CH_3SO_3裂解反应的机理和热力学性质(英文)  

Mechanism and Thermodynamic Properties of CH_3SO_3 Decomposition

作　　者：曹佳[1,2] 王文亮[2] 高楼军[1] 付峰[1] 

机构地区：[1]延安大学化学与化工学院,陕西延安716000 [2]陕西师范大学化学化工学院,陕西省大分子科学重点实验室,西安710062

出　　处：《物理化学学报》2013年第6期1161-1167,共7页Acta Physico-Chimica Sinica

基　　金：supported by the National Natural Science Foundation of China(21173139);Foundation of Shaanxi Education Department(2013JK0667)~~

摘　　要：在G3XMP2//B3LYP/6-311+G(3df,2p)水平上对CH3SO3裂解反应的机理进行了研究,获得了6条通道(10条路径),并构建了其势能剖面.同时采用单分子反应理论计算了各个通道在温度200-3000K区间的速率常数.研究结果表明,在计算温度范围内,CH3SO3裂解反应的主产物为P1(CH3+SO3),产物P2(CH3O+SO2)和P3(HCHO+HOSO)仅在温度大于3000K时对总产物有贡献,而产物P4(CHSO2+H2O)、P5(CH2SO3+H)和P6(CHSO3+H2)贡献相对较少.将裂解反应总的速率常数拟合为ktotal=1.40×1012T0.15exp(-7831.58/T).此外,根据统计热力学原理,预测了所有物种的生成焓(ΔfH298K,ΔfH0K)、熵(S298K)和热容(Cp,298-2000K),计算的结果与实验值较接近.The mechanism and kinetics of unimolecular decomposition of CH3SO3 are studied at the G3XMP2//B3LYP/6-311 ＋G（3df,2p） level of theory. Six possible dissociation channels and potential energy surface for the CH3SO3 decomposition are investigated. Rate constants over the temperature range of 200-3000 K are calculated using Rice-Ramsperger-KasseI-Marcus （RRKM） theory. The results indicate that the product PI（CH3＋SO3） is dominant between 200-3000 K. Products P2（CH30＋SO2） and P3（HCHO＋ HOSO） increase significantly at higher temperatures （〉3000 K）. Products P4（CHSO2＋H2O）, P5（CH2SO3＋H）, and P6（CHSO3＋ H2） show little formation in the temperature range （200-3000 K）. The total rate constant can be expressed as ktotal=1.40 x 1012T0.15exp（-7831.58/T）. Thermodynamic properties including enthalpies of formation （A,H^BK, A,H0k）, entropies e （$298K）, and heat capacities （Cp1 298-2000 K） of all the minima and transition states are predicted from statistical mechanics, and found to be in good agreement with the available experimental values.

关 键 词：CH3SO3 裂解机理 热力学性质 速率常数 

分 类 号：O642.1[理学—物理化学]