Metal-containing Ionic Liquids as Catalyst in PET Glycolysis

Metal-containing ionic liquids with general formula [Rmim]+MX3- (R=n-butyl or n-lauryl; M=Zn, Cd; X=Cl, Br) were synthesised and then characterized by nuclear magnetic resonance spectroscopy and infrared spectroscopy. The catalytic activity was tested in glycolysis of poly(ethylene terephthalate) (PET) with ethylene glycol (EG) with the main product being bis-2-hydroxyethyl terephthalate (BHET). The following parameters were varied: the catalyst type, the catalyst loading and the molar ratio between PET and EG. For every reaction conversion and selectivity were calculated. All these reactions arose with high selectivity in the desired product, the conversion of PET being quasi-total.