Title
Roles of Silica Gel in Polycondensation of Lactic Acid in Organic Solvent
Document Type
Article
Publication Date
Fall 2003
Abstract
Poly(lactic acid) is among the most important biodegradable, biocompatible polymers. To explore the feasibility of making poly(lactic acid) through potentially more selective enzymatic methods, the lipase-catalyzed direct polycondensation of lactic acid in organic solvents was investigated. At 37 °C the reaction was found to favor nonpolar solvents with larger logP values and smaller logSw/o values. The addition of silica gel appeared to greatly enhance the lactic acid conversion (up to 98%) and the lipase stability under the reaction condition. However, upon further investigations, the silica gel itself was found to catalyze the polycondensation, in addition to the role of water removal. The conversion catalyzed by silica gel alone was actually higher than that by (or lipase alone). Up to 93% conversion of the acid functional group (or about 99.5% conversion of lactic acid monomer) was obtained in 120 h with silica gel as the catalyst. The finding is especially significant for interpreting (or reconsidering) the results of many presumably enzyme-catalyzed organic-phase reactions in the presence of silica gel.
Volume
87
Issue
1
First Page
69
Last Page
73
Recommended Citation
Ju, Lu-Kwang, "Roles of Silica Gel in Polycondensation of Lactic Acid in Organic Solvent" (2003). Chemical, Biomolecular, and Corrosion Engineering Faculty Research. 108.
https://ideaexchange.uakron.edu/chemengin_ideas/108