Method for producing caprolactam by methylbenzene

Abstract

The invention relates to a method for producing caprolactam by methylbenzene, which comprises the following processes of oxidation, esterification, hydrogenation, distillation, amidation, hydrolyzing and refining, wherein in the oxidation process, the methylbenzene is completely converted into benzoic acid by adopting an ester solvent; in the esterification process, the benzoic acid dissolved in ester reacts with alcohol to form corresponding benzoate; in the hydrogenation reaction, a benzene ring of the benzoate is hydrogenated till saturation to form cyclohexanecarboxylate in a fixed bed reactor, and the cyclohexanecarboxylate enters the amidation process; and in the amidation process, the cyclohexanecarboxylate reacts with nitrosyl sulfuric acid, the reaction product is subjected to hydrolyzing rearrangement in the sulfuric acid to form the caprolactam by refining. In the method, the conventional rectification of the benzoic acid is changed into the rectification of the benzoate, a granular catalyst replaces the original powder palladium-carbon catalyst, the processes of catalyst sedimentation, centrifugal separation and the like are reduced, the generation of ammonium sulfate is reduced, and dimethyl sulfate serving as a by-product is produced simultaneously.

Description

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AI Technical Summary

Benefits of technology

This patented technology describes an improved method for producing lactic esters that have fewer impurities than traditional methods like naphtha cracked with ethanol. Instead, it involves changing certain chemical components during manufacturing instead of replacing them altogether. These changes help prevent damage caused by these compounds while still maintain their effectiveness over longer periods of time. Additionally, this new design allows for more efficient utilization of expensive metals compared to current designs without sacrifices. Overall, this innovative approach helps produce higher quality lactic acids efficiently and effectively.

Problems solved by technology

The current methods involve multiple steps involved including different starting materials like tetrahydronaphthalene, dimethylcyclohexanone, acrylonitrile, formalin, and adiponcyclodimide. These techniques have drawbacks such as long cycle times during manufacturing due to their complexity, excessive waste streams generated, and difficulties in recovering and operating cost reduction.

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