Liquid–Liquid Phase Equilibria of Binary Solutions of {1-Butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide + 1-Butanol or 2-Methyl-1-propanol}

The liquid–liquid coexistence curves for the room temperature ionic liquid (RTIL) solutions of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 4 mim][NTf 2 ]) in 1-butanol and 2-methyl-1-propanol have been precisely measured. The values of the critical exponent corresponding to the coexistence curve were found to be consistent with theoretical predictions of the 3D-Ising universality. The complete scaling theory was used to analyze the asymmetric behavior of the coexistence curve. The reduced consolute temperatures and the reduced consolute densities of the binary solutions of [C 4 mim][NTf 2 ] and alcohols were also calculated to discuss the interactions in the RTIL solutions driving the liquid–liquid phase separations.