Heteroatomic molecular sieve and its synthesis

Abstract

A molecular sieve MCM-49 containing heteroatoms is prepared by direct hydrothermal synthesis. Said molecular sieve has the X-ray diffraction characteristics and the mole ratio of SiO2 to Al2O3 of conventional molecular sieve MCM-49 and contains the heteroatoms of transition metal chosen from Ti, V, Cr, Mo, W, Co, Ni, Cu and Zn.

Description

technical field [0001] The invention relates to a molecular sieve (MCM-49) with a special crystal structure and its synthesis, in particular to the MCM-49 molecular sieve containing transition metal heteroatoms and its synthesis. Background technique [0002] The zeolite molecular sieve framework is composed of a rigid three-dimensional structure of SiO 4 Tetrahedron and AlO 4 Tetrahedral structure, the ratio of the number of silicon aluminum atoms to the number of oxygen atoms is 1:2. Among them, aluminum is a trivalent element, so each AlO 4 A tetrahedron has a negative charge. In this way, the entire molecular sieve framework is negatively charged, for which it is necessary to rely on the adsorption of cations (such as K + 、Na + , Ca 2+ etc.) to maintain electrical neutrality. These cations are easily exchanged for other ions (such as H + ), which is the source of the acidity of molecular sieves. [0003] The silica-to-alumina ratio of zeolite molecular sieves is...

AI Technical Summary

Problems solved by technology

As far as the present inventors know, except for the above-mentioned reports of Kumar et al. and the report of synthesizing trivalent elements Ga and Fe into MCM-22 molecular sieves, there is no report of MCM-49 molecular sieves containing heteroatoms

Images