Measurements of the Speed of Sound in Liquid Toluene

Comprehensive and accurate measurements of the speed of sound in liquid toluene have been carried out by a double-path-length pulse-echo technique. The measured data cover the temperature range from (240 to 420) K with pressures up to 100 MPa. The measurement uncertainties amount to 3 mK for temperature, 0.01 % for pressures below 10 MPa, and 0.005 % for pressures between (10 and 100) MPa, and 0.03 % for speed of sound. Comparisons with literature data and equation of state models show that our data are more accurate than all presently available literature data for the speed of sound in liquid toluene.