Lipase‐Catalyzed Ring‐Opening Polymerization of Molecularly Pure Cyclic Oligomers for Use in Synthesis and Chemical Recycling of Aliphatic Polyesters

Abstract

The lipase-catalyzed ROP of molecularly pure cyclic oligomers with a definite degree of oligomerization is analyzed with respect to the molecular weights of the resulting polymers and certain kinetic parameters of the enzymatic reaction. Cyclic BA dimers, trimers, and tetramers polymerize faster than the equivalent monomer; however, the latter produces PBA of significantly higher molecular weight. The reason is that the ring opening of the cyclic monomer is slow, leading to a lower initiator concentration than that produced by the cyclic BA dimer and trimer. Similarly, the cyclic BS dimer produces PBS of higher molecular weight than that obtained from the cyclic BS trimer.

Enzymatic Synthesis and Chemical Recycling of Novel Polyester-Type Thermoplastic Elastomers

“…In addition, using a lipase as the catalyst in anhydrous dilute solution, polyesters can be easily depolymerized into repolymerizable cyclic oligomers. In such a way, lipases may also contribute to the establishment of sustainable polymer production and chemical recycling systems [10][11][12].…”

Enzymatic Synthesis and Chemical Recycling of Polythiocaprolactone

“…Contrary to these results, the ring-opening reaction of the cyclic thioester oligomers occurred relatively slowly, with only about 50% of the oligomers having undergone ring-opening after a reaction time of 4 h. In order to evaluate the reactivity of the cyclic oligomers with lipase CA, the kinetic parameters for the ring-opening reaction of MTCL and DTCL were determined using Lineweaver-Burk plots according to the method described in the literature. [23,[34][35][36] The ring-opening reactions of MTCL and DTCL were carried out in anhydrous pxylene (0.13-0.8 M) using lipase CA at 100 8C for 15 min-2 h. As reference points, kinetic parameters for CL and DCL were also determined, with these reactions also carried out in anhydrous p-xylene (0.15-0.4 M) using lipase CA at 100 8C, but for 0.3-1.5 min. The ring-opening reaction was found to follow Michaelis-Menten kinetics; the Lineweaver-Burk plots showed linearity for all cyclic oligomers.…”

“…Lipase catalyzed degradation of polyesters in dilute organic solvent produced repolymerizable cyclic oligomers irrespective of the type of polyester used. [21][22][23][24][25] This lipasecatalyzed degradation method seems to be applicable to the chemical recycling of PTCL. For green and sustainable development of PTCL, further studies are now needed.…”

Chemo-enzymatic Synthesis and Properties of Novel Optically Active Cationics Containing Carbonate Linkages

“…This was performed to mimic the formation of the acyl-enzyme intermediate AEI . The mechanism for the proposed lipase-catalyzed hydrolysis of the cationics is essentially the same as that for ester-containing compounds 29 , that is, the cationic reacts with the hydroxyl group of the Ser105 residue at the active site of lipase CA forming an AEI. Nucleophilic attack by water on the AEI then produces N-2-hydroxypropyl-N,N,N-trimethylammonium iodide HT and 1-dodecanol DD , as illustrated in Scheme 5.…”