Surface‐active and highly stable cobalt nanoparticles generated from alkali ion‐promoted gold catalyst for catalyzed carbonylative [2+2+1] cyclization reaction, is described. The gold nanoparticle‘s (AuNPs) role was assumed to dissociate the CO and H2 into atomic species on the catalyst surface by spillover, which in‐situ reduces the robust mesoporous cobalt oxide to metallic cobalt (Co3+→Co2+→Co), as the active catalytic species that catalyzed the reaction; thereby providing up to 93 % yield of cyclopentenone adducts. Prior to this, catalyst pre‐treatment with H2 gas (130 °C, 3 h, 20 atm) was performed to reduce the catalyst. It appeared that the low reducibility temperature and increased surface basicity ascribed to the presence of alkali ion‐promoters in the catalyst revealed a strong correlation with the catalyst activity, for the intra‐ and intermolecular reactions under milder reaction conditions. Thus, a sustainable, highly reusable, and environmentally friendly green catalyst for the carbonylation reaction, such as Pauson‐Khand, was developed.
The scope of the present study aims at demonstrating the application of 3-D printing technology for catalytic applications. A novel microreactor containing immobilized palladium nanocatalyst (Pd/Co 3 O 4 ) was designed and fabricated in-house for the efficient upgrade of liquid phase morin oxidation from batch to flow procedure. Reaction conditions such as time, reaction temperature, catalyst amount and hydrogen peroxide (H 2 O 2 ) concentration were investigated to fully benchmark the catalytic efficiency in both systems. The conversion and the kinetic data obtained in both systems reveal that the reaction proceeds faster in the flow reactor compared to batch under similar reaction conditions. In addition to enhanced catalytic activity, the stability of both systems was evaluated exemplarily by recycling and reusing recovered catalyst. The microreactor demonstrates an extended service life based on the recyclability studies conducted. Based on these results, the simple, low-cost 3-D printed reactionwares described in this study appears as a promising approach for the oxidation of morin dye in continuous flow.
The advantage of dendritic monodisperse macromolecules’ dual templating ability was employed for the formation of silica-supported copper nanoparticles Cun@SiO2NPs. This was acquired by the initial synthesis of a silica framework...
An eco-friendly alkali-promoted (CsÀ Au/Co 3 O 4 ) catalyst, with redox and basic properties for the oxidative dehydrogenative coupling of anilines to symmetrical and unsymmetrical aromatic azo compounds, was developed. We realized a base additiveand molecular O 2 oxidant-free process (using air), with reasonable reusability of the catalyst achieved under milder reaction conditions. Notably, the enhanced catalytic activity was also linked to the increased basic site concentration, low reduction temperatures, and the effect of lattice oxygen on the nanomaterials. The increased basic strength of the cation-promoted catalyst improved the electron density of the active Au species, resulting in higher yields of the desired aromatic azo compounds.
The benefits of 3D-printing technology in the manufacturing of laboratory equipment, in particular catalytic applications, have recently been brought to the limelight. In this paper, continuous-flow reaction devices consisting of syringe pumps and flow reactors were fabricated using a 3D-printing technique which aims at circumventing the high cost of procuring the convectional reactors for catalytic reactions. Mesoporous manganese metal oxide (MnMMO) and mesoporous cobalt metal oxide (CoMMO) catalysts were synthesized and fully characterized. The catalytic activity of the prepared nanocatalysts was evaluated in a continuous-flow operation using an in-house 3D-printed flow device for the reduction of hexacyanoferrate ion into a useful intermediate compound industrially. Different reaction parameters such as flow rates, temperature, and catalyst amount were investigated for the systemÕs optimization. The result showed an impressive output with an outstanding conversion of 94.1% hexacyanoferrate ion in 6-minute reaction time. Also, the excellent stability of five-run reusability on hexacyanoferrate ion was performed in a safe, faster, and well-controlled microenvironment.
To establish an environmentally friendly green chemical process, we minimized and resolved a significant proportion of waste and hazards associated with conventional organic acids and molecular gases, such as carbon monoxide (CO).
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