Straight-through mesoporous l-type molecular sieve and preparation method thereof

Abstract

The invention relates to a through-type mesoporous L-type molecular sieve and a preparation method thereof. The method mainly solves the problems that microporous channels cannot completely communicate with mesoporous channels when a mesoporous L-type molecular sieve is prepared in the prior art, and the mesoporous channels are easy to collapse. The method comprises the steps of adopting a secondary treatment method, impregnating a microemulsion rich in a silicon / aluminum / an L templating agent into a mesoporous molecular sieve, and performing crystallization for two times to epitaxially growan L-type molecular sieve at the inner surface of the mesoporous molecular sieve, so as to generate the through-type mesoporous L-type molecular sieve. The method provided by the invention perfectly solves the above mentioned problems, and can be used in the industrial production of a plurality of through-type mesoporous molecular sieves.

Description

technical field [0001] The invention relates to a straight-through mesoporous L-type molecular sieve and a preparation method thereof. Background technique [0002] L-type molecular sieve belongs to the chabazite series, which is composed of double six-membered rings and can cage connections, with a pore size of 0.71 nanometers. The molecular sieve has high hydrothermal stability, strong acidity and hydrophobicity. Because of its unique pore structure and high anti-carbon performance, it plays an important role in the field of host-guest materials. L-type molecular sieve was first developed by linde company, and it was prepared by crystallization at 100-175°C for 6h-10 days by using potassium hydroxide as a structure-directing agent. The active centers of microporous molecular sieves are mostly inside the pores. The longer main channel of molecular sieve will increase the diffusion resistance of molecules in the channel, so that the target product molecules cannot diffuse...

AI Technical Summary

Problems solved by technology

A common method for synthesizing hierarchically porous molecular sieves is to add not only microporous templates to promote the formation of molecular sieve frameworks, but also mesoporous templates to induce mesopore formation in the synthesis system, including carbon black particles, carbon nanotubes, and carbon as hard templates. Aerogels, polysaccharide compounds, etc., as well as cationic polymers as soft templates and amphiphilic organic silanes, etc., but the use of mesoporous templates not only increases the cost but also complicates the synthesis steps, which is not suitable for industrialization

So far, the preparation of directly connected mesoporous L-type molecular sieves has not been reported, indicating that conventional synthesis methods cannot synthesize straight-through mesoporous L-type molecular sieves.

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