Quantitation of estolides by Fourier transform infrared spectroscopy

Estolides were produced from meadowfoam oil fatty acids, oleic, linoleic, petroselinic, andcis-5,cis-13 docosadienoic acids. Estolide reaction mixtures were quantitated by Fourier transform infrared spectroscopy and compared to the area percentages determined by high-performance liquid chromatography. The absorbance frequency of estolide carbonyl (1737 cm⁻¹) is different than the lactone carbonyl (1790 cm⁻¹) and the acid carbonyl (1712 cm⁻¹). Estolide standards were obtained by wiped-film molecular-still distillations and column chromatography.