Pressure and temperature dependence of the speed of sound and related properties in normal octadecane and nonadecane

The speed of sound was mesured in liquid n-octadecane and n-nonadecane usin g a pulse technique operating at 3 MHz. The measurements were carried out a t pressures up to 150 M Pa in the temperature range from 313 to 383 K. The experimental results combined with atmospheric density measurements were th en used to evaluate volumetric properties such as the density and the isent ropic and isothermal compressibilities up to 150 M Pa in the same range of temperature. The density data were fitted with a six-parameter modified Tai t equation within the experimental uncertainty.