Facile recovery of terephthalic acid from PET bottles via acid hydrolysis with nitric acid and applications in synthesis of cobalt MOFs

Abstract

Poly(ethylene terephthalate) (PET) taken from postconsumer commercial water bottles was subjected to acid hydrolysis with HNO₃ to recover terephthalic acid (H₂TPA). The H₂TPA was submitted to mono-nitration with HNO₃/H₂SO₄ to produce 2-nitro-terephthalic acid (NO₂-H₂TPA) in good yield. Both compounds were well characterized by NMR (¹H; ¹³C; ¹H-¹³C HSQC). These two molecules were used as ligands for the syntheses of two new cobalt-based Metal-Organic Frameworks (MOFs) via solvothermal methodology, in dimethylformamide (DMF) or dimethylacetamide (DMA). The MOFs Co-TPA-DMA (1) and Co-(NO₂-TPA)-DMF (2) were obtained and characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD) and scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS).