube"
is referred to as "column volume", and in the following it is
represented by A, too. On the other hand, "the volume of the raw
material gas introduced into the reaction tube per second" is
represented by B. The value of B is calculated from mol number of
the raw material introduced per second, from pressure and from
temperature, assuming that the raw material gas is ideal gas. Upon
this, the value (=A/B) obtained by dividing A by B is referred to
as "raw material input standard contact time". In the reaction
tube, HF and other gases are produced as by-products, and the mole
number change occurs. However, these are not taken into
consideration upon calculating "contact time". The contact time of
the reaction gas in ideal condition in which selectivity of the
dehydrofluorination is 100% with 100% conversion becomes a half of
the raw material input standard contact time herein referred
to.
[0021] The thus calculated "raw material input standard contact
time" is not particularly limited. In the case of maintaining the
reaction temperature in a range of 400.degree. C.-550.degree. C. as
mentioned above, from about 60 column volume to 300 column volume
per hour (about 12 seconds to 60 seconds in raw material input
contact time) is preferable. The introduction with from about 90
column volume to about 200 column volume per hour (about 18 seconds
to 40 seconds in raw material input contact time) is more
preferable. On the other hand, when the raw material input contact
time exceeds 200 seconds, side reactions tend to occur. When the
raw material input contact time is less than 1 second, conversion
is low. Therefore, it is not preferable.
[0022] From the above, under a base-free condition, the passing of
1,1,1,3,3-pentafluorobutane through a reaction tube heated at
400.degree. C.-550.degree. C. with an input raw material contact
time of from 18 second to 40 seconds is a particularly preferable
embodiment in the first process of the present invention.
[0023] The optimum contact time depends on the temperature
(reaction temperature), shape and filler of the reaction tube.
Therefore, it is desirable to set the optimum value by suitably
adjusting the raw material supply rate raw material input contact
time) for each set temperature, each reaction tube shape and each
filler type. In conducting the present invention, a person skilled
in the art is not prevented from such optimization. In general, the
adoption of a contact time capable of obtaining a raw material
conversion of 25% or higher is preferable from the viewpoint of the
recovery and the reuse of the unreacted raw material. More
preferably, it is adjusted so that the conversion becomes 70% or
more.
[0024] Although the reaction pressure may be lower or higher than
the atmospheric pressure or under atmosphere, under the atmospheric
pressure is generally preferable. It is also possible to conduct
the reaction in the presence of an inert gas (such as nitrogen and
argon) that is stable under the reaction conditions or in the
presence of an excessive HF.
[0025] The dehydrofluorination process of this invention can be
conducted in a gas phase using a well-known chemical engineering
apparatus. The reaction tube, a related raw-material introduction
system, an outflow system and a related unit are made of a material
strong against hydrogen fluoride. As typical materials,
particularly stainless steel material such as austenite-type, or
high nickel alloy and copper clad steel such as Monel nickel-copper
alloy, Hastelloy nickel alloy and Inconel nickel-chromium alloy can
be exemplified. However, it is not limited to this.
[0026] In a reaction mixture obtained by the first process,
1,1,1,3,3-pentafluorobutane (the raw material) and (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes (by-products) are coexistent with
the target product, 2,4,4,4-tetrafluoro-1-butene. However, the
present inventors found that these compounds have boiling points
sufficiently different from each other and do not cause azeotropic
phenomena (2,4,4,4-tetrafluoro-1-butene boiling point:
29-30.degree. C., 1,1,1,3,3-pentafluorobutane boiling point:
40.degree. C. (E)-1,1,1,3-tetrafluoro-2-butene: 18-19.degree. C.,
and (Z)-1,1,1,3-tetrafluoro-2-butene: 48-49.degree. C. Each is the
boiling point at atmospheric pressure.)
