Preparation method of layered nano-mordenite molecular sieve

Abstract

The invention discloses a preparation method of a layered nano-mordenite molecular sieve. A template used by the method is hexadecyltrimethylammonium p-toluenesulfonate. The method specifically comprises the steps of: first dissolving a silica source in an alkaline solution which contains different aluminium sources, and carrying out isothermal stirring; then adding the solution dropwise in an aqueous solution which contains the template, continuing to carry out stirring, and transferring the solution to an enclosed reactor for crystallization after the solution cools to room temperature; after carrying out filtering and washing as well as drying on a crystallization product, finally carrying out roasting to obtain the layered nano-mordenite molecular sieve. The method of the invention uses the hexadecyltrimethylammonium p-toluenesulfonate as the template, thereby greatly reducing the use amount of a synthetic system surface active agent. The prepared layered nano-mordenite molecular sieve has a high degree of crystallization, high purity, and abundant secondary accumulation pores, and therefore the method of the invention is an environmentally friendly synthetic method.

Description

technical field [0001] The invention relates to the synthesis of zeolite molecular sieves, in particular to a synthesis method of layered nano-mordenite molecular sieves. Specifically, the layered small-grain mordenite molecular sieve with hierarchical pores is directly prepared by using cetyltrimethyl ammonium p-toluenesulfonate as a template agent through a hydrothermal synthesis method. Background technique [0002] Microporous molecular sieves have uniform pore structure, suitable acidity and good hydrothermal stability, and have become important catalytic materials in petrochemical industry. Hydrogen-type mordenite with one-dimensional twelve-membered ring straight cylindrical channels (pore size 0.695 nm × 0.581 nm) exhibits excellent catalytic performance in toluene disproportionation, alkylation, isomerization of C8 aromatics and selective disproportionation of toluene . The current research focus on mordenite molecular sieves is mainly to synthesize nano-sized mor...

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Problems solved by technology

Chinese patent CN 1050011A reported that mordenite with high silicon-aluminum ratio was prepared by using cheap water glass as the silicon source without dealuminated mordenite as the seed crystal. The highest silicon-aluminum ratio can reach 25, but the synthetic particle size is greater than 1.0 μm

Recently, Tago et al. prepared nano-sized small crystal mordenite molecular sieves in cyclohexane organic solvent, using non-ionic surfactant Polyoxyethylene-(15)-oleylether (O-15) as a particle growth inhibitor, but this method A large number of organic templates and organic solvents are used in the process, which greatly increases the synthesis cost of zeolite molecular sieves, and easily causes a lot of pollution to the environment

[0005] The results of literature and Chinese patent surveys show that the synthesis of nano-mordenite with both layered and hierarchical porous structures has not been reported yet.

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