| α-Pinene andβ-pinene are mainly used as important raw materials to synthesize the high value-added essential oil chemicals. At present, the a-Pinene and P-pinene are mostly obtained from the oil of turpentine, whose purities often are not high enough. The study on liquid-liquid equilibria of a-Pinene and P-pinene is indispensable to gain the high purity. These liquid-liquid equilibria data provide the vital support for the seperation and process design of a-Pinene andβ-pinene.Gas chromatograph technique has been applied to determine the liquid-liquid equilibrium of both the ternary and binary systems of a-pinene orβ-pinene at 293.13, 303.15,313.15 and 323.15 K and at atmospheric pressure, respectively. This simple and fast method had satisfied repetition and low accuracy of measurement within±0.001 in mole fraction. These systems are consist of the (water+1-pentanol+a-pinene,(water+1-pentanol+β-pinene) and the (water+1-pentanol). The distribution coefficient from liquid-liquid equilibria date draws some conclusions:both of ternary and binary liquid-liquid equilibria data were measured; the 1-pentanol and a-pinene or P-pinene are completely miscible;the ternary systems phase diagrams belong to the seconed category; the impact of temperature on liquid-liquid equilibria has little.The Extended UNIQUAC and Modified UNIQUAC models were used for prediction and correction with the experimental data. For binary system the two calculated models got almost the same results, but for ternary system the model of Modified UNIQUAC had better performance on the predicted values of the liquid-liquid equilibrium. For the system contained water, pentanol and a-pinene, the average of root mean square deviations of the Modified UNIQUAC and Extended UNIQUAC are 0.86% and 1.42%, respectively. For another system with water, pentanol and P-pinene are 1.26% and 1.79%, respectively.
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