Isochoric Heat Capacity for Toluene Near Phase Transitions and the Critical Point

Published

October 1, 2001

Author(s)

N. G. Polikhronidi, I M. Abdulagatov, Joe W. Magee, Rabiyat G. Batyrova

Abstract

New measurements of isochoric heat capacity C_V for toluene near phase transitions and the critical point are presented. Measurements were made with a high-temperature, high-pressure, adiabatic calorimeter of nearly constant-volume . The inner volume of the calorimeter is (104.441 0.002 cm³ at 297.15 K and 0.1 Mpa. The heat capacity of the empty calorimeter CO was measured by use of a reference fluid (helium-4) with a well-known heat capacity (uncertainty of 0.1%). The temperature of the sample was measured with a 10 ω PRT with an uncertainty of 10 mK. Uncertainties of the heat capacity measurements are estimated to be 2% to 3%. Measurements were made in the single- and two-phase regions. The experimental values of phase transition temperatures TS(p) and single- and two-phase isochoric heat capacities (C_V1,C_v2) on each measured isochore were determined using a quasi-static thermogram method. Measurements were made along 13 isochores between (199.3 and 525.0) kg.m^-3 in the temperature range from (411 to 620) K. The temperature dependence of one-(C_V1) and two-phase(C_V2) isochoric heat capacities along the coexistence curve and along near-critical isochores, isochoric heat capacity jumps δCV, density and temperature on the coexistence curve near the critical point are discussed. The values of the critical temperature and critical density of toluene are derived from experimental saturated density measurements in the immediate vicinity of the critical point. The results of the measurements are compared with values calculated from preliminary Lemon (2000) and Goodwin (1989) equations of state (EOS). The data can be used for improved the equation of state and develop crossover equation in the critical region.

Citation

Journal of Chemical and Engineering Data

Volume

46

Issue

No. 5

Pub Type

Journals

Keywords

critical region, isochoric heat capacity, toluene

Citation

Polikhronidi, N. , Abdulagatov, I. , Magee, J. and Batyrova, R. (2001), Isochoric Heat Capacity for Toluene Near Phase Transitions and the Critical Point, Journal of Chemical and Engineering Data (Accessed March 13, 2025)