Characterization of monomers produced from thermal high-pressure conversion of meadowfoam and oleic acids into estolides |
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Authors: | Terry A Isbell Robert Kleiman Selim M Erhan |
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Affiliation: | (1) New Crops Research, USDA-ARS-NCAUR, 1815 North University Street, 61604 Peoria, IL |
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Abstract: | The monomers produced from thermal high-pressure conversion of meadowfoam or oleic acids into estolides were characterized
as a complex mixture of fatty acids. Mild reaction conditions produced little change in the starting acids. However, vigorous
reaction conditions,e.g. ≥3 h at 250°C with stirring, significantly altered the starting fatty acids.Cis/trans isomerization occurred readily, with the proportion oftrans isomers reaching 57%. In addition, the double bonds migrated throughout all positions of the hydrocarbon chain with concentrations
diminishing outward from the starting double bond position. Branching was also observed to a small extent under these conditions
and was even more pronounced in the absence of water. Lactones were also identified in the reaction mixture, with contents
near 16% in the meadowfoam series. All products can be explainedvia carbocation rearrangement mechanisms that result from protonation of the starting olefins. |
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Keywords: | Branched fatty acids cis/trans isomerization estolides lactones meadowfoam monomers montmorillonite olefin migration oleic |
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