用MINDO/3,MNDO和AMI三种SCF-MO方法,在全优化分子几何构型的基础上,系统地计算研究了32个硝酸酯化合物的生成热.与实验值相比,MNDO计算结果偏大很多;MINDO/3计算值与凝聚相实验值符合较好,由于克服了MNDO法过高地估算原子之间Van der W...用MINDO/3,MNDO和AMI三种SCF-MO方法,在全优化分子几何构型的基础上,系统地计算研究了32个硝酸酯化合物的生成热.与实验值相比,MNDO计算结果偏大很多;MINDO/3计算值与凝聚相实验值符合较好,由于克服了MNDO法过高地估算原子之间Van der Waals核排斥能的缺点,AM法给出了较满意的结果:与七个气态实验值之间存在良好的线性关系(相关系数为0.992),其间的平均绝对差值和平均差值分别只有10.28和-101kJ/mol.展开更多
Cycloaddition of carbon dioxide to epoxides was catalyzed by the binary catalyst systems of phthalocyaninatoaluminium chloride (PcAlCl) and Lewis bases (such as tributylamine, 1 methylimidazole, triphenylphosphine, tr...Cycloaddition of carbon dioxide to epoxides was catalyzed by the binary catalyst systems of phthalocyaninatoaluminium chloride (PcAlCl) and Lewis bases (such as tributylamine, 1 methylimidazole, triphenylphosphine, triethylamine, pyridine and quinoline). The Lewis bases were the excellent promoters, but either component of the binary catalyst systems had low catalytic activity individually. For example, when 0 18 mol of propylene oxide was reacted with 0 36 mol of CO 2 at 140 ℃ for 1 7 h in the presence of 0 18 mmol of PcAlCl and 0 81 mmol of tributylamine, the yield of propylene carbonate was 99 7%; while the yield was 17 4% when used PcAlCl only. Promoting effects of Lewis bases were in the order: 1 methylimidazole>triphenylphosphine>tributylamine>triethylaminepyridinequinoline. Reactivity of the epoxides used was in the order: CH 2Cl>H, CH 3.展开更多
文摘用MINDO/3,MNDO和AMI三种SCF-MO方法,在全优化分子几何构型的基础上,系统地计算研究了32个硝酸酯化合物的生成热.与实验值相比,MNDO计算结果偏大很多;MINDO/3计算值与凝聚相实验值符合较好,由于克服了MNDO法过高地估算原子之间Van der Waals核排斥能的缺点,AM法给出了较满意的结果:与七个气态实验值之间存在良好的线性关系(相关系数为0.992),其间的平均绝对差值和平均差值分别只有10.28和-101kJ/mol.
文摘Cycloaddition of carbon dioxide to epoxides was catalyzed by the binary catalyst systems of phthalocyaninatoaluminium chloride (PcAlCl) and Lewis bases (such as tributylamine, 1 methylimidazole, triphenylphosphine, triethylamine, pyridine and quinoline). The Lewis bases were the excellent promoters, but either component of the binary catalyst systems had low catalytic activity individually. For example, when 0 18 mol of propylene oxide was reacted with 0 36 mol of CO 2 at 140 ℃ for 1 7 h in the presence of 0 18 mmol of PcAlCl and 0 81 mmol of tributylamine, the yield of propylene carbonate was 99 7%; while the yield was 17 4% when used PcAlCl only. Promoting effects of Lewis bases were in the order: 1 methylimidazole>triphenylphosphine>tributylamine>triethylaminepyridinequinoline. Reactivity of the epoxides used was in the order: CH 2Cl>H, CH 3.
