Lipase-catalyzed synthesis of hyperbranched poly-l-lactide in an ionic liquid

Hyperbranched poly- l -lactides have been synthesized by eROP in [C 4 MIM][PF 6 ] media. The bis(hydroxymethyl)butyric acid molecule was used as the AB 2 core co-monomer and immobilized lipase B from Candida antarctica as biocatalyst. The degree of branching could be controlled by the reaction conditions, with the maximum achieved being 0.21. The successful achievement of the hyperbranched structure is attributed to the high solvent power of substrates and products in the ionic liquid besides sustained lipase activity.