Enzymatic acylation of hydroxypropyl cellulose in organic media and determination of ester formation by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy

Esters were prepared by acylation of hydroxypropyl cellulose with fatty aci d catalyzed by immobilized lipase from Candida antarctica in tert-butanol. The nature of the substrates used, the initial water activity of the system , and the molecular weight of the hydroxypropyl cellulose were investigated . Moreover, Fourier transform-infrared (FT-IR) spectroscopy was used for de termination of ester content on hydroxypropyl cellulose. Specifically, a li near relationship was established between the peak height assigned to the a bsorption of the esterified carboxyl groups of the cellulose and the ester content. At optimum reaction conditions, the ester content on the hydroxypr opyl cellulose was about 11%. (C) 2001 John Wiley & Sons, Inc.