PvT properties of heptane, octane, nonane, decane, thiophene, and eugenol at temperatures between (313 and 363) K and pressures up to 25 MPa comparing three calibration methods

Abstract

Compressed liquid densities (ρ) of heptane, octane, nonane, decane, thiophene, and eugenol are reported in the temperature range from (313 to 363) K and pressures up to 25 MPa. The experimental measurements were performed by a vibrating tube densimeter (VTD) using three different calibration methods (classical using nitrogen and water as references, classical with hexane and water as references, and with water and applying vacuum to the VTD). The reliability and validation of this equipment were verified by determining and comparing the experimental density data of heptane, octane, nonane, and decane with models available in the international literature obtaining a maximum deviation of 0.21 %, 0.15 % and 0.09 % for the classical method (with nitrogen and water as references), classical method (with hexane and water as references) and with water and applying vacuum, respectively. The reported density data are obtained using the vacuum applied method, estimating a maximum relative expanded uncertainty (k=2) of 0.21 % in the temperature range from (313 to 363) K and pressures up to 25 MPa. The pure compound densities were successfully modeled with an empirical equation reporting a maximum deviation of 0.09 %. Finally, the isothermal compressibility and isobaric thermal expansivity were evaluated from density data.