Production of hydroxy acids from agricultural feedstocks

Authors: Cermak, Steven - Steve; ISBELL, TERRY - Retired ARS Employee

Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 2/14/2024
Publication Date: 4/28/2024
Citation: Cermak, S.C., Isbell, T.A. 2024. Production of hydroxy acids from agricultural feedstocks [abstract]. American Oil Chemists' Society Annual Meeting and Expo.

Interpretive Summary:

Technical Abstract: Hydroxy acids are used in a wide range of industrial products such as resins, waxes, nylons, plastics, lubricants, cosmetics, and additives in coatings and paints. A new method was developed to produce hydroxy fatty acids from agricultural sources that would compete commercially with castor oil. In the most basic case, methyl oleate was epoxidized with hydrogen peroxide and formic acid in 95% yield and used as a starting material to evaluate catalytic hydrogenation to form mono-hydroxy stearates. A series of reactions were performed to investigate the reaction parameters, including the metal catalyst, temperature, hydrogen pressure, solvent, organic acid catalyst and acid catalyst concentration. Pd/C metal catalyst was found to be the most effective at concentrations of 0.3 - 0.8 mol %. The choice of organic acid catalyst had a large impact on the rate of reaction where the pKa of the organic acid demonstrated that stronger acids like oxalic (pKa 1.25) provided faster rates of reaction than acetic (pKa 4.76), which was also much faster than reactions run in the absence of organic acid catalyst. Increasing temperature also increased the rate of reaction but simultaneously increased the rate of formation of saturated side products. Optimum reaction conditions were determined and will be reported. Reactions were analyzed by GC using an FID and all products were characterized by NMR using 1H, 13C, DEPT, HSQC, HMBC and COSY experiments to confirm structural assignments.