Method for reducing generation of by-product ethyl 3-(phenylamino)but-2-enoate in production of N-acetoacetanilide

A technology of acetoacetanilide and ethyl crotonate is applied in the field of reducing the generation of by-product 3--2-ethyl crotonate, can solve problems such as poor crystal form and easy agglomeration, and achieves reduced consumption and improved yield. rate and prevent caking

Active Publication Date: 2015-01-21
NANTONG ACETIC ACID CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to solve problems such as poor crystal form and easy agglomeration in the placement process during product crystallization, the object of the present invention is to provide a method for reducing by-product 3-(phenylamino)-2-butanol in the production of N-acetoacetanilide. The method that ethyl enoate generates, the method uses alcohol as a solvent, and the alcohol can be recycled and applied mechanically. In the distillation process, diketene and ethanol react in the alcohol filtrate to generate ethyl acetoacetate, and aniline reacts with ethyl acetoacetate to generate 3-( Phenylamino)-2-butenoic acid ethyl ester, this substance is easy to make N-acetoacetanilide agglomerate, adding strong acid, medium strong acid acid catalyst in the filtered alcohol filtrate can effectively inhibit 3-(phenylamino) -The generation of ethyl 2-butenoate, optimize the crystal form of the product, prevent the agglomeration of the product during placement, improve the appearance and performance of the product, increase the yield and purity of the product, and reduce the consumption of aniline and diketene

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] A method for reducing by-product 3-(phenylamino)-2-butenoic acid ethyl ester in the production of N-acetoacetanilide, comprising the following steps:

[0031] Add 419.0g of 60% fresh alcohol into a 1000ml three-necked flask, cool down to 10°C, add 84.1g (1mol) of diketene and 93.1g (1mol) of aniline dropwise at the same time, naturally raise the temperature to 35°C, keep the temperature for 4 hours, then cool to 10°C ℃, filter out 388.9g alcohol mother liquor, dry to obtain N-acetoacetanilide finished product 176.7g, product yield is 99.5%, and product content is 99.8%.

[0032] The product was placed for 120 days and sieved through a 20-mesh sieve with a passing rate of 96.5%, and no caking phenomenon occurred.

Embodiment 2

[0034]Add 388.9g of the alcohol filtrate filtered out in Example 1 into a 500ml three-neck flask, add 0.93g of 31% concentrated HCl, heat up, and stop distillation when the kettle temperature reaches 98°C. 232.2 g of alcohol distillate was recovered, and the ethanol content was 68.0%. Add 119.4 g of deionized water to make 451.6 g of 50% alcohol application solution.

[0035] Add 372.5g of the above-mentioned ethanol application solution into a 1000ml three-neck flask, cool down to 10°C, add 92.5g (1.1mol) of diketene and 93.1g (1mol) of aniline dropwise at the same time, naturally raise the temperature to 50°C, keep the temperature for 4 hours, and cool to 10 DEG C, filter out 340.6g alcohol mother liquor, dry to obtain N-acetoacetanilide 176.7g, product yield is 99.5%, and product content is 99.78%.

[0036] The product was placed for 120 days, sieved with 20 meshes, the pass rate was 96.1%, and no caking phenomenon occurred.

Embodiment 3

[0038] The 340.6g alcohol filtrate filtered out in Example 2 is added in a 500ml three-necked flask, and 0.56g65% concentrated HNO is added 3 , heat up, and stop distillation when the kettle temperature reaches 98°C. 285.7 g of alcohol distillate was recovered, and the ethanol content was 57.4%. Add 78.3g of deionized water to prepare 364.0g of 45% alcohol application solution.

[0039] Add 325.9g of the above-mentioned alcohol application solution into a 1000ml three-necked flask, cool down to 10°C, and add 100.9g (1.2mol) of diketene (1.2mol) and 93.1g (1mol) of aniline dropwise at the same time, keep warm at 30°C, keep the temperature for 3 hours, and cool to 10 DEG C, filter out 291.4g alcohol mother liquor, dry to obtain N-acetoacetanilide 176.4g, product yield is 99.38%, and product content is 99.8%.

[0040] The product was placed for 120 days and sieved through a 20-mesh sieve with a passing rate of 95.9%, and no caking phenomenon occurred.

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Abstract

The invention provides a method for reducing generation of a by-product ethyl 3-(phenylamino)but-2-enoate in production of N-acetoacetanilide, and belongs to the field of chemical industry. The method takes ethanol as a solvent, and ethanol can be recycled and reused; in a distillation process of an ethanol mother liquor obtained from filtration, ketene dimer and ethanol are subjected to a reaction to generate ethyl acetoacetate, and phenylamine and ethyl acetoacetate are subjected to a reaction to generate ethyl 3-(phenylamino)but-2-enoate; ethyl 3-(phenylamino)but-2-enoate easily makes N-acetoacetanilide caked, and strong acid and medium-strong acid acidic catalysts are added in the ethanol filtrate obtained from filtration, so that the generation of ethyl 3-(phenylamino)but-2-enoate can be effectively inhibited, a product crystal is optimized, product cracking in a placement process is prevented, the appearance and performance of the product are improved, besides, the product yield and the product purity are increased, and consumption of phenylamine and ketene dimer is reduced.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a method for reducing the generation of by-product 3-(phenylamino)-2-butenoic acid ethyl ester in the production of N-acetoacetanilide. Background technique [0002] The appearance of N-acetoacetanilide is white crystalline solid, slightly soluble in water, soluble in organic solvents such as ethanol, ether, chloroform and hot benzene, and also soluble in dilute caustic soda aqueous solution, hardly soluble in ammonia water and sodium carbonate solution, Case of ferric chloride was purple. The molecular weight of N-acetoacetanilide is 177.20, the melting point is 83-88°C, the isotonic specific volume (90.2K): 395.6, the autoignition temperature: 450.56°C, the boiling point: 129°C 24mmHg, the density: 1.26, the flash point: 162°C, and the relative vapor density ( Air=1): 6.1, water solubility: 5g / L (20°C). [0003] Uses of N-acetoacetanilide: [0004] (1) N-acetoace...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C233/07C07C231/02
Inventor 丁彩峰朱小刚刘芳姚俊生张锦凤徐晶晶章建凤
Owner NANTONG ACETIC ACID CHEM
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