The Physicochemical Properties For The Binary Mixture Of Ether-Based Trifluoromethylsulfonate With Alcohols

Ionic liquids are considered to be an emerging green solvent and have received widespread attention in academia and industry over the past decade.However,the main reasons for limiting the widespread use of ionic liquids are the high cost and viscosity.It has been found that the ether-based functionalized ionic liquid which prepared by introducing an ether group into an ionic liquid can effectively reduce the viscosity and is widely used in carbon dioxide supplementation and functional material preparation.It is well known that by mixing with common organic solvents,not only the viscosity and cost can be lowered,but also the microstructure and physicochemical properties can be changed,which is very advantageous for expanding the application range of ionic liquids.For this,a binary mixture of ether-functionalized ionic liquid and ethanol,propanol and isopropanol was prepared.The physical and chemical properties of the solution were determined by experimental determination and calculation,which laid a foundation for its industrial application.1.N-ethylimidazole and 1-Bromo-2-methyethane as raw materials,ether-based functionalized ionic liquid 3-ethylimidazolium 1-（2-methoxyethyl）-trifluoromethyl-sulfonate[C₂2O1IM][TfO],and it is confirmed by ¹H NMR),¹³C NMR and element-al analysis（EA）.2.The binary mixtures of ether-based functionalized ionic liquid[C₂2O1IM]-[TfO]and short-chain alcohols（ethanol,1-propanol and 2-propanol）are prepared firstly across the entire composition range（x₁=0.0000¹.0000）by using the gravimetric method.The density and surface tension are measured at T=（288.15 to318.15）K interval 5K and p=0.1MPa.Based on the measured density and surface tension values,the average molar volume（V）,thermal expansion coefficient（α）and excess molar volume（V^E）of the three binary mixtures are calculated,and V^E are well fitted by Redlich-Kister equation,and the interaction between the ionic liquid and the short chain alcohol molecules in the binary mixture is discussed,and establishing the semi-empirical method for estimating the average molar volume of the mixtures.3.Based on the measured surface tension value and the calculated average molar volume,the molar surface Gibbs free energy（g_s）of the binary mixture is obtained,and then using the modified E?tv?s equation to calculate the molar surface entropy（s）and the molar surface（h）of the mixtures.According to the definition of the excess function,the excess molar surface Gibbs free energy for the binary mixture of ionic liquid with short-chain alcohols is obtained.The surface property is also discussed,and the semi-empirical method for estimating the surface tension of the mixtures is established.4.The viscosity of the ionic liquids[C₂2O1IM][TfO]and the short-chain alcohols（ethanol,1-propanol and 2-propanol）are measured over the entire composition range（x₁=0.0000¹.0000）at T=（288.15 to 318.15）K interval 5K and p=0.1MPa.The relationship between viscosity and temperature is fitted by the VTF equation.And the solvation between the ionic liquid and the short chain alcohols is explored by viscosity deviation.The improved excess Gibbs energy,ΔG^≠E,of activation for viscous flow of mixture is obtained based on the relative viscosity and volume,and it is fitted by Redlich-Kister equation,and the semi-empirical method for estimating the viscosity of the mixtures is founded.