Vapor-liquid-solid equilibria for the propane + dodecanoic acid + tetradecanoic acid and 2-methylpropane + dodecanoic acid + tetradecanoic acid systems have been measured. The relationship between the temperature and the pressure of the three-phase equilibria is described. The liquefied gases (propane or 2-methylpropane) decreased the temperatures of solid-liquid equilibrium (SLE) for the dodecanoic acid + tetradecanoic acid system. The effect of the liquefied gas on the SLE for the binary fatty acids system was presented. The three-phase equilibria could be well correlated by an associated solution model combined with the NRTL equation.