SF_5CF_3与还原性自由基C_2H_3脱氟反应机理研究  

Study on the fluoride removal mechanisms for the reactions of SF_5CF_3 with reduction radicals C_2H_3

作　　者：刘艳[1,2] 任宏江[3] 

机构地区：[1]渭南师范学院军民两用材料重点实验室,陕西渭南714000 [2]陕西师范大学化学化工学院,陕西西安710119 [3]西安文理学院化学系,陕西西安710065

出　　处：《分子科学学报》2015年第5期368-372,共5页Journal of Molecular Science

基　　金：陕西省自然科学基金资助项目(2014JQ2074);渭南市科技扶贫基金资助项目(2013JCYJ-2);渭南师范学院科研计划项目(13YKP006;15ZRRC07);秦东化工材料技术调查项目(14TSXK04)

摘　　要：用密度泛函B3PW91/6-311g(d,p)方法对SF5CF3与还原性自由基C2H3反应机理进行了理论研究,优化了反应通道上反应物、过渡态、中间体和产物的几何构型,用内禀反应坐标计算和频率分析确认了过渡态.用精确模型算法G3(MP2)计算了各物种单点能量.研究结果表明:SF5CF3与C2H3自由基反应为多通道反应,C2H3可脱去SF5CF3分子中不同位上的F原子,分别生成3个中间体IM1,IM2和IM3.然后3个中间体发生自分解反应生成产物P1[CF2SF5+C2H3F],P2[CF3SF4(a)+C2H3F]和P3[CF3SF4(b)+C2H3F],其中Path 2和Path 3能垒高度分别为141.9和147.0kJ·mol-1,为竞争反应通道,P2和P3为反应主产物.The reaction mechanisms of SF5CF3 with reduction radicals C2H3 were investigated with the density functional theory by B3PW91/6-311g（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 with G3（MP2）method.The results show that the reactions of SF5CF3 and C2H3radicals are multichannel reactions.C2H3 may abstract the F atoms on the different sites of SF5CF3 molecule and forming three intermediates IM1,IM2 and IM3 viatransition states TS1,TS2 and TS3,respectivily.The intermediates then decompose into three products P1[CF2SF5＋C2H3F],P2[CF3SF4（a）＋C2H3F]and P3[CF3SF4（b）＋C2H3F].The energy barriers of Path 2and Path 3are 141.9and 147.0kJ·mol-1,respectively.Thus,Path 2and Path 3are competitive reactions,as well as P2 and P3 are the main products because of the low energy barriers.

关 键 词：SF5CF3 C2H3 反应机理 脱氟反应 

分 类 号：O643[理学—物理化学]