Quantum Chemistry Study of Hydrolysis Mechanism of 1,2-Thiazetidine 1,1-Dioxide

The hydrolysis of 1,2-thiazetidine 1,1-dioxide has been studied by using ab initio and density functional theory at HF/6-31G*, MP2/6-31G* and B3LYP/6-31G* levels, showing there exist two potential theoretical products. One is N-ethyl amino-methyl sulfonate (P1) in which breaking of bond S–C is concerted, the other is 2-taurine methyl ester (P2) which involves two reaction processes with two different mechanisms: concerted and stepwise. There are two pathways of a and b in stepwise, and the former is the lowest in energy barrier in the hydrolysis of 1,2-thiazetidine 1,1-dioxide. The energy barriers of water-assisted hydrolysis of 1,2-thiazetidine 1,1-dioxide are obviously lower than those of no-water-assisted hydrolysis. Solvent effects have been considered by means of a polarizable continuum model (PCM).

大气中农药乙酰甲胺磷水解机理的量子化学研究

运用Gamess和wxMacmolplt程序,在RHF/6-311G基组水平上对农药乙酰甲胺磷在大气中的水解机理进行了量子化学计算。结果表明,乙酰甲胺磷的水解过程可以有C-N、P-O、P-N、P-S四个水解通道,按照这四个水解通道进行水解的难度依次为:C-N<P-S<P-N<P-O,且温度降低,水解速度加快。