Pd catalysts supported on dual-pore monolithic silica beads for chemoselective hydrogenation under batch and flow reaction conditions

Abstract

Two different types of palladium catalysts supported on dual-pore monolithic silica beads [5% Pd/SM and 0.25% Pd/SM(sc)] for chemoselective hydrogenation were developed. Alkyne, alkene, azide, and nitro functionalities and the...

PdRu Bimetallic Nanoparticles/Metal–Organic Framework Composite through Supercritical CO2–Assisted Immobilization

“…However, impregnating sufficient amounts of metal precursors and/or NPs into the micropores of MOFs is challenging owing to their complex pore structure . Impregnation with supercritical carbon dioxide (scCO 2 ) is an effective approach for the uniform decoration and impregnation of porous materials. − ScCO 2 -assisted immobilization of metal NPs on porous materials results in high catalytic activity. − Furthermore, scCO 2 -based emerging technology allows us to obtain unique and varied morphologies, such as dispersed species, films, and high-surface-area NPs. The morphology of the products could be improved by varying the operating temperature, pressure, contact time, and CO 2 volume rate. , ScCO 2 can surpass the diffusivity and mass transfer limitations of conventional solvents and load sufficient amounts of target materials, such as metal precursors, into the pores and MOF surfaces .…”

“… 20 − 24 ScCO 2 -assisted immobilization of metal NPs on porous materials results in high catalytic activity. 25 − 28 Furthermore, scCO 2 -based emerging technology allows us to obtain unique and varied morphologies, such as dispersed species, films, and high-surface-area NPs. The morphology of the products could be improved by varying the operating temperature, pressure, contact time, and CO 2 volume rate.…”

Hydrogenation of Epoxides to Anti‐Markovnikov Alcohols over a Nickel Heterogenous Catalyst Prepared from Biomass (Rice) Waste

“…[42] A major drawback of these heterogenous systems is that high catalyst loadings are required, and their tolerance to functional groups is limited, reducing their substrate scope mostly to styrene oxide. [43,44] In this contribution, nickel-containing hydrogenation catalysts have been prepared successfully from waste RH. Nickel nanoparticles are generated on the catalysts surface by coordinating Ni(II) ions on the RH followed by pyrolysis, where carbothermal reduction leads to catalytically active nickel species.…”

“…Thus, Ni‐catalysts have been prepared using various supports, [38,39] including MgO‐Al 2 O 3 , MgO, [40,41] and saponites [42] . A major drawback of these heterogenous systems is that high catalyst loadings are required, and their tolerance to functional groups is limited, reducing their substrate scope mostly to styrene oxide [43,44] …”

Mass Transfer in Hierarchical Silica Monoliths Loaded With Pt in the Continuous-Flow Liquid-Phase Hydrogenation of p-Nitrophenol

“…Owing to the extensively studied surface chemistry and versatility in synthesis steps, HSM supports can be functionalized via in situ as well as post-synthesis treatment with a variety of moieties and applied in numerous catalytic applications. Recent studies show successful implementation of silica monolithic catalysts as flow reactors in various chemical and biochemical transformations (El Kadib et al, 2009;Sachse et al, 2010;Linares et al, 2012;Sachse et al, 2012;Sachse et al, 2013;Szymańska et al, 2013;Hakat et al, 2016;Ciemięga et al, 2017;Haas et al, 2017;Liguori et al, 2017;Pélisson et al, 2017;Mrowiec-Białoń et al, 2018;Russell et al, 2020;Yamada et al, 2020;Ahmad et al, 2021;Turke et al, 2021).…”