October 19, 2022
Journal Article

Effect of Reaction Conditions on the Hydrogenolysis of Polypropylene and Polyethylene into Gas and Liquid Alkanes

Abstract

Hydrogenolysis of polypropylene (PP) and polyethylene (PE) provides a pathway to convert these plastics into smaller hydrocarbons at relatively low temperature. Among carbon (C)-supported transition metals, ruthenium (Ru) exhibited the highest efficacy, producing mixtures of C1-C38 alkanes. The branching degree of the products depends on the position of the C-C cleavage, which can be tuned by the pressure of H2. Liquid alkanes are produced below 225°C and 200°C from PP and PE, respectively, at 30 bar. The C distribution and branching level of the products remain invariant below full conversion of the initial polymer. Increasing H2 pressure favors the hydrogenolysis of internal C-C bonds, reducing methane (CH4) production, and favors linear over branched products. A liquid yield of >57% was achieved with PE under optimum conditions. We reveal the impact of the starting polyolefin structure, reaction conditions, and presence of chlorine on the product distribution and branching degree.

Published: October 19, 2022

Citation

Chen L., Y. Zhu, L. Meyer, L.V. Hale, T.D. Le, A.J. Karkamkar, and J.A. Lercher, et al. 2022. Effect of Reaction Conditions on the Hydrogenolysis of Polypropylene and Polyethylene into Gas and Liquid Alkanes. Reaction Chemistry & Engineering 7, no. 4:844-854. PNNL-SA-170008. doi:10.1039/d1re00431j

Research topics