Chemistry: electrical and wave energy – Processes and products – Processes of treating materials by wave energy
Patent
1995-05-01
1997-09-02
Tsang, Cecilia J.
Chemistry: electrical and wave energy
Processes and products
Processes of treating materials by wave energy
20415787, 20415789, 20415794, 20415811, C07B 3900
Patent
active
056635435
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for producing a polyfluoropropionyl halide.
BACKGROUND ART
As methods for producing polyfluoropropionyl halides, (1) a method of oxidizing 1,1,1,3-tetrachlorotetrafluoropropane with fuming sulfuric acid in the presence of a halogen and under irradiation with light (Japanese Unexamined Patent Publication No. 237040/1985), and (2) a method by electrolytic fluorination of butyryl fluoride (U.S. Pat. No. 2,717,871) are, for example, known.
The method (1) can not be regarded as an industrial method, since a waste acid containing chlorine is formed in a large amount as a by-product. On the other hand, the method (2) can not be regarded as an economical method, since a large quantity of electric power is required, and a cost is required for separation from hydrogen gas formed as a by-product.
DISCLOSURE OF THE INVENTION
The present invention has been made to overcome the drawbacks of the conventional methods and is a method for producing a polyfluoropropionyl halide of the formula RCF.sub.2 COX (wherein R is a CF.sub.3 group or a CClF.sub.2 group, and X is a Cl atom or a F atom), which is characterized by oxidizing at least one dichloropentafluoropropane (hereinafter referred to as R-225) selected from 3,3-dichloro-1,1,1,2,2-pentafluoropropane (hereinafter referred to simply as R-225ca) and 1,3-dichloro-1,1,2,2,3-pentafluoropropane (hereinafter referred to simply as R-225cb) by oxygen under irradiation with light and in the presence of chlorine.
The reaction of the present invention can be conducted in either a liquid phase or a gas phase. In the liquid phase reaction, it is preferred to employ a solvent having a high solubility of oxygen and chlorine to be present in the reaction system, for example, a perfluoro compound such as perfluorohexane, R-225ca or R-225cb.
The amount of the chlorine present is not particularly limited. However, if it is too small, the reaction rate decreases, and if it is too large, the by-product increases. Therefore, it is advisable to employ chlorine preferably in an amount of from 0.01 to 200 mols, more preferably from 0.3 to 200 mols, further preferably from 5 to 50 mols, per 100 mols of R-225. Such an amount of the chlorine present, may, of course, be varied to some extent depending upon various reaction conditions such as the temperature, the pressure or the reaction solvent.
The reaction temperature is not particularly limited so long as it is above the dew point of R-225 in the feed gas composition in the gas phase reaction. It is usually preferably within a range of from room temperature to 200.degree. C., particularly within a range of from 50.degree. to 150.degree. C. In the liquid phase reaction, it is usually preferably within a range of from -50.degree. to 100.degree. C., particularly within a range of from -20.degree. to 70.degree. C.
The reaction pressure is not particularly limited in the gas phase reaction or in the liquid phase reaction, and the reaction readily proceeds under an optional pressure, for example, under atmospheric pressure. It of course depends upon other conditions such as the reaction temperature. For example, when the reaction is conducted in a liquid phase, it is preferred to conduct the reaction under a pressurized system in order to increase the dissolved amount of oxygen. Also in the gas phase reaction, it is preferred to conduct the reaction under a pressurized system in view of the reaction rate and the efficiency of the apparatus, so long as the temperature is above the dew point of R-225 in the feed gas composition, and the pressure is usually within a range of from atmospheric pressure to 5 kg/cm.sup.2 (gauge), more preferably within a range of from atmospheric pressure to 3 kg/cm.sup.2 (gauge). By increasing the amount of oxygen, the conversion of R-225 will usually increase.
The oxidation reaction by oxygen under irradiation with light according to the present invention can be carried out while diluting the oxygen preliminarily with a compound inert to the reaction intermedi
REFERENCES:
patent: 3715294 (1973-02-01), Browell et al.
patent: 3883407 (1975-05-01), Dittman et al.
patent: 4004572 (1977-01-01), Nathan et al.
patent: 4449516 (1984-05-01), Kitao et al.
patent: 5259938 (1993-11-01), Huang et al.
Kurata Hideyuki
Morikawa Shinsuke
Ohnishi Keiichi
Okamoto Hidekazu
Sato Yoshio
AG Technology Co., Ltd.
Delacroix-Muirheid Cybille
Tsang Cecilia J.
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