# Driving Hydrolysis and Acetolysis of Poly(ethylene terephthalate) (PET) by Microwave and Thermal Energy Inputs: A Comparative Study

## TL;DR

This study compares microwave and thermal heating for breaking down PET plastic, finding no significant difference in results between the two methods.

## Contribution

The study demonstrates that microwave and thermal heating yield similar PET depolymerization results under identical conditions.

## Key findings

- Microwave and thermal heating produced comparable terephthalic acid yields from PET.
- Reaction results were consistent regardless of solvent type or energy input method.
- Bulk fluid temperature, not heating method, controls PET depolymerization.

## Abstract

This study compares
microwave and conventional thermal energy inputs
for the hydrolysis and acetolysis of both virgin and postconsumer
poly­(ethylene terephthalate) (PET). Reaction conditions in these experiments
range from 200 to 300 °C and from 5 to 90 min. In no instances
did the yields of terephthalic acid monomer or incompletely depolymerized
PET demonstrate statistically significant or practically significant
differences with these two different energy inputs. For fixed reaction
conditions, yields of terephthalic acid were comparable from both
methods, regardless of whether the reaction medium was water, acetic
acid, or a mixture of the two. The visual appearance of the unreacted
plastic was likewise the same for microwave and conventional thermal
energy inputs when using identical solvents. These results suggest
that the bulk fluid temperature is the controlling factor for PET
depolymerization in a homogeneous fluid phase of water and/or acetic
acid with no added catalyst. The reacting system responds similarly
whether the heating is via microwave irradiation or via conduction
across the reactor wall.