Measurement and prediction of isothermal vapor–liquid equilibrium of α-pinene + camphene/longifolene + abietic acid + palustric acid + neoabietic acid systems

The vapor–liquid equilibrium (VLE) data of α-pinene + camphene + [abietic acid + palustric acid + neoabietic acid] and α-pinene + longifolene + [abietic acid + palustric acid + neoabietic acid] systems at 313.15 K, 333.15 K and 358.15 K were measured by headspace gas chromatography (HSGC). These data was compared with the predictions value by conductor-like screening model for realistic solvation (COSMO-RS). Moreover, the calculated data of COSMO-RS and Non-Random Two-Liquids (NRTL) models showed good agreement with the experimental data. It was found that the three resin acids inhibited the volatility of α-pinene, camphene and longifolene and resulted in the decrease of total pressure. Moreover, H^E(HB) contributes the most to the excess enthalpy and the hydrogen bonding interaction is the dominant intermolecular force of α-pinene, camphene and longifolene with the three resin acids. In addition, the geometric structures optimization and binding energy were obtained by the DFT to further illustrate the hydrogen bonding interaction and the effects of the addition of the three resin acids on the isothermal VLE.