Thin-layer MCM-22 molecular sieve microsphere with microporous/mesoporous structure as well as preparation and application of thin-layer MCM-22 molecular sieve microsphere

Abstract

The invention provides a thin-layer MCM-22 molecular sieve microsphere with a microporous / mesoporous structure as well as preparation and application of the thin-layer MCM-22 molecular sieve microsphere. The molecular sieve microspheres have the shape of'desert rose '. The method comprises the following steps: preparing a main template agent, a second template agent and water into a solution A; preparing an aluminum source, NaOH and water into a solution B; mixing and aging the solution A, the solution B and a silicon source to obtain mixed glue; the molar ratio of the components in the mixed glue meets the following conditions: SiO2 / Al2O3 is equal to 5-200, OH <-> / SiO2 is equal to 0.005-1, H2O / SiO2 is equal to 5-100, R1 / SiO2 is equal to 0.01-1, and R2 / SiO2 is equal to 0.005-0.5; and carrying out hydrothermal crystallization on the mixed glue, and then carrying out post-treatment to obtain the MCM-22 molecular sieve microspheres. In a liquid phase alkylation reaction of benzene and ethylene, the molecular sieve prepared by the method shows relatively high benzene conversion rate and ethylene selectivity.

Description

technical field [0001] The invention belongs to the field of chemical industry. Specifically, the invention relates to a thin-layer MCM-22 molecular sieve microsphere with a microporous mesopore structure and its preparation and application. Background technique [0002] Ethylbenzene is an important chemical raw material. Although there is a small amount of ethylbenzene in crude oil, mass production still relies on the reaction of benzene and ethylene under acid catalysis. Up to now, a large number of laboratory and industrial production studies have shown that the MWW series molecular sieves represented by MCM-22 and their matching liquid-phase benzene-ethylene alkylation process have high ethylbenzene selectivity and long stable operation time of the catalyst , the reaction temperature is low, and a higher ethylene conversion can be maintained at a lower benzene molar ratio (2-5). Therefore, the development of catalysts with high performance in liquid-phase alkylation rea...

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Problems solved by technology

In this case, post-processing is required, the operation process is cumbersome, the reaction temperature is high, and it takes a long time, and additional templates are added to cause waste of resources and increase costs. Therefore, the method for synthesizing mesoporous MCM-22 molecular sieves needs further improvement.

[0009] Patent US5362697 is the first to disclose the synthesis method of thin-layer MCM-56 molecular sieve, but the crystal phase of the product is difficult to control, and it is prone to crystallization into MCM-49, and the hydrothermal stability of single-layer MWW molecular sieve is poor, so it is difficult to apply in practice in production

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