[0027] Therefore, it is possible to isolate the target
2,4,4,4-tetrafluoro-1-butene with high purity by obtaining a
reaction mixture by the first process and then by subjecting this
reaction mixture to distillation. Although there are no particular
limitations on the conditions of this distillation, it is the
simplest to conduct that at normal pressure. According to the
present invention, it is possible to easily isolate the target
2,4,4,4-tetrafluoro-1-butene without conducting a complicated
purification operation after the reaction. Therefore, it is
particularly advantageous in producing 2,4,4,4-tetrafluoro-1-butene
industrially.
[0028] Furthermore, after recovery of the unreacted starting
material (1,1,1,3,3-pentafluorobutane), its reuse becomes possible
by introducing it again into the reactor.
[0029] Next, the second process of the present invention, a process
for highly selectively providing (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes by dehydrofluorinating
1,1,1,3,3-pentafluorobutane, is described in detail.
[0030] As mentioned in the first process, it is possible to obtain
(E)- and (Z)-1,1,1,3-tetrafluoro-2-butenes together with
2,4,4,4-tetrafluoro-1-butene (a main product) by subjecting
1,1,1,3,3-pentafluorobutane to a heating treatment at from about
200.degree. C. to about 700.degree. C.
[0031] However, the inventors found that it is particularly
effective to bring 1,1,1,3,3-pentafluorobutane into contact with a
base to dehydrofluorinate it, thereby obtaining (E)- and
(Z)-1,1,1,3-tetrafluoro-- 2-butenes with higher selectivity and
yield.
[0032] Hereinafter, a dehydrofluorination of
1,1,1,3,3-pentafluorobutane using a base is described in detail.
(E)- and (Z)-1,1,1,3-tetrafluoro-2-b- utenes are novel compounds,
and there have been no synthesis reports in the past. These are
isomers of 1-butene obtained from the above-described thermal
dehydrofluorination. The above-mentioned thermal
dehydrofluorination of 1,1,1,3,3-pentafluorobutane (the first
process) and a dehydrofluorination of 1,1,1,3,3-pentafluorobutane
by a base (the second process) are complementary, and it becomes
possible to produce useful, different positional isomers of
tetrafluorobutene.
[0033] Although there are no particular limitations on the base to
be used, it is possible to cite alkali metal hydroxides (potassium
hydroxide, sodium hydroxide, lithium hydroxide and the like),
alkali metal carbonates (sodium carbonate, potassium carbonate,
sodium hydrogencarbonate, potassium hydrogencarbonate and the
like), alkali earth metal hydroxides (calcium hydroxide, magnesium
hydroxide and the like), organic bases (tertiary amines such as
triethylamine, tributylamine, and trimethylamine; primary amines
such as monoethylamine, monobutylamine, cyclohexylamine, and
aniline; secondary amines such as diethylamine and dibutylamine;
aromatic bases such as pyridine, picoline, lutidine, and
ethylpyridine; and strong bases such as guanidine and
1,8-diazabicyclo[5.4.0]dec-7-ene (DBU)) or other strong bases (such
as sodium methoxide, sodium ethoxide, potassium methoxide, and
potassium ethoxide) that are commonly used in analogous reactions.
Of these, potassium hydroxide, sodium hydroxide and calcium
hydroxide and the like of low prices are particularly
preferable.
[0034] Although the reaction is achieved by bringing the raw
material 1,1,1,3,3-pentafluorobutane with a base, it is desirable
to gradually mix both in order to maintain the reaction conditions
mildly. For example, it is possible to cite a process such as a
gradual addition of the raw material 1,1,1,3,3-pentafluorobutane
with stirring of a base-containing liquid. On the contrary, it is
also possible to allow the reaction to proceed by adding a base to
the raw material 1,1,1,3,3-pentafluorobutane. The base can be used
as an aqueous solution or a simple substance, and it is possible to
add a phase transfer catalyst. For example, since 85% potassium
hydroxide melts by heating to 100.degree. C. or higher, it is
convenient that this liquid in the melted condition is stirred and
the raw material 1,1,1,3,3-pentafluorobutane is added dropwise
thereto.
