Process for producing trifluoro benzene acetic acid

A technology of trifluorophenylacetic acid and trifluorophenylacetic acid ester, which is applied in the field of preparation of trifluorophenylacetic acid, can solve the problems of reduced total yield, difficult product quality control, multiple pollutants, etc., and achieves mild reaction conditions and high product quality. The effect of stable quality and easy availability of raw materials

Inactive Publication Date: 2009-06-10
QUZHOU CHEMSPEC CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

U.S. Patent No. 6,870, reported a kind of use 2,4,5-trifluorobromobenzene to make Grignard reagent and bromide reaction in 067, obtain 2,4,5-trifluorophenylacetic acid in oxidation, oxidizing agent in this method Raw materials such as sodium periodate and catalyst ruthenium trichloride are relatively expensive, and there will be more side reactions when the Grignard reagent reacts with vinyl bromide, and the product quality is difficult to control
Chinese patent 1,003,471,42C has reported a method to obtain 2,4,5-trifluorophenylacetic acid through chloromethylation, cyanation and hydrolysis reaction with 1,2,4-trifluorobenzene, this method will CN (-) waste water, polluting the environment
European patent EP148,430, 4A1 reported a kind of reaction with bromobenzene and Mg to generate Grignard reagent, and then with ZnCl 2 Reaction generates Zn reagent, then reacts with bromoacetate, and then obtains the method of phenylacetic acid through hydrolysis, needs Grignard reagent and ZnCl in this method 2 Carry out metal exchange reaction, increase reaction step, cause total yield to reduce, industrialization cost is high, and will use at least equimolar ZnCl 2 , which increases the difficulty of post-treatment and creates more pollutants

Method used

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  • Process for producing trifluoro benzene acetic acid
  • Process for producing trifluoro benzene acetic acid
  • Process for producing trifluoro benzene acetic acid

Examples

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preparation example Construction

[0030] The preparation method of trifluorophenylacetic acid of the present invention: take trifluorobromobenzene as raw material and carry out Grignard reaction with Mg to obtain Grignard reagent, and then react Grignard reagent with bromoacetate in the presence of catalyst to obtain trifluorophenylethyl Ester, and then hydrolyzed under acidic or alkaline conditions to obtain the crude product of trifluorophenylacetic acid, and the content of trifluorophenylacetic acid obtained through post-treatment is ≥99%.

[0031] Beneficial effects of the present invention: the preparation method of trifluorophenylacetic acid of the present invention has easy-to-obtain raw materials, low cost, mild reaction conditions, simple and convenient operation, environment-friendly, and easy industrialization. The product quality is stable and suitable for large-scale industrial production.

Embodiment 1

[0034] Example 1 Preparation of ethyl 3,4,5-trifluorophenylacetate.

[0035] Add THF 200ml, Mg 26.4g (1.2mol) into a 500ml four-necked bottle, and add dropwise a solution of 3,4,5-trifluorobromobenzene 211g (1mol) and 150ml THF at about 30°C while stirring. Insulate and stir for 0.5 to 1 hour to end the reaction, the Grignard reagent is prepared, and insulate for later use. Put THF 250ml, CoCl 2 6.5g (0.05mol), 5.8g (0.05mol) of tetramethylethylenediamine. Stir at around 30°C for 15 minutes, cool down to -10-0°C, and slowly add Grignard reagent dropwise. After the dropwise addition, keep it warm for 0.5h, add 10% HCl dropwise below 10°C, adjust the pH to 3, remove the solvent, evaporate THF, and wash the residue with water until neutral to obtain 3,4,5-trifluorobenzene Ethyl acetate crude product 335.3g, content 57.76%, yield 88.8%. The boiling point is 103°C / mmHg.

Embodiment 2

[0036] Example 2 Preparation of 3,4,5-trifluorophenylacetic acid.

[0037] Put 3,4,5-trifluorophenylacetate ethyl 335.3 (content 57.76%, 0.888mol) and 20% NaOH aqueous solution 500g (2.5mol) into a 500ml four-necked bottle, heat up at 60-70°C for 2-3 hours, cool down Add 50ml of toluene to below 50°C and stir for 15 minutes, then let it stand for stratification, wash the water phase with 50ml of toluene*2 and put it back into the reaction bottle, add 30% hydrochloric acid dropwise below 30°C to adjust the pH of the system to 1, cool down to about 0°C and keep it warm for 30 minutes , suction filtration, the filter cake is 3,4,5-trifluorophenylacetic acid, washed with ice water, and dried to obtain 136g of the product, with a content of 99.5%, a yield of 80.6%, and a total yield of 71.6%. The boiling point is 131°C / 25mmHg.

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Abstract

The invention provides a method for preparing trifluorobenzene acetic acid. The method comprises: trifluorobromobenzene is used as raw material and magnesium undergo Grignard reaction to generate a Grignard reagent; in the presence of cobalt salt catalyst, the Grignard reagent reacts with bromoacetic acid ester to form trifluorobenzene acetate; under conditions of acid or alkali, the trifluorobenzene acetate is hydrolyzed to form a coarse product of the trifluorobenzene acetic acid; and the coarse product is post-treated to form the trifluorobenzene acetic acid with the concentration of more than 99 percent. The method has the advantages of easily bought raw material, low cost, mild reaction condition, simple operation, environmental protection and easy realization of industrialization, and the product prepared by the method has stable quality, and is easy in mass industrialized production.

Description

technical field [0001] The present invention relates to a kind of preparation method of trifluorophenylacetic acid Background technique [0002] Trifluorophenylacetic acid is an important intermediate that plays an irreplaceable role in the synthesis of pharmaceuticals and electronic materials. U.S. Patent 6,395,921 reports a reaction between trifluorobromobenzene and malonic acid diester under the action of alkali, decarboxylation and hydrolysis to obtain trifluorophenylacetic acid. This method is not suitable for large-scale industrial production. U.S. Patent No. 6,870, reported a kind of use 2,4,5-trifluorobromobenzene to make Grignard reagent and bromide reaction in 067, obtain 2,4,5-trifluorophenylacetic acid in oxidation, oxidizing agent in this method Raw materials such as sodium periodate and catalyst ruthenium trichloride are relatively expensive, and more side reactions will occur when the Grignard reagent reacts with vinyl bromide, and the product quality is diff...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/58C07C51/347
Inventor 张显飞李功勇张国鑫宋尚海陈金华
Owner QUZHOU CHEMSPEC CORP
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