Method for preparing m-chloroaniline by using meta-position oil

Abstract

The invention relates to a method for preparing m-chloroaniline by using meta-position oil and belongs to the technical field of preparation of m-chloroaniline. The method specifically comprises the steps of carrying out an ingredient reaction, carrying out water washing, carrying out drying, carrying out third-stage vacuum distillation, carrying out crystallization, carrying out reduction and carrying out re-distillation. According to the method, m-chloroaniline is prepared from waste, i.e., meta-position oil of production of p-nitrophenol and o-nitrophenol and industrial waste liquid, i.e., sodium hydrosulfide, which serve as raw materials, by using methoxylation, crystallization and reduction, and byproducts, i.e., o-aminoanisole and p-aminoanisole are produced, so that low cost and high yield are achieved, and the method has an obvious cost advantage and higher economic benefit compared with the existing production technologies.

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, toxic, is an important fine chemical intermediate, mainly used as an intermediate of azo dyes and pigments, drugs, insecticides, and pesticide chemicals. [0003] Meta-position oil, the main components are m-, o-, and p-chloronitrobenzene. It is a general term for the two products of p-nitrate and o-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. Traditional nitro reduction methods mainly include iron powder reduction method, alkali sulfide reduct...

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 the high cost of raw material m-nitrochlorobenzene, the environmental pollution caused by the reduction of auxiliary raw material iron powder, the high cost of sodium sulfide reduction, the easy dechlorination of hydrogenation reduction, and the corrosion of equipment.