CHARACTERIZATION OF ESTOLIDES FROM DIHYDROXYSTEARIC ACID

摘要

Dihydroxystearic acid estolides (DHSA-estolides) were produced by intermolecular esterification between the hydroxyl group and carboxyl group in dihydroxystearic acid (DHSA). The products obtained were characterized by Fourier transform infrared (FTIR), proton and carbon nuclear magnetic resonance spectroscopy (~1H-NMR, ~(13)C-NMR). The appearance of two ester peaks at 1734 cm~(-1) and 1740 cm~(-1) wavenumber revealed the formation of DHSA-estolides. The ester methine signal at 4.84 ppm was an indication of an estolide linkage in the ~1H-NMR spectrum while the ~(13)C-NMR showed two carbonyl signals at 178.78 ppm for acid and 172.08 ppm for estolide. Titration of carboxylic acid with a standardized base was used to determine the average molecular weights of the estolides as well as their estolide numbers (EN).