Nano hierarchical pore BEA structure molecular sieve catalyst and preparation method and application thereof

Abstract

The invention discloses a nano hierarchical pore BEA structure molecular sieve catalyst as well as a preparation method and application thereof, and relates to the technical field of a catalyst for a process of preparing ethylbenzene by alkylation. The preparation method specifically comprises the following steps: fully mixing a silicon source, an aluminum source, an inorganic alkali source, a template agent, a co-auxiliary agent and deionized water, slowly evaporating excessive water in an aging process to obtain concentrated sol, and performing low-temperature-high-temperature two-stage hydrothermal crystallization to obtain the molecular sieve catalyst. The used co-auxiliary agent is a binary co-auxiliary agent consisting of a water-soluble polyamide and a water-soluble small organic molecule containing amino and carboxyl. The molecular sieve catalyst disclosed by the invention has a BEA framework topological structure, a grain size of 50-200nm, a micropore-mesopore hierarchical pore channel and a core-shell structure, has a relatively high mesopore volume ratio, and shows excellent selectivity and catalytic stability in industrial production of ethylbenzene by liquid phase alkylation of benzene and ethylene.

Description

technical field [0001] The invention relates to the technical field of catalysts for the process of producing ethylbenzene by alkylation, and more specifically relates to a nanometer hierarchical porous BEA structure molecular sieve catalyst and its preparation method and application. Background technique [0002] Ethylbenzene is an important organic chemical raw material, but in the current industrial production of ethylbenzene, only about 2% of ethylbenzene comes from the extraction of C8 aromatics fraction of reformed light oil, and most of the rest is alkylated by benzene and ethylene under the action of a catalyst Reaction preparation. After a long period of development, the alkylation ethylbenzene process has been replaced by the traditional AlCl 3 method and modified AlCl 3 The method has been developed into a production process using various types of solid acids as catalysts. Since the ethylbenzene production process using solid acid as a catalyst is pollution-fre...

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Problems solved by technology

[0008] In view of this, the present invention provides a molecular sieve catalyst with a nanoscale hierarchical porous BEA structure and its preparation method and application, wherein the molecular sieve catalyst with a nanoscale porous BEA structure has a particle size of nanometer size, a special core-shell structure, a large The specific surface area, shorter pore length and higher mesopore volume can significantly reduce the carbon deposition rate and improve the catalytic efficiency of molecular sieves, further improve the catalytic selectivity and stability of molecular sieves, and solve the problem to a large extent. The problem of catalytic deactivation caused by diffusion and mass transfer caused by a single micropore channel is more suitable for the operating conditions of low temperature and low styrene ratio; the disclosed preparation method is simple, which is conducive to industrialization

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