甲酸苯酯氨解反应的机理和溶剂效应的理论研究

采用密度泛函理论方法B3LYP/6-31G(d,p)研究了甲酸苯酯与氨在气相中的反应机理. 考虑了两条可能的反应途径: 中性协同的和中性分步的机理. 采用自洽反应场极化连续模型(CPCM模型)研究了反应体系在水、乙醇和乙腈溶液中反应的溶剂化效应. 计算结果表明气相和溶液中协同机理均是最优途径. 水、乙醇和乙腈溶剂可降低协同途径的活化能, 溶剂化效应的大小对溶剂的极性不敏感.

Theoretical Studies on the Aminolysis of Phenyl Formate.Mechanism and Solvent Effect

The density functional theory B3LYP/6-31G(d,p) was employed to study the mechanism of aminolysis of phenyl formate with ammonia in gas phase. Two reaction pathways, the concerted and the stepwise pathways were considered through neutral intermediates. The effect of various solvents such as water, ethanol and acetonitrile on the title reaction was assessed by the polarizable continuum model. The calculated results show that the neutral concerted pathway is the most favorable one in the gas phase and solutions. The reduction of energy of activation in the concerted path of the aminolysis of phenyl formate was found to be more significant than that in the neutral stepwise process due to the solvent effect of water, ethanol and acetonitrile. The solvation effect of different solvents was not sensitive to their polarities in this reaction of phenyl formate with ammonia.