Study On Thermodynamics Properties And Hydrogen Bonding Interactions Of Binary Systems Containing [Emim][MeSO₄]/[NH₂-Pmim][BF₄]+DMSO/ACN

Ionic liquid was point to in room temperature or near room temperature conditions of liquid ionic compounds.All the fuse salt compounds that indecomposable or non-vaporizable can be used as ionic liquids.Ionic liquid has the tasteless,the non-flammable,the negligible vapor pressure,the good solubility,the thermal stability and chemical stability.Ionic liquid is easily separated from other substances,and also can be recycled.Because of the unique properties,it was seen as a kind of green solvent.It has a good application prospect and attracted many scientists to study.In this paper,two kinds of dialkylimidazole ionic liquids were selected,they were 1-ethyl-3-methylimidazolium methylsulfate?[Emim][MeSO₄]?and1-aminopropyl-3-methylimidazolium tetrafluoroborate?[NH₂-Pmim][BF₄]?,receptively,which is mixed with stable performance propylene carbonate?DMSO?and lower viscosity acetonitrile?ACN?in the whole composition range of binary system.The density,electrical conductivity,refractive index,and surface tension of the pure ILs and the binary systems at different temperatures were determined.The Vogel-Fulcher-Tamman?VFT?and Arrhenius equations were used to fit the temperature dependences of conductivity.The excess molar volumes?V^E?and the deviation in refractive index??n_D?,of the binary systems were estimated base on the experimental densities and refractive index.The results of the V^E and?n_D were correlated to the Redlich-Kister polynomial equation.The variations in V^E become more negative,implying that more efficient packing and/or attractive interactions occur upon mixing the ILs with solvent,and the?n_D increased with the temperature increasing,which showed the stronger polarization happened in high temperature.In order to investigations concerning on H-bonding interactions have been carried out to understand the change of the properties of binary system,we selected 1-ethyl-3-methylimidazolium methylsulfate ionic liquid and dimethyl sulfoxide/acetonitrile,respectively.The characteristic spectra of the mixture were obtained by infrared spectroscopy?IR?,and the characteristic spectra were analyzed from the energy and hydrogen bonding angle by means of excess infrared spectroscopy combined with DFT calculation.The results show that the solvent can form H-bonding with ionic liquid,weaken the H-bonding between cation and anion of ionic liquid,improve the conductivity and decrease the surface tension.