A kinetic study of the thermally induced isomerization reactions of 9c,12c linoleic acid triacylglycerol using gas chromatography

In this study, the kinetics of the thermally induced isomerization of 9c,12c linoleic acid was studied in order to better understand the geometric and positional isomerization of triacylglycerol and the various factors controlling isomeric ratios. Trilinolein was placed in glass ampoules and sealed in the absence or presence of air (O2) and then subjected to thermal treatment at 180, 200, 220, 230 or 240 °C for regular time intervals. The glass ampoules were removed and the contents were analyzed using gas chromatography. The results indicate that the consumption of trilinolein is a second-order reaction. The formation reactions of cis,trans, trans,cis and trans,trans isomers are zero-order and dependent on both temperature and time. The presence of O2 does not change the order of the reaction. In addition, the rate constants and activation energies involved in the isomerization reaction of linoleic acid with or without O2 are presented.