物理化学学报 >> 2011, Vol. 27 >> Issue (01): 11-16.doi: 10.3866/PKU.WHXB20110122

热力学,动力学和结构化学 上一篇    下一篇

自由能微扰法研究系列烷基芳基磺酸盐的胶束化焓-熵补偿现象

刘国宇1, 顾大明1, 刘海燕1, 丁伟2, 李钟2, 程杰成3   

  1. 1. 哈尔滨工业大学理学院化学系, 哈尔滨150001;
    2. 大庆石油学院化学化工学院, 黑龙江大庆163318;
    3. 大庆油田有限责任公司科技发展部, 黑龙江大庆163453
  • 收稿日期:2010-10-13 修回日期:2010-11-12 发布日期:2010-12-31
  • 通讯作者: 刘国宇 E-mail:liuguoyu1@yahoo.com.cn
  • 基金资助:

    国家重点基础研究发展规划项目(973) (2005CB221300)和黑龙江省研究生创新科研项目(YJSCX2008-044HLJ)资助

Free Energy Perturbation of Enthalpy-Entropy Compensation for the Micellization of Alkyl Aryl Sulfonates

LIU Guo-Yu1, GU Da-Ming1, LIU Hai-Yan1, DING Wei2, LI Zhong2, CHENG Jie-Cheng3   

  1. 1. Department of Chemistry, School of Sciences, Harbin Institute of Technology, Harbin 150001, P. R. China;
    2. Chemistry and Chemical Engineering College, Daqing Petroleum Institute, Daqing 163318, Heilongjiang Province, P. R. China;
    3. Development Department of Science and Technology, Daqing Oil Field Corp. Ltd., Daqing 163453, Heilongjiang Province, P. R. China
  • Received:2010-10-13 Revised:2010-11-12 Published:2010-12-31
  • Contact: LIU Guo-Yu E-mail:liuguoyu1@yahoo.com.cn
  • Supported by:

    The project was supported by the National Key Basic Research Program of China (973) (2005CB221300) and Postgraduate Innovative Science Research Program of Heilongjiang Province, China (YJSCX2008-044HLJ).

摘要:

为了研究不同结构的表面活性剂分子在水溶液中的胶束化焓-熵补偿现象, 采用自由能微扰(FEP)法计算了系列烷基芳基磺酸盐的溶剂化自由能, 并根据胶团化过程的质量作用模型讨论了相关热力学性质. 结果表明: 自由能微扰法得到的溶剂化自由能大小与用传统热力学表面张力法测定的吉布斯自由能相近, 能够用于比较不同结构的烷基芳基磺酸盐间胶束化能力; 烷基芳基磺酸盐在水溶液中的胶束化过程是自发进行的, 且存在焓-熵补偿现象, 补偿温度范围均在(302±2) K; 随着分子结构中芳环向长烷基链中间位置移动, 胶束化能力和胶束的稳定性均下降; 而随着芳环上短烷基链或长烷基链碳数的增加, 形成胶束的能力与稳定性均提高.

关键词: 烷基芳基磺酸盐, 胶束化, 自由能微扰, 溶剂化自由能, 焓-熵补偿

Abstract:

We used the free energy perturbation (FEP) method to calculate the solvation free energy according to the mass action model. We did this to investigate the enthalpy-entropy compensation effect of surfactant molecular structures on micellization in solution. The thermodynamic properties of micellization in an aqueous solution for several alkyl aryl sulfonates are discussed. Results show that the solvation free energy calculated from the free energy perturbation is consistent with that from the surface tension method and can be used to discriminate between the capacities of micellization for alkyl aryl sulfonates. The micellization of alkyl aryl sulfonate in an aqueous solution is a spontaneous process and the micellization is enthalpy-entropy compensated. The compensation temperature was found to be (302± 2) K. As the aromatic ring shifts from the edge to the middle of the long carbon chain, the formation ability of the micelle and micelle stability decrease. However, with an increase in the number of carbon atoms on the short or long alkyl chains on the aromatic rings the formation ability and the stability of the micelles increase.

Key words: Alkyl aryl sulfonate, Micelle, Free energy perturbation, Solvation free energy, Enthalpy-entropy compensation

MSC2000: 

  • O641