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Updated: May 19, 2026

Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
Published on: August 23, 2018
Impact of Small-Alkane Solvents on Polyolefin Hydrogenolysis over a Ruthenium Catalyst
Pavel A Kots1,2, Zachary R Hinton1, Mehdi Zare1
1Center for Plastic Innovation, University of Delaware, 221 Academy Street, Newark, Delaware 19716, United States.
None:
Selective catalytic hydrogenolysis of polyolefins is a promising route to convert plastic waste into valuable liquid products, such as lubricants, waxes, and surfactants. However, the high viscosity of polymer melts imposes mass transfer limitations on this reaction. Solvents can mitigate these challenges, but their effects on reaction kinetics and product selectivity remain underexplored. Here, we systematically explore the effects of small n-alkanes and cycloalkanes on the hydrogenolysis of polyethylene and polypropylene over a Ru/TiO2 catalyst. Using kinetic measurements and isotopic labeling, we show that n-octane at high mass fractions alters the mechanism from direct hydrogenation to solvent-mediated hydrogen transfer, reducing the rate of C-C bond cleavage. Longer alkanes further inhibit reactivity due to stronger surface binding. 1,4-Dimethylcyclohexane suppresses methane formation, favoring heavier products, while decalin likely forms surface-bound aromatics that poison the catalyst. Overall, alkane solvents modulate product selectivity and reduce the yield of methane byproduct, allowing for ∼35-40% selectivity to valuable C20-C30 alkane products. This work highlights the complex impact of polymer-alkane mixtures on hydrogenolysis kinetics relevant to the design of commercial-scale plastic waste valorization processes.
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