物理化学学报 >> 2016, Vol. 32 >> Issue (1): 267-273.doi: 10.3866/PKU.WHXB201510303

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吡啶基离子液体[C6py][DCA]热力学性质及利用新Eötvös方程预测其表面张力

卜晓雪1,樊本汉1,魏杰1,邢楠楠1,2,马晓雪1,关伟1,*()   

  1. 1 辽宁大学化学院,沈阳 110036
    2 黄山学院化学化工学院,安徽黄山 245041
  • 收稿日期:2015-09-09 发布日期:2016-01-13
  • 通讯作者: 关伟 E-mail:guanweiy@sina.com
  • 基金资助:
    国家自然科学基金(21173107);辽宁省高等学校优秀人才支持计划(2015025)

Thermodynamic Properties and Predicting the Surface Tension of Pyridinium-Based Ionic Liquids of [C6py][DCA] Using a New Eötvös Equation

Xiao-Xue BU1,Ben-Han FAN1,Jie WEI1,Nan-Nan XING1,2,Xiao-Xue MA1,Wei GUAN1,*()   

  1. 1 College of Chemistry, Liaoning University, Shenyang 110036, P. R. China
    2 College of Chemistry and Chemical Engineering
  • Received:2015-09-09 Published:2016-01-13
  • Contact: Wei GUAN E-mail:guanweiy@sina.com
  • Supported by:
    the National Natural Science Foundation of China(21173107);Liaoning Excellent Talents in University, China(2015025)

摘要:

制备了吡啶类离子液体N-己基吡啶二氰胺盐[C6py][DCA],并用核磁共振氢谱([1]H NMR)、核磁共振碳谱([13]C NMR)、差热扫描量热(DSC)、傅里叶变换红外(FT-IR)光谱对其进行表征。在288.15-338.15 K温度范围内,采用标准加入法,测定其密度(ρ)、表面张力(γ)和折光率(nD)。在测得的实验数据的基础上,得到了离子液体[C6py][DCA]的分子体积(Vm)、表面能(Ea)、摩尔极化度(Rm)和极化率(αp)。结果显示EaRmαp几乎不随温度的变化而发生改变。本文还提出了摩尔表面Gibbs自由能(gs)的概念,并改进了Eötvös方程。同时还计算了gs、临界温度(Tc)和Eötvös方程经验参数(kE),并预测了离子液体[C6py][DCA]的表面张力,预测值与实验值具有较好的一致性。

关键词: 吡啶基离子液体, 密度, 表面张力, 摩尔表面Gibbs自由能, Eötvös方程

Abstract:

The pyridinium-based ionic liquids [C6py][DCA] (N-hexyl-pyridinium dicyanamide) was prepared and characterized using [1]H and [13]C nuclear magnetic responancec (NMR) spectroscopies, Fourier transform infrared (FT-IR) spectroscopy, and differential scanning calorimetry (DSC). The density (ρ), surface tension (γ), and refractive indices (nD) were measured at the temperature range from 288.15 to 338.15 K. Molecular volume (Vm), energy of surface (Ea), molar polarization (Rm), and polarization coefficient of [C6py][DCA] (αp) were calculated from the experimental data. Ea, Rm, and αp were approximately temperature-independent. The concept of molar surface Gibbs free energy (gs) was conceived, for which a new Eötvös equation was derived. The gs, critical temperature (Tc), and Eötvös empirical parameter related to polarity (kE) were also obtained. The new Eötvös equation was used to predict the surface tension and the predicted values of [C6py][DCA] are in close agreement with the corresponding experimental ones.

Key words: Pyridinium-based ionic liquid, Density, Surface tension, Molar surface Gibbs free energy, Eötvös equation

MSC2000: 

  • O643