# 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.

## Key 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.