物理化学学报 >> 2013, Vol. 29 >> Issue (06): 1161-1167.doi: 10.3866/PKU.WHXB201304021

热力学,动力学和结构化学 上一篇    下一篇

CH3SO3裂解反应的机理和热力学性质

曹佳1,2, 王文亮2, 高楼军1, 付峰1   

  1. 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
  • 收稿日期:2012-12-17 修回日期:2013-04-01 发布日期:2013-05-17
  • 通讯作者: 王文亮 E-mail:wlwang@snnu.edu.cn
  • 基金资助:

    国家自然科学基金(21173139)和陕西省教育厅科学研究计划(2013JK0667)资助项目

Mechanism and Thermodynamic Properties of CH3SO3 Decomposition

CAO Jia1,2, WANG Wen-Liang2, GAO Lou-Jun1, FU Feng1   

  1. 1 College of Chemistry & Chemical engineering, Yan’an University, Yan’an 716000, P. R. China;
    2 Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry &Chemical engineering, Shaanxi Normal University, Xi’an 710062, P. R. China
  • Received:2012-12-17 Revised:2013-04-01 Published:2013-05-17
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21173139) and 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200-3000 K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3000 K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(DfHΘ298 K, DfH0 K), 熵(SΘ298 K)和热容(Cp, 298-2000 K), 计算的结果与实验值较接近.

关键词: CH3SO3, 裂解机理, 热力学性质, 速率常数

Abstract:

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-Kassel-Marcus (RRKM) theory. The results indicate that the product P1(CH3+SO3) is dominant between 200-3000 K. Products P2(CH3O+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=1.40×1012T0.15exp(7831.58/T). Thermodynamic properties including enthalpies of formation (DfHΘ298 K, DfH0 K), entropies (SΘ298 K), and heat capacities (Cp, 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.

Key words: CH3SO3, Decomposition mechanism, Thermodynamic property, Rate constant

MSC2000: 

  • O641