The catalytic activity of metal-organic frameworks (MOFs) and post-synthetic modified MOF towards depolymerisation of polycarbonate

Chemical recycling of polycarbonate (PC) recovers valuable chemicals like monomers but often requires catalysts for mild reaction conditions and high conversion rates. This study explores the use of metal-organic frameworks (MOFs) as catalysts for PC methanolysis. We investigated the catalytic activity of amine-containing MOFs, specifically ZIF-8, MAF-6, and UiO-66-NH2, 2 , which have basic active sites favouring PC depolymerisation. MOFs were characterised using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analysis. We examined the effects of temperature, catalyst content, and time on PC recycling efficiency and also conducted post-synthetic modification (PSM) of MOF-5 to assess its catalytic performance in PC depolymerisation. Methanolysis yielded bisphenol A (BPA) and dimethyl carbonate (DMC), with conversion rates confirmed by nuclear magnetic resonance (NMR). MOF catalysts significantly enhanced conversion rates compared to reactions without catalysts, with ZIF-8 and MAF-6 achieving nearly 100% PC conversion. PSM of MOF-5 with ethylenediamine (ED) led to increased PC conversion. Additionally, the MOF-based catalysts were recovered and reused for up to three cycles.