Ring‐Opening Polymerization of ϵ‐Caprolactone by Benzoic Acid in the Presence of Benzyl Alcohol as Initiator

Abstract The development of a feasible industrial method for poly(ϵ‐caprolactone) (PCL) preparation is great of significant and challenging. The bulk ring‐opening polymerization of ϵ‐caprolactone (ϵ‐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 ϵ‐CL under mild conditions. The conversion of ϵ‐CL to PCL was 84.7 % under the optimized reaction conditions, with number‐average molecular weight ( M n ) 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.