A kind of method utilizing meta-position oil to prepare m-chloroaniline

Abstract

The invention relates to a method for preparing m-chloroaniline by using meta-position oil, which belongs to the technical field of preparing m-chloroaniline, and specifically includes the steps of batching reaction, water washing, drying, three-stage vacuum distillation, crystallization, reduction, redistillation and the like. The present invention uses waste meta-oil produced by p- and o-nitrogen and industrial waste liquid sodium hydrosulfide as raw materials, utilizes methoxylation, crystallization and reduction to prepare m-chloroaniline, and generates by-products o-aminoanisole and p- Anisole, thereby realizing low cost, high output, compared with existing production technology, has obvious cost advantage, has higher economic benefit.

Description

technical field [0001] The invention belongs to the technical field of preparation of m-chloroaniline, and in particular relates to a method for preparing m-chloroaniline by utilizing meta-position oil. Background technique [0002] m-Chloroaniline, colorless liquid to light amber liquid, poisonous, is an important fine chemical intermediate, mainly used as an intermediate of azo dyes and pigments, drugs, insecticides, and pesticide chemicals. [0003] Meta-oil, mainly composed of m-, o-, and p-chloronitrobenzene, is a general term for the two products of p-nitrate and ortho-nitrate in the production process of p-o-nitrate, as well as the waste liquid rich in m-nitrochlorobenzene and high boiling point organic matter. [0004] Most of the existing methods for preparing m-chloroaniline are to reduce the nitro group of m-nitrochlorobenzene to obtain m-chloroaniline. The traditional nitro reduction methods mainly include iron powder reduction method, alkali sulfide reduction m...

AI Technical Summary

Problems solved by technology

The iron powder reduction method produces a large amount of iron sludge, which seriously pollutes the environment; the alkali sulfide reduction method has the characteristics of complex reduction route, low product yield, and large amount of waste liquid; the electrochemical reduction method consumes too much energy; the catalytic hydrogenation method has a reaction route , low energy consumption, and environmental friendliness. However, during the catalytic hydrogenation of m-nitrochlorobenzene, the meta-activation of the nitro group can also increase the side reaction of C-CL bond hydrogenolysis and dechlorination to generate aniline, thereby Reduced yield of main product

At the same time, the hydrogen chloride generated by dechlorination will also cause corrosion to equipment

[0005] To sum up, at present, the existing technology has problems such as high cost of raw material m-nitrochlorobenzene, environmental pollution caused by reduction of auxiliary raw material iron powder, high cost of sodium sulfide reduction, easy dechlorination by hydrogenation reduction, corrosion of equipment, etc.