Epoxidation of Lesquerella and Limnanthes (Meadowfoam) oils

Lesquerella gordonii (Gray) Wats and Limnanthes alba Benth. (Meadowfoam) are species being studied as new and alternative crops. Triglyceride oil from lesquerella contains 55–60% of the uncommon 14‐hydroxy‐ cis ‐11‐eicosenoic acid. Meadowfoam oil has 95% uncommon acids, including ca. 60% cis ‐5‐eicosenoic acid. Both oils are predominantly unsaturated (3% saturated acids), and have similar iodine values (90–91), from which oxirane values of 5.7% are possible for the fully epoxidized oils. Each oil was epoxidized with m ‐chloro‐peroxybenzoic acid, and oxirane values were 5.0% (lesquerella) and 5.2% (meadowfoam). The epoxy acid composition of each product was examined by gas chromatography of the methyl esters, which showed that epoxidized L. gordonii oil contained 55% 11,12‐epoxy‐14‐hydroxyeicosanoic acid, and epoxidized meadowfoam oil contained 63% 5,6‐epoxyeicosanoic acid, as expected for normal complete epoxidation. Mass spectrometry of trimethylsilyloxy derivatives of polyols, prepared from the epoxidized esters, confirmed the identity of the epoxidation products and the straightforward nature of the epoxidation process. Synthesis and characterization of these interesting epoxy oils and derivatives are discussed.