摘要
用量子化学B3LYP/6-311+G(d,p)方法优化了H2ClCS单分子分解反应驻点物种的几何构型,并在相同水平上通过频率计算和内禀反应坐标(IRC)分析对过渡态结构及连接性进行了验证.用QCISD(T)/6-311++G(d,p)方法计算各物种的单点能,并对总能量进行了零点能校正.利用经典过渡态理论(TST)与变分过渡态理论(CVT)并结合小曲率隧道效应模型(SCT),计算了主反应通道在200 K～2 000 K温度范围内的速率常数kTST,kCVT和kCVT/SCT.结果表明,H2ClCS存在8条可能的裂解通道,可生成产物P1(HCS+HCl),P2(CSH+HCl),P3(H2S+CCl)和P4(ClHCS+H).所有反应均为吸热反应.相对于H2ClCS,各产物能量分别为60.9,222.9,275.7和156.9 kJ.mol-1.通道H2ClCS→TS3→P1的反应势垒为81.5 kJ.mol-1,是标题反应的主反应通道,其余通道为次反应通道.在200 K～2 000 K温度区间内得到主反应通道的表观反应速率常数三参数表达式为.kCVT/SCT=8.7610T0.79exp(-4 053.6/T)s-1.
The unimolecular decomposition reactions of H2ClCS is carried out with B3LYP/6-311＋G（d,p） method.Relationships of reactants,intermediates,transition states and products are confirmed by the intrinsic reaction coordinate（IRC） calculations.More accurate energy information is provided by single-point calculations at QCISD（T）/6-311＋ ＋G（d,p） method.Four intermediates,eight small molecules and twelve transition states are located and a variety of possible reaction pathways are probed.The results show that all the channels are endothermic reactions and the energies of products P1—P4 are 60.9,222.9,275.7 and 156.9 kJ·mol-1.The elimination reaction of HCl via the path H2ClCS→TS3→P1 is the dominant channel of the title reaction and the energy barrier is 81.5 kJ·mol-1.The fitted Arrhenius expressions of the calculated CVT/SCT rate constants are kCVT/SCT=8.7610T0.79exp（-4 053.6/T）s-1 in the temperature range of 200 K～2 000 K.
出处
《分子科学学报》
CAS
CSCD
北大核心
2011年第6期416-421,共6页
Journal of Molecular Science
基金
陕西省教育厅专项科研基金资助项目(11JK0581)
渭南师范学院科研计划资助项目(11YKF009)
关键词
H2ClCS
反应机理
分解反应
H2ClCS
reaction mechanism
decomposition reactions
