Method for producing 2-amino-4-acetamido benzene alkyl ether by reduction with sodium bisulfide

Abstract

The invention relates to a method for producing 2-amino-4-acetamido benzene alkyl ether by reduction with sodium bisulfide. The method comprises the following steps: adding 2-nitro-4-acetamido benzene alkyl ether in water the mass of which is 3-5 times of that of a reactant; adding glacial acetic acid; regulating the pH value of the material to 5-6 by using liquid caustic soda; raising the temperature to 90-105 DEG C, dropwise adding a 10-25% sodium bisulfide solution, carrying out insulation reaction for 1 hour after dropwise addition; cooling slowly to crystallize and separate out the product; filtering the crystal, washing the crystal with cold water until the pH value of the filtrate is 7 to obtain 2-amino-4-acetamido benzene alkyl ether, wherein the washing sleeve is still used in the next-batch reduction. The method disclosed by the invention has the advantages that (1) the reaction yield is above 90%; (2) the reaction speed is high so that the product is not easy to oxidize, and has good colour and high quality; (3) complex aftertreatment is not required, and the equipment and operation are simple; (4) wastewater is little and easy to treat, thus the method is a low-emission clean process; and (5) resource utilization is realized for recycling and managing hydrogen sulfide waste gas so as to obtain the sodium bisulfide solution in industries such as petrifaction industry, and cost is low.

Description

technical field [0001] The invention relates to a production method of important dyestuff and pharmaceutical intermediate 2-amino-4-acetamido phenyl alkyl ether. Background technique [0002] 2-amino-4-acetamido phenyl alkyl ether of the present invention is the compound with following structure: [0003] [0004] In the formula: R is -CH 3 、-C 2 h 5 、-C 3 h 7 、-C 4 h 9 [0005] 2-Amino-4-acetamidophenyl ether is an important pharmaceutical intermediate and a key intermediate for the production of azo-type disperse dyes such as C.I. Disperse Blue 79, 79:1, 291, 291:1, and 301. Disperse dyes account for about 40% of the global dye production. Because dark dyes with 2-amino-4-acetamidoanisole as coupling components have good color matching compatibility, they are widely used in polyester, acetate and other dyes. The dyeing of blended fibers has a huge demand, accounting for about 35% of the output of disperse dyes, so the trade name of 2-amino-4-acetamido anisole i...

AI Technical Summary

Problems solved by technology

In this process route, because the intermediate product 2,4-diaminoanisole is a carcinogen, and is unstable and easily oxidized; during the 4-position selective acylation reaction, it is not easy to control the acylation end point, and the product should not contain 2,4 -Diaminoanisole, there must be a certain amount of bisacylate, the quality cannot meet the requirements of pharmaceutical and dye production

For example, the initial melting point of 2-amino-4-acetamidoanisole should reach above 115°C. In order to improve the product quality, the separation and refining process must be added, which complicates the process, loses the advantages of the four-step reaction, and costs more. High (see CN1861577A)

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