Carbonylolysis of waste polyesters into high-value organic acids

TL;DR

A new method called carbonylolysis efficiently converts waste polyesters into valuable carboxylic acids using mild conditions and a catalyst.

Contribution

The novel one-pot carbonylolysis process enables valorization of polyester waste into high-value products with improved sustainability.

Findings

PET is converted to terephthalic and propionic acids with high yields (99% and 96%) using a Rh–iodide catalyst.

The method works for various polyester wastes, including textiles and bio-based plastics.

Life-cycle and economic analyses show significant improvements in energy efficiency and environmental impact.

Abstract

Polyesters such as PET contribute substantially to global plastic waste, yet current recycling approaches are hindered by high energy demands, inefficient product separation, and limited valorization pathways. We report a one-pot “carbonylolysis” strategy that couples polyester depolymerization with in situ carbon-chain reconstruction, producing high-value C3+ carboxylic acids under relatively mild conditions (170 °C, 2 MPa CO). Using a Rh–iodide catalyst, PET is quantitatively converted to terephthalic acid (99%) and propionic acid (96%). Mechanistic studies show that ethylene glycol released from PET hydrolysis undergoes iodide-assisted elimination followed by Rh-catalyzed carbonylation. The method applies broadly to diverse polyester wastes, including textiles and bio-based plastics. Life-cycle assessment and techno-economic analysis reveal substantial gains in energy efficiency, carbon footprint reduction, and wastewater minimization over conventional recycling routes. By integrating molecular-level reconstruction into polyester recycling, carbonylolysis establishes a sustainable blueprint for converting waste polyesters into high-value carboxylic acid.

Current plastic recycling is often limited by high energy costs and low-value outputs. This carbonylolysis strategy transforms polyester waste into high-value carboxylic acids through a combined depolymerization and carbonylation process.

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