Universality and corresponding state behaviour in the phase diagrams of alcohol solutions of ionic liquids with the BF4− anion

The phase diagrams of solutions of room temperature ionic liquids butyl- and hexyl-methylimidazolium tetrafluoroborate (Cnmim BF4) in various alcohols, reported in the literature, are analysed by means of a novel function, which presumes Ising behaviour and the applicability of the rectilinear diameter rule. The fit parameters obtained (critical temperature, critical composition, amplitude of the phase diagram, and slope of the diameter) allow for a good representation of the data. Estimates of the critical point data are in good agreement with that determined independently by the equal volume criteria. Two different types of corresponding state analysis are carried out.