A kind of cyclohexanone ammoximation method

Abstract

The invention innovatively provides a cyclohexanone ammoximation method. The method comprises steps as follows: hydrogen peroxide, an inhibitor of hydrogen peroxide, cyclohexanone and a low-carbon alcohol aid are mixed in a certain proportion to form a mixed liquid, and the mixed liquid is sent to the top of an oximation reactor to be dispersed into 1-200 mu m fine particles; mixed gas of inert gas and ammonia gas is preheated and sent into the oximation reactor to be contacted with the dispersed fine particles, and the dispersed fine particles are further gasified; the gasified fine particles and ammonia gas are placed on a titanium-containing catalyst in the oximation reactor for a cyclohexanone ammoximation reaction, the reacted mixture is separated, and a product is obtained. The problems that a catalyst in the prior art is easily inactivated, follow-up separation is difficult, membrane blocking is serious, the effective utilization rate of hydrogen peroxide is lower and the like can be effectively solved, and the cyclohexanone ammoximation method has broad and good industrial prospect.

Description

technical field [0001] The invention belongs to the technical field of catalytic synthesis of organic chemicals, and relates to a method for preparing cyclohexanone oxime by using a titanium-containing catalyst, and further explains that it is about a gas-solid phase cyclohexanone ammoximation reaction to prepare cyclohexanone oxime Methods. Background technique [0002] Cyclohexanone oxime is an important chemical synthesis intermediate, which can synthesize caprolactam (CPL) through Beckmann rearrangement reaction, and is a key intermediate in the production of caprolactam. Caprolactam can be polymerized to produce nylon-6, and nylon-6 can be further processed into nylon fibers, engineering plastics and plastic films. [0003] At present, there are three process routes for industrial production of caprolactam: (1) Cyclohexanone-hydroxylamine production route, including traditional Raschig process, DSM / HPO process, BASF-NO reduction process, Inventa-NO reduction process, A...

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Problems solved by technology

[0006] 1. The current preparation method of cyclohexanone oxime is generally a liquid phase reaction. The titanium-containing catalyst is placed in a strong alkaline environment for a long time, which cannot avoid the dissolution of the skeleton silicon on the catalyst, resulting in the ineffective loss of the catalyst, shortening the service life of the catalyst, and affecting ammonia oxime. Stable operation of chemical reaction system;

[0007] 2. The liquid-solid phase reaction has the disadvantage of large mass transfer resistance, and the phenomenon of catalyst diffusion is seriously affected;

[0008] 3. In order to effectively solve the above-mentioned catalyst diffusion phenomenon and maintain good catalytic reaction conditions, titanium-containing catalysts can be prepared into nanoscale. However, although this can ensure suitable catalytic activity, it also brings another technical defect, that is To separate the catalyst from the liquid phase raw material in the slurry bed reactor, it is necessary to use an expensive membrane separation device, which increases the cost of subsequent separation and the phenomenon of membrane plugging is unavoidable;

[0009] 4. In the ammoximation reaction, most of them will install a porous plate in the reactor to effectively separate the catalyst, but the separation effect is not good, not only the catalyst is easy to block the orifice plate, but also causes great inconvenience to subsequent maintenance and replacement;

[0010] 5. The effective utilization rate of hydrogen peroxide is generally not high

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