Determination of thermodynamic parameters of oleic acid under high pressure

Abstract

Results of high-pressure research on oleic acid are presented. The pVT data from a few compression and decompression cycles were used to determine an approximation to the equation-of-state surface in the thermodynamical space. From this approximation, thermodynamical derivatives of oleic acid, such as isothermal compressibility and isobaric expansion as a function of pressure, have been evaluated. The analysis of the pVT diagram determines the order of the phase change induced by high-pressure application. The thermodynamic parameters can be utilized in further calculations, yielding isobaric specific heat of the sample before and after the phase transition.

Keywords:

• isothermic compressibility
• isobaric expansivity
• approximation to the equation-of-state