Chemical Recycling of Waste PET with Super-Acid Catalysts

This study focused on developing and applying novel super-acid catalysts to chemical recycling of waste polyethylene terephthalate (PET). Acid hydrolysis reaction of PET produces terephthalic acid (TPA) and ethylene glycol (EG). The effect of 8M H₂SO₄ as acid catalyst at 150 ^oC was measured to establish a baseline reaction kinetics. The goal of this work is to develop recoverable catalysts with increased activity in hydrolysis of PET to avoid the highly corrosive environment acid environment. Superacid catalysts prepared with AlCl₃ and H₂SO₄ or poly(styrene sulfonate) (PSSA) were prepared and characterized for acid hydrolysis of PET at 150 ^oC. The impact of catalyst type, composition and concentration on PET conversion and TPA yield were monitored. The recovered TPA was characterized with FTIR and NMR to compare with commercial TPA . The PSSA based acid/super-acid catalysts can be recovered for reuse thereby avoiding the acid disposal issue in usage of homogeneous acid catalysts.