The large-scale synthesis of oleic-based estolides: Current progress and challenges

Authors: Lin, Randy; Cermak, Steven; Lowery, Benjamin; ISBELL, TERRY - Retired ARS Employee

Submitted to: Regional Meeting of American Chemical Society
Publication Type: Abstract Only
Publication Acceptance Date: 10/25/2024
Publication Date: 10/25/2024
Citation: Lin, R.L., Cermak, S.C., Lowery, B.A., Isbell, T.A. 2024. The large-scale synthesis of oleic-based estolides: Current progress and challenges. Illinois Heartland ACS Chemistry Conference, Peoria, IL, October 25, 2024.

Interpretive Summary:

Technical Abstract: There is a demanding need to shift away from traditional fossil-based fuel, especially as the interest for green renewable bio-fuel is ever increasing. Estolides, which are bio-based oligomeric esters of fatty acids or vegetable oils, have demonstrated their potential to replace diesel fuels as a biodiesel-based substitute. Additionally, estolides are being investigated for applications in motor oils, lubricants, cosmetics, and plasticizers. Due to their expansive industrial applications, a protocol that is economical, safe, and scalable to access this salient class of compounds would be highly desirable. One proposed method of estolide synthesis would be to obtain the requisite hydroxy fatty ester (HFE) on a scale feasible for industry via synthesis. Formation of HFEs first involves the acid-catalyzed esterification of an unsaturated free fatty acid, followed by epoxidation via in situ formation of peroxyacid, which is then opened to form the free hydroxy fatty ester. While the first two steps have been achieved on a large scale, the latter step (ring opening) has proven to be challenging during scale-up due to reaction conditions that are acceptable on the benchtop but present massive hurdles on a gallon scale. Here, we report our current findings as well as obstacles that we have encountered in this project.