Liquid-Liquid Phase Equilibria of (1-Propanol or 2-Propanol + Water) Containing Dipotassium Hydrogen Phosphate

Liquid-liquid equilibria (LLE) for the systems 1-propanol + water + K 2 HPO 4 and 2-propanol + water + K 2 -HPO 4 were measured at temperatures of (288.15, 298.15, and 308.15) K. The binodal curves of the systems were fitted to a nonlinear equation relating the mass fraction of 1- or 2-propanol to that of K 2 HPO 4 , and the tie lines were successfully correlated with the Othmer-Tobias and Bancroft equations. LLE results were predicted using a pair of the binodal and Bancroft equations and one of the binodal and Othmer-Tobias equations. Both predictions showed close agreement with experimental values, and the average root-mean-square deviations of the values predicted from the former pair were 0.28 % and 0.27 % for the systems 1-propanol + water + K 2 HPO 4 and 2-propanol + water + K 2 HPO 4 , respectively.