Phase equilibrium engineering of glycerol acetates fractionation with pressurized CO2

Abstract

Glycerol acetates are considered important chemicals as part of the glycerol valorization roadmap. In this work, we evaluate their fractionation using CO2 as extracting agent, based on a predictive thermodynamic model, since there is an important lack of experimental equilibrium information. We show that GCA-EOS predicts experimental data available for glycerol and tri-acetyglycerol, while achieves the phase behaviors of mono- and di-acetylglycerols by group contribution. The extension of the GCA-EOS was done by means of correlating phase equilibrium data of low molecular weight alcohols and esters. The predictive model is an essential tool to assess properly the supercritical fractionation of glycerol acetates. In this regard, we show here the effect of temperature, pressure and solvent-to-feed ratio for the design of a feasible phase scenario. Phase equilibrium engineering allows uncoupling the effect of variables, which is key for the design of future experimental studies on glycerol acetates fractionation using supercritical CO2.