Study On The Thermodynamic Properties Research Of New Working Pairs Of Ionic Liquid [EMIM] AC And Water/Alcohol

Because of the unique features of energy-saving and environmental protection, absorption heat pump is widely used in the fields of chemical engineering and construction. Among them, the properties of the working pairs have an important influence on the performance of the heat pump. At present, the working pairs widely used in the industry are mainly LiBr-H2O and NH3-H2O. However, the two working pairs exist much defects, such as easy crystallization, easy corrosion and big toxicity. Therefore, exploring new working pairs of the heat pump has been the focus of the research by many scholars and companies.Ionic liquid is a novel green solvent. It has many excellent properties, such as low vapor pressure, high thermal stability, good solubility of inorganic and organic materials. These features show that it has potential as an absorption heat pump working medium. In this paper, the binary systems consisted of ionic liquid of1-ethyl-3-methyl imidazole acetate ([EMIM] AC) and water/ethanol/methanol are considered as the absorption heat pump working pairs and study the vapor pressure, specific heat and mixing heat of the binary systems.Prepared the ionic liquid [EMIM]AC in the laboratory. The ionic liquid was characterized by nuclear magnetic resonance spectrometer and the thermal stability of the ionic liquid was analyzed.Measured the vapor pressure of the three binary systems [EMIM]AC+H2O/CH3CH2OH/CH3OH by inclined ebulliometer. Results showed that the vapor pressure data of the three binary systems were negative deviation of Raoult’s law. Used the model of NRTL to correlate the measured experimental data, the average relative error between the experimental data and the associated value was2.39%,2.89%and2.89%respectively.Measured the mixing enthalpy of the three binary systems [EMIM]AC+H2O/CH3CH2OH/CH3OH at atmospheric pressure and room temperature. Results showed that the mixing enthalpy of the three binary systems was less than zero and the mixture of three binary systems was exothermic process.Simulated the mixing enthalpy of the three binary systems containing [EMIM]AC. Explained the phenomenon the mixture of the three binary systems by calculating the radial distribution functions and interaction energy between the anions or cations of [EMIM]AC with H2O/CH3CH2OH/CH3OHMeasured the specific heat of the three binary systems [EMIM]AC+H2O/CH3CH2OH/CH3OH at atmospheric pressure. Results showed that the specific heat of the three binary systems increased with the rise of the temperature under the cetain concentration of the ionic liquid; The specific heat of the three binary systems decrease with the rise of the concentration of the ionic liquid under the certain temperature. Use the RK equation to associate the experimental data. Experimental values agreed well with the associated values and the average relative errors were2.39%,2.89%and2.89%respectively, showing that RK equation could be used to correlate the specific heat data of the binary systems containing ionic liquids.