Preparation method for high-dispersion zeolite molecular sieves

Abstract

The invention relates to a preparation method for high-dispersion zeolite molecular sieves. The preparation method includes preparing gel and performing hydrothermal crystallization on nanometer molecular sieves, pressing organochlorosilane in a crystallization kettle filled with crystallized matter through pressurization of nitrogen under the condition of stirring when the crystallization of the molecular sieves is finished so as to enable the organochlorosilane to fully contact and react with the surfaces of the molecular sieves, and collecting products after reaction of the organochlorosilane and the crystallized matter is finished. The mass ratio of the added organochlorosilane R is R / SIO2=0.01-2, the reaction time is no more than 100 hours, and the reaction temperature ranges from room temperature to 200 DEG C. The organochlorosilane is added when the crystallization of the molecular sieves is finished, and the condensation reaction of the organochlorosilane and the surface hydroxyl groups of the molecular sieves is utilized to block agglomeration among the molecular sieves, so that the defect that prior methods affect crystallization kinetics of the molecular sieves is overcome. Obtained molecular sieve products have good dispersibility and large specific surface areas, and are easy to filter.

Description

technical field [0001] The invention belongs to the field of preparation of zeolite molecular sieves, and relates to a method favorable for preparing highly dispersed small crystal grain zeolite molecular sieves. Background technique [0002] Zeolite molecular sieve is the most important component of inorganic microporous materials. It is a crystal material that can sieve substances at the molecular level. Its skeleton is composed of TO 4 A multi-dimensional four-connected structure formed by sharing vertices between tetrahedra, where T refers to Si, Al or other heteroatoms. Zeolite molecular sieves are widely used in industrial processes and high-tech materials due to their regular pore structure, unique ion exchange properties, shape-selective adsorption properties, easy modulation of composition and properties, high activity and selectivity of many small molecule catalytic reactions, etc. It is widely used in the field, especially the research fields of catalysis, adsorp...

AI Technical Summary

Problems solved by technology

Materials with zeolite mesoporous composite structure can improve the diffusion properties of products, make up for the deficiency of microporous molecular sieves, and provide a favorable spatial configuration for macromolecular reactions, but their acidity is weak and their hydrothermal stability is relatively low, etc. problem persists

However, when the amount of organic additive added is small, it cannot play a role in dispersing; when the amount is slightly larger, it will seriously hinder the crystallization of molecular sieves, resulting in significantly prolonged crystallization time and increasing the production cost of molecular sieves.

In addition, polyhydroxyl substances are added in the early stage of gel synthesis or crystallization. Since the hydroxyl groups of organic matter combine with the primary or secondary structure of molecular sieves to hinder the growth of molecular sieve crystals, there are inevitably defects in the obtained molecular sieve products, which leads to the performance of molecular sieves. decline