(Liquid + liquid) equilibrium for the ternary systems {heptane + toluene + 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide} and {heptane + toluene + 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide} ionic liquids

► Values of D1 and D2 for [mpim][Tf2N] are higher than those for [amim][Tf2N]. ► Values of α2,1 for [mpim][Tf2N] are lower than those for [amim][Tf2N]. ► Values of D2 for both ionic liquids are higher than those for sulfolane. ► Values of α2,1 for [mpim][Tf2N] are lower than those for sulfolane at x2I < 0.4. ► Only [amim][Tf2N] could be considered as an alternative solvent to sulfolane.