Fe-containing magnetic ionic liquid as an effective catalyst for the glycolysis of poly(ethylene terephthalate)

The depolymerization of poly(ethylene terephthalate) (PET) in ethylene glycol could be catalyzed by imidazolium-based Fe-containing ionic liquid, 1-butyl-3-methylimidazolium tetrachloroferrate ([bmim]FeCl4). This magnetic ionic liquid exhibits higher catalytic activity for the glycolysis of PET, compared with FeCl3 or ionic liquid, 1-butyl-3-methylimidazolium chloride ([bmim]Cl). Investigation also shows that the onset reaction temperature of the glycolysis process catalyzed by [bmim]FeCl4 is much lower, being 140 °C. The proposed mechanism indicates that the high catalytic activity of [bmim]FeCl4 is attributed to the synergic effect of its cation and anion.