Studying The Structure And Acidity Of Zeolite Using Quantum Chemistry

As envioriment friendly good effect catalyzer in petroleum and chemical processes,zeolite is displaying usual catalyzer of liquid acid with strong corrosive like vitriol,hydrofluoric acid and three chlorination aluminum in many chemical process.And the structure and acid are the important factor of catalyzed perfomance of zeolie.So it is very important to study the structure and acid of zeolite.The main content and result of this article as follows:1.Calculate models of zeolite using quantum chemistry method.We calculated zeolite models separately using Hartree-Fock method,the best using B3LYP/6-31g method of Density Function Theory,B3LYP/6-31g^** method considering H atoms dispersion,and the method considering big atoms dispersion B3LYP/6-31g^* method.The results tell that under low-grade calculation method,small models can not simulate zeolite.However,using high-grade calculation method can remedy limitation at some extent.2.Using the best using B3LYP/6-31g method of Density Function Theory to calculate serial models from 3T to 20T ofβ,MCM-22,ZSM-5 zeolite,in order to validate the rationality of the models,we calculate the token value further more.3.Using the best using B3LYP/6-31g method of Density Function Theory to calculate large models ofβ,MCM-22,ZSM-5 zeolite,and find that 42T model we constructed puts up the general character of zeolite at this calculation method.And it validites the experimental token value of zeolite in theory.Based on this model we also study the acid strength of different acid site,and the influence of silicon aluminum ratio to zeolite acid property.And we find that acidity ofβzeolite in sieve pore cross is stronger than that in pores.The acidity is creasing with silicon aluminum ratio growing.