| The vapor-liquid equilibrium data for products of turpentine systems weredetermined by using experimental method with vapor-liquid atternativecirculation. A gas chromatograph method was introduced for quantitativeanalysis of samples. Area correction was used to determine the sample andrelative errors were also calculated. Four equations of Wilson, NRTL,UNIQUAC and UNIFAC were choused to calculate and obtain the binaryparameters. This paper covers the contents as follows:A method gas chromatograph was introduced for quantitative analysis ofα-pine,β-pinene and p-cymene with FID and a 30 m×0.32 min×0.25μm, DB-5fixed phase, fused silica capillary column. The separating effect of the maincomponents of the sample being separated under different chromatogramconditions was investigated. Area correction was used to determine the sampleand relative errors was also calculated. The experiments indicate thatquantitative analysis ofβ-pinene and p-cymene by area correction is accurateunder certain chromatograph conditions: 318.15 K(1 min)(?)323.15K(2 min)(?)393.15 K (5 min). The average relative errors ofβ-pinene and p-cymene are 0.54％by area correction, and moreover, the average relativeerrors are 1.89％and 2.66％by area, respectively. A good linear relationship ofrelative mass correction factors ofβ-pinene and cymene with the concentrationofα-pine was observed. The regression equations ofβ-pinene and cymene werey=0.6942x+0.8359, y=0.4372x+0.9248 with the correlation coefficient of0.9996 and 0.9994. The present method can precisely determine the masspercent ofβ-pinene and p-cymene.The vapor-liquid equilibrium data ofα-pinene+β-pinene(428.82K～438.13K),α-pinene+p-cymene(429.05K～447.15K),β-pinene+p-cymene(439.20K～448.66K) andα-pinene+β-pinene+p-cymene(432.17K～448.11K)were determined at atmospheric (100.7kPa) by Ellis still.Thermodynamic consistency of the experimental data was confirmed by meansof Herington method,α-pinene+β-pinene,β-pinene+p-cymene: D＞J, D-J＜10;α-pinene+p-cymene: D＜J. Four activity coefficient models, Wilson,NRTL,UNIQUAC and UNIFAC were used to correlate and calculate the VLEdata of these binary systems to obtain the binary parameters. For Wilsonequation:α-pinene(1)+β-pinene(2)system,λ12-λ11=228.2233,λ21-λ22=-55.9261;α-pinene(1)+p-cymene(2)system,λ12-λ11=-846.7,λ21-λ22=1485.7,β-pinene(1)+p-cymene(2) system,λ12-λ11=-855.7,λ21-λ22=1474.3 (J·mol-1). Average relative deviations between calculated values andexperimental data of gas phase mole fraction were all less than 0.40％. Thebinary parameters of Wilson equation were also used to calculate the bubble point temperature and the vapor phase composition for the temary mixtureswithout any additional adjustment. The predicted VLE for the ternary systemwas in a good agreement with the experimental results. The Average absolutedeviation between calculated and experimental equilibrium temperature for theternary system was 0.16K. The vapor-liquid equilibrium data for ternary systemofα-pinene(1)+β-pinene(2)+p-cymene(3) have been estimated by Wilsonequation, and the average deviation ofα-pinene was 0.0019, the averagedeviation ofβ-pinene was 0.0021, the average deviation of p-cymene was0.0008.
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