GB2271989A

GB2271989A - Process for the preparation of fluorinated ethanic compounds

Info

Publication number: GB2271989A
Application number: GB9317591A
Authority: GB
Inventors: Valentin Vasil Evic Satalov; Valentin Timofeevic Orechov
Original assignee: INT CHEM TECH CO Ltd
Current assignee: INT CHEM TECH CO Ltd
Priority date: 1992-08-25
Filing date: 1993-08-24
Publication date: 1994-05-04
Anticipated expiration: 2013-08-24
Also published as: FR2695123A1; TW232680B; ES2072817A1; ITMI931843A0; IT1287886B1; CN1085538A; GB9317591D0; ITMI931843A1; MX9305161A; GB2271989B; JPH06219976A; KR960008639B1; ES2072817B1; FR2695123B1; KR940003903A; DE4328606C2; DE4328606A1; CA2104654A1

Description

1 2271989 PROCESS FOR THE PREPARATION OF FLUORINATED ETHANIC COMPOUNDS The

present invention relates to a process for preparing halogenated organic compounds; and, particularly to a process for preparing fluorinated ethanic compounds as a substitute for WC(chlorofluorocarbon) known to be destructive of the ozone layer.

There are a number of catalytic methods known for the manufacture of fluorinated ethanic compounds. In the Proposal on Replacement of the Freons Destroying the Earth's Ozone Layer with Ozone-Safe substitutes (Proceedings of All-Union Conference on Refrigerating and Ozone-Safe Freons, Leningrad, Ozone-Safe, 1989), there is provided a catalytic hydrofluorination for the preparation of fluorinated ethanic compounds, which uses antimony pentachloride as a catalyst in liquid phase. The process is carried out at a temperature ranging from 130 to 1600C and a pressure ranging from 6 to 8 kg/CM2G. The hydrofluorination in gaseous phase is carried out at a temperature ranging from 150 to 3501C on a catalyst.

The prior methods for manufacturing a chlorofluorocarbon - 2 are generally based on the concept of replacing the chlorine atoms with fluorine atoms.

For example, United States Patent No. 3,235,608(1966) describes the fluorination process of chlorinated or fluorochlorinated Cl-12 hydrocarbons using uranium hexafluoride. The fluorination is conducted by employing an inorganic fluoride catalyst such as fluorides of sodium, potassium, calcium, etc. in a fluidized bed at a temperature ranging from 70 to 6000C. However, this method is not economical since it requires the fluoride catalyst and an excess amount of uranium hexafluoride.

Further, United States Patent No. 3,382,049 describes a method of fluorinating trichloroethylene by employing uranium hexaf luoride. The main purpose of fluorination in this method is to obtain uranium tetrafluoride, and, therefore, detailed information on organic compound, an auxiliary product, is not provided. Furthermore, it is observed that any excess amount of uranium hexafluoride in the reactor may destroy the HWC122a compound produced to CFC-113 compound.

The present inventors have pursued to solve the above-mentioned problems; and, as a result, succeeded in developing a method for preparing a fluorinated ethanic compound, which can be less harmful to the ozone layer, by lowering the excess amount of ethylenic compound as starting material to uranium hexafluoride as a catalyst a during the reaction between said two components.

V Summarv of the Invention Accordingly, it is an.aim of the present invention to provide an improved process for preparing a fluorinated ethanic compound.

In accordance with one aspect of the invention, there is provided a process for preparing a fluorinated ethanic compound, which comprises reacting ethylene or a halogenated ethylenic compound with uranium hexaf luoride at an elevated temperature wherein the molar ratio of ethylene or the halogenated ethylenic compound to uranium hexafluoride ranges from 1:1 to 1.2:1.

In the process of the present invention, a fluorinated organic compound is obtained by the fluorination of an unsaturated ethylenic compound with uranium hexaf luoride as shown in the following reaction formula(l):

.I.I "C C + UF W - CF,-, + UF le, 6 4 (1) The halogenated ethylenic compound used in the process of the present invention may Include trichloroethylene(C2 HC13)I vinylidene chloride (C2H2C12), vinyl chloride (C2H3C1). vinylidene fluoride(C2H2F2) and the like.

