ITLE PAGE OPTIMIZATION IN THE PRODUCTION OF TEREPHTHALIC ACID FROM WASTE PLASTIC BOTTLES

Abstract

Abstract This study investigates the optimization of terephthalic acid (TPA) production from waste polyethylene terephthalate (PET) bottles via Ethanolysis. The objective was to maximize TPA recovery while using different temperature conditions . Waste PET was cleaned, shredded into flakes and subjected to Ethanolysis in the presence of a potassium hydroxide catalyst. Key process variables—reaction temperature, catalyst concentration, ethanol-to-PET ratio, and reaction time—were systematically varied using an experimental design approach to determine their effects on conversion and TPA yield. Product separation included filtration and acidification; the solid and liquid fractions were characterized by Fourier Transform Infrared spectroscopy (FTIR) and melting-point determination to confirm TPA formation and purity. Optimization showed that all examined variables significantly influenced depolymerization efficiency: yield increased with temperature, catalyst concentration and ethanol ratio up to a point, beyond which side reactions and material loss reduced effective recovery. An optimum region of operating conditions was identified that balanced high conversion, product purity, and practical reagent usage. Under these optimized conditions the process delivered a marked improvement in TPA recovery and produced material whose FTIR spectrum matched that of standard terephthalic acid. The optimized method demonstrates a feasible route for valorizing post-consumer PET into a valuable monomer using accessible reagents and relatively mild conditions.