摘要
采用ＣＮＤＯ／２法计算乙烯在Ｚｉｅｇｌｅｒ－Ｎａｔｔａ催化剂主体（ＴｉＣｌ４）上的络合反应机理．计算结果为：乙烯和四氯化钛单体处于优化构型时的能量分别为－１７．０７３２ａ．ｕ．和－６８．８５４０ａ．ｕ．，乙烯Ｃ＝Ｃ双键的Ｍｕｌｉｋｅｎ键级为１．１７３；络合体系处于优化构型时的能量为－８６．０１４６ａ．ｕ．，与吸附前单体乙烯和四氯化钛的能值相比，乙烯在四氯化钛上的吸附热为－２２９．３ｋＪ／ｍｏｌ，乙烯Ｃ＝Ｃ双键的Ｍｕｌ－ｌｉｋｅｎ键级为１．０９５，与络合前相比受到了削弱．通过计算所得的分子轨道能级、轨道特征以及Ｍｕｌｉｋｅｎ约化重叠集居等数据，分析了催化剂的催化机理。
Semiemperical molecular orbitals CNDO/2 calculations have been performed for the reaction mechanism of ethylene ( C 2H 4 ) coordinated on Ziegler-Natta type catalyst(TiCl 4) The calculations show that the optimal energies of C 2H 4, TiCl 4 and C 2H 4-TiCl 4 are respectively -17 0732 a u ,-68 8540 a u and -86 0146 a u The Mulliken bond order of C=C double bond in coordinated system C 2H 4-TiCl 4 is 1 095, which is weakened, and 1 173 in C 2H 4 The adsorption energy of C 2H 4 coordinated on TiCl 4 is -229 3 kJ/mol The catalytical mechanism is analyzed in terms of MO energies, MO characters and Mulliken reduced overlap populations
出处
《福建师范大学学报（自然科学版）》
CAS
CSCD
1998年第4期52-56,共5页
Journal of Fujian Normal University：Natural Science Edition
