Using a natural chlorite as catalyst in chemical recycling of waste plastics: Hydrolytic depolymerization of poly-[bisphenol A carbonate] promoted by clinochlore

Waste Manag. 2021 Feb 1;120:642-649. doi: 10.1016/j.wasman.2020.10.031. Epub 2020 Nov 15.

Abstract

The present study describes the first example of utilization of a natural clay mineral as catalyst in a process addressed to chemical valorization of poly-[bisphenol A carbonate] (PC; (1)) wastes. A natural clinochlore was investigated for the first time as the catalyst of the hydrolysis reaction of 1, a potential route to chemical recycling of wastes of this polymeric material. At 473 K, in tetrahydrofuran (THF) as the solvent, the mineral promoted effectively the depolymerization (up to 99%, after 6 h) of 1 by H2O and the selective (~99%) regeneration of the monomer bisphenol A (BPA, (2)). Temperature, catalyst loading, reaction time, H2O/PC weight ratio affected markedly the productivity of the process. The role of the catalyst was also focused: the experimental data showed that the exposed brucite-like sheets of clinochlore are involved in the hydrolysis reaction and take active part in promoting the depolymerization process.

Keywords: Chlorite; Clinochlore; Hydrolysis; Plastics chemical recycling; Poly-[bisphenol A carbonate]; Waste valorization.

MeSH terms

  • Benzhydryl Compounds
  • Carbonates
  • Chlorides
  • Hydrolysis
  • Phenols
  • Plastics*
  • Recycling*

Substances

  • Benzhydryl Compounds
  • Carbonates
  • Chlorides
  • Phenols
  • Plastics
  • bisphenol A
  • chlorite