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One- and Two-phase Isochoric Heat Capacities and Saturated Densities of 2-Propanol in the Critical and Supercritical Regions
Published
Author(s)
Nikolai Polikhronidi, Rabiyat Batyrova, Ilmutdin Abdulagatov, Joe W. Magee
Abstract
One- (C_v1) and two-phase (C_v2 ) liquid + vapor equilibrium isochoric heat capacities, densities (rho_s), and phase-transition temperatures (T_s) of 2-propanol were measured in the critical region. Measurements were made in the immediate vicinity of the liquid-gas phase transition and critical point in order to accurately determine the locus of phase transition properties. Additional measurements were made over an extended temperature range from (317 to 525) K for 9 liquid and 3 vapor isochores between (234 and 697) kg m-3 at pressure up to 6.5 MPa. The measurements were performed using a high-temperature, high-pressure, nearly constant-volume adiabatic calorimeter. The combined expanded uncertainty of the density, temperature, and isochoric heat capacity, C_v, measurements at the 95 % confidence level with a coverage factor of k = 2 is estimated to be 0.15 %, 0.02 K, and 3 %, respectively. The measured one- (C_v1) and two-phase (C_v2) isochoric heat capacities along the critical isochore and the saturated liquid (rho'_s) and vapor (rho"_s) densities near the critical point were used to derive theoretically meaningful asymptotic critical amplitudes and related amplitudes for other properties and their universal relations and asymmetric parameters of the coexistence curve singular diameter. Experimental two-phase heat capacity C_v2 as a function of specific volume V, along various isotherms, were used to calculate second temperature derivatives of vapor-pressure and chemical potential and to estimate the value of Yang-Yang anomaly strength parameter for 2-propanol. The relative contributions of the vapor-pressure and the chemical potential to the measured total two-phase C_v2 were estimated.
Polikhronidi, N.
, Batyrova, R.
, Abdulagatov, I.
and Magee, J.
(2019),
One- and Two-phase Isochoric Heat Capacities and Saturated Densities of 2-Propanol in the Critical and Supercritical Regions, Journal of Chemical Thermodynamics, [online], https://doi.org/10.1016/j.jct.2019.03.023
(Accessed February 11, 2025)