Speed of Sound, Density, and Isobaric Heat Capacity Measurements of Liquid Glycerol

Experimental speed of sound, density, and isobaric heat capacity data for liquid glycerol (CAS 56-81-5) are presented across a wide temperature and pressure range. The pressure spans from 0.1 to 20 MPa, while the temperature is considered between 340 and 450 K for the speed of sound and between 298 and 390 K for both the density and the isobaric heat capacity. Consistency with literature values is shown through extensive comparisons. The overall relative expanded (k = 2) uncertainty of the present experimental speed of sound data is U(c)/c = 0.001 and of the isobaric heat capacity is U(cp)/cp = 0.01, while the absolute uncertainty of the density is 1 kg·m–3. A modified Tait equation is employed to correlate the experimental data for the speed of sound with a maximum deviation of 0.4%. The present speed of sound data are integrated to obtain the density and isobaric heat capacity over most of the measurement range. The Grüneisen parameter of glycerol varies between 0.709 at 340 K and 20 MPa and 0.582 at 450 K and 0.1 MPa.