Caprolactam production method

Abstract

The present invention provides a caprolactam production method, which comprises the following processes that: toluene is oxidized under an effect of a cobalt salt catalyst to generate benzoic acid, benzoic acid is subjected to hydrogenation under an effect of a palladium carbon catalyst to generate cyclohexanecarboxylic acid, the cyclohexanecarboxylic acid and nitrosylsulfuric acid are subjected to an amidation reaction in an amidation reactor to generate an amide liquid, cyclohexanone is subjected to an oximation reaction to generate cyclohexanone oxime, the amide liquid and the cyclohexanone oxime are subjected to a rearrangement reaction in a rearrangement reactor, and the reaction product is subjected to processes such as neutralization, crystallization, extraction and refinement to prepare the ??caprolactam, wherein a rearrangement reaction temperature is 70-130 DEG C, pressure is 0-1.0 MPa, and a molar ratio of the acid in the amide liquid to the cyclohexanone oxime is 1-2:1. With the present invention, combination of the two processes such as a toluene method and a cyclohexanone-hydroxylamine method is achieved, a caprolactam yield is increased without increase of ammonium sulfate by-production, nicotinic acid consumption and ammonium sulfate by-production are reduced, the production process is simplified, and construction investment and production cost are saved.

Description

technical field [0001] The invention belongs to the technical field of chemical product production, and relates to a method for producing caprolactam, in particular to a method for preparing caprolactam by mixing cyclohexanone oxime by cyclohexanone-hydroxylamine method and amide solution by toluene method for rearrangement reaction. Background technique [0002] Caprolactam is an important organic chemical raw material, mainly used in the production of nylon 6 engineering plastics and nylon 6 fibers. Nylon 6 engineering plastics are mainly used as components and components of automobiles, ships, electronic appliances, industrial machinery and consumer goods. Nylon 6 fiber can be made into textiles, industrial silk and carpet silk, etc. In addition, caprolactam can also be used to produce anti-platelet drugs, laurocaprazine, etc., and has a wide range of uses. [0003] The production methods of caprolactam mainly include cyclohexanone-hydroxylamine method, photonitrosation ...

AI Technical Summary

Problems solved by technology

The refining system of this method is complex, expensive precious metal catalysts are used, and the by-product thiamin is much more, and the by-product thiamine is 3.1~4.1 tons / ton caprolactam

However, its raw material toluene is rich in resources, and there are many intermediate products with high added value

All three processes have the problems of low reaction product yield, large consumption of oleum, many by-products and serious environmental pollution

However, this patent cannot solve the problems of large consumption of oleum and many by-products in the production of caprolactam by cyclohexanone-hydroxylamine method and toluene method

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