Lipase‐Catalyzed Reactive Extrusion: Copolymerization of ε‐Caprolactone and ω‐Pentadecalactone. Issue 22 (12th October 2020) - Li, Changcun
Abstract: This study assesses the use of immobilized lipase catalyst N435 during reactive extrusion (REX) versus magnetically stirred bulk and solution reaction conditions for the copolymerization of ε‐caprolactone with ω‐pentadecalactone (CL/PDL 1:1 molar). N435‐catalyzed REX for reaction times from 1 to 3 h results in total %‐monomer conversion, Mn, and Đ values increase from 92.7% to 98.8%, 36.1 to 51.3 kDa, and 1.85 to 1.96, respectively. Diad fraction analysis by quantitative 13 C NMR reveals that, after just 1 h, rapid N435‐catalyzed transesterification reactions occur that give random copolyesters. In contrast, for bulk polymerization with magnetic stirring in round bottom flasks, reaction times from 1 to 3 h result in the following: Mn increases from 12.4 to 25.6 kDa, Đ decreases from 2.98 to 1.87, and the randomness index increases from 0.74 and 0.86 as PDL*–PDL diads are dominant. These results highlight that REX avoids problems associated with internal batch mixing that are encountered in bulk polymerizations. In sharp contrast to a previous study of 1:1 molar PDL/δ‐valerolactone (VL) copolymerizations by N435‐catalyzed REX, VL %‐conversion increases to just 40.1% in 1 h whereas CL reaches 94.7%. Abstract : ε‐Caprolactone/ω‐pentadecalactone copolymerization is conducted by reactive extrusion (REX), catalyzed by immobilized Candida antarctica Lipase B (CALB). Results are compared to magnetically stirred bulk and solution conditions. REX avoids problems in bulk polymerizations of internal batch mixing. CALB‐catalyzed REX for 3 h results in random copolymers with total %‐monomer conversion, Mn, and Đ values of 98.8%, 51.3 kDa, and 1.85, respectively.