An apparatus proposed for density measurements in compressed liquid regions at pressures of 0.1-60 MPa and temperatures of 288.15-413.15 K

In this work, an apparatus for density measurements in the compressed liquid regions is presented. This installation is based on the use of a DMA HP density measuring cell and a DMA 5000 densimeter (both instruments are products of Anton Paar, Gratz, Austria). Calibration of the DMA HP cell was performed by applying the classical method in which a vacuum, water and n-decane were recommended to be used as calibration fluids. To test the capabilities of the set-up, the densities of n-hexane, toluene and dichloromethane were measured in the temperature interval 288.15 to 413.15 K and the pressure range 0.1-60 MPa. The obtained results were compared with the corresponding values found in the literature. Depending on the literature selected for comparison (the temperature and pressure ranges available), the average absolute percentage deviations were for n-hexane, 0.03-0.10 %; for toluene, 0.04-0.08 % and for dichloromethane, 0.02-0.03 %. A deeper insight into the results of this work showed that most of them were in good agreement with the literature values; higher discrepancies were evidenced in the vicinity of the ends of the temperature and pressure ranges.