Evaluation Of Physicochemical Properties Of N-(2-methoxyethyl)-N-Methyl Pyrrolidinium Binary Systems

Ionic liquids have attracted much attention because of their unique properties.ether-group functionalized ionic liquids have been widely studied for their low melting point,low viscosity and high conductivity,and ether-group functionalized ionic liquids have been successfully applied to cellulose dissolution,electrochemical equipment and gas absorption fields.However,the study of binary systems of ether-group functionalized ionic liquids with molecular solvents are still in the primary stage.In this paper,two ether-group functionalized ionic liquids,N-（2-methoxyethyl）-N-methyl-pyrrolidiniumbis（trifluoromethylsulfonyl）amide[C₁OC₂pyrr][NTf₂]and N-（2-methoxyethyl）-N-methyl-pyrrolidinium dicyanamide[C₁OC₂pyrr][DCA],were synthesized and characterized by ¹H-NMR,¹³C-NMR and TGA.After analysis,the purity of ionic liquids of[C₁OC₂pyrr][NTf₂]and[C₁OC₂pyrr][DCA]were higher than 99%.Two monohydric alcohols（methanol and ethanol）were mixed with the ionic liquids to obtain binary liquid mixtures with different mole fractions.And the densities,viscosities,and surface tensions of[C₁OC₂pyrr][NTf₂]、[C₁OC₂pyrr][DCA]and of binary mixtures with monohydric alcohols were measured over the entire range of mole fraction in the temperature range from 288.15 K to 318.15 K interval 5K at atmospheric pressure.The effects of temperature and mole fraction of ionic liquids on density,viscosity and surface tension were discussed.Thermodynamic properties of the average molar volume,thermal expansion coefficient and excess molar volume of the mixture were calculated from the measured density data,and the effects of temperature and composition on these properties were also discussed.Redlick-Kister equation was used to fit the excess molar volume of the binary mixtures,and the interaction between ionic liquids and alcohols were analyzed;The thermodynamic properties such as viscosity deviation,the excess Gibbs energy of viscous flow activation,the excess entropy of viscous flow activation and the excess enthalpy of viscous flow activation were calculated from the measured viscosity data and density data of binary system.Redlick-Kister equation was also used to fit the excess Gibbs energy of viscous flow activation.Finally,the molar surface Gibbs energy of the mixture was also calculated from the measured surface tension and density data.The molar surface Gibbs energy of the mixture was correlated with the E?tv?s equation proposed by Adamson,and the modified E?tv?s equation was obtained.The thermodynamic properties of the mixture,such as molar surface entropy and molar surface enthalpy,were also calculated.