Method for preparing catalyst containing molecular sieve of MFI structure

Abstract

The invention provides a method for preparing a catalyst containing MFI-structure molecular sieves. The method comprises the steps of molding, drying and roasting a mixture containing the MFI-structure molecular sieves and a SiO2 carrier, wherein the method also comprises the step of allowing a product obtained after roasting to be in contact with an alkaline buffer solution of nitrogen-containing compounds. The catalyst containing MFI-structure molecular sieves, which is prepared by the method has high crushing strength, and can be used for a fixed bed process for preparing caprolactam by cyclohexanone-oxime gas phase Beckmann rearrangement. In addition, when the catalyst prepared by the method is used to perform the gas-phase Beckmann rearrangement reaction of cyclohexanone-oxime, both the conversion rate of cyclohexanone-oxime and the selectivity of caprolactam are high.

Description

Preparation method of catalyst containing molecular sieve with MFI structure technical field The invention relates to a preparation method of a catalyst containing molecular sieve with MFI structure. Background technique Caprolactam is the main raw material for the production of three series of products including nylon, industrial cord and nylon engineering plastics, and its demand has been relatively strong. The caprolactam is generally obtained by Beckmann rearrangement of cyclohexanone oxime. At present, the liquid phase rearrangement process using concentrated sulfuric acid or oleum as a catalyst is usually used in industry. The caprolactam produced by this process accounts for about 90% of the world's total production of caprolactam, but this process needs to consume a large amount of sulfuric acid and ammonia water. Generally, 1.3-1.8 tons of ammonium sulfate will be produced as a by-product for every ton of caprolactam produced, and the production cost is relativel...

AI Technical Summary

Problems solved by technology

The purpose of the present invention is to overcome the insufficient crushing strength of the molecular sieve catalyst containing the MFI structure in the prior art, the conversion rate of cyclohexanone oxime and the selection of caprolactam when it is used for the gas phase Beckmann rearrangement of cyclohexanone oxime to prepare caprolactam In order to solve the disadvantages of not being high enough, to provide a molecular sieve catalyst containing MFI structure with high crushing strength, the conversion rate of cyclohexanone oxime and the high selectivity of caprolactam when it is used in the gas-phase Beckmann rearrangement of cyclohexanone oxime to prepare caprolactam Preparation