Solid−Liquid Equilibria of Dibenzothiophene and Dibenzothiophene Sulfone in Organic Solvents

Abstract

This work reports the solid−liquid equilibria of several binary systems formed by solvent (1) + dibenzothiophene (2) and solvent (1) + dibenzothiophene sulfone (2). At least six experimental points were obtained to trace the solid−liquid equilibrium curve, using the visual technique to determine the change of phase. The experimental data were obtained at atmospheric pressure and from a (280 to 353) K temperature range. The experimental uncertainties were ± 0.0005 in mole fraction and ± 0.5 K in temperature, respectively. A classical equilibrium solid−liquid equation was used to derive the activity coefficient from the solubility experimental data. The following solution models were employed to correlate the activity coefficient: UNIQUAC, Wilson, Tsuboka−Katayama−Wilson, van Laar, and Margules. A good agreement can be obtained between derived and correlated activity coefficients for selected systems. Additionaly, the following thermophysical properties were obtained experimentally for the pure dibenzothiophene sulfone: enthalpy of fusion, melting temperature, and heat capacity for both solid and liquid phases. These values have not been previously reported in the open literature, and the corresponding entropy of fusion was derived from the experimental information. The systems studied in this work are of industrial importance in the production of ultralow sulfur fuels.