RESEARCH ARTICLE

Journal of Oil Palm Research Vol. 19 (1) June 2007, p. 350-355

CHARACTERIZATION OF ESTOLIDES FROM DIHYDROXYSTEARIC ACID

ROILA Awang* ; AMINAH NOR Azizan** ; SALMIAH Ahmad* ; WAN MD ZIN Wan Yunus**

ABSTRACT

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, 13C-NMR). The appearance of two ester peaks at 1734 cm-1and 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 13C-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).

KEYWORDS:


* Malaysian Palm Oil Board, P. O. Box 10620, 50720 Kuala Lumpur, Malaysia.
E-mail: roila@mpob.gov.my

** Department of Chemistry,
Faculty of Science,
Universiti Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.