Mixed acid catalysis system for ketoxime beckmann rearrangement reaction

Abstract

The invention discloses a mixed acid catalysis system for a ketoxime beckmann rearrangement reaction. The mixed acid catalysis system is characterized in that the catalysis system is a homogeneous system consisting of an organic acid and an inorganic acid, and serves as a catalyst in a reaction of preparing amide through ketoxime rearrangement; the reaction temperature is 60-130 DEG C, preferably 80-120 DEG C; the reaction time is 1-240min, preferably 20-90min; the molar ratio of the organic acid to the inorganic acid is 0.5-50, preferably 3-20; the molar ratio of the inorganic acid to the ketoxime is 0.1-10, preferably 1-5. According to the catalysis system, the ketoxime can be efficiently converted into a corresponding amide compound in a relatively mild reaction condition; moreover, the content of byproducts of the reaction can be controlled, and particularly, the content of heavy byproducts is very low. The organic acid part of the catalysis system can be recycled, and the reaction condition in use is mild; the conversion rate of the ketoxime rearrangement reaction is high, and the selectivity is good; the content of byproducts after the rearrangement reaction is low, and particularly, the content of heavy byproducts is very low in an optimized condition; the aftertreatment process is hopefully to be simplified; the catalysis system has a good potential in industrial application.

Description

technical field [0001] The invention belongs to the technical field of chemical catalysis, and in particular relates to a mixed acid catalytic system for ketoxime Beckmann rearrangement reaction. Background technique [0002] Beckmann rearrangement is a kind of rearrangement reaction that occurs under acid catalysis, and it is mainly used in the conversion of ketoxime to the corresponding amide. Take caprolactam as an example, it is an important organic chemical raw material, mainly used in the production of nylon 6 fiber (nylon 6) and nylon 6 engineering plastics. Among them: nylon 6 fiber is widely used in wool spinning, knitting, weaving, carpet and other industries, and nylon 6 engineering plastics is widely used in electronics, automobiles, packaging films and other industries. In 2016, the consumption of caprolactam in my country has reached 2.005 million tons, the domestic output is 1.8 million tons, and the self-sufficiency rate is 89.8%. The domestic production cap...

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Problems solved by technology

At the same time, although the process only produces less than 1% of heavy by-products (swahydrophenazine, etc.), in the subsequent refining process, caprolactam with a content of more than 99% needs to be evaporated and separated, and the energy consumption of the process is extremely high. Greatly increased production costs

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