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Preparation of 4-aminobenzoic acid (4-aminophenyl)-ester

A technology of aminobenzoic acid and aminophenyl, which is applied in the field of preparation of 4-aminobenzoic acid ester, can solve difficult problems and achieve the effects of low production cost, strong market competitiveness, and low environmental pollution

Active Publication Date: 2009-07-15
CHANGZHOU SUNLIGHT PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved in the present invention is: for the difficult problem of prior art industrialization, a kind of preparation method of 4-aminobenzoic acid (4-aminophenyl) ester that is easy to industrialized production is provided

Method used

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  • Preparation of 4-aminobenzoic acid (4-aminophenyl)-ester

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In a 500ml three-neck flask, add 56g of p-nitrophenol, 43g of p-nitrobenzoyl chloride, 350ml of dimethylformamide DMF, 3g of KI, start stirring and heat up to 140°C, and carry out heat preservation and reflux reaction. The HCl gas generated is water Absorb into hydrochloric acid solution, react for 8 hours until the reaction is completely stopped, cool down and cool until the product precipitates crystals and carry out suction filtration. The filter cake is a dinitro intermediate of light yellow sand-like particles, and the component of the dinitro intermediate is 4-nitro 4-nitrobenzoic acid (4-nitrophenyl) ester, for the hydrogenation reaction that can be directly used in the next step, the purity of 4-nitrobenzoic acid (4-nitrophenyl) ester is 98.5%, and the whole condensation reaction The yield of the product is 97%, and the melting range of the dinitro intermediate is 160-163°C, which prevents HCl from siphoning in the process of water absorption.

[0022] Add 40g o...

Embodiment 2

[0024] In a 500 ml three-necked flask, add 56 g of p-nitrophenol, 48 g of p-nitrobenzoyl chloride, 250 ml of xylene, and 3 g of dimethylaminopyridine DMAP catalyst, start stirring and heat up to 135 ° C, and carry out heat preservation and reflux reaction, and the generated HCl The gas is absorbed into hydrochloric acid solution with water, and the reaction is completely stopped after 3 hours of reaction. The temperature is lowered and cooled until the product precipitates crystals, and suction filtration is performed. The filter cake is the dinitro intermediate of light yellow sand-like particles, 4-nitrobenzoic acid (4 -Nitrophenyl) ester has a purity of 98%, and the yield of the entire condensation reaction is 93%, preventing siphoning during HCl water absorption.

[0025] Add 40g of dinitro intermediate, 150ml of ethanol, and 5g of Pd / C catalyst with a palladium content of 3% into the autoclave, stir and heat up to 80°C, and the pressure rises to 2.0MPa for hydrogenation re...

Embodiment 3

[0027] In a 500ml three-neck flask, add 56g of p-nitrophenol, 38g of p-nitrobenzoyl chloride, 150ml of toluene, and 2g of catalyst KCl, start stirring and heat up to 115°C, and carry out heat preservation and reflux reaction, and the generated HCl gas is absorbed by water to form hydrochloric acid solution, stop the reaction after 3 hours of complete reaction, lower the temperature and cool until the product precipitates crystals and carry out suction filtration, the filter cake is the dinitro intermediate of light yellow sand-like particles, the yield of the entire condensation reaction is 93%, and the dinitro intermediate The melting range of the solid is 160-163°C.

[0028] Add 40g of dinitro intermediate, 250ml of methanol, and 0.5g of Raney-Ni catalyst into the autoclave, stir and raise the temperature and pressure to 80°C and 0.8MPa for catalytic hydrogenation reaction, filter the Raney-Ni catalyst, and distill the filtrate to obtain Yellow loose product 4-aminobenzoic a...

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Abstract

The invention relates to a method for preparing 4-aminobenzoic acid (4-aminophenyl) ester, comprising a catalytic condensation reaction process and a hydrogenation reduction process; wherein the catalytic condensation reaction process comprises the following steps: paranitrobenzoyl chloride and p-nitrophenol are added to solvent I and the solvent I is added with a condensation catalyst; at the temperature of 50-200 DEG C, the reaction lasts for 2-8 hours and then the reaction is ceased and the temperature is lowered to separate out a pale yellow crystal binitro intermediate, namely 4-nitrobenzoic acid (4-nitrobenzophenone) ester. The hydrogenation reduction process comprises the following steps: the binitro intermediate obtained in the catalytic condensation reaction process is added in solvent II; a hydrogenation catalyst is added into the solvent II and the reaction is carried out at the temperature of 50-120 DEG C and under the pressure of 0.5-2.0 MPa; after the reaction, a yellow loose product of the 4-aminobenzoic acid (4-aminophenyl) ester is obtained by distilling. The method solves the problem of difficulty in industrial production adopting the existing preparation method for the 4-aminobenzoic acid (4-aminophenyl) ester.

Description

Technical field [0001] The invention relates to a preparation method of 4-aminobenzoic acid (4-aminophenyl) ester. Background technique [0002] 4-Aminobenzoic acid (4-aminophenyl) ester is a material chemical intermediate product with excellent performance. Due to the presence of ester groups in the molecule, the polyimide material synthesized from it has a very low linear expansion coefficient and Water absorption, with unique properties. [0003] It is understood that there is no report on the preparation patent of 4-aminobenzoic acid (4-aminophenyl) ester and an industrialized manufacturer both at home and abroad at present. Contents of the invention [0004] The technical problem to be solved in the present invention is: to provide a kind of preparation method of 4-aminobenzoic acid (4-aminophenyl) ester that is easy to industrialized production for the difficult problem of prior art industrialization. [0005] The technical scheme that the present invention adopts ...

Claims

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Application Information

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IPC IPC(8): C07C229/60C07C227/04
Inventor 胡国宜薛建伟闵雪峰李玉玲
Owner CHANGZHOU SUNLIGHT PHARMA
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