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Preparation method of p-trifluoromethyl salicylic acid

A technology of trifluoromethyl salicylic acid and trifluoromethyl benzoate, which is applied in the field of preparation of p-trifluoromethyl salicylic acid, can solve the problem of increased safety hazards, low yield, and unsuitability for large-scale production and other issues to achieve the effect of improving the reaction efficiency

Active Publication Date: 2014-02-05
CHANGZHOU SUNLIGHT PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this method are: (1) the reaction pressure is as high as 40atm, which increases the potential safety hazard; (2) the reaction time is long, which takes about a week; (3) the yield is low, only 65%, which is not suitable for large-scale industrialization Production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1）

[0011] The preparation method of trifluoromethyl salicylic acid of the present embodiment has the following steps:

[0012] ①Add 162g of m-trifluoromethylphenol (1mol) and 318g of anhydrous sodium carbonate (3mol) into the autoclave, then feed carbon dioxide (about 2mol) into the autoclave, slowly under the pressure of 10atm Raise the temperature to 160°C and react at this temperature for 24h to obtain a mixture containing sodium 2-hydroxy-4-trifluoromethylbenzoate.

[0013] ② Cool the mixture containing sodium 2-hydroxy-4-trifluoromethylbenzoate obtained in step ① to ambient temperature (0°C-40°C, the same below), and then add it to 3L of hot water at a temperature of 70°C to dissolve to obtain The solution containing 2-hydroxy-4-trifluoromethylbenzoate was cooled to ambient temperature and extracted twice with ether.

[0014] ③ Adjust the extract obtained in step ② to pH 3 with hydrochloric acid, then filter, then wash the filter cake with deionized water, and recrystallize...

Embodiment 2）

[0016] The preparation method of trifluoromethyl salicylic acid of the present embodiment has the following steps:

[0017] ① Add 162g of m-trifluoromethylphenol (1mol) and 318g of anhydrous sodium carbonate (3.5mol) into the autoclave, and then feed carbon dioxide (about 2.5mol) into the autoclave, at a pressure of 12atm Slowly raise the temperature to 165°C, and react at this temperature for 20h to obtain a mixture containing sodium 2-hydroxy-4-trifluoromethylbenzoate.

[0018] ② The mixture containing 2-hydroxyl-4-trifluoromethylbenzoate obtained in step ① is cooled to ambient temperature, and then added to 2.8L of hot water at a temperature of 90°C to obtain a mixture containing 2-hydroxyl-4-trifluoromethylbenzoate The solution was cooled to ambient temperature and extracted twice with diethyl ether.

[0019] ③Adjust the extract obtained in step ② with hydrochloric acid to a pH value of 2.5, then filter, then wash the filter cake with deionized water, and recrystallize tw...

Embodiment 3）

[0021] The preparation method of trifluoromethyl salicylic acid of the present embodiment has the following steps:

[0022] ①Add 162g of m-trifluoromethylphenol (1mol) and 345g of anhydrous potassium carbonate (2.5mol) into the autoclave, and then feed carbon dioxide (about 1.5mol) into the autoclave, at a pressure of 8atm The temperature was slowly raised to 150° C., and reacted at this temperature for 22 hours to obtain a mixture containing sodium 2-hydroxy-4-trifluoromethylbenzoate.

[0023] ② The mixture containing 2-hydroxyl-4-trifluoromethylbenzoate obtained in step ① is cooled to ambient temperature, and then added to 3L of hot water at a temperature of 60° C. to obtain a mixture containing 2-hydroxyl-4-trifluoromethylbenzoate The solution was cooled to ambient temperature and extracted twice with diethyl ether.

[0024] ③Adjust the extract obtained in step ② with sulfuric acid to a pH value of 3.5, then filter, then wash the filter cake with deionized water, and recry...

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PUM

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Abstract

The invention discloses a preparation method of p-trifluoromethyl salicylic acid. The preparation method includes the following steps of firstly adding m-hydroxybenzotrifluoride and carbonate into a reaction device, feeding carbon dioxide into the reaction device, performing reaction for 20 hours to 24 hours at the temperature from 150 DEG C to 165 DEG C under the pressure of 8atm-12atm, and obtaining a mixture containing 2-hydroxyl-4-trifluoromethyl benzoate; secondly cooling the mixture to the ambient temperature, adding the mixture into hot water at the temperature from 60 DEG C to 90 DEG C to dissolve, cooling the solution to the ambient temperature, and subjecting the solution to extraction; and thirdly, adding acid to an extract solution so that the pH is within a range of 2 to 4, sequentially subjecting the extract solution to filtering, washing and recrystallization, and obtaining the p-trifluoromethyl salicylic acid. According to the preparation method of the p-trifluoromethyl salicylic acid, reaction pressure and reaction temperature are decreased, so that reaction time is greatly shortened, and the yield can reach over 90%.

Description

technical field [0001] The invention relates to a preparation method of a fluorine-containing drug intermediate, in particular to a preparation method of p-trifluoromethylsalicylic acid. Background technique [0002] p-Trifluoromethylsalicylic acid is the key raw material and intermediate of pesticides and medicines. [0003] Example 1 of US patent document US4110442 discloses a preparation method of 2-hydroxy-4-trifluoromethylbenzoic acid (ie, p-trifluoromethylsalicylic acid). The method is to react 162.11g of m-trifluoromethylphenol (1mol), 414.60g of anhydrous potassium carbonate (3mol) and carbon dioxide at a pressure of 40atm and a temperature of 190°C for one week. 2-Hydroxy-4-trifluoromethylbenzoic acid. The disadvantages of this method are: (1) the reaction pressure is as high as 40atm, which increases the potential safety hazard; (2) the reaction time is long, which takes about a week; (3) the yield is low, only 65%, which is not suitable for large-scale industria...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C65/05C07C51/15C07C51/02
CPCY02P20/141
Inventor 胡国宜吴建华金晓贤丁志伟
Owner CHANGZHOU SUNLIGHT PHARMA