| 3-Caryophyllene,p-cymene,and 3-carene are monoterpene and sesquiterpene compounds of turpentine oil,and are important fine chemical raw materials and spices components.Turpentine oil,obtained by steam distillation of pine resins,is one of the world’s largest output of essential oils and is known as "oil that grows on trees".The turpentine is widely used in the synthesis of fine chemicals,such as pharmaceuticals,flavors and spices,etc.The vapor-liquid equilibrium(VLE)data and excess enthalpy data of turpentine systems are of great significance to its deep processing and separation process.The main research work has the following aspects:(1)In this work,the saturated vapor pressure data of 3-carene at different temperatures were measured indirectly using the modified Ellis still.The Antoine equation of 3-carene in the experimental temperature range of 356.07 to 444.44 K using the 1stOpt software was regressed as:log(ps/kPa)=5.8919-1423.9794/(T/K)-78.1960.The correlation coefficient R2 is 0.9982,and the maximum relative deviation between the calculated boiling point temperature and the literature value was 1.43%.The temperature dependence(356.07 to 444.44 K)of the molar evaporation enthalpy is AvapHm/J·mol-1=0.7508(T/K)2-1.1640×10-3(T/K)3 and the mean molar evaporation enthalpy[ΔvapHm)is 40.98 kJ·mol-1.(2)The vapor-liquid equilibrium data of binary and ternary systems of(-)-β-caryophyllene,p-cymene,and 3-carene at atmospheric pressure were measured also using the modified Ellis still.The vapor and liquid phase composition was determined using a 7890B Agilent gas chromatograph,and the thermodynamic consistency test of the measured data were using the Herington semi-empirical method and the Van Ness point to point test.(3)The binary VLE data of(-)-β-caryophyllene,p-cymene,and 3-carene were regressed by the Wilson,NRTL,and UNIQAC activity coefficient models using the Aspen Plus V8.4 on the basic of the maximum likelihood method.The results showed that the root-mean-square deviations of equilibrium temperature and vapor phase molar composition were less than 0.44 K and 0.0049,respectively.The binary interaction parameters of the activity coefficient models were used to predict the VLE data of the(-)-β-caryophyllene + p-cymene +3-carene system.The predicted values were compared with the experimental values.The average deviation were δT = 0.57K,δy1 = 0.0060,and δy2 = 0.0057,respectively.(4)The excess enthalpies of three binary systems p-cymene +(-)-β-caryophyllene,3-carene +(-)-β-f-caryophyllene,and 3-carene + p-cymene were determined using the C80 microcalorimeter at atmospheric pressure and 298.15 K.The experimental data were correlated using the Redlich-Kister equation.The results showed that the experimental data agreed well with the correlation results,the standard deviations were 0.2151 J ·mol-1,0.1733 J·mol’1,and 0.4483 J·mol-1,respectively.The experimental results show that the excess enthalpy of the three binary systems are all positive,the maximum value of each system was observed in the vicinity of x≈ 0.5 and curves showed a symmetrical trend.The order of the enthalpy of the three binary systems was 3-carene +p-cymene>p-cymene +(-)-β-caryophyllene>3-carene +(-)-β-caryophyllene. |
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