Mechanism of duel acid/base catalysis

摘要

A little researched alternative to enzymatic or metal catalysed ring opening polymerisations is the use of organo-catalysts. The authors report on the simultaneous action of a duel (acid/base) catalysed ROP of lactide. The catalyst system used was a 50:50 mix of N,N-(dimethylamino)pyridine and its protonated form. Various alcohols were utilised as initiators and several reaction conditions were investigated. The authors propose the following mechanism of polymerisation.