[0035] The base may be used as a solution by dissolving it in a
solvent. As the solvent of this case, there may be used water,
ethers (e.g., diethyl ether, dibutyl ether, methyl butyl ether,
phenetole, dioxane, tetrahydrofuran, tetrahydropyran, anisole,
benzyl ether, glymes (e.g., monoglyme, diglyme, and triglyme)) and
halogen-containing solvents (e.g., methylene chloride,
1,1-dichloroethane, 1,2-dichloroethane, chloroform, carbon
tetrachloride, chlorobenzene, 1,4-bis(trifluoromethyl)benzene) and
the like. In other cases, it may be preferable to use in the
reaction a commonly-used phase-transfer catalyst (e.g., 18-crown-6,
dibenzo-18-crown-6, dicyclohexano-18-crown-6,
12-crown-4,15-crown-5, dibenzo-24-crown-8, tetraethylammonium
chloride, tetraethylammonium bromide, tetrabutylammonium chloride,
tetrabutylammonium bromide, ethyltributylammonium bromide,
tetraphenylammonium bromide, and tetraphenylphosphonium
bromide).
[0036] Although there are no particular limitations on the reaction
temperature of the process for producing (E)- and
(Z)-1,1,1,3-tetrafluoro- -2-butenes by the contact with this base,
from 0.degree. C. to 300.degree. C. is preferable, and more
preferably it is a range of from 30.degree. C. to 250.degree.
C.
[0037] The reaction pressure may be lower or higher than
atmospheric pressure. In general, the vicinity of atmospheric
pressure is simple and preferable.
[0038] Although there are no particular limitations on the reaction
time, the reaction is fast under a heated condition, and the
reaction occurs immediately when the raw material and a base are
mixed together. Therefore, as shown in the after-mentioned Example
2, a process is simple, in which mixing of the raw material and a
base is conducted under an open condition (atmospheric pressure),
and a mixed gas of the raw material and the product is cooled down,
thereby collecting it as a liquid (reaction mixture).
[0039] However, it is not limited to such process. A
dehydrofluorination process of the second process can be conducted
by a batch manner or in a continuous reaction apparatus using a
known chemical engineering technique. The apparatus and its related
raw material introducing line, the outflow line, and related units
should be made from a material that is resistant against strong
bases. Typical examples of the material are stainless steel, carbon
steel, or high nickel alloys such as Monel-nickel copper alloy,
Hastelloy-nickel alloy and Inconel nickel-chromium alloy, and
copper clad steel. In limited cases, it is possible to use glass or
glass-lined steel.
[0040] Similar to the first process, itis also possible to separate
each component from the reaction mixture obtained by this second
process by a distillation operation. Specifically, it is possible
to isolate the unreacted 1,1,1,3,3-pentafluorobutane (boiling
point=40.degree. C.), (E)-1,1,1,3-tetrafluoro-2-butene (boiling
point=18-19.degree. C.), and (Z)-1,1,1,3-tetrafluoro-2-butene
(boiling point=48-49.degree. C.) as each distillate. Although there
are no particular limitations on this distillation condition, it is
the simplest to conduct it at normal pressure. Since by-products
generated by the present reaction are low-boiling-point compounds
such as butadiene and butyne, it is easy to separate these. Since
it is possible to easily obtain (E)- and
(Z)-1,1,1,3-tetrafluoro-2-butenes of high purity, it is possible to
obtain a high purity diastereomer by apply a diastereoselective
reaction. Therefore, it is highly useful as a synthesis raw
material.
[0041] The recovered raw material 1,1,1,3,3-pentafluorobutane can
be reused as a reaction raw material of the first process or second
process.
[0042] In the following, the present invention is illustrated in
detail by examples. The present invention is not limited to these
examples.
