物理化学学报 >> 2016, Vol. 32 >> Issue (2): 445-452.doi: 10.3866/PKU.WHXB201512013

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十二烷基苯磺酸钠和无机阳离子之间相互作用的密度泛函理论研究

刘志宏1,范成成2,张田田2,纪贤晶2,陈生辉2,孙霜青2,3,胡松青2,3,*()   

  1. 1 中国石化胜利油田有限公司地质科学研究院, 山东东营 257015
    2 中国石油大学(华东)理学院, 山东青岛 266580
    3 山东省高校新能源物理与材料科学重点实验室, 山东青岛 266580
  • 收稿日期:2015-07-28 发布日期:2016-01-30
  • 通讯作者: 胡松青 E-mail:ccupc@upc.edu.cn
  • 基金资助:
    中国石油科技创新基金(2015D-5006-0213);中央高校基本科研业务费专项资金(14CX02221A, 14CX06157A)

Density Functional Theory Study of the Interaction between Sodium Dodecylbenzenesulfonate and Mineral Cations

Zhi-Hong LIU1,Cheng-Cheng FAN2,Tian-Tian ZHANG2,Xian-Jing JI2,Sheng-Hui CHEN2,Shuang-Qing SUN2,3,Song-Qing HU2,3,*()   

  1. 1 Geological Scientific Research Institute, Shengli Oilfield Company Ltd., Dongying 257015, Shandong Province, P. R. China
    2 College of Science, China University of Petroleum (East China), Qingdao 266580, Shandong Province, P. R. China
    3 Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, Qingdao 266580, Shandong Province, P. R. China
  • Received:2015-07-28 Published:2016-01-30
  • Contact: Song-Qing HU E-mail:ccupc@upc.edu.cn
  • Supported by:
    the PetroChina Innovation Foundation, China(2015D-5006-0213);Fundamental Research Funds for the CentralUniversities, China(14CX02221A, 14CX06157A)

摘要:

研究阴离子表面活性剂和阳离子之间的相互作用对于理解阴离子表面活性剂的沉淀和溶解现象具有十分重要的理论和实际意义,但关于两者相互作用的相关理论模型鲜有报道。本文采用密度泛函理论(DFT)方法研究了十二烷基苯磺酸根阴离子(DBS-)与阳离子(Na+, Mg2+和Ca2+)在溶液内及气/液界面处的相互作用。在溶液内,在两种不同溶液环境中(水相和正十二烷)构建DBS-/阳离子相互作用模型,并对其进行优化。结果表明, DBS-能够与阳离子以双齿结构稳定结合。DBS-与阳离子的结合能不仅取决于参与的无机盐离子种类,还与溶剂的性质有关。在气/液界面处, DBS-与六个水分子相互作用形成的水合物DBS-·6H2O最为稳定。但是,无机盐离子的引入会严重破坏DBS-·6H2O水合物的水化层结构。本文定义无量纲参量def用来对水化层结构的变化程度进行评价。无机盐离子对DBS-·6H2O水化层结构破坏程度的顺序为:Ca2+ > Mg2+ >Na+。电荷分析结果表明水化层在十二烷基苯磺酸钠(SDBS)头基与阳离子的相互作用中起了重要作用。

关键词: 十二烷基苯磺酸钠, 阳离子, 相互作用, 气/液界面, 电荷分布, 密度泛函理论

Abstract:

Investigating the interactions between anionic surfactants and cations is of great theoretical and practical significance to understanding the precipitation and solubility of anionic surfactant products but relevant theoretical interaction models are seldom reported. In this paper, the density functional theory (DFT) method was used to investigate the interactions of the dodecylbenzenesulfonate anion (DBS-) with Na+, Mg2+, and Ca2+ both in the solution and at the air/water interface. In the solution, DBS-/cation interaction models were built and optimized with consideration of two different solutions (i.e. water and n-dodecane). The results indicate that DBScan bind stably with the cations in a bidentate form. The binding energy of the DBS-/cation depends on the properties of both the participating cation and the solvent. At the air/water interface, DBS- formed a stable hydrated complex with six water molecules (i.e. DBS-·6H2O). However, the structure of DBS-·6H2O was greatly disturbed by the introduction of the cation. A dimensionless parameter, def, was proposed to evaluate the deformation extent of the hydration shell. The degree of disturbance by the cations follows the order: Ca2+ >Mg2+ > Na+. A charge analysis reveals that the hydration shell plays an important role in the interactions between the sodium dodecyl benzene sulfonate (SDBS) headgroup and the cation.

Key words: SDBS, Cation, Interaction, Air/water interface, Charge distribution, Density functional theory

MSC2000: 

  • O641