MnO2 @Fe3 O4 Magnetic Nanoparticles as Efficient and Recyclable Heterogeneous Catalyst for Benzylic sp3 C-H Oxidation

Herein, we report a highly chemoselective and efficient heterogeneous MnO₂ @Fe₃ O₄ MNP catalyst for the oxidation of benzylic sp³ C-H group of ethers using TBHP as a green oxidant to afford ester derivatives in high yield under batch/continuous flow module. This catalyst was also effective for the benzylic sp³ C-H group of methylene derivatives to furnish the ketone in high yield which can be easily integrated into continuous flow condition for scale up. The catalyst is fully characterized by spectroscopic techniques and it was found that 0.424 % MnO₂ @Fe₃ O₄ catalyzes the reaction; the magnetic nanoparticles of this catalyst could be easily recovered from the reaction mixture. The recovered catalyst was recycled for twelve cycles without any loss of the catalytic activity. The advantages of MnO₂ @Fe₃ O₄ MNP are its catalytic activity, easy preparation, recovery, and recyclability, gram scale synthesis with a TOF of up to 14.93 h^-1 and low metal leaching during the reaction.

Functionalized Ordered Mesoporous Silicas (MCM-41): Synthesis and Applications in Catalysis

Mesoporous silica sieves are among the most studied nano-objects due to their stable pore structure and easy preparation. In particular, MCM-41 have attracted increasing research attention due to their chemical versatility. This review focuses on the synthesis and regioselective functionalization of MCM-41 to prepare catalytic systems. The topics covered are: mono and di-functionalized MCM-41 as basic and acid catalysts, catalysts based on metallic complexes and heteropolyacids supported onto MCM-41, metallic nanoparticles embed onto functionalized MCM-41 and magnetic MCM-41 for catalytic purposes.

A versatile, immobilized gold catalyst for the reductive amination of aldehydes in batch and flow

A process for the reductive amination of aldehydes in continuous flow catalyzed by gold nanoparticles immobilized onto mesoporous silica has been developed.

Controllable integration of ultrasmall noble metal nanoparticles into mesoporous silica matrixes by a self-assembly method

Various noble metal nanoparticles smaller than 2 nm were immobilized into spherical mesoporous silica (30 nm) via a self-assembly method.

Direct Synthesis and Catalytic Application of Ordered Mesoporous Ru/C Composites with Homogeneously Dispersed Ruthenium Nanoclusters

Direct synthesis of metal/carbon nanocomposites with ordered mesoporous frameworks has attracted increasing interest in various applications including catalysis, optics, and electronics. Herein, we demonstrate a simple one-pot co-assembly route to synthesize Ru/carbon composites by using resol, ruthenium chloride, and Pluronic F127 as a template with the assistance of 8-hydroxyquinoline. 8-Hydroxyquinoline exerts a significant influence on the mesostructure ordering and specific surface area of the Ru/carbon composites. The obtained Ru/carbon materials show well-ordered hexagonal arrays of mesopores with homogeneously dispersed sub-2 nm Ru nanoclusters throughout the carbon frameworks, which can efficiently and quantitatively hydrogenated nitrobenzene to aniline with H₂ in the absence of solvent for multiple recycling runs without loss of activity.

Single molecule study of samarium oxide nanoparticles as a purely heterogeneous catalyst for one-pot aldehyde chemistry

Heterogeneous catalysis holds distinct advantages over homogeneous catalysis; however, it is only truly advantageous if unaffected by metal ion leaching or in situ formation of a soluble catalytically active species.

Copper iodide nanoparticles supported on magnetic aminomethylpyridine functionalized cellulose: a new heterogeneous and recyclable nanomagnetic catalyst for facile access to N-sulfonylamidines under solvent free conditions

A highly active catalyst based on CuI nanoparticles supported on magnetic aminomethylpyridine functionalized cellulose has been synthesized. It well catalyzes the multicomponent synthesis of N-sulfonylamidines under solvent free conditions.

Supercritical fluid deposition of Ru nanoparticles onto SiO2 SBA-15 as a sustainable method to prepare selective hydrogenation catalysts

Ru/SiO₂ SBA-15 materials prepared using supercritical CO₂ (scCO₂) are efficient and selective catalysts in partial hydrogenation reactions.

Catalytic, oxidant-free, direct olefination of alcohols using Wittig reagents

Catalytic acceptorless coupling of alcohols with in situ generated phosphonium ylides forms olefins and H₂, with significant stereospecificity.

Ruthenium nanoparticle-intercalated montmorillonite clay for solvent-free alkene hydrogenation reaction

A small- to medium-angle X-ray scattering (SAXS) analysis was carried out to study the change between the basal spacing of Ru MMT with respect to neat MMT.