Abstract
The production of estolide from oleic acid with sulfuric acid as a catalyst was optimized for minimal acid concentration and temperature. Commercial oleic acid forms estolide optimally when reacted at 55°C with 5% vol/vol concentrated sulfuric acid for 24 h under vacuum. The extent of oligomerization was 1.2 estolide units under these reaction conditions. Temperature plays a critical role in the rate of estolide formation as well as in the overall yield, with higher temperatures providing faster rates but lower yields. The ratio of sulfuric acid to oleic acid equivalents also plays a role, where higher acid concentrations gave faster rates and higher yields of estolide. Vacuum had a minor effect on oligomerization and estolide yield.
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Isbell, T.A., Frykman, H.B., Abbott, T.P. et al. Optimization of the sulfuric acid-catalyzed estolide synthesis from oleic acid. J Amer Oil Chem Soc 74, 473–476 (1997). https://doi.org/10.1007/s11746-997-0109-x
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DOI: https://doi.org/10.1007/s11746-997-0109-x