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Method for producing m-dimethylaminobenzoic acid

A technology of dimethylaminobenzoic acid and production room, applied in the direction of chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve problems such as unfavorable, large residual hydrogen, and cost reduction, so as to reduce investment cost and save The effect of hydrogen

Inactive Publication Date: 2017-08-18
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This shortcoming is that in addition to the use of pressure kettles in industrial production, the residual amount of hydrogen in steel cylinders is relatively large, which is not conducive to reducing costs.

Method used

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  • Method for producing m-dimethylaminobenzoic acid
  • Method for producing m-dimethylaminobenzoic acid

Examples

Experimental program
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Effect test

example 1

[0014] In a 250mL glass three-neck flask, add 95mL of methanol and 3mL of tetrahydrofuran, 16.7g of m-nitrobenzoic acid, 0.2g of 5% palladium carbon, and add 15.2mL of 37% formaldehyde aqueous solution in a constant pressure dropping funnel. The air in the reaction system was pumped away, and then hydrogen gas at normal pressure was introduced. Raise the temp to 64 o C, stirring the reaction until no more hydrogen is absorbed. Add formaldehyde solution from the dropping funnel, and continue to stir and hydrogenate at this temperature until hydrogen is no longer absorbed. Stirring was stopped, the catalyst was recovered by filtration, the filtrate was concentrated, and the product was precipitated. Collect the product by filtration, wash the product with a small amount of water, and then re-100 o C was dried to obtain 15.3 g of product m-dimethylaminobenzoic acid, and the productive rate was 93%. After the catalyst is recovered, it is washed with a reaction solvent and used...

example 2

[0016] In a 250mL glass three-neck flask, add 100mL of tetrahydrofuran, 16.7g of m-nitrobenzoic acid, 0.2g of 5% palladium carbon, and add 15.2mL of 37% formaldehyde solution in a constant pressure dropping funnel. The air in the reaction system was pumped away, and then hydrogen gas at normal pressure was introduced. Raise the temperature to 66 o C, stirring the reaction until no more hydrogen is absorbed. Add formaldehyde solution from the dropping funnel, and continue to stir and hydrogenate at this temperature until hydrogen is no longer absorbed. Stirring was stopped, the catalyst was recovered by filtration, the filtrate was concentrated, and the product was precipitated. Collect the product by filtration, wash the product with a small amount of water, and then re-100 o C was dried to obtain 15.2 g of product m-dimethylaminobenzoic acid, and the productive rate was 92%. After the catalyst is recovered, it is washed with a reaction solvent and used for the next reacti...

example 3

[0018] In a 250mL glass three-neck flask, add 98mL of methanol and 2mL of butyl ether, 16.7g of m-nitrobenzoic acid, and 0.2g of 5% palladium carbon, and add 15.2mL of 37% formaldehyde aqueous solution into a constant pressure dropping funnel. The air in the reaction system was pumped away, and then hydrogen gas at normal pressure was introduced. Raise the temperature to 65 o C, stirring the reaction until no more hydrogen is absorbed. Add formaldehyde solution from the dropping funnel, and continue to stir and hydrogenate at this temperature until hydrogen is no longer absorbed. Stirring was stopped, the catalyst was recovered by filtration, the filtrate was concentrated, and the product was precipitated. Collect the product by filtration, wash the product with a small amount of water, and then re-100 o C was dried to obtain 14.9 g of product m-dimethylaminobenzoic acid, and the productive rate was 90%. After the catalyst is recovered, it is washed with a reaction solvent...

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Abstract

The invention relates to a method for producing m-dimethylaminobenzoic acid. The method comprises the steps: carrying out stirred hydrogenation on m-nitrobenzoic acid, which serves as a raw material, in a manner of taking palladium-on-carbon as a catalyst and taking a mixture of methanol and ethers as a solvent at the temperature of 30 DEG C to 60 DEG C under normal pressure (water column of 30cm to 50cm) so as to produce m-aminobenzoic acid, adding a formaldehyde solution after hydrogen absorption of nitro reduction of a first step is completed, and continuing to carry out stirred hydrogenation under the same temperature and pressure; and stopping the reaction after hydrogen absorption of hydrogenation of a second step is completed, carrying out filtration to recover the catalyst for next-time use, concentrating the filtrate to distill off the solvent, carrying out filtration to collect a product, washing the product with a small volume of water, and then, drying the product at the temperature of 100 DEG C, thereby obtaining the product, i.e., m-dimethylaminobenzoic acid. According to the method, the yield is 90% to 93%, and the melting point is 151 DEG C.

Description

technical field [0001] The invention relates to a method for producing m-dimethylaminobenzoic acid. Background technique [0002] m-Dimethylaminobenzoic acid is an important intermediate, mainly used in the synthesis of pressure-sensitive dyes and heat-sensitive dyes, and can also be used in the synthesis of liquid crystal materials and pigments. Existing technologies for synthesizing m-dimethylaminobenzoic acid mainly include: 1) m-nitrophthalic acid is used as a raw material, and m-dimethylaminobenzoic acid is obtained through steps such as reductive methylation and decarboxylation. The disadvantage of this method is that the reaction by-product Many, the total yield is low; 2) take m-bromoaniline as raw material, obtain m-dimethylaminobenzoic acid through steps such as methylation and carboxylation, this method also has many by-products of reaction, the shortcomings such as low total yield; 3 ) using m-aminobenzoic acid as a raw material, and obtain m-dimethylaminobenzoi...

Claims

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Application Information

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IPC IPC(8): C07C227/18C07C227/04C07C229/60
CPCC07C227/18C07C227/04C07C229/60
Inventor 欧阳昆冰阳年发杨利文
Owner XIANGTAN UNIV
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