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在B3LYP/6-311++G(2df,p)水平下对单分子水参与下的CH_2SH+NO_2反应的微观机理进行了研究.为了获得更准确的能量信息,采用HL复合方法和CCSD(T)/aug-ccpvtz方法进行单点能校正.结果表明,加入单分子水后的CH_2SH+NO_2反应体系,共经过10条不同的反应路径,得到6种反应产物.与裸反应(CH_2SH+NO_2)相比,水分子在反应中起到了明显的正催化作用.不仅使生成产物trans-HONO的能垒(-52.84kJ·mol~(-1))降低了176.94kJ·mol~(-1),而且不需经过复杂的重排和异构化过程便可得到产物cis-HONO.在生成产物cis-HONO通道(Path3和Path4)中,活化能垒分别为143.65和126.70kJ·mol~(-1),而其裸反应的活化能垒却高达238.34kJ·mol~(-1).生成HNO_2的通道中(Path5和Path6)活化能垒分别为295.23和-42.19kJ·mol~(-1).其中Path6的无势垒过程使HNO_2也成为该反应的主要产物.另外,单分子水还可通过氢迁移的方式直接参与CH_2SH+NO_2的反应,活化能垒(TS7-TS10)分别为-10.62,151.03,186.22和155.10kJ·mol~(-1).除直接抽氢通道中的(Path8-Path10)外,其余反应通道均为放热反应,在热力学上是可行的.
Under the condition of B3LYP / 6-311 ++ G (2df, p), the microcosmic mechanism of CH_2SH + NO_2 reaction with single molecule water was studied.In order to obtain more accurate energy information, HL composite method and CCSD (T ) / aug-ccpvtz method.The results showed that six reaction products were obtained through 10 different reaction pathways after CH 2 SH + NO 2 reaction system was added with monomolecular water.The results showed that CH_2SH + In addition, the water molecules played a significant positive catalysis in the reaction, which not only reduced the energy barrier (-52.84 kJ · mol -1) of trans-HONO to 176.94 kJ · mol -1, And the product cis-HONO can be obtained without complex rearrangement and isomerization process.The activation energy barriers of cis-HONO channels (Path3 and Path4) were 143.65 and 126.70 kJ · mol -1 ), While the activation barrier of naked reaction was as high as 238.34 kJ · mol -1. The activation energy barriers of Path 5 and Path 6 in generating HNO 2 were 295.23 and-42.19 kJ · mol -1, respectively. In addition, the single-molecule water can directly participate in the reaction of CH 2 SH + NO 2 by means of hydrogen migration, and the activation energy barrier (TS7-T S10) were -10.62, 151.03, 186.22 and 155.10 kJ · mol -1, respectively.Except for the direct hydrogen channel (Path8-Path10), the other reaction channels were exothermic and thermodynamically feasible .