【作者】 马倩； 赵强莉； 王渭娜； 刘峰毅； 王文亮；

【Author】 MA Qian-Li;ZHAO Qiang-Li;WANG Wei-Na;LIU Feng-Yi;WANG Wen-Liang;School of Chemistry and Chemical Engineering, Shaanxi Normal University,Key Laboratory for Macromolecular Science of Shaanxi Province;

【机构】 陕西省大分子科学重点实验室陕西师范大学化学化工学院；

【摘要】 采用CCSD（T）//B3LYP/6-311+G（d,p）方法对Criegee中间体RCHOO（R=H,CH₃）与NO₂反应的机理进行了详细地理论研究。结果表明,上述反应主要存在加成-分解及氧化两类反应机理。加成-分解反应机理又包括NO₂中O和N分别加成到Criegee中间体α-C上的两种情况,而O加成反应能垒低,较易进行。NO₂上的O加成到CH₂OO的C上并分解生成NO+O₂+H₂CO,表观活化能为9.19 kJ·mol^-1（通道R1）。加成到syn-CH₃CHOOα-C（通道R7）和加到anti-CH₃CHOOα-C（通道R4）生成NO+O₂+CH₃CHO,表观活化能垒分别为31.58和15.32 kJ·mol^-1。另外,比较CH₂OO,syn-CH₃CHOO及anti-CH₃CHOO与NO₂中的O加成反应基元能垒发现,甲基取代使得反应不易进行;syn-CH₃CHOO与NO₂的反应能垒高于anti-CH₃CHOO。氧化反应中RCHOO（R=H,CH₃）首先转移端位氧生成NO₃,然后继续通过CH₂OO及syn-CH₃CHOO（β-H）中的H迁移生成产物HNO₃+HCO和HNO₃+CH2CHO,在（β-H）迁移过程中所需基元能垒为46.82 kJ·mol^-1而在CH₂OO中H迁移仅需11.05 kJ·mol^-1,说明CH₂OO参与的H转移反应更容易进行。更多还原

【Abstract】 A comprehensive theoretical study on the reaction mechanism of Criegee Intermediates RCHOO（R=H, CH₃）with NO₂ is performed at the CCSD（T）//B3LYP/6-311+G（d,p） level. The results show that the mechanism includes addition–decomposition and oxidation reactions. For the addition–decomposition, two reaction channels have been found which involves the α-C interacts with the NO₂ nitrogen and oxygen. The latter one shows lower reaction energy barrier. The calculated apparent activation energy（Eapp） for the addition of one oxygen on CH₂OO carbon,syn-CH₃CHOO and anti-CH₃CHOO are 9.19 k J·mol^-1, 31.58 and 15.32 kJ ·mol^-1, respectively. The reactions involve the methyl-substituted CI more difficultly. The barriers of syn-CH₃CHOO reaction with NO₂ is the highest. In the oxidation reaction, the reaction proceeds via terminal oxygen atom transfer to form NO₃, and followed by H-abstraction. The energy barriers of H-abstraction invloves the oxidation of CH₂OO and syn-CH₃CHOO are11.05 k J·mol^-1and 46.82 kJ ·mol^-1, which suggest that the reaction involves CH₂OO proceeds more easily.更多还原