Isolation and Structure Investigation of Esters Formed During Fatty Acid Methyl Esters Aerobic Oxidation

The present work is devoted to the study of oxidation products of fatty acid methyl esters with atmospheric oxygen in a bubble column. Raw material with a predominant content of monounsaturated fatty acids (methyl esters of high oleic sunflower oil fatty acids) was used for the study. During oxidation, an increase in the ester value of the product mixture is observed. To study the structure of the formed compounds with “new” ester groups, preliminary separation of the oxidation products was carried out by two‐stage preparative column chromatography with silica gel. The “new” esters were concentrated with this methodology. Due to the preliminary concentration procedure, characteristic signals appeared in the 1 H‐ and 13 C NMR spectra, which were previously inaccessible for observation by spectroscopic methods of the total mixture of all oxidation products. Thus, differences in the structure of the “new” esters from the initial esters were established. These ester groups are located inside the hydrocarbon chain. Pathways for the formation of “new” esters are proposed in the article.