Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Reexamination Certificate
2000-03-01
2002-05-28
Siegel, Alan (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
Reexamination Certificate
active
06395940
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to methods for producing chlorofluorocyclopentenes and octafluorocyclopentene, which are useful as intermediates for 1,2,3,3,4,4,5,5-octafluorocyclopentane, which is useful as a fluorine-containing detergent, a fluorine-containing drying solvent, or the like, and as intermediates for various fluorine-containing compounds.
It is known that fluorinated cyclopentanes are produced at first by fluorinating chlorinated cycloalkenes corresponding to the fluorinated cyclopentanes to obtain vicinally chlorinated fluorocyclopentene derivatives, and then by fluorinating and hydrogenating these derivatives. It is known that vicinally chlorinated fluorocyclopentene derivatives are produced by a first method, in which perchlorocycloolefins are used, or a second method, in which perchloro cycloconjugated dienes are used. As an example of the first method, J. Am. Chem. Soc., 67, 1235 (1945) discloses a method for producing 1,2-dichlorohexafluorocyclopentene by reacting octachlorocyclopentene with a mixture of antimony trifluoride and antimony trifluorodichloride. Furthermore, German Patent No. 3935493 discloses a method for producing 1,2-dichlorohexafluorocyclopentene by reacting octachlorocyclopentene with chlorine and hydrogen fluoride in the presence of antimony pentachloride. As an example of the second method, Japanese Patent First Publication JP-A-8-333285 discloses a method for producing 1,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene at first by reacting hexachlorocyclopentadiene with chlorine in the presence of antimony trichloride, thereby to respectively convert the hexachlorocyclopentadiene and antimony trichloride to octachlorocyclopentene and antimony pentachloride, and then by adding hydrogen fluoride thereto. On the other hand, U.S. Pat. No. 2,459,783 discloses a method for producing 1,2-dichlorohexafluorocyclopentene by reacting hexachlorocyclopentene with antimony pentafluoride. U.S. Pat. No. 2,449,233 discloses a method for producing 1,2-dichlorohexafluorocyclopentene by reacting hexachlorocyclopentadiene with hydrogen fluoride in the presence of antimony pentachloride.
In each of the above-mentioned conventional methods, a liquid phase reaction in the presence of an antimony halide catalyst is used. Thus, corrosiveness of the antimony halide may cause problems. Furthermore, in case that hydrogen fluoride is used as a fluorination-agent in an industrial scale production, the reaction pressure may become as high as 10-30 kg/cm
2
. This may cause some limitations in the selection of devices.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method for producing a perhalogenated cyclopentene, particularly octafluorocyclopentene, which method is appropriate for the production of the same in an industrial scale.
According to the present invention, there is provided a method for producing a first perhalogenated cyclopentene represented by the general formula C
5
Cl
B
F
8−B
where B is an integer of from 0 to 7. The method comprises a step of (a) fluorinating a second perhalogenated cyclopentene by hydrogen fluoride in a gas phase in the presence of a fluorination catalyst. The second perhalogenated cyclopentene is represented by the general formula C
5
Cl
A
F
8−A
where A is an integer of from 1 to 8, and A is not smaller than B. With this method, the first perhalogenated cyclopentene (e.g., 1,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene, another chlorofluorinated cyclopentene, or octafluorocyclopentene) can continuously easily be produced, for example, from octachlorocyclopentene obtained by chlorination of hexachlorocyclopentadiene that is easily available. Therefore, the above method is very useful as an industrial scale production method.
According to the present invention, in case that the first 1o perhalogenated cyclopentene is octafluorocyclopentene, the above method may further comprise a step of (b) fluorinating a reaction product of the step (a) in a way that is different from that of the step (a), thereby to convert the reaction product of the step (a) into octafluoropentene. The reaction product of the step (a) is a perhalogenated cyclopentene represented by the general formula C
5
Cl
B
F
8−B
where B is an integer of from 0 to 7 or the general formula C
5
Cl
A
F
8−A
where A is an integer of from 1 to 8, and A is not smaller than B.
