离子液体[C_nmmim][NTf_2](n=2,4)的物理化学性质研究

Study on Physicochemical Properties of Ionic Liquids[C_nmmim][ NTf_2],( n = 2,4)

制备了两种离子液体[Cnmmim][NTf2]（n=2,4）,并分别用核磁共振氢谱1H NMR和差示扫描量热仪（DSC）对其进行了表征.在（298.15~338.15±0.01）K温度范围内,测定了离子液体[Cnmmim][NTf2]（n=2,4）的密度ρ,电导率σ,运动粘度ν.计算了离子液体[Cnmmim][NTf2]（n=2,4）的动力粘度η,摩尔体积Vm和摩尔电导率Λ.根据Nernst-Einstein方程和Eyring液体粘度理论分别计算得到了离子扩散系数D和粘性流动活化Gibbs自由能ΔG≠.通过VFT方程和Arrhenius方程对离子液体的动力粘度和电导率值进行线性拟合,并讨论了电导率、动力粘度和温度的关系.通过计算[Cnmmim][NTf2]（n=2,4）及其他15种离子液体的W（Walden）系数,发现不同离子液体有不同的W值,即W系数是离子液体的特征物理量.

Two bis（ trifluoromethyl-sulfonyl） imide ionic liquids [Cnmmim][NTf2]（ n = 2,4）{ 1-Alkyl-2,3-dimethylimidazolium-N,N-bis（ trifluoromethyl-sulfonyl） imide} were prepared and characterized by1 H NMR spectroscopy and differential scanning calorimetry（ DSC）. The values of the density,ρ,conductivity,σ,and kinematic viscosity,ν,were measured in the temperature range of（ 298. 15 to 338. 15 ± 0. 01） K. The dynamic viscosity,η,molar volume,Vm,and molar conductivity,Λ,were calculated. The diffusion coefficients of ions,D,and the viscous activation Gibbs free energy values,ΔG≠,were obtained by Nernst-Einstein equation and Eyring＇s liquid viscosity theory,respectively. The dynamic viscosity and conductivity values were fitted by VogelFulcher-Tammann（ VFT） and Arrhenius equations,the relationship between conductivity,dynamicviscosity and temperature was discussed. A series of W alden product,W,for [Cnmmim][NTf2]（ n = 2,4） and 15 other kinds of ILs were calculated. The results showed that different ionic liquids have the different W alden product,W,which is the feature physical parameter for ILs.