牛磺酸离子液体[C_nmim]Tau(n=3,4)的摩尔表面Gibbs自由能

The Molar Surface Gibbs Free Energy for Taurine Ionic Liquids[C_nmim][Tau](n = 3,4)

通过中和法合成一类新的离子液体,1-烷基-3-甲基咪唑牛磺酸离子液体[C_nmim][Tau](n=3,4),用1H NMR和13C NMR表征其结构.使用标准加入法,测定了[C_nmim][Tau](n=3,4)的密度,表面张力和折射率.以Glasser理论为基础,计算出[C_nmim][Tau](n=3,4)的标准熵与晶格能.根据摩尔表面Gibbs自由能的概念和实验数据,求得[C_nmim][Tau](n=3,4)的摩尔表面Gibbs自由能.通过热力学关系计算出摩尔表面熵与摩尔表面焓.将摩尔表面Gibbs自由能与Lorentz-Lorenz方程结合,得到一个新的表面张力预测方程.应用这个方程对[C_nmim][Tau](n=3,4)的表面张力进行预测,预测值与实验值非常相近.这说明这种半经验方法具有一定的合理性.

A new series of ionic liquids,1-alkyl-methylimidazolium taurine,[Cnmim][Tau](n=3,4),was synthesized by neutralization method and characterized by 1H NMR and 13C NMR.The values of density,surface tension and refractive index of[Cnmim][Tau](n=3,4) were determined by standard addition method.On the basic of Glasser′s theory,standard entropy and lattice energy of[Cnmim][Tau](n=3,4) were obtained.According to the concept of molar surface Gibbs free energy and the experimental data,the values of molar surface Gibbs free energy of[Cnmim][Tau](n=3,4) were calculated.In terms of thermodynamic relationship,the values of molar surface entropy and molar surface enthalpy were obtained.Combined with the concept of molar surface Gibbs free energy with Lorentz-Lorenz equation,a new equation was put forward,which can be used to estimate surface tension.For[Cnmim][Tau](n=3,4),the estimated values are quite similar to the experimental ones.It indicates that this semi-empirical equation is reasonable.