4 - The uranium hexaf luoride may be diluted with an inert diluent gas to make a concentration of 20-100>. by volume for the fluorination reaction, particularly for obtaining a stable organic compound. - The inert diluent may include nitrogen, neon, argon and the like. As a diluent, the product, fluorinecontaining orgainc substances may be employed by recycling.

The choice of the limited molar ratios pertaining to ethylene or the halogenated ethylenic compound and uranium hexafluoride to be fed is based on the fact that if uranium hexafluoride is fed in an amount greater than the upper limit of the range, it makes the end product to be subjected to degradation or decomposition due to its interreaction with the excessive uranium hexafluoride; and, if uranium hexafluoride is fed in a smaller amount than the lower limit, it leads to an overexpenditure of ethylene or the halogenated ethylenic compound and overall impairment of the final product.

Ethylene or the halogenated ethylenic compound is preferably fed into the reactor in a dispersed form, thereby to improve the reaction efficiency and to provide the desirable fluorination process in the flare. Accordingly, the reaction of ethylene or the halogenated ethylenic compound with uranium hexafluoride is carried out by spraying each component into the reaction system and mixing and contacting with each other.

The fluorination reaction is conducted at an elevated temperature ranging from 80 to 4001C, preferably 100 to 3500C c A 1 and under a slightly lower pressure than atmospheric pressure, preferably -20mm H 20- The fluorinated organic compounds obtained in accordance with the present invention have f luorines in both 1 and 2 positions of their chains.

The quantitative and qualitative analyses of the compounds thus obtaind can be conducted by a gas chromatography, IR spectrometry and NMR method(using H and F19) to determine their composition.

The following Examples illustrate the present invention more specifically, without limiting the scope of the invention.

Examr)le 1 In a reactor was continuously fed uranium hexafluoride gas as a fluorinating agent at a flow rate of 2.0 kg/hr (5.682 moles/hr) through a spray nozzle. Simultaneously, nitrogen gas was charged into the reactor at a flow rate of 318.1 NI/hr(I4.2 moles/hr) as a diluent.

Trichloroethylene was fed into the reactor through another spray nozzle while maintaining the molar ratio of trichloroethylene to uranium hexafluoride in the reactor at 1.08:1.0. The fluorination process was carried out as follows:

CHcl = CC1 2 + UF 6 - CHClF - CC12F + UF4 (HCFC-122a) 6 - Fluorination was carried out at the temperature of 200C and under a pressure of -20mm H20.

The reaction product mixture was passed through the filter made of a porous nickel to remove uranium tetraf luoride dusts and the remaining gas was condensed in a trap cooled with liquid nitrogen to obtain the product as a liquid.

The content of 1,2-difluorotrichloroethane contained in the organic product was 88.7 wt>. and that of 1,1-difluorotrichloroethane did not exceed 1 wt."...

Example 2

The procedures described in Example 1 above were repeated except that the molar ratio of trichloroethylene to uranium hexafluoride was maintained at 1.07:1.0.

The content of 1,2-difluoro-trichloroethane in the organic product was 85 wt>. and that of 1,1-difluorotrichloroethane did not exceed 1 wt>..

ExamDle 3 The procedures described in Example 1 above were repeated except that the molar ratio of trichloroethylene to uranium hexafluoride was maintained at 1.01:1.0.

The content of 1,2-difluoro-trichloroethane in the organic product was 81 wt>. and that of 1,1-difluoro- J_ trichloroethane did not exceed 1 wt>..

Example 4

Similarly to Example 1, the fluorination process was carried out by using vinylidene chloride as the starting material as follows:

CH2 = CC1 2 + UF 6 -"' CH 2 F - CC1 2 F + UF (HWC 132C) The molar ratio of vinylidene chloride to uranium hexafluoride was maintained at 1.07:1.0. The fluorination reaction was carried out at the temperature of 1500C and under a pressure of -20mm H 2 0.

