Ring-opening polymerisation transesterification reactions

Tetrasubstituted guanidines catalyse the methylation of phenols using dimethylcarbonate. When DBU is used as catalyst, the reaction temperature is lower. Methylation of acids has also been accomplished. TBD has been demonstrated to be an excellent catalyst for acyl transfer and transesterification reactions. Vinyl acetate with TBD forms AT-acetyl TBD that hy adding benzyl alcohol results in formation of the corresponding acetate and regeneration of the TBD. TBD has also heen used for the ring-opening polymerisation of cyclic esters. ... 

Addition of L-lactide monomer to preformed active PCL chains gave 98% conversion of lactide monomer and formation of block copolymer. That is, the PCL end groups initiated the ring-opening polymerisation of L-lactide. It was also demonstrated that there was no transesterification reaction during the polymerisation the end groups of the propagating lactide chain did not attack the preformed PCL chain. 

Intra- and intermolecular transesterification reactions during ring-opening polymerisation initiated by anionic species. 

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