EXAMPLE 1
[0043] A nickel reaction tube of {fraction (3/4)} inches (1.905 cm)
diameter and 36 inches (91.4 cm) total length (filled with 200 ml
of nickel Propack (void ratio=96%) of 0.24 inches (0.61 cm)) was
heated at temperatures shown in 1-1 to 1-4 of the following Table.
Under these conditions, 1,1,1,3,3-pentafluorobutane was vaporized
by a vaporizer and was allowed to flow at a rate of 70 g/hr. The
outflow gas, which had passed through the reaction tube, was passed
through water in order to remove hydrogen fluoride (HF). Then, it
was dried with calcium sulfate and collected, followed by analysis
by gas chromatography (FID, hereinafter the same).
[0044] The inside volume of the reaction tube in the present
example is 261 cm.sup.3, and the volume ("column volume") except
the solid phase section of the filler is 253 cm.sup.3. The raw
material input standard contact time is from 29 seconds (1-4) to 32
seconds (1-1).
[0045] The results were shown in Table. "GC %" refers to areal % of
each component of the above reaction mixture measured by FID.
1TABLE Temp. 365 mfc CF.sub.3CH.sub.2CF.dbd.CH.sub- .2
(E)-CF.sub.3CH.dbd.CFCH.sub.3 (Z)-CF.sub.3CH.dbd.CFCH.sub.3 No.
.degree. C. GC % GC % GC % GC % 1-1 450 73.7 18.6 3.8 2.7 1-2 470
69.5 23.4 4.3 2.8 1-3 500 63.5 29.6 4.3 1.3 1-4 520 36.4 56.9 3.4
1.6
[0046] The products were identified by mass spectrometry and NMR
(1H, 19F and 13C) and isolated with a purity of 97% by distillation
(boiling point: 29-30.degree. C.) under normal pressure. The data
are written in the following.
[0047] (1) CF.sub.3CH.sub.2CF.dbd.CH.sub.2
[0048] a colorless, transparent liquid
[0049] .sup.1H-NMR solvent: CDCl.sub.3, standard substance: TMS
.delta.: 4.88 (dd, J=16.2 Hz, 3.5 Hz, 1H), 4.59 (dd, J=47.3 Hz, 3.5
Hz, 1H), 3.01(dq, J=16.7 Hz, 9.9 Hz, 2H)
[0050] .sup.19F-NMR solvent: CDCl.sub.3, standard substance:
CFCl.sub.3 .delta.: -66.2 (s, 3F), -95.5.about.-96.5 (m, 1F)
[0051] .sup.13C-NMR solvent: CDCl.sub.3, standard substance: TMS
.delta.: 156.54 (d, J=254 Hz), 124.54 (q, J=277 Hz), 96.40(d,
J=18.0 Hz), 37.63(dq, J=32 Hz, 30 Hz)
[0052] GLC-MS m/z rel. intensity), 128(M.sup.+, 75.2), 113(5.6),
109(9.2), 95(7.6), 89(23.2), 77(9.6), 75(3.2), 69(22.8), 64(100),
59(68.8), 51(13.6), 45(16.4)
[0053] (2) (E)-CF.sub.3CH.dbd.CFCH.sub.3
[0054] a colorless, transparent liquid
[0055] .sup.1H-NMR solvent: CDCl.sub.3, standard substance: TMS
.delta.: 5.44 (dq, J=16.9 Hz, 7.6 Hz, 1H), 2.14 (d, J=18.7 Hz,
3H)
[0056] .sup.19F-NMR solvent: CDCl.sub.3, standard substance:
CFCl.sub.3 .delta.: -57.2 (S, 3F), -79.5 (s, 1F)
[0057] GLC-MS m/z (rel. intensity), 128(M.sup.+, 44.0), 113(70.4),
109(32.0), 89(29.2), 78(12.8), 77(23.6), 69(22.4), 64(22.8),
59(29.6), 57(24.4), 51(18.8), 45(14.8), 39(100)
[0058] (3) (Z)-CF.sub.3CH.dbd.CFCH.sub.3
[0059] a colorless, transparent liquid
[0060] .sup.1H-NMR solvent: CDCl.sub.3, standard substance: TMS
.delta.: 5.00 (dq, J=32.7 Hz, 7.6 Hz, 1H), 1.99 (d, J=18.7 Hz,
