Preparation method for p-aminobenzamide

A technology of aminobenzamide and nitrobenzamide, which is applied in the field of preparation of p-aminobenzamide, can solve the problems of high production cost, inability to apply waste water, backward technology, etc., and achieve product quality and yield improvement, discharge Effects of reduced waste water and simple process

Active Publication Date: 2014-12-10
内蒙古美力坚科技化工有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Chinese patent CN201210310292.X discloses a synthesis method of p-nitrobenzoyl chloride, which is catalyzed by a quaternary ammonium salt (benzyltrialkylammonium halide), by directly reacting p-nitrobenzoic acid and thionyl chloride, Recover the remaining thionyl chloride by distillation, and then obtain high-concentration p-nitrobenzoyl chloride by distillation under reduced pressure, which uses a large amount of thionyl chloride as both an acid chloride reagent and a solvent, and requires distillation to recover thionyl chloride , complicated operation and high production cost
[0011] (1) The reduction of iron powder has been eliminated, the technology is backward, and the pollution is large;
[0012] (2) Waste water cannot be used mechanically, and the waste is large;
[0013] (3) Product quality and yield are not ideal

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0044] A preparation method for p-aminobenzamide, comprising the steps of:

[0045] (1) Preparation of p-nitrobenzoyl chloride: Add 50g of 100% p-nitrobenzoic acid into a 500ml reaction vessel, add 2g of catalyst DMF, inhale 48g of thionyl chloride, start stirring, heat up to 50-60°C, pressure 0.1 React under MPa for 3 hours to obtain p-nitrobenzoyl chloride solution.

[0046] (2) Prepare p-nitrobenzamide: add 165g 20% ​​ammoniacal liquor in 500ml reaction vessel, add step (1) gained p-nitrobenzoyl chloride solution dropwise under pressure 0.1MPa at temperature 15~20 ℃, reaction 4 hour, suction filtration to obtain 48.8 g of p-nitrobenzamide with a purity of 99.1% and a yield of 96.72%. The filtrate is used as a liquid for absorbing waste gas generated by acid chlorination.

[0047] (3) Preparation of p-aminobenzamide: Add 48.8g of p-nitrobenzamide obtained in step (2), 0.5g of ferric hydroxide, 100g of water into a 500ml reaction vessel, start stirring, and add 26g of it dr...

Embodiment 2

[0049]This example provides a kind of preparation method of p-aminobenzamide, which is basically the same as Example 1. The difference is: in the third step of Example 1, p-aminobenzamide was prepared and the filtered mother liquor was used as the bottom water of the reduction reaction to prepare p-aminobenzamide to obtain 38.36 g of p-aminobenzamide, which was a white crystal with a melting point ≥ 182.5°C , with a purity of 99.3% and a yield of 95.5%.

Embodiment 3

[0051] A kind of preparation method of p-aminobenzamide under preferred conditions, it comprises the steps:

[0052] (1) Preparation of p-nitrobenzoyl chloride: Add 50g of 100% p-nitrobenzoic acid into a 500ml reaction vessel, add 1g of catalyst DMF, inhale 48g of thionyl chloride, start stirring, heat up to 75-80°C, pressure 0.2 React under MPa for 3 hours to obtain p-nitrobenzoyl chloride solution.

[0053] (2) Prepare p-nitrobenzamide: add 165g 20% ​​ammoniacal liquor in 500ml reaction vessel, add step (1) gained p-nitrobenzoyl chloride solution dropwise under pressure 0.2MPa at temperature 50~60 DEG C, reaction 4 hours, suction filtration, to obtain p-nitrobenzamide 49.1g, the purity is 99.2%, and the yield is 97.41%. The filtrate is used as a liquid for absorbing waste gas generated by acid chlorination.

[0054] (3) Preparation of p-aminobenzamide: add step (2) gained 49.1g p-nitrobenzamide, 1g ferric hydroxide, 60g water, 50g90% ethanol in a 500ml reaction vessel, sta...

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Abstract

The invention relates to a preparation method for p-aminobenzamide. The preparation method comprises the following steps: (1) enabling p-nitrobenzoic acid to react with thionyl chloride in the presence of an organic base catalyst to obtain paranitrobenzoyl chloride liquor which is directly used for next-step reaction; (2) dropwise adding the paranitrobenzoyl chloride liquor into 10wt%-30wt% ammonium hydroxide, reacting and carrying out suction filtration on the mixture to obtain p-nitrobenzamide; and (3) enabling p-nitrobenzamide and hydrazine hydrate to carry out reaction in a solvent in the presence of ferric hydroxide or a material attached with ferric hydroxide to obtain p-aminobenzamide, wherein filtrate produced in the step is recycled for the next batch of reactions. The preparation method is high in product yield, low in cost, good in quality, capable of satisfying green and environment-friendly production requirements, simple and convenient to operate, and convenient for industrialization.

Description

technical field [0001] The invention relates to a preparation method of fine chemical products, in particular to a preparation method of p-aminobenzamide. Background technique [0002] 4-aminobenzamide, whose structure is shown in formula I, is a kind of important fine chemical intermediate, is widely used in dyestuff industry, is used for manufacturing such as organic pigment red 170# etc., and market demand is big. [0003] [0004] Chinese patent CN201210310292.X discloses a synthesis method of p-nitrobenzoyl chloride, which is catalyzed by a quaternary ammonium salt (benzyltrialkylammonium halide), by directly reacting p-nitrobenzoic acid and thionyl chloride, Recover the remaining thionyl chloride by distillation, and then obtain high-concentration p-nitrobenzoyl chloride by distillation under reduced pressure, which uses a large amount of thionyl chloride as both an acid chloride reagent and a solvent, and requires distillation to recover thionyl chloride , complic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C237/30C07C231/12
Inventor 张正富易元龙骆惠东
Owner 内蒙古美力坚科技化工有限公司
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