High Pressure Densities and Derived Thermodynamic Properties of Pure (1R)-(+)-α-Pinene, (1S)-(−)-β-Pinene, and Linalool: Experiment and Modeling

Abstract

Terpenes usually found in plants have a wide range of applications, especially as additives in various types of fuels, and most recently in the aviation industry, where they can be blended with jet fuels or kerosene. In this work, the densities of pure terpenes (1R)-(+)-α-pinene, (1S)-(−)-β-pinene, and linalool were measured over the temperature range T = (293.15 to 413.15) K and at high pressures p = (0.1 to 60) MPa. The experimental density data were fitted by the modified Tammann-Tait equation where the absolute average percentage deviation between measured and calculated densities was less than 0.02%, the percentage maximum deviation was less than 0.2%, and the average percentage deviation was less than 0.02% for all three measured terpenes. The obtained parameters were used to determine isothermal compressibility (κT), isobaric thermal expansivity (αp), internal pressure (pint), and the difference between specific heat capacity at constant pressure (cp) and constant volume (cv). Furthermore, the PC-SAFT model was applied for liquid density prediction at high pressures. Derived thermodynamic properties such as isothermal compressibility and isobaric thermal expansivity increase as temperature increases and decrease with pressure for all of the studied compounds.