Liquid–liquid equilibria of systems containing cottonseed biodiesel + glycerol + ethanol at 293.15, 313.15 and 333.15 K

Liquid–liquid equilibrium (LLE) data for the ternary system (cottonseed biodiesel + glycerol + ethanol) have been determined at T = 293.15, 313.15 and 333.15 K and atmospheric pressure. The solubility (binodal) curves and tie-line compositions were obtained by means of density measurements. The reliability of the data has been tested by using Othmer–Tobias equation, with a squared correlation coefficient better than 0.99 for all systems studied. Selectivity and distribution coefficients have been determined from equilibrium data. Experimental LLE data have been correlated using NRTL model with an average global deviation of 0.89%. Additionally, binary interaction parameters of ternary systems components have been calculated.

Graphical abstractPhase diagram for the system cottonseed biodiesel + glycerol + ethanol system at T = 293.15 K (■), 313.15 K (○) and 333.15 K (×).Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Ethanol shows to be a good solvent for extraction of cottonseed biodiesel. ► NRTL has been able to correlate LLE cottonseed–glycerol–ethanol data. ► Temperature effect was negligible for solubility in the range studied.