According to the present invention, the above step (a) may be conducted by a multistep reaction wherein there are provided “m” of reaction zones in number where m is an integer of from 2 to 10. The reaction zones are arranged in series and such that a reaction temperature of each reaction zone is independently controllable. With this multistep reaction, it becomes possible to decrease the production of tarry substances and thus maintain the fluorination catalyst in lifetime. Therefore, it becomes possible to produce the first perhalogenated cyclopentene continuously for a long time without interrupting the operation.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the invention, 1,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene-1 is 1,2-dichlorohexafluorocyclopentene or 1,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene. Hereinafter, unless otherwise described, octachlorocyclopentene used as the raw material of the method of the invention may be replaced with a chlorofluorocyclopentene obtained by partially fluorinating octachlorocyclopentene. Furthermore, “1,2-dichlorohexafluorocyclopentene” as the reaction product may include other chlorofluorocyclopentenes, chloroheptafluorocyclopentene, and octafluorocyclopentene.
As stated above, the first perhalogenated cyclopentene, the aimed product of the invention, is represented by the general formula C
5
Cl
B
F
8−B
where B is an integer of from 0 to 7. In other words, the number of chlorine atoms of this cyclopentene is an integer of 0-7, and the number of fluorine atoms thereof is an integer of 1-8, and the total of the number of chlorine atoms and that of fluorine atoms is 8. In this cyclopentene, the halogen atom may be bonded to any carbon atom. The first perhalogenated-cyclopentene is not particularly limited, and its nonlimitative examples are octafluorocyclopentene, 1-chloro-heptafluorocyclopentene, 1,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene, 1,2,4-trichloro-3,3,4,5,5-pentafluorocyclopentene, 1,2,3,4-tetrachloro-3,4,5,5-tetrafluorocyclopentene, 1,2,3,4,4-pentachloro-3,5,5-trifluorocyclopentene, hexachloro-3,3-difluorocyclopentene, hexachloro-4,4-difluorocyclopentene, and heptachloro-5-fluorocyclopentene.
As stated above, the second perhalogenated cyclopentene, the raw material of the invention, is represented by the general formula C
5
Cl
A
F
8−A
where A is an integer of from 1 to 8. In other words, the number of chlorine atoms of this cyclopentene is an integer of 1-8, and the number of fluorine atoms thereof is an integer of 0-7, and the total of the number of chlorine atoms and that of fluorine atoms is 8. In this cyclopentene, the halogen atom may be bonded to any carbon atom. The second perhalogenated cyclopentene is not particularly limited, and its nonlimitative examples are 1-chloro-heptafluorocyclopentene, 1,2-dichloro-3,3,4,4,5,5-hexafluorocyclopentene, 1,2,4-trichloro-3,3,4,5,5-pentafluorocyclopentene, 1,2,3,4-tetrachloro-3,4,5,5-tetrafluorocyclopentene, 1,2,3,4,4-pentachloro-3,5,5-trifluorocyclopentene, hexachloro-3,3-difluorocyclopentene, hexachloro-4,4-difluorocyclopentene, heptachloro-5-fluorocyclopentene, and octachlorocyclopentene.
The first or second perhalogenated cyclopentene of the invention can be synthesized by a conventional method. For example, Newcomer; McBee, J. Amer. Chem. Soc., 71<1949>946, 950 discloses a method for producing octachlorocyclopentene by chlorinating hexachlorocyclopentadiene by chlorine in the presence of a catalyst (e.g., metal chloride). Furthermore, Henne et al., J. Am. Chem. Soc., 67, 1235 (1945) discloses a reaction of octachlorocyclopentene with a mixture of antimony trifluoride and antimony trifluorodichlorid
Imura Hideaki
Kanai Masatomi
Komata Takeo
Nishimiya Takayuki
Sakyu Fuyuhiko
Central Glass Company Limited
Crowell & Moring LLP
Siegel Alan
LandOfFree
Method for producing perhalogenated cyclopentene does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for producing perhalogenated cyclopentene, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for producing perhalogenated cyclopentene will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2915739