R. Varushchenko, A. Druzhinina, E. Sorkin
Jun 1, 1997
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Journal
The Journal of Chemical Thermodynamics
Abstract
Abstract The heat capacities of crystalline and liquid 1-bromoperfluorooctane, Br(CF2)7CF3, were measured by a full-automatic adiabatic calorimeter in the temperature range from 5 K to 346 K. The calorimeter, experimental procedure and results of testing the apparatus by standard substances (copper and heptane) were described. 1-Bromoperfluorooctane was found to be capable of existing in metastable and stable solid forms. Two solid-to-solid transitions at the temperatures 146.4 K and 179.5 K, and a fusion atT=278.90 K have been discovered. The enthalpies and entropies of phase transitions, as well as the main thermodynamic functions {G°(T)−H°(0)}/T, {H°(T)−H°(0)}/Tand {S°(T)−S°(0)}, have been determined. The Gibbs free energy of formation of the substance under study was determined on the basis of these experimental data and the enthalpy of formation estimated by means of the Benson and Buss group additivity method.