Measurement and Prediction of Isothermal Vapor-Liquid Equilibrium and Thermodynamic Properties of a Turpentine + Rosin System Using the COSMO-RS Model

ACS Omega. 2022 May 4;7(19):16270-16277. doi: 10.1021/acsomega.1c05167. eCollection 2022 May 17.

Abstract

The vapor-liquid equilibrium (VLE) of components of a turpentine + rosin system were measured at 313.2 and 333.2 K using headspace gas chromatography. The thermodynamic properties of the turpentine + rosin system such as activity coefficients, total pressure, partial pressure, excess Gibbs energies, and excess enthalpies were calculated using the COSMO-RS model. The results showed that the activity coefficients were greater than 1 for all components of turpentine except for longifolene, indicating a positive deviation from Raoult's law for all components of turpentine except for longifolene. The total pressures were about 1 kPa at 313.2 K and about 3 kPa at 333.2 K. Meanwhile, the excess Gibbs energies G E and excess enthalpies H E of the system were positive, indicating that the mixing of the components of turpentine and rosin was endothermic. Moreover, the hydrogen bonding interaction energy H E(hydrogen bonding) contributed the most for the excess enthalpies H E.