Hydrolysis of fatty acid esters in subcritical water

Abstract

Hydrolysis of esters of higher fatty acids by subcritical water, performed in a flow-through tubular reactor, was investigated at temperatures from 280 up to 340 °C and pressures exceeding 12 MPa, using an ester/water ratio of 1:2 or 1:4 (vol/vol). The kinetics of the hydrolysis of both the triacylglycerols and the methyl esters obeyed the rate equation valid for first-order reactions. Conversion of the esters to free fatty acids exceeding 95% was reached at the temperature of 340 °C during 12 min. IR spectroscopy revealed structural changes in the chains of the unsaturated fatty acids and their partial polymerization during the hydrolysis. © 2006 WILEY-VCH Verlag GmbH & Co. KGaA.