One- and two-phase isochoric heat capacities (C-V) and saturated liquid and vapor properties (T-S, rho(S)', rho(S)'' of sec-butanol in the wide temperature and density ranges including near- and supercritical conditions have been measured with a high-temperature and high-pressure nearly constant-volume adiabatic calorimeter. The measurements were made in the temperature range from 307 K to 551 K for 22 liquid and vapor isochores from 76.44 kg m(-3) to 794.06 kg m(-3). The isochoric heat capacity jump (quasi-static thermograms) technique have been used to accurately measure of the phase transition parameters (T-S, rho(S)) near the critical point. The total experimental uncertainty of density (rho), temperature (7), and isochoric heat capacity (C-V) measurements at the 95% confidence level with a coverage factor of k=2 were estimated to be 0.06%, 15 mK, and 2-3%, respectively. The critical temperature (T-C = 535.95 +/- 0.02 K) and the critical density (rho(C) = 276.40 +/- 2 kg m(-3)) for sec-butanol were determined from the measured saturated properties (C-VS,T-S, rho(S)) near the critical point. The values of the asymptotical critical amplitude of the two-phase C-V along the critical isochore (A) over bar (-)(0) = 37.95) and saturated density (B-0 =1.7441) near the critical point have been calculate using the measured isochoric heat capacity data. The measured two-phase liquid and vapor isochoric heat capacities at saturation and saturation liquid and vapor specific volumes (V', V '') were used to calculate the values of second temperature derivatives of the vapor pressure and chemical potential near the critical point. The values of asymmetry parameters a(3) = -0.3664 and b(2) = -0.2527 of the coexistence curve diameter for sec-butanol were determined from the measured heat capacity and saturated density data near the critical point. A new technique of the Yang-Yang anomaly strength parameter (R-mu) determination from the direct simultaneously two-phase isochoric heat capacity (C-V2 '', CV2') and specific volumes (V '', V') measurements at saturation have been proposed. The value of Yang-Yang anomaly strength parameter (R-mu = -0.59) for sec-butanol has been determined using the new technique. (C) 2013 Elsevier B.V. All rights reserved.