The enzymatic synthesis of some functional oligomers based on ε-caprolactone or vinyl acetate repeat structures

Poly(vinyl acetate) was prepared by radical polymerization with chain transfer to solvent (2-propanol). The low molecular weight PVAc was then exposed to a range of lipases in different reaction media. When the reaction was carried out in a two-phase organic/aqueous system, lipases from Pseudomonas fluorescens and Rhizopus arrhizus were effective in catalysing partial hydrolysis. On the other hand, these enzymes were not active in THF/butanol medium. In related experiments, epsilon -caprolactone was oligomerized in the presence of pyridine-3-methanol or benzyl alcohol as initiators. In a series of seven lipases, porcine pancreatic lipase and lipase from Candida antarctica gave conversions of monomer that were similar to the traditional metal catalysed polymerizations, when pyridine-3-methanol was used as the initiator. Dibutyl tin oxide gave the highest yields when benzyl alcohol was used as the initiator. (C) 2001 Elsevier Science BN. All rights reserved.