Measurement Of Thermodynamic Properties For Ternary Solutions Containing [EMIM][DEP]

Recently, ionic liquids have attracted a lot of scientific attention for their unique nature. So in this paper, several thermodynamic properties of methanol/ethanol+water+[EMIM][DEP](1-ethyl-3-methylimidazolium diethyl phosphate) ternary systems have been investigated.[EMIM][DEP] was synthesized in the lab with purity of97.97%. The vapor pressures and activity coefficients of methanol+[EMIM][DEP], ethanol+[EMIM][DEP] and water+[EMIM][DEP] binary systems were measured by using static method. All the activity coefficients were smaller than1and showed a considerable negative deviation from Raoult’s Law. NRTL model was used to predict the methanol/ethanol+water+[EM IM][DEP] ternary systems, and the average deviation between experimental data and predicted ones were3.77%and3.54%respectively.The mixing heats (excess enthalpy) for five systems were investigated at isobaric298.15K with different concentration. And then, UNIQUAC and NRTL model were used to predict the measured data of ternary systems and gave satisfactory results by the over all ARD for mixing heat calculations of2.14%,2.24%,4.95%and3.63%respectively.Heat capacities of two ternary systems have been measured over the temperature range298.15K-313.15K. The results showed that heat capacities decreased with increasing [EMIM][DEP] molar concentration at the same temperature. An extended Redlich-Kister-type equation was used to correlate the measured data and showed a very small deviation from the experimental ones of0.18%and0.26%respectively. It can be considered that present measurements are of sufficient accuracy and the extended Redlich-Kister-type equation is suitable for the correlation of ternary solutions containing [EMIM][DEP].