| Ionic liquids（ILs）are a new type of solvent.Due to their unique physical and chemical properties and designability,they have great potential for development in many fields such as scientific research and industrial engineering.By adjusting the anion and cation structure of the ionic liquid,it can make it have functional characteristics and obtain a functionalized ionic liquid.Designing ionic liquids with specific functions and properties can reflect better goal orientation in applications and enhance the application expansibility of ionic liquids.In this paper,two new nitrile-based functionalized imidazole ionic liquids were synthesized and used as research objects to explore the specific relationship between their thermodynamic properties and their microscopic interactions.The two ionic liquids are 1-cyanopropyl-3-methyl Trifluoromethanesulfonate（[C3CNmim][OTf]）and 1-cyanopropyl-3-methylimidazole bistrifluoromethanesulfonimide（[C3CNmim][NTf2]）.After being characterized by infrared spectroscopy（IR）,proton nuclear magnetic resonance spectroscopy（1H NMR）,and elemental analysis,the two ionic liquids were mixed with the high-performance organic solventγ-butyrolactone（GBL）to prepare two full concentrations A range of mixed systems,and measured the thermodynamic properties of the two mixed systems at different temperatures,such as density（ρ）,viscosity（η）,conductivity（σ）and surface tension（γ）.According to experience or semi-empirical equations,the important thermodynamic parameters of pure ionic liquids are estimated,and the thermal expansion coefficientα,molecular volume Vm,lattice energy UPOT,porosity and other thermodynamic parameters that are difficult to directly measure are obtained.The relationship between temperature,viscosity and conductivity is described by Vogel-Fulcher-Tamman（VFT）equation and Arrhenius equation.The excess molar volume（VE）of the two mixed systems was estimated based on the density value,and the Redlich-Kister（R-K）equation was used to fit the VE.In order to better explore the changes in the internal micro-effects of the mixed system and the relationship with the thermodynamic properties,the infrared spectrum and DSC curve of the system were measured first,and the ion pair of the ionic liquid was calculated by density functional theory（DFT）.COSMO-RS is used to predict the interaction energy between ionic liquid molecules and gamma-butyrolactone（GBL）molecules,as well as the optimized structure and hydrogen bond position,combined with spectroscopic characteristics and DSC curve analysis,to compare the ionic liquid The internal effects and energy changes of the mixed system are systematically discussed and analyzed. |