The content of 1, 2-dif luoro-dichloroethane in the organic product was 65 wt% and that of 1, 1-dif luoro-dichloroethane did not exceed 1 wt%.

Example 5

Similarly to Example 1, the fluorination process was carried out by using vinyl chloride as the starting material as follows:

CH 2 CHCl + UF 6 -" CH 2F - CHCIF + UF WCFC 142a) 4 8 - The molar ratio of vinyl chloride to uranium hexaf luoride was maintained at 1.06:1.0. The fluorination reaction was carried out at the temperature of 1200C and under a pressure of -20mm H 20.

The content of 1,2-difluoro-chloroethane in the organic product was 63 wt> . and that of 1,1-difluoro-chloroethane did not exceed 1 wt%.

Exami:)1e 6 Similarly to Example 1, the fluorination process was carried out by using ethylene as the starting material as f ollows:

CH 2 CH 2 + UF 6 _ CH 2 F - CH 2 F + UF (HFC - 152) The molar ratio of ethylene to uranium hexafluoride was maintained at 1. 08:1.0. The reaction was carried out at the temperature of 1000C and under a pressure of -20mm H 20 The content of 1, 2-dif luoro-ethane in the organic product was 54wtk and that of 1,1-difluoro-ethane did not exceed 1 wt>..

Example 7

Similarly to Example 1, the fluorination process was carried out by using vinylidene fluoride as the starting material as follows:

CH2 " W 2 + UF 6 -,' CH 2 F - W 3 + UF 4 (HFC - 134a) The molar ratio of vinylidene fluoride to uranium hexafluoride was maintained at 1.06:1.0. The reaction was carried out at the temperature of 3500C and under a pressure of -20mm H 2 0.

The content of 1,1,1,2-tetrafluoroethane in the organic product was 47 wt% and that of 1,1,2,2-tetrafluoroethane did not exceed 1 wt%.

As shown in the above Examples, in accordance with the present invention, the fluorination of unsaturated ethylenic organic compounds with uranium hexafluoride produces organic compounds containing fluorines in the 1 and 2 positions of the their chains in surprisingly high yields, which has not been possible hitherto.

The use of the present method has an added advantage in that it provides a basically wasteless process. The fluoroorganic isomers obtained have a smaller polarity, and, therefore, a higher solubility with respect to fats, oils, - 10 etc. Besides, the process makes it possible to obtain uranium tetrafluoride.

While the present invention has been shown and described with reference to the particular embodiments, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the spirit and scope of the invention as defined in the claims.

14

Claims

CLAIMS:

A process for preparing a fluorinated ethanic organic compound, which comprises reacting ethylene or a halogenated ethylenic compound with uranium hexaf luoride at an elevated temperature wherein the molar ratio of ethylene or the halogenated ethylenic compound to uranium hexafluoride ranges from 1:1 to 1.2:1.
2. A process according to claim 1, wherein the uranium hexafluoride is diluted with an inert gas to a concentration of 20 to 100% by volume.
3. A process according to claim 2, wherein the inert gas is selected f rom the group consisting of nitrogen, neon, argon and fluorinated organic substances recycled from the reaction system.
4. A process according to any one of claims 1 to 3, wherein the halogenated ethylenic compound is selected from the group consisting of trichloroethylene (C 2 HCl 3)l vinylidene chloride (C 2 H 2 cl 2)l vinyl chloride (C 2 H 3 Cl) and vinylidene fluoride (C 2 H 2 F 2)
5. A process according to any one of the preceding claims, wherein the reaction of ethylene or the halogenated ethylenic compound and uranium hexaf luoride is carried out by spraying each component into the reaction system in a dispersed form and mixing and contacting with each other.
6. A process for preparing a fluorinated ethanic compound, substantially as hereinbef ore described with reference to any one of the Examples.

6i v