Liquid–liquid equilibrium for ethanolysis systems of fish oil

Abstract

Enzymatic alcoholysis of fish oil can produce monoacylglycerols rich in polyunsaturated fatty acids at atmospheric pressure and low temperature. Biocatalysis in organic solvents helps to create a homogeneous reaction system for the reactants, ethanol and fish oil. This work presents liquid–liquid equilibrium at two different temperatures (303.2 K and 323.2 K) and at atmospheric pressure for two solvent-systems in the ethanolysis of fish oil: ethanol + oil + tert-pentanol and ethanol + oil + hexane. Experimental solubility (binodal) curves were obtained by the cloud point method and tie-line composition was obtained by density and high-temperature gas chromatography. The consistency of experimental tie-line data was checked by using the Othmer–Tobias equation. The experimental liquid–liquid data were correlated satisfactorily by the nonrandom two liquid model for activity coefficient calculations.