Synthesis and Catalytic Application of New Structure Molecular Sieves

Synthesis and Catalytic Application of New Structure Molecular Sieves

(1) Large pore and ultra-large pore molecular sieves

Although the application of zeolite catalysts in petrochemical and fine chemical industry has made great progress, many molecules (such as heavy crude oil components, fine chemicals and intermediate molecules, etc.) are too large to enter the zeolite pores. It can not achieve the expected catalytic effect or even react. Therefore, the preparation of zeolites and zeolite-like molecular sieve materials with macropores (12-membered rings) or ultra-large pores (greater than 12-membered rings) multidimensional structures has become an important goal that people have been striving for in the past decade.

(2) Chiral molecular sieves

At present, highly selective reactions have important application prospects in the synthesis industry such as pharmaceuticals, development of crops, agricultural chemicals, and food additives. When zeolite molecular sieves are used as catalytic materials for asymmetric synthesis reactions, molecular sieves are often used as the main body. Complexes and metal organics with asymmetric structures, etc., to make new chiral catalysts. However, the chiral catalyst prepared in this way can only introduce chirality through bridge bonds or auxiliary reagents, so the stability and catalytic life of the catalyst have always hindered its further industrial development and application. If molecular sieve materials with chiral structures can be synthesized, the problem of their stability may be solved.

(3) Modification of molecular sieves

United Carbide Corporation (UCC) developed a new type of molecular sieve with non-silicon and aluminum framework in 1992, namely phosphorus and aluminum series molecular sieves. Later, silicon was introduced into phosphorus and aluminum series molecular sieves, and a series of silicon, phosphorus and aluminum molecular sieves such as sAP011 were synthesized, and its selectivity was better than that of ZSM-5. In addition, heteroatoms such as No, Fe, Co, Ti can also be introduced to increase the modulation of the charge of the molecular sieve framework and effectively change its catalytic function.