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CH2Cl与OH自由基反应机理的理论研究
刘颖,裴克梅,李海洋*
作者单位E-mail
刘颖 中国科学院安徽光学精密机械研究所环境光谱学实验室,合肥,230031  
裴克梅 中国科学院安徽光学精密机械研究所环境光谱学实验室,合肥,230031  
李海洋* 中国科学院安徽光学精密机械研究所环境光谱学实验室,合肥,230031 hli@aiofm.ac.cn 
摘要:
用量子化学从头算方法对CH2Cl与OH自由基反应生成HCCl+H2O、 HCOCl+H2和H2CO+HCl的机理进行了研究.在UMP2(FC)/6-311+ +G*水平上计算出了各物种的优化构型、振动频率;并在Gaussian-3(G3)水平上计算了他们的零点能(ZPE)、相对能量及总能量.结果表明, CH2Cl和OH自由基反应首先经无垒过程生成一个富能中间体CH2ClOH,中间体再经过一系列原子转移、基团旋转和键断裂分别生成产物HCCl+H2O、 HCOCl+H2和H2CO+HCl;三者均为放热反应,放热量分别为72.81、 338.54和354.08 kJ/mol;生成H2CO+HCl放出的热量比生成HCCl+H2O放出的热量多281.27 kJ/mol,与实验结果吻合.
关键词:  从头算方法  CH2Cl自由基  OH自由基  Gaussian-3(G3)  反应机理
DOI:10.1088/1674-0068/17/6/670-674
分类号:
基金项目:
Theoretical Study of the Reaction Mechanism of CH2Cl with OH
Liu Ying,Pei Kemei,Li Haiyang*
Abstract:
The reaction mechanism of CH2Cl radical with OH radical to produce HCCl+H2O,HCOCl+H2 and H2CO+HCl has been studied by using quantum chemistry ab initio calculations. The optimized geometrical parameters,and vibrational frequencies of all species were obtained at the UMP2(FC)level of theory in conjunction with 6-311++G* basis set. Besides,the zero-point energies(ZPE),relative energies and total energies of all species were calculated using Gaussian-3(G3)model. The results of theoretical study indicate that the activated intermediate CH2ClOH is first formed through a barrierless process,followed by atoms migration,radical groups rotation and bonds fission to produce HCCl+H2O,HCOCl+H2 and H2CO+HCl,respectively. And all channels are exothermic by 72.81,338.54 and 354.08 kJ/mol. The reaction heat of reactants to H2CO+HCl is 281.27 kJ/mol more than that of reactants to HCCl+H2O. This result accords with that of experiments.
Key words:  ab initio,CH2Cl radical,OH radical,Gaussian-3(G3),Reaction mechanism