Carbon-carbon bond cleavage mechanisms play a key role in the selective deconstruction of alkanes and polyolefins. Here, we show that the product distribution, which encompasses carbon range and formation of unsaturated and isomerization products, serves as a distinctive feature that allows the reaction pathways of different catalysts to be classified. Co, Ni, or Ru nanoparticles immobilized on amorphous silica-alumina, Zeo-Y and ZSM-5, were evaluated as catalysts in the deconstruction of n-hexadecane model substrate with hydrogen to delineate between different mechanisms, i.e., monofunctional- (acid site dominated) or bifunctional-hydrocracking (acid site & metal site) versus hydrogenolysis (metal site dominated), established from the product distributions. The ZSM-5-based catalysts were further studied in the depolymerization of polyethylene. Based on these studies, the catalysts are plotted on an activity-mechanism map that functions as an expandable basis to benchmark catalytic activity and to identify optimal catalysts that afford specific product distributions. The systematic approach reported here should facilitate the acceleration of catalyst discovery for polyolefin depolymerization.
We report a ruthenium‐modified zeolite which efficiently transforms propylene carbonate to propylene glycol and methane, under solvent‐free conditions. The catalyst achieved high product selectivity and no significant ageing effect was observed after multiple cycles. The resulting liquid product (water‐containing glycol) can be directly used as anti‐freeze solution and the gas phase can directly be used as an energy carrier in the form of H2‐enriched methane. This process efficiently bridges energy storage and an important chemical synthesis under sustainable (CO2 consuming) conditions.
A nickel-catalyzed highly regioselective 1,4-addition reaction of boronic acids to dienones to form products with an all-carbon quaternary center is described. The 3-alkenyl group of dienones is the key for the reaction to proceed smoothly. A mechanism involving the coordination of the dienyl group to the nickel center is proposed.
We report ar uthenium-modified zeolite which efficiently transforms propylene carbonate to propylene glycol and methane,under solvent-free conditions.The catalyst achieved high product selectivity and no significant ageing effect was observed after multiple cycles.T he resulting liquid product (water-containing glycol) can be directly used as antifreeze solution and the gas phase can directly be used as an energy carrier in the form of H 2 -enriched methane.T his process efficiently bridges energy storage and an important chemical synthesis under sustainable (CO 2 consuming) conditions.
Angewandte ChemieCommunications 557
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.