3H)
[0061] .sup.19F-NMR solvent: CDCl.sub.3, standard substance:
CFCl.sub.3 .delta.: -58.9 (dd, J=17.1 Hz, 6.4 Hz, 3F),
-83.2.about.-83.7 (m, 1F)
[0062] GLC-MS m/z (rel. intensity), 128(M.sup.+, 44.0), 113(72.0),
109(37.2), 89(31.2), 78(11.6), 77(25.6), 69(25.6), 64(22.4),
59(29.6), 57(25.2), 51(20.0), 45(15.2), 39(100)
EXAMPLE 2
[0063] A (polytetrafluoroethylene) coating magnetic stirring bar, a
dropping funnel (under the liquid level), and a Vigreux column were
attached to a 250 ml flask. The outlet of the column was passed
into an oil bubbler, and it was connected to a collector cooled
down to -78.degree. C. 80 g of 85% potassium hydroxide (in the form
of flakes) were added to the flask, and it was heated to
210.degree. C. using an oil bath, followed by gradual dropping of
1,1,1,3,3-pentafluorobutane. The products and the unreacted raw
material were collected by the collector. The obtained mixture
contained seven kinds of products in addition to the raw material.
In gas chromatograph area at the reaction termination, the raw
material was in 50%, (E-) configuration was in 17.8%, (Z-)
configuration was in 17.8%, CF.sub.3CH.sub.2CF.dbd.CH.sub.2 was in
8.0%, and the remainder of 6.4% was a mixture containing butadiene
and butyne. It was possible to easily separate
(E)-CF.sub.3CH.dbd.CFCH.sub.3 (boiling point: 18-19.degree. C.) and
(Z)-CF.sub.3CH.dbd.CFCH.sub.3 (boiling point: 48-49.degree. C.)
with a purity of 98% or higher by distillation. These structures
were identified by mass spectroscopy and NMR.
COMPARATIVE EXAMPLE 1
[0064] A nickel reaction tube of {fraction (3/4)} inches (1.91 cm)
diameter and 36 inches (91.4 cm) total length was heated to
630.degree. C., and the reaction tube was filled with a nickel
Pro-pack (void ratio=96%) of 0.24 inches (0.61 cm)) for the purpose
of obtaining higher mixing effect and heat transfer effect. In this
condition, 1,1,1,4,4,4-hexafluorobutane was gasified by the same
process as that of Example 1 and introduced at a flow rate such
that the contact time became 30 seconds. The gas, which had passed
the tube, was passed through water in order to remove hydrogen
fluoride (HF), followed by drying with calcium sulfate and then gas
chromatograph analysis.
[0065] As a result, the gas chromatograph area of the raw material
1,1,1,4,4,4-hexafluorobutane was 43.2%, and 30.6%
3,3,3-trifluoropropene and 17.1% trifluoromethane were additionally
detected. The target 1,1,4,4,4-pentafluoro-1-butene was not
detected.
COMPARATIVE EXAMPLE 2
[0066] Using the same apparatus as that of Comparative Example 1,
2-(trifluoromethyl)-1,1,1-trifluoropropane was introduced in the
form of gas at 660.degree. C. As a result of conducting the GC
analysis of the outflow gas, the raw material was in 18.9%,
3,3,3-trifluoropropene was in 24.5%, and trifluoromethane was in
43.5%. The target 2-trifluoromethyl-1,1 difluoropropene was not
detected.
* * * * *