Liquid densities and excess molar volumes for (ionic liquids + methanol + water) ternary system at atmospheric pressure and at various temperatures

Excess molar volumes, VmE have been evaluated from density measurements over the entire composition range for ternary liquid system of ionic liquid (1-ethyl-3-methyl-imidazolium diethylenglycol monomethylether sulphate {[EMIM][CH3(OCH2CH2)2OSO3]) (1) + methanol (2) + water (3)} at T = (298.15, 303.15, and 313.15) K. A vibrating tube densimeter was used for these measurements at atmospheric pressure. The VmE values were found to be negative at T = (298.15 and 303.15) K. For {[EMIM][CH3(OCH2CH2)2OSO3] (1) + methanol (2) + water (3)} at T = 313.15 K the VmE values become positive at higher mole fraction of ionic liquid and at a corresponding decrease in mole fraction of water. All the experimental data were fitted with the Redlich–Kister equation. The results have also been analysed in term of graph theoretical approach.