Activity coefficients at infinite dilution in the temperature range between 303.15 K and 353.15 K, vapor-liquid equilibria at 353.15 K and excess enthalpies at 353.15 K of binary systems containing the Ionic Liquids 1-ethyl-3-methyl-imidazolium ethylsulfate [EMIM](+)[EtSO4](-), 1-ethyl-3-methyl-imidazolium methylsulfate [EMIM](+)[MeSO4](-) and 1-ethyl-3-methyl-imidazolium hydrogensulfate [EMIM](+)[HSO4](-) have been measured. The obtained experimental data are used together with literature data to fit modified UNIFAC interaction parameters between the sulfate anion and the main groups OH and CH3OH. The predictions are compared with the experimental values. Additionally an overview about the current status of the modified UNIFAC parameter matrix for Ionic Liquids is given. (c) 2012 Elsevier B.V. All rights reserved.