Functionalization of Polymers Using Candida Antarctica Lipase B (CALB) Catalysis

Abstract

The objective of this research was to investigate the enzyme-catalyzed functionalization of polymers. For this purpose, first, model small molecules were employed in Candida antarctica lipase B (CALB)-catalyzed transesterification and Michael addition reactions(1).Lipase B is more active towards a broad range of esters, amides and thiols(2). CALB-catalyzed transesterification of ethyl acetate and vinyl acetate with 2-phenyl-1-propanol (2PPOH), the model compound for primary hydroxyl-functionalized polyisobutylene (PIB) prepared from the a-methylstyrene epoxide (a-MSE)/TiCl4 initiator system, indicated that the latter was a more effective acyl donor as it formed unstable vinyl alcohol which instantly tautomerized to acetaldehyde and thus rendered the reaction irreversible. The comparison of the catalytic activity of CALB with that of a commercially available transesterification catalyst, bis[dibutylchlorotin(IV)] oxide, revealed that in the transesterification of vinyl acetate with 2PPOH, CALB was the more reactive catalyst.