Process of preparing 3-trifluoromethyl benzoic acid

A technology of trifluoromethylbenzoic acid and trichloromethyltrifluoromethylbenzene, which is applied in the field of preparation of 3-trifluoromethylbenzoic acid, can solve problems such as unfavorable industrial production, affecting product purity, and difficulty in obtaining raw materials

Inactive Publication Date: 2007-11-07
SHANGHAI CHEMSPEC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main shortcoming of above-mentioned method is: (1) raw material is difficult to obtain, and price is expensive, (2) hydrolysis reaction uses the sodium hydroxide solution (2.5 -10%); then use the very dilute hydrochloric acid (10%) of concentration to acidify and separate out 3-trifluoromethylbenzoic acid, thus causing a large amount of alkali, acid, water, and producing a large amount of waste water, thus It leads to high cost of industrialization, and at the same time creates a large burden on the process and wastewater treatment
[0005] The method reported by German patent (DE3813452, 1988) is to use m-ditrifluoromethylbenzene as a raw material, and reflux hydrolysis with 30% oleum of 1.3 moles to obtain 3-trifluoromethylbenzene with a yield of 66%. Formic acid; the shortcoming of this method is to produce a large amount of waste acid, and contain a large amount of hydrofluoric acid in the waste water liquid, strict to equipment material requirement, in addition the by-product m-dibenzoic acid that generates also influences product purity (product purity is 97.5%)
[0006] The cost of preparing 3-trifluoromethylbenzoic acid in the prior art is high, and a large amount of waste water and waste liquid are produced, which is not conducive to large-scale industrial production

Method used

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  • Process of preparing 3-trifluoromethyl benzoic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0064] Preparation of m-Ditrichloromethylbenzene

[0065] After mixing 563 mol parts of m-ditrichloromethylbenzene and 1689 mol parts of m-xylene, the temperature in the reactor was raised to 120°C, then the ultraviolet lamp was turned on, chlorine gas was introduced, and the temperature in the reactor was maintained at 120-140°C. The reaction proceeded for 30 hours. According to the analysis by gas chromatograph, the content of m-dichloromethyltrichloromethylbenzene, an intermediate of the chlorination reaction, is less than 0.5%. Measured by GC-MS method, the reaction product is m-dichloromethylbenzene.

[0066] Degas under reduced pressure, and distill the reaction liquid under reduced pressure. Collect the fractions at 154-158℃ / 10mmHg to obtain 2068 parts of m-ditrichloromethylbenzene. The yield of the chlorination reaction is 89.3%. The purity of benzene is 97.2%.

Embodiment 2-9

[0068] Preparation of m-Ditrichloromethylbenzene

[0069] It was carried out in the same manner as in Example 1, except that the reaction temperature, raw material ratio and reaction time were as shown in Table 1. Table 1 also shows the yield and purity of m-ditrichloromethylbenzene and the content of high boilers in the resulting product.

[0070] In addition, Example 8 used 2% by weight of azobisisobutyronitrile (based on the weight of meta-xylene) as the initiator instead of UV initiation.

Embodiment 9

[0071] Example 9 uses 2% by weight of benzoyl peroxide (based on the weight of meta-xylene) as the initiator instead of UV initiation.

[0072] Implement

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Abstract

The process of preparing 3-trifluoromethyl benzoic acid includes the following steps: preparing meta-bis(trichloro methylbenzene) through the reaction of metaxylene and chlorine in meta-bis(trichloro methylbenzene) solvent under the action of initiator or photoinitiator; preparing meta-trichloromethyl trifloromethyl benzene through the fluoridation of meta-bis(trichloro methylbenzene) and hydrogen fluoride in the presence of catalyst, and preparing 3-trifluoromethyl benzoic acid through the hydrolysis reaction of meta-trichloromethyl trifloromethyl benzene in the presence of zinc-containing catalyst and water.

Description

Technical field [0001] The invention relates to a preparation method of 3-trifluoromethyl benzoic acid. Background technique [0002] 3-Trifluoromethyl benzoic acid is a very useful intermediate, which has been widely used in the fields of pesticides, medicine and fine chemicals. [0003] U.S. Patent (US305203,1962) discloses the use of m-halogenated trifluorotoluene as a raw material to carry out a Grignard reaction, and then react with carbon dioxide to prepare 3-trifluoromethyl benzoic acid; however, because of the Grignard reaction, As a result, the production cost of this route is relatively high, and it is not conducive to mass production. [0004] The Chinese patent (CN1356306) discloses the use of m-trifluoromethyl benzyl chloride as a raw material, the chlorination reaction occurs under the catalysis of an initiator, followed by a hydrolysis reaction in a dilute sodium hydroxide solution and acidification with dilute hydrochloric acid to obtain 3-trifluoromethylbenzyl ch...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C63/70C07C51/093
Inventor 蔡国荣姜宝仅陈旻
Owner SHANGHAI CHEMSPEC CORP
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