Mechanisms of isomerization and oxidation in heated trilinolein by DFT method

Abstract

In order to investigate the molecular mechanisms of the heat-induced cis/trans isomerization and oxidative cleavage of trilinolein, a highly purified sample was heated at a range of temperatures (120, 140, 160, 180, 200, 220 °C) for 5 h.

Oxidative Stability of Vegetal Oil-Based Lubricants

“…For example, for linoleic acid (C18:2), the C−H bond dissociation energy in the configuration C18:2-9c-12c is 328.0 kJ mol −1 , while it is 334.8 kJ mol −1 is for the C18:2-9t-12t configuration, a difference of 6.8 kJ mol −1 which indicates that oxidation takes place preferentially at cis double bonds. 36 Also, different polar bonds in TAGs are active sites making them easily attackable by humidity, oxygen, and other chemical and physical agents (Figure 5B). In particular, one of the main weakness is the degrees of unsaturated double bonds that function as active points for many reactions, with autoxidation common to TAGs and FFAs.…”

“…The trans-configuration is thermodynamically more stable than the cis. For example, for linoleic acid (C18:2), the C–H bond dissociation energy in the configuration C18:2-9c-12c is 328.0 kJ mol –1 , while it is 334.8 kJ mol –1 is for the C18:2-9t-12t configuration, a difference of 6.8 kJ mol –1 which indicates that oxidation takes place preferentially at cis double bonds …”

Mechanisms of the Formation of Nonvolatile and Volatile Oxidation Products from Methyl Linoleic Acid at High Temperatures

“…DFT has been extensively applied to lipid chemistry research. 26,27 In our previous research, DFT was used to investigate the molecular mechanisms underlying heat-induced cis/trans isomerization, 28 as well as side and chain reactions during methyl oleate oxidation. 29 In this study, we investigated the nonvolatile and volatile oxidation products of Me-LA at high temperatures.…”

“…The density functional theory (DFT) can determine the reaction thermodynamic parameters, activation energy, and active sites of different reactants to conduct feasibility analyses of reaction mechanisms. DFT has been extensively applied to lipid chemistry research. , In our previous research, DFT was used to investigate the molecular mechanisms underlying heat-induced cis/trans isomerization, as well as side and chain reactions during methyl oleate oxidation …”