Isothermal vapor–liquid equilibrium data of the binary system (−)-α-pinene + (−)-β-pinene and the quaternary system (−)-α-pinene + (−)-β-pinene + water + phenoxyacetic acid were measured at 313.2, 323.2, and 333.2 K using headspace gas chromatography. The experimental data showed that the addition of phenoxyacetic acid and water promoted the separation of (−)-α-pinene and (−)-β-pinene. The experimental data were correlated using the UNIQUAC and NRTL models. The two models showed good correlation for the binary system, whereas the UNIQUAC model gave more accuracy for the quaternary system. Moreover, the COSMO-RS model can be an efficacious method for predicting VLE data of the determined binary and quaternary systems. In addition, the optimal spatial configuration and binding energy between the molecules were obtained by DFT, and the effects on (−)-α-pinene and (−)-β-pinene with the addition of phenoxyacetic acid and water were discussed on the molecular scale.

Investigating phase equilibrium on the terpenoid of the pine oleoresin system is of great importance for the usage relevant to the oleoresin. Herein, the binary and ternary isothermal vapor–liquid equilibrium (VLE) of α-pinene, longifolene, and abietic acid (three main components of oleoresin) at 313.15, 323.15, and 333.15 K were measured by headspace gas chromatography (HS-GC). There was no azeotropic behavior observed of α-pinene and longifolene. Abietic acid’s influence on separating α-pinene and longifolene was discussed. The relative volatilities of α-pinene and longifolene decrease in the presence of abietic acid, indicating a negative impact of abietic acid on their separation. The experimental data were correlated well with the nonrandom two-liquid, universal quasichemical, and Wilson models. The binary interaction parameters for each equation were also obtained, and the largest mean relative deviation of vapor-phase mole fraction and the largest absolute average deviation of pressure are 0.1975% and 0.0856 kPa, respectively.

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 .

Petroleum-based liquids are from an important petroleum-based polymer, whose application and preparation involve multiple operations related to gas–liquid two-phase flow. Due to insufficient research on gas–liquid two-phase flow, there is a gap in bubble dynamics and mass transfer characteristics in petroleum-based liquids. Accordingly, we have systematically investigated the bubble formation process, bubble rising dynamics, and mass transfer of coaxial bubbles. Herein, the contour of bubbles was obtained for analyzing the bubble formation process. It was found that the increase of gas flow rate contributed to the increase of bubble generation size, while the liquid viscosity had an inhibitory influence on the increase of bubble generation size. Moreover, the variation of bubble rising velocity was considered and the force analysis of the rising bubble was provided. A new model of drag coefficient applicable to petroleum-based liquids was proposed. Finally, variations in the amount of dissolved oxygen in the liquid were measured to analyze the mass transfer characteristics. The increase in nozzle inner diameter and gas flow rate both promoted mass transfer, but the increased liquid viscosity hindered mass transfer.

For the isolation and purification of (−)-α-pinene and (−)-limonene from pine resin tapping by spraying ethephon solution on the cutting surface of pine tree, vapor–liquid equilibrium data for (−)-α-pinene and (−)-limonene with ethephon are indispensable. In this work, the isothermal vapor–liquid equilibria of binary system (−)-α-pinene + (−)-limonene and quaternary system (−)-α-pinene + (−)-limonene + water + ethephon were determined using headspace gas chromatography. The thermodynamic consistency of the experimental data was tested by the Van Ness point test and Redlich-Kister area test. The universal quasi-chemical (UNIQUAC) and nonrandom two-liquid (NRTL) models were applied to correlate the experimental data, and the absolute mean deviation of the vapor phase mole fraction and the relative mean deviation of the total system pressure were calculated. The results showed that the UNIQUAC model correlated the system more accurately than the NRTL model. The relative volatility of (−)-α-pinene to (−)-limonene was promoted by adding ethephon solution. In addition, the binding energies of (−)-α-pinene + water + ethephon and (−)-limonene + water + ethephon were calculated by DFT. The results showed that the intermolecular interaction between ethephon solutions with (−)-limonene was greater than that with (−)-α-pinene.