Liquid-Liquid Phase Equilibria of (Ethanol or Methanol + Water) Containing either Dipotassium Hydrogen Phosphate or Sodium Dihydrogen Phosphate

摘要

Liquid-liquid equilibria (LLE) for (ethanol + water + K_2HPO_4),(ethanol + water + NaH_2PO_4),and (methanol + water + K_2HPO_4) were measured at temperatures of (288.15,298.15,and 308.15) K.A nonlinear equation was used to describe the binodal curves,in terms of the mass fraction of phosphate versus that of ethanol,and the tie lines were successfully correlated with the Othmer-Tobias and Bancroft equations.LLE results were predicted using the binodal and Othmer-Tobias equations as well as by the binodal and Bancroft equations.Both predictions showed close agreement with experimental values,and the average deviations of the former pair of equations were 0.41,0.24,and 0.19 for (ethanol +water + K_2HPO_4),(ethanol + water + NaH_2PO_4),and (methanol + water + K_2HPO_4),respectively.