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Characterization of monomers produced from thermal high‐pressure conversion of meadowfoam and oleic acids into estolides
Author(s) -
Isbell Terry A.,
Kleiman Robert,
Erhan Selim M.
Publication year - 1992
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02637676
Subject(s) - isomerization , chemistry , double bond , monomer , protonation , branching (polymer chemistry) , carbocation , oleic acid , organic chemistry , photochemistry , medicinal chemistry , catalysis , biochemistry , ion , polymer
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 of trans 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 explained via carbocation rearrangement mechanisms that result from protonation of the starting olefins.