Separation process of molecular sieve catalyst in ketone oxamidinating reaction system

Abstract

In the ketone oxamidinating reaction system with water mutually soluble low-carbon alcohol of 30-50 wt% concentration and excessive ammonia water content, the material including titania-silica molecular sieve is deposited at 60-85 deg.c in deposition rate of 0.5-3 cm / min for at least 10 min. The present invention can realize the continuous separation of titania-silica molecular sieve from reaction liquid and is suitable for cyclohexanone oxamidinating reaction system with titania-silica molecular sieve catalyst of 0.1-0.3 micron size.

Description

technical field [0001] The present invention relates to a method for separating molecular sieve catalysts, and more particularly relates to a method for separating molecular sieve catalysts in a ketoammoxime reaction system. Background technique [0002] Cyclohexanone oxime is a key intermediate for the synthesis of caprolactam and an important chemical raw material, mainly used as a raw material for the preparation of nylon 6 monomer for fiber nylon 6 and engineering plastics. [0003] The preparation of cyclohexanone oxime is disclosed in documents such as EP0384390, EP0311983 and EP0496385. EniChem Company first disclosed the method of ammoximation of cyclohexanone to generate cyclohexanone oxime, which is the next step to generate cyclohexanone oxime in the presence of cyclohexanone, ammonia and hydrogen peroxide in the presence of tert-butanol or toluene solvent and titanium silicon molecular sieve catalyst . The method has the characteristics of mild reaction conditi...

AI Technical Summary

Problems solved by technology

[0005] (1) The molding of molecular sieves and the use of binders in the molding process not only cause the loss of molecular sieves, but also affect the pore volume and specific surface area of ​​catalysts;

[0006] (2) Install a 5 μm porous plate directly in the reactor to intercept the molecular sieve catalyst. Although the separation is relatively simple, such a small hole is very easy to block without backflushing, and this situation also poses a high demand for stirring. Poor stirring can easily cause parking accidents; and the reactor has a built-in separation element, which is extremely inconvenient to maintain and replace;

Images