The vapor-liquid equilibrium(VLE)data of α-pinene+β-pinene(428.82—438.13 K),α-pinene+p-cymene(429.05—447.15 K),β-pinene+p-cymene(439.20—448.66 K)and α-pinene+β-pinene+p-cymene(432.17—448.11 K)were determined at atmospheric pressure(100.7 kPa)with the modified Ellis still.The thermodynamic consistency of the experimental data was confirmed by means of the Herington method.Three activity coefficient models,Wilson,NRTL,UNIQUAC,were used to correlate and calculate the VLE data of these binary systems to obtain the binary parameters.Average relative deviations between calculated values and experimental data of vapor phase mole fraction were all less than 0.40%.The binary parameters of Wilson equation were also used to calculate the bubble point and the vapor phase composition for the ternary mixture without any additional adjustment.The predicted VLE for the ternary system was in good agreement with the experimental results.
