物理化学学报 >> 2010, Vol. 26 >> Issue (09): 2473-2480.doi: 10.3866/PKU.WHXB20100922

光化学与光谱 上一篇    下一篇

盐对甲醇微观结构的影响

余小春, 林珂, 胡乃银, 周晓国, 刘世林   

  1. 中国科学技术大学化学物理系, 合肥微尺度物质科学国家实验室(筹),合肥 230026
  • 收稿日期:2010-05-25 修回日期:2010-06-08 发布日期:2010-09-02
  • 通讯作者: 刘世林 E-mail:slliu@ustc.edu.cn
  • 基金资助:

    国家自然科学基金(20873131, 20928002)和国家重点基础研究发展规划项目(973) (2007CB815204)资助

Effects of Salts on theMicrostructure ofMethanol

YU Xiao-Chun, LIN Ke, HU Nai-Yin, ZHOU Xiao-Guo, LIU Shi-Lin   

  1. Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics,University of Science and Technology of China, Hefei 230026, P. R. China
  • Received:2010-05-25 Revised:2010-06-08 Published:2010-09-02
  • Contact: LIU Shi-Lin E-mail:slliu@ustc.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20873131, 20928002) and National Key Basic Research Programof China (973) (2007CB815204).

摘要:

利用拉曼光谱研究盐对甲醇微观结构的影响.比较了不同盐/甲醇体系的O—H伸缩谱段和C—O 伸缩 谱段的超额拉曼光谱, 对比给出了阴、阳离子与甲醇的相互作用. O—H 伸缩谱段的超额拉曼光谱明显地显示了 阴离子与甲醇形成弱氢键, 氢键强度排序为CH3OH-CH3OH>Cl--CH3OH> NO-3 -CH3OH>ClO-3 -CH3OH, 在这个 波段内, 基本观察不到阳离子与甲醇的相互作用. 在C—O 伸缩谱段内, 阴阳离子均有显著的体现, 且与它们作 用的甲醇C—O 伸缩振动频率有如下的关系: CH3—OH(阴离子)3—OH(体相)3—OH(阳离子). 根据C—O 伸缩谱段的超额拉曼光谱,拟合了该谱段的拉曼光谱, 由分解的谱峰强度得到阴、阳离子第一溶剂化层中甲醇 分子的数目, 结果显示在该浓度(~0.005)下离子对第一溶剂化层以外的甲醇氢键网络结构没有明显影响.

关键词: 拉曼光谱, 阴离子, 阳离子, 甲醇, 第一溶剂化层

Abstract:

We studied the effects of salts on the microstructure of liquid methanol using the Raman spectra. We compared the excess Raman spectra of different methanolic salt solutions in the O—H and C—O stretching regions. These regions reflect the interactions between anions (cations) and methanol molecules. In the O—H stretching region, the excess spectra show that the anions interact with methanol molecules by weak hydrogen bonding and the strength of the hydrogen bonds decrease according to the order: CH3OH-CH3OH>Cl--CH3OH>NO- 3 -CH3OH>ClO- 3 -CH3OH. Additionally, no interactions between cations and methanol molecules are apparent, as determined after analysis of this region. In the C—O stretching region, the excess Raman spectra show the interactions between anions (cations) and methanol molecules. The C—O stretching vibration frequencies of methanol that interact with the anions and cations increase according to the order: CH3—OH (anions)3—OH (bulk)3—OH (cations). According to the excess Raman spectra in the C—O stretching region, we fitted the Raman spectra and used the fitting results to determine the solvation numbers in the first solvation shell of the ions. The Raman spectra show that the ions do not affect the microstructure of liquid methanol beyond the first solvation shell at this concentration (~0.005).

Key words: Raman spectrum, Anion, Cation, Methanol, First solvation shell

MSC2000: 

  • O645