Thermodynamic Properties and Phase Equilibria of Dihydrolevoglucosenone and Its Mixtures with Hydrocarbons

Abstract

Thermodynamic and computational study of a biomass-derived solvent dihydrolevoglucosenone (DLG) and its mixtures with hydrocarbons is presented in this work. Density and dynamic viscosity of DLG were measured within the temperature range of 293.15−353.15 K. Phase behavior of DLG above 183 K was analyzed using heat-flux differential scanning calorimetry, providing data on its melting temperature and enthalpy of fusion. Heat capacity of DLG was measured using a Tian-Calvet calorimeter at temperatures between 253 and 353 K. Two static apparatuses were utilized to measure the vapor pressure of DLG in the temperature range of 253−363 K. A thermodynamically consistent description was achieved by simultaneous correlation of experimental values of phase behavior, heat capacities, vapor pressures, and theoretical calculations. Liquid−liquid equilibria (LLE) data in four binary DLG and hydrocarbons (n-hexane, cyclohexane, n-decane, and ntetradecane) systems were determined using a combination of volumetric, cloud-point, and direct analytical methods. The obtained LLE data were employed to thermodynamically describe the binary mixtures using the nonrandom two-liquid (NRTL) equation and estimate critical points using the Extended-Scaling Law (ESL) equation. Furthermore, the pure-component data developed in this work were used to determine two new sets of parameters for DLG within the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state: one with and one without the explicit inclusion of the dipole moment of DLG in the model theory. In addition, one more set of parameters for DLG developed earlier by other authors was included. PC-SAFT with all three parameter sets was then examined in terms of its performance regarding the description of the LLE in the systems studied. Both correlations (with optimized k ij ) and pure predictions (k ij = 0) were considered and discussed. Interestingly, it appears that the better PC-SAFT with a particular parameter set for DLG performs for the properties of pure DLG, the worse are the results for the LLE in the DLG + hydrocarbon systems. For example, PC-SAFT with the nonpolar parameters for DLG provided more accurate results for pure DLG than its polar counterparts, while it quantitatively failed for the LLE.