Speed of sound for ethanol in vicinity of the critical point from Rayleigh-Brillouin light scattering spectroscopy

The speed of sound in ethanol was measured in liquid, near-critical and supercritical fluid over the temperature range from (298.52–655.67) K along five isobaric lines from (0.1–9.0) MPa from Rayleigh-Brillouin light scattering spectroscopy . The expanded relative uncertainty for the reported speed of sound is estimated to be 1.3% with the level of confidence of 0.95 (coverage factor k  = 2). The correlation for experimental speeds of sound in liquid ethanol are presented, and the averaged absolute percentage deviation between the calculated values and literature data is 0.16%. The variation tendencies of the speed of sound in ethanol with increasing temperature and pressure were illustrated over the whole investigated p - T region. The accuracy of the three fundamental equations available in the NIST Standard Reference Database 23 were assessed by the experimental speeds of sound in ethanol.