Mechanism of the Oxidation of Drying Oils

Summary Pure ethyl linolenate was prepared and autoxidized; and dimeric and trimeric fractions were separated by solvent fractionation. These fractions were subjected to quantitative, functional group‐analysis. On a basis of oxygen known to be present but not detected in the functional groups the possibility that polymerization had taken place through an oxygen linkage was considered. The mild nature of the reagent causing depolymerization suggested that this linkage was of the peroxide type rather than the dioxane ring.

Section: Discussionmentioning

confidence: 69%

The isolation and characterization of the polymers formed during the autoxidation of ethyl linolenate

Witting

Chang

Kummerow

1957

“…Autoxidation of ethyl linolenate and methyl docosahexaenoate was performed to expose to atmospheric oxygen using UV illumination [21]. Some autoxidation studies of the PUFA and PUTG were also performed at elevated temperatures in the presence of oxygen [22][23][24]. When lipids are exposed to oxygen at elevated temperature they undergo oxidative modifications, leading to the formation of a variety of products.…”

Section: Introductionmentioning

confidence: 99%

Efficiency of Gold Nano Particles on the Autoxidized Soybean Oil Polymer: Fractionation and Structural Analysis

Hazer

Akyol

2015

Polyunsaturated plant oils have gained great interest as monomers to produce biodegradable polymers obtained from renewable resources due to the limited existing sources of petroleum oil and environmental issues. Soybean oil was autoxidized by exposure to atomospheric oxygen at room temperature with or without the presence of gold nanoparticles (Au NPs) 5-41 days. When the autoxidation process was catalyzed with Au NPs, the molecular weight of the oxidized oil was increased in 5 days. In contrast to this, without Au NPs, the oxidized oil was still a fluidized liquid. Autoxidized soybean oil polymer in toluene solution with gold NP showed a surface plasmon resonance at λ max = 540 nm in a UV-VIS spectrometer and a fluorescence emission spectrum at λ max = 450 nm, when it was irradiated at λ max = 390 nm. The higher molecular weight of the polymeric oils was successively fractionated by the extraction from the solvent-non-solvent mixture CHCl 3 / petroleum ether with the volume ratio of 5:15. Three polymeric oils fractions with different molecular weight (ca 1000, 4000, and 40,000 g/mol) were obtained. GC-MS analysis, 1 H-NMR and GPC techniques were used in the structural analysis of the fractionated polymeric oils.

“…W HEN FATS are exposed to high temperatures in the presence of air or oxygen, they undergo chemical and structural changes. Most of the work carried out in different laboratories has been based on the use of naturally occurring fats which are complex mixtures of glycerol esters of fatty acids (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). Data from studies of a particular natural fat or oil cannot be extrapolated to predict the results of oxidation of another fat because of the varied and complex nature of different fats.…”

mentioning

confidence: 99%

Thermal oxidation of synthetic triglycerides I. composition of oxidized triglycerides

Endres

Bhalerao

Kummerow

1962

Tripalmitin, 1-and 2-1auryl dipalmitin and 1-and 2-oleyl dipalmitin were subjected to thermal oxidation at 200C in the presence of air for various lengths of time. The triglyc-~ showed a loss in weight, and an increase in carbonyl, hydroxyl and acid vMues. The I.V. increased in the ease of saturated triglycerides and decreased in the case of unsaturated triglycerides.Hydrolysis of the ester linkage between glycerol and fatty acid was found to occur during thermal oxidation of the triglycerides. The hydrolysis occurred irrespective of the type and position of the fatty acid in the triglyeeride molecule. The fatty acids released from the triglyceride by hydrolysis were found either to be oxidized further to short chain fatty acids, or were oxygenated with the introduction of a carbonyl or hydroxyl group in the molecule. Moreover, the unsaturated fatty acid in the triglyeeride molecule was found to be oxidized more readily than the saturated fatty acid.A hydroxy fatty acid with a carbon number of 13.5 on a diethylene glycol succinate column was isolated from oxidized tripalmitin and was also found to occur in the free fatty acid fraction of oxidized tripalmitin, 1-1auryl, 2-3 dipalmitin, and 1-oleyl, 2-3 dipalmitin. The presence of lauric or oleie acid in the 2-position of the triglyccride prevented the formation of this acid, which suggested that it is an oxidation product of palmitic acid.