Neutral hydrolysis of poly(ethylene terephthalate) catalysed by highly active terephthalate-based ionic liquids at low loadings.

Novel ionic liquid catalysts comprising terephthalate anions are capable of promoting the neutral hydrolysis of relatively large flake sizes of poly(ethylene terephthalate) at 0.5 mol% loading (200 °C, 4 h, 94% yield) without either attendant product inhibition or product contamination by protonated catalyst. Catalysts with large, lipophilic phosphonium cations outperform more polar variants.