HZSM-5,Co/ZSM-5及Ni/ZSM-5分子筛催化选择性研究(Ⅲ)--甲苯烷基化和间二甲苯异构化的量化处理

Selectivity Studies for Molecular Seive Catalysts HZSM-5 Co/ZSM-5 and Ni/ZSM-5(Ⅲ)--CNDO/2 Calculation for Alkylation of Toluene and the Mechanism of Isomerization of Meta-Xylene

根据Kaeding等提出的以HZSM-5作催化剂的甲苯烷基化机理和Guisnet等提出的以HZSM-5作催化剂的间二甲苯异构化机理,用CNDO/2法计算了HZSM-5、Co/ZSM-5、Ni/ZSM-5通道中不同σ络合物的总能量,从理论上解释了HZSM-5和Co、Ni改性的ZSM-5催化剂提高对二甲苯选择性的原因。描述了HZSM-5通道及金属原子在催化反应中的作用。

According to the mechanism of alkylation of toluene and the mechanism of isomerization of meta-xylene,which were suggested by Kaeding and Guisnet seperately,CNDO/2 method has been used to calculate the total energy of complexes in the pore of HZSM-5,Co/ZSM-5 and Ni/ZSM-5.The result can be used to explain the increase selectivity of para-xylene when the ZSM-5 modified with Co and Ni was used as catalyst.We also describe the functions of the pore of ZSM-5 and the metal atom in the pore by analyzing the diatomic interaction energy.