Method for preparing phenylhydrazine

Abstract

The invention discloses a method for preparing phenylhydrazine. The method uses phenol and hydrazine hydrate as raw materials, and uses HD-8 macroporous strong acid cation exchange resin as a catalyst, a reaction is performed at a certain temperature to prepare the phenylhydrazine, the hydrated hydrazine is kept excess in the reaction system to make the phenol reacted fully, water formed by the reaction is continuously separated and removed in the reaction process, after the reaction is completed, reduced-pressure distillation is performed to recover the hydrazine hydrate, the catalyst is recovered, the remaining liquid is washed by using a sodium carbonate solution and pure water, and therefore a finished product of the phenylhydrazine is obtained. Compared with a traditional diazotization reaction process for synthesizing the phenylhydrazine, the method provided by the invention has mild reaction conditions, less reaction steps, simple operation, less by-products and waste and low energy consumption, the yield is 90% or more, the catalyst can be recycled, the production costs are low, and the method is a novel energy-saving environmentally-friendly process.

Description

technical field [0001] The invention belongs to the technical field of chemical synthesis, and in particular relates to a method for preparing phenylhydrazine. Background technique [0002] Phenylhydrazine is a white monoclinic prism crystal or oily liquid, slightly soluble in water, with a melting point of 19.5°C and a boiling point of 243.5°C. It has an aromatic smell and gradually oxidizes to yellow in air. Phenylhydrazine is used in the production of pesticides to synthesize the intermediate 1-phenylsemicarbazide of the organophosphorus insecticide triazophos and the intermediate 1-phenyl-3,6-dihydroxypyridazine of pyridazine, which is also bactericidal In addition, as an organic synthesis raw material, phenylhydrazine is also used as an intermediate in dyes, pharmaceuticals and other industries, and is also used as an analytical reagent. It can react with the aldehyde and ketone groups of sugars to form stable glycosides, and use the crystal form and melting point of g...

AI Technical Summary

Problems solved by technology

Synthesis of phenylhydrazine by diazotization reaction, the intermediate diazonium salt is unstable and easy to decompose, it needs to be carried out under low temperature conditions, the reaction steps are many, the production process is complicated, the energy consumption is high, and the total yield is only about 80%. There are many products and wastes, and a large amount of organic salty wastewater will be produced. Environmental protection treatment is difficult and costly, and it is easy to pollute the environment.