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Method for preparing p-chloromethyl benzoic acid

A technology of chloromethylbenzoic acid and p-toluic acid, which is applied in the field of preparation of p-chloromethylbenzoic acid, can solve problems such as ineffective utilization, difficult purification and treatment, and increased production costs, so as to reduce the pressure on environmental protection , Reduce production costs, save raw materials

Inactive Publication Date: 2019-03-22
唐更好
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this method is that the conversion rate of the main product of monochlorine is only 75% to 80%, the purity is lower than 90%, the purification process is very difficult, the pressure on environmental protection is relatively large, and 10% to 15% of p-toluic acid is obtained. Less than effective use, increasing production costs

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  • Method for preparing p-chloromethyl benzoic acid
  • Method for preparing p-chloromethyl benzoic acid
  • Method for preparing p-chloromethyl benzoic acid

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Embodiment 1

[0025] The invention provides a kind of preparation method of p-chloromethylbenzoic acid, comprises the following steps:

[0026] (1) P-xylene is catalyzed and oxidized to obtain p-toluic acid;

[0027] (2) P-toluic acid and chlorobenzene are miscible at a ratio of 1:4 (w / v), exposed to light, and reacted with chlorine gas at 85°C until the melting point of the product is 190°C. After the reaction is terminated, the temperature is lowered to 80°C to obtain a mixture product;

[0028] (3) Step (2) gained mixed product is joined in the sodium carbonate solution of 0.5mol / L, separates chlorobenzene, utilizes the hydrochloric acid of 12mol / L to carry out acidification to saline solution, free monochlorine, dichloro, trichloro and Mixed products of p-toluic acid;

[0029] (4) Methanol is used to recrystallize the mixed product of step (3) gained monochloro, dichloro, trichloro and p-toluic acid to obtain a monochlorine main product, and its high performance liquid chromatogram is...

Embodiment 2

[0031] The invention provides a kind of preparation method of p-chloromethylbenzoic acid, comprises the following steps:

[0032] (1) P-xylene is catalyzed and oxidized to obtain p-toluic acid;

[0033] (2) P-toluic acid and chlorobenzene are miscible at a ratio of 1:3 (w / v), lighted, and reacted with chlorine gas at 90°C until the melting point of the product is 188°C. After the reaction is terminated, the temperature is lowered to 75°C to obtain a mixture product;

[0034] (3) Step (2) gained mixed product is joined in the sodium carbonate solution of 0.6mol / L, separates chlorobenzene, utilizes the hydrochloric acid of 10mol / L to carry out acidification to saline solution, dissociated monochlorine, dichloro, trichloro and Mixed products of p-toluic acid;

[0035] (4) Methanol is used to recrystallize the mixed product of monochloro, dichloro, trichloro and p-toluic acid obtained in step (3) to obtain monochlorine main product, and reclaim p-toluene after the mother liquor ...

Embodiment 3

[0037] The invention provides a kind of preparation method of p-chloromethylbenzoic acid, comprises the following steps:

[0038] (1) P-xylene is catalyzed and oxidized to obtain p-toluic acid;

[0039] (2) P-toluic acid and chlorobenzene are miscible at a ratio of 1:4 (w / v), lighted, and reacted with chlorine gas at 88°C until the melting point of the product is 189°C. After the reaction is terminated, the temperature is lowered to 76°C to obtain a mixture product;

[0040] (3) the mixed product of step (2) gained is joined in the sodium carbonate solution of 0.7mol / L, separates chlorobenzene, utilizes the hydrochloric acid of 11mol / L to carry out acidification to salt solution, free monochlorine, dichloro, trichloro and Mixed products of p-toluic acid;

[0041] (4) Methanol is used to recrystallize the mixed product of monochloro, dichloro, trichloro and p-toluic acid obtained in step (3) to obtain monochlorine main product, and reclaim p-toluene after the mother liquor co...

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Abstract

The invention discloses a method for preparing p-chloromethyl benzoic acid and belongs to the technical field of medicine synthesis. The method comprises the following steps: (1) preparing p-toluylicacid; (2) mixing and melting the p-toluylic acid with chlorobenzene, carrying out lighting treatment, introducing chlorine to carry out a reaction till the melting point of a product is 188-190 DEG C,and cooling after the reaction is completed so as to obtain a mixed product; (3) putting the mixed product into a sodium carbonate solution, separating chlorobenzene, acidifying the salt solution with hydrochloric acid, and separating a mixed product of monochloro, dichloro, trichlorine and methyl benzoic acid; (4) recrystallizing the mixed product by using methanol, thereby obtaining a main monochloro product. The main monochloro product prepared by using the method has the purity of 95% or greater, the conversion rate of the main monochloro product is up to 80-85%, the quality is stable, and the product has good competitiveness in the market. The mother liquid of the recrystallization process is concentrated and fed back for chlorination, then the p-toluylic acid in the mother liquid can be recycled, the environment protection burden of a company can be alleviated, raw materials are saved, and the production cost is lowered.

Description

technical field [0001] The invention belongs to the technical field of medicine synthesis, in particular to a preparation method of p-chloromethylbenzoic acid. Background technique [0002] p-Chloromethylbenzoic acid, systematically named 4-chloromethylbenzoic acid, molecular formula C 8 h 7 ClO 2 , the English name is: 4-(Chloromethyl)benzoic acid, the molecular weight is 170.59, and the structural formula is as follows: [0003] [0004] p-Chloromethylbenzoic acid is acicular crystallization, is a kind of very important medicine and dyestuff intermediate, at present, the technology of industrially preparing p-chloromethylbenzoic acid is: (1) by catalytic oxidation of p-xylene, preparation p-toluic acid; (2) miscible p-toluic acid and chlorobenzene, feed chlorine gas, and react under appropriate conditions to obtain the product. The disadvantage of this method is that the conversion rate of the main product of monochlorine is only 75% to 80%, the purity is lower than...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/363C07C51/42C07C51/43C07C51/48C07C63/70C07C51/16C07C63/04
CPCC07C51/16C07C51/363C07C51/42C07C51/43C07C51/48C07C63/70C07C63/04
Inventor 唐更好
Owner 唐更好