Identifying selective catalysts in polypropylene hydrogenolysis by decoupling scission pathways

Boosting the catalytic performance of metal–zeolite catalysts in the hydrocracking of polyolefin wastes by optimizing the nanoscale proximity

“…This can be ascribed to the fact that the branched PP has a higher tendency to form carbenium ions as the key intermediate. 12,50,51 The conversion of PP and PS catalyzed by 0.1Pt/USY-CI is more than 2 times higher than that of 0.1Pt/USY-IE. This suggests the advantage of locating Pt NPs on the surface of USY since the branched PP and PS have a much larger configuration and higher resistance to diffusion in the micropores of USY.…”

Effect of Hydrogen Spillover on the Ru/TiO2-Catalyzed Guaiacol Hydrodeoxygenation: Rutile vs Anatase TiO2

“…Thus, cyclic compounds that were undoubtedly produced from guaiacol were used to calculate the total molar yield. A lowered total molar yield indicates that hydrogenolysis of products progressed, resulting in the carbon loss. – …”

“…Guaiacol, which possesses two different oxygen functional groups (hydroxyl and methoxy group), is converted into phenol by removal of the methoxy group or 2-methoxycyclohexanol by aromatic ring hydrogenation, and finally converted into cyclohexane through successive hydrogenation and deoxygenation reactions. Meanwhile, since the Ru catalysts show high activity in hydrogenolysis and isomerization of alkanes at high temperatures, – cyclohexane is further converted to linear alkanes or cyclopentane. Anisole, which can be obtained by removing the hydroxyl group of guaiacol, was not detected in the product mixture under the current reaction conditions.…”

Review on Catalytic Depolymerization of Polyolefin Waste by Hydrogenolysis: State-of-the-Art and Outlook

“…The reaction conditions can be optimized to give appropriate reactivity and selectivity for the polyolefin feedstock used, and in this way, the energy consumption is reduced substantially. However, a comprehensive mechanistic pathway for the hydrogenolysis of polyolefins is unknown . The first communication on the hydrogenolytic depolymerizing of polypropylene and polyethylene to hydrocarbon fuels oils was about two decades ago .…”

“…In another investigation, they used cerium oxide supported ruthenium to investigate the same hydrogenolysis of polyolefins that gave a different mechanism, and the products obtained were of better yield and selectivity than those of the carbon supporting material (Table , entry 6) . The methane production during hydrogenolysis of polyolefin is undesirable; hence, Shibashish et al investigated the preferred plastic backbone scission pathway with fine-tuned reaction conditions to mitigate the formation of methane as an approach to burst the production of higher molecular weight hydrocarbons . Tamura and co-workers examined other supporting materials such as CeO 2 , SiO 2 , Nb 2 O 5 , Al 2 O 3 , and TiO 2 for the hydrogenolysis of LDPE (Table , entries 7–12) .…”