Synthesis method of p-chlorophenyl hydrazine

Abstract

The invention discloses a synthesis method of p-chlorophenyl hydrazine. The method comprises the following steps: (1) adding hydrazine hydrate into a four-neck flask, starting to stir and adding a hydrochloric acid solution dropwise at a certain reaction temperature to obtain a hydrazine hydrochloride solution; (2) adding p-chloroaniline into the four-neck flask, starting to stir by using glycol as a solvent, adding the hydrazine hydrochloride solution obtained in the step (1) dropwise at the reaction temperature of 100 to 120 DEG C, performing heat-insulating reflux reaction for 2 to 6 hours, and filtering, washing and drying after the reaction is finished to obtain the p-chlorophenyl hydrazine. By the method, one-step synthesis of the p-chlorophenyl hydrazine is realized by using the p-chloroaniline and the hydrazine hydrate, the yield can reach more than 85%, and the method is suitable for enterprise large-scale production; by the method provided by the invention, the tedious operation steps, such as diazotization, reduction and acidolysis, in the traditional method are avoided, and the process safety is improved; by the method, the use amount of water can be reduced, the discharge quantity of waste water is greatly reduced, waste water treatment in the later period is avoided, and the cost is reduced.

Description

technical field [0001] The invention belongs to the fields of organic synthesis and pesticide synthesis, and in particular relates to a synthesis method of p-chlorophenylhydrazine. Background technique [0002] p-Chlorophenylhydrazine is a widely used organic synthesis intermediate, which can be used in the synthesis of dyes, medicines and other chemicals. At present, the synthesis method of p-chlorophenylhydrazine mainly uses p-chloroaniline as raw material, carries out diazotization reaction with sodium nitrite and hydrochloric acid at 0-5°C, and uses tin dichloride, sodium sulfite, sodium bisulfite, ammonium sulfite etc. as a reducing agent for the reduction reaction, and finally for the hydrolysis reaction to obtain p-chlorophenylhydrazine. [0003] Yet above-mentioned several reducing agents all have some defects: 1) the method cost of preparing p-chlorophenylhydrazine with tin dichloride as reduction diazonium liquid is higher, and yield is lower, and reaction can pro...

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Problems solved by technology

[0003] Yet above-mentioned several reducing agents all have some defects: 1) the method cost of preparing p-chlorophenylhydrazine with tin dichloride as reduction diazonium liquid is higher, and yield is lower, and reaction can produce a large amount of waste water, recycling and processing Both are troublesome; 2) When sodium sulfite is used as reducing agent, due to the low solubility of sodium sulfite in aqueous solution, it is easy to agglomerate, and it is not easy to dissolve after agglomeration, so the operation and feeding requirements are relatively high; 3) When ammonium sulfite is used as reducing agent, The reaction will produce a large amount of industrial wastewater, and the wastewater contains a large amount of double salts, and the recycling value is low