Computational Studies on Mechanisms for the Organocatalytic Depolymerization of Poly(ethylene) Terephthalate

G.O. Jones, H.W. Horn, D.S. Wei, K. Fukushima, J.M. Lecuyer, D.J. Coady, J.L. Hedrick, J.E. Rice
IBM, US

Keywords: PET, depolymerization, recycling, computational, DFT

Summary:

Poly(ethylene) terephthalate (PET) is a widely used thermoplastic commonly found in packaging products and that constitutes a large percentage of total plastic refuse. We have examined the depolymerization of PET with alcohols and amines, a process with obvious environmental benefits, but which may also potentially lead to the formation of monomers which could potentially be used as feedstock for the reformulation of PET and other monomers. We describe theoretical investigations on mechanisms for the organocatalyzed depolymerization of PET into ester and amide products. We employ model systems involving the trans-esterification and amidation of methylbenzoate (MB) with ethylene glycol (EG), ethylenediamine (EDA) and ethanolamine (EA) organocatalyzed by 1,5,7-triazabicyclododecene (TBD).