We report mutual solubilities of water + methyl ethyl ketone and water + methyl propyl ketone at temperatures between 25 and 55 degrees C, and binodal curves and liquid-liquid equilibria for water + propanoic acid + methyl ethyl ketone and water + propanoic acid + methyl propyl ketone in the same temperature range. UNIQUAC equations fitted the experimental data better than NRTL equations : the average rms phase composition error was 0.2% for UNIQUAC as compared to 0.3% for NRTL, and the rns relative error in the solute distribution ratio was 5% for UNIQUAC as compared to 7.5% for NRTL.