Energy Efficient Routes to Renewable Terephthalic Acid: Pathways Toward Sustainable Polyethylene Terephthalate, PET

ABSTRACT

Poly(ethylene terephthalate), PET is indispensable in the packaging and textile industry and thereby significantly increases consumer demand. Rising demand of PET inevitably increases the production of both its monomers, i.e., Terephthalic acid (TA) and ethylene glycol. While bio‐based ethylene glycol (EG) production is commercially established, sustainable TA synthesis remains the primary challenge for economically viable, renewable PET production. Currently, TA is produced via the oxidation of petroleum‐derived p ‐xylene, requiring an energy‐intensive purification process to separate from its constitutional isomers ( o ‐ and m ‐xylene). Though fossil feedstock‐based conventional process is economically viable at large‐scale, it conflicts with the distributed bio‐based feedstock availability and sustainability principles. Developing selective TA production routes that eliminate energy‐intensive separations is thus critical for process efficiency. This review discusses the recent technologies and their underlying chemistry to produce TA from renewable feedstocks. We highlight available renewable pathways, evaluating feedstock sources, reaction conditions, and catalyst systems. Particular emphasis is placed on selective synthesis strategies that reduce purification requirements and overall energy consumption. Overall, this review article provides state‐of‐the‐art renewable TA production pathways and provides a comparative framework that is available to date.