Ring-Opening Polymerization of ?-Caprolactone by Benzoic Acid in the Presence of Benzyl Alcohol as Initiator

The development of a feasible industrial method for poly(e-caprolactone) (PCL) preparation is great of significant and challenging. The bulk ring-opening polymerization of e-caprolactone (e-CL) using various organic acid catalysts and benzyl alcohol (BnOH) as the initiator was developed. Benzoic acid (BA) has been proved to be an efficient catalyst for the ROP of e-CL under mild conditions. The conversion of e-CL to PCL was 84.7 % under the optimized reaction conditions, with number-average molecular weight (Mn) and dispersity (PDI) of 7700 g/mol and 1.25, respectively. Moreover, a monomer-activated ring-opening polymerization mechanism mediated by benzoic acid was proposed. Overall, this work is expected to provide a feasible industrial method for the preparation of PCL using benzoic acid as organocatalyst.