N?Heterocyclic Phosphines as Precatalysts for the Highly Selective Degradation of Poly(lactic acid)

An N-heterocyclic phosphine (NHP) has been investigated as a catalyst for transesterification of range commercial polymer samples. NHP catalysed degradation poly(lactic acid) with methanol provides access to methyl lactate (MeLA) in high yields over the course days. In situ NMR spectroscopy and kinetic analysis provided quantitative assessment catalyst, solvent screen is reported. Surprisingly attempts depolymerise polycaprolactone (PCL) polyethylene terephthalate (PET) were unsuccessful, reactions mixed PLA/PCL PLA/PET completely specific PLA alone. insight into its solution speciation, indicating that does not remain intact under conditions. The enediamine, tBuN(H)CH=CHN(H)tBu, was shown be formed via methanolysis proved selective degradation. Assessment depolymerisation activity by-products suggest this active catalyst.