Preparation method of trifluoroacetic acid

A technology of trifluoroacetic acid and trifluoroacetyl fluoride, applied in the preparation of acid halide, preparation of acid halide, preparation of halogenated hydrocarbons, etc., can solve the problems of difficult separation, high cost, and production of many by-products, etc.

Inactive Publication Date: 2014-01-22
CHANGSHU 3F ZHENFU NEW MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Among the above methods, the cost of trifluoroacetyl fluoride, an intermediate of trifluoroacetic acid produced by electrolytic fluorination, is relatively high in the process of separating from hydrogen, and the cost of preparing trifluoroacetic acid from CFC-113a is relatively high, while HCFC-123 itself is relatively expensive. Difficult to separate from its isomer HCFC-123a, more by-products will be produced during the reaction

Method used

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  • Preparation method of trifluoroacetic acid
  • Preparation method of trifluoroacetic acid
  • Preparation method of trifluoroacetic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Add 4230g of 1,1-difluoro-1,2,2-trichloroethane into a 5L enamel reactor with a reflux condenser, and illuminate with ultraviolet light, the material in the kettle is heated to 40°C, and then Feed chlorine, the chlorine feeding rate is 600g / hour, and the reaction time is 3 hours. The reaction product was degassed and rectified to obtain 3155 g of 1,1-difluorotetrachloroethane with a purity of 99.5%, and the yield was 84.7%.

[0023] Add 3840g of sulfur trioxide and 35g of chlorosulfonic acid in a 5L enamel reactor with a reflux condenser, and drop 3155g of the above-prepared 1,1-difluorotetrachloroethane into the reactor through a conduit for 2 hours After dripping, the temperature in the reactor is controlled at 50°C, and the temperature of the reflux condenser is controlled at 28°C. The gas generated by the reaction passes through concentrated sulfuric acid to absorb unreacted sulfur trioxide, and then obtains 2565g of liquid through compression distillation, which is...

Embodiment 2

[0027] Add 3375g of 1,1-difluoro-1,2-dichloroethane into a 5L enamel reactor with a reflux condenser, and illuminate with ultraviolet light, the temperature of the material in the kettle is raised to 45°C, and then the Chlorine, the chlorine feed rate is 1300g / hour, and the reaction time is 3 hours. The reaction product was degassed and rectified to obtain 2879 g of 1,1-difluorotetrachloroethane with a purity of 99.5%, and the yield was 77.3%.

[0028] Add 3840g of sulfur trioxide and 50g of chlorosulfonic acid in a 5L enamel reactor with a reflux condenser, and drop 2879g of the above-prepared 1,1-difluorotetrachloroethane into the reactor through a conduit for 2 hours After dripping, the temperature in the reactor is controlled at 60°C, and the temperature of the reflux condenser is controlled at 28°C. The gas generated by the reaction passes through concentrated sulfuric acid to absorb unreacted sulfur trioxide, and then obtains 2421.6g of purity 99.3%1 through compression ...

Embodiment 3

[0032] Add 2515g of 1,1-difluoro-1-chloroethane into a 5L enamel reactor with a reflux condenser, and illuminate with ultraviolet light. The feeding rate is 1770g / hour, and the reaction time is 4 hours. The reaction product was degassed and rectified to obtain 2340 g of 1,1-difluorotetrachloroethane with a purity of 99.5%, and the yield was 62.8%.

[0033] Add 3840g of sulfur trioxide and 50g of chlorosulfonic acid in a 5L enamel reactor with a reflux condenser, and drop 2340g of the above-prepared 1,1-difluorotetrachloroethane into the reactor through a conduit for 2 hours After dripping, the temperature in the reactor was controlled at 70°C, and the temperature of the reflux condenser was controlled at 28°C. The gas generated by the reaction passed through concentrated sulfuric acid to absorb unreacted sulfur trioxide, and then obtained 1953.3g of 1953.3g with a purity of 99.0%1 through compression distillation. 1-Difluoro-1-chloroacetyl chloride, yield 83.5%.

[0034] Add...

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Abstract

The invention discloses a preparation method of trifluoroacetic acid low in synthesis cost. The preparation method comprises the steps of (1) preparing 1,1-difluoro tetrachloroethane from 1,1-difluoroethane or chloride thereof through ultraviolet catalysis and a chlorine reaction; (2) implementing catalytic oxidation on the 1,1-difluoro tetrachloroethane to obtain 1,1-difluoro-1-chloroacetyl chloride, wherein in the catalytic oxidation, mol ratio of the 1,1-difluoro tetrachloroethane to an oxidizing agent is 1: (2-4), dosage of the catalyst is 0.5-5% of the total weight of an reactant, and reaction temperature is 50-70 DEG C; (3) carrying out hydrogen fluoride (HF) fluoridation on the 1,1-difluoro-1-chloroacetyl chloride under the catalyst to obtain trifluoroacetyl fluoride, wherein mol ratio of the 1,1-difluoro-1-chloroacetyl chloride to the HF is 1: (2-3), reaction temperature is 40-60 DEG C, and the catalyst is either antimony or antimony pentachloride; and (4) hydrolyzing the prepared trifluoroacetyl fluoride to obtain trifluoroacetic acid.

Description

technical field [0001] The invention relates to a preparation method of fluorine-containing carboxylic acid, in particular to a preparation method of trifluoroacetic acid. Background technique [0002] Trifluoroacetic acid (TFA for short) is an important starting material in the fields of medicine and pesticides. It can also be used as a solvent or catalyst for many reactants to improve its reaction performance, such as some esterification and polycondensation reactions. So far the known preparation methods of trifluoroacetic acid are as follows: [0003] (1) US 2,396,076 discloses that 1,1,1-trifluoro-2,2,2-trichloroethane (CFC-113a) and SO 3 Preparation of trifluoroacetyl chloride as raw material, hydrolysis with alkali, acidification with sulfuric acid and distillation of trifluoroacetic acid. [0004] (2) US 4,022,824 discloses a method for preparing trifluoroacetic acid by electrolytic fluorination of acetyl fluoride. [0005] (3) US 4,647,695 discloses a method for ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C53/18C07C51/04
CPCC07C51/04C07C17/10C07C51/58
Inventor 沈达
Owner CHANGSHU 3F ZHENFU NEW MATERIALS CO LTD
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