Preparation method of cyclohexanone oxime

Abstract

The invention discloses a preparation process for cyclohexanone oxime which is characterized in that the process is carried out continuously and circularly in a loop reactor, wherein the loop reactorconsists of a loop and a solid-liquid separating component and makes the reaction slurry comprising catalyzer, ammonia, cyclohexanone, hydrogen peroxide and solvent have an ammoximation reaction in the loop, then the reaction slurry is made a solid-liquid separation by a filtering element in the solid-liquid separating component in a cross-current way, the obtained clear liquid flows out along theradial direction of the filtering element and is reclaimed, the concentrated slurry continues to circulate in the loop.

Description

Technical field [0001] The invention relates to a method for preparing cyclohexanone oxime, more specifically, the invention relates to a method for preparing cyclohexanone oxime by ammoximation of cyclohexanone. Background technique [0002] Caprolactam is the monomer raw material for producing nylon 6 fiber and nylon 6 engineering plastics. At present, there are three process routes for industrialized production of caprolactam: (1) Cyclohexanone-hydroxylamine production process, including traditional Raschig process, DSM / HPO process, BASF-NO reduction process, Inventa-NO reduction process, Allied cumene / phenol Process and Capropol process; (2) Cyclohexane photonitrosation process of Toray Company of Japan; (3) Toluene process of SNIA Company of Italy. The production capacity of the cyclohexanone-hydroxylamine route accounts for 91.3% of the world's total capacity. [0003] The production of caprolactam by the cyclohexanone-hydroxylamine route takes benzene as the raw material, ...

AI Technical Summary

Problems solved by technology

The process is complicated and the production cost is high

[0008] To sum up, when the trickle bed is operated, on the one hand, there are higher requirements for the uniform distribution of the feed liquid, and on the other hand, there are higher requirements for the strength of the catalyst, and the catalyst must have a long life; The use of binders will block a part of the pores of the molecular sieve, resulting in a decrease in pore volume and specific surface area, which will eventually lead to a decrease in the effective utilization of the molecular sieve catalyst, and the reaction effect will decrease under the same catalyst concentration; The porous plate directly intercepts the catalyst, and there is no automatic backflushing system, which is easy to block and cause parking accidents; in addition, the separation element is installed inside the reactor, which is extremely inconvenient to replace

Adopting two-step method (EP0564040) can improve the conversion rate of ketone, but increased reaction step, makes flow process complicated, especially the yield of generating hydroxylamine by hydrogen peroxide and ammonia under the action of titanium-silicon molecular sieve catalyst is low, if directly adopt hydroxylamine Salt, its source is inconvenient; in addition, fine-grained catalysts are more likely to adhere to the walls of reactors, heat exchangers and pipes, which not only reduces the effective utilization of catalysts, but also reduces the heat transfer efficiency

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