Synthesis of estolides from oleic and saturated fatty acids

Oleic acid and various saturated fatty acids, butyric through stearic, were treated with 0.4 equivalents of per chloric acid at either 45 or 55 degree sC to produce complex estolides. Yields varied between 45 and 65% after Kug elrohr distillation. The estolide number (EN), i.e., the average number of fatty acid units added to a base fatty acid, varied as a function of temper ature and saturated fatty acid. The shorter-chain saturated fatty acids, i. e., buryric and hexanoic, provided material with higher degrees of oligomer ization (EN = 3.31)than stearic acid (EN = 1.36). The individual, saturated fatty acid estolides each have very different characteristics, such as col or and type of hy-products. The higher-temperature reactions occurred at fa ster rates at the expense of yield, and lactones were the predominant side products. At 55 degreesC, lactone yields increased, but the delta-gamma -la ctone ratio decreased; this led to lower estolide yields. The opposite tren d was observed for the 45 degreesC reaction. The saturate-capped. oleic est olides were then esterified with 2-ethylhexyl alcohol, and the chemical com position of these new estolides remained consistent throughout the course o f the reaction.