Tandem Heterogeneous Catalysis for Polyethylene Depolymerization via an Olefin-Intermediate Process

Published

January 8, 2021

Author(s)

Kathryn L. Beers, Sara Orski, Lucas Ellis, Andrew Norman, Yuriy Rom?n-Leshkov, Gregg T. Beckham

Abstract

The accumulation of plastic waste in the environment has prompted the development of new chemical recycling technologies. A recently reported approach employed homogeneous organometallic catalysts for tandem dehydrogenation and olefin cross metathesis to depolymerize polyethylene (PE) feedstocks to a mixture of alkane products. Building on that work, here a fully heterogeneous catalyst system was developed using a physical mixture of SnPt/-Al2O3 and Re2O7/-Al2O3. This heterogeneous catalyst system produces a distribution of linear alkane products from a model, linear C20 alkane, n-eicosane, and from high-density polyethylene substrate, both in an n-pentane solvent. For the PE substrate, a molecular weight decrease of 74% was observed at 200°C in 15 hr. This type of tandem chemistry, in which, poorly reactive aliphatic substrates are first activated through dehydrogenation, then functionalized or cleaved by a highly active olefin catalyst, has been called an Olefin-Intermediate Process. Olefin-intermediate processes like that examined here offer both a selective and versatile means to depolymerize polyolefins at lower severity than traditional pyrolysis or cracking conditions.

Citation

ACS Sustainable Chemistry & Engineering

Volume

9

Issue

2

Pub Type

Journals

Download Paper

DOI Link

Keywords

depolymerization, Polyethylene, Circular Economy

Citation

Beers, K. , Orski, S. , Ellis, L. , Norman, A. , Rom?n-Leshkov, Y. and Beckham, G. (2021), Tandem Heterogeneous Catalysis for Polyethylene Depolymerization via an Olefin-Intermediate Process, ACS Sustainable Chemistry & Engineering, [online], https://doi.org/10.1021/acssuschemeng.0c07612. (Accessed January 14, 2025)