Synthesis method of 3,4-dichloroaniline

Abstract

The invention relates to a technique for electrochemical synthesis of 3,4-dichloroaniline. Synthesis is carried out in a two-room electrolytic cell which is separated by virtue of a cation exchange membrane; the materials such as platinum and titanium are utilized as an anode; the materials such as titanium and stainless steel are utilized as a cathode; a cathode liquid is a water solution containing the following raw materials: 0.2-2.0mol / L sulfuric acid, 0.1-1.0mol / L 3,4-dichloronitrobenzene, 0.0002-0.004mol / L intermedium and 0-50% ethanol; an anode liquid is 0.2-2.0mol / L sulphuric acid solution; electrochemical reaction is carried out at ordinary pressure, a relatively low temperature and the constant voltage (relatively saturated calomel reference electrode) from minus 1.0 to minus 0.4V; and a cathode reaction product is 3,4-dichloroaniline. The method provided by the invention has the advantages of simple synthesis process, simple equipment requirements, mild reaction condition, high yield, low environmental pollution and low cost, and is a green synthesis method; and the electrode is easy to prepare and cheap.

Description

technical field [0001] The invention relates to a method for synthesizing 3,4-dichloroaniline, in particular to a method for synthesizing 3,4-dichloroaniline by electrochemical reduction, which belongs to the field of fine chemicals. Background technique [0002] 3,4-Dichloroaniline is an intermediate of important pesticides, medicines, dyes, pigments and other fine chemical products. It is widely used in the synthesis of herbicides and azo dyes, and can also be used in the synthesis of pharmaceutical fungicides. There are three main reduction methods to obtain 3,4-dichloroaniline by reducing 3,4-dichloronitrobenzene: (1) Iron powder reduction method under acidic conditions; (2) Catalytic hydrogenation under neutral conditions Reduction method; (3) Alkali sulfide reduction method under alkaline conditions. The iron powder reduction method has a large amount of "three wastes" and seriously pollutes the environment. It has been listed as an outdated production process ordered...

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Problems solved by technology

This method also has the following problems: (1) the recycling of the catalyst is poor and the conversion rate is low; (2) the reaction mechanism of the traditional hydrogenation reaction is complicated, and the selectivity of the reaction product is affected. For example, in the catalytic hydrogenation process, C- Cl bond hydrogenolysis

Therefore, this method has problems such as how to suppress dehalogenation, which increases the difficulty of catalyst design and preparation, and cannot completely avoid the occurrence of hydrogenolysis dehalogenation, which seriously affects the synthesis effect.

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