Rhodium Nanoparticles as Precursors for the Preparation of an Efficient and Recyclable Hydroformylation Catalyst

Abstract

Despite all the advances in the application of nanoparticle (NP) catalysts, they have received little attention in relation to the hydroformylation reaction. Herein, we present the preparation of a hydroformylation catalyst through the immobilization of air‐stable rhodium NPs onto a magnetic support functionalized with chelating phosphine ligands, which serves as an alternative to air‐sensitive precursors. The catalyst was active in hydroformylation and could be used in successive reactions with negligible metal leaching. The interaction between the rhodium NPs and the diphenylphosphine ligand was evidenced by an enhancement in the Raman spectrum of the ligand. Changes occurred in the Raman spectrum of the catalyst recovered after the reaction, which suggests that the rhodium NPs are precursors of active molecular species that are formed in situ. The supported catalyst was active for successive reactions even after it was exposed to air during the recycling runs and was easily recovered through magnetic separation.

Support Functionalization with a Phosphine‐Containing Hyperbranched Polymer: A Strategy to Enhance Phosphine Grafting and Metal Loading in a Hydroformylation Catalyst

“…The support functionalization with diphenylphosphine moieties played ak ey role in the recyclability of the Rh catalyst under hydroformylation conditions. [17] The strategy used in our previousw ork was based on the condensation of (3-aminopropyl)triethoxysilane with the silica surface silanol groups followed by the phosphomethylation of the surface amino groups to produce bis(methylenediphenylphosphine) moieties [Fe 3 O 4 @SiO 2 -N(CH 2 PPh 2 ) 2 ]w ith 0.4 mmol of PPh 2 per gram of the solid material. The Rh catalyst, Fe 3 O 4 @SiO 2 -N(CH 2 PPh 2 ) 2 Rh, was then prepared by the impregnation of Rh NPs (synthesized through the sol immobilization method);h owever,t he metal uptake obtained wasq uite low (0.2 wt %R h).…”

“…The phosphine moieties were introduced through the reaction of the terminal amino groups of the hyperbranched structures with paraformaldehyde and diphenylphosphine. [17,21] The incorporation of organic ligandso nt he surfaceo ft he silica-coated magnetic material was evaluated by FTIR spectroscopy and thermogravimetric ChemCatChem 2016ChemCatChem , 8,1951ChemCatChem -1960 www.chemcatchem.org (TG) analysis( Figures S2 and S3). The FTIR spectrum of Fe 3 O 4 @SiO 2 -NH 2 exhibits characteristicv ibrational bands of silica and vibrational bands at ñ = 2700-2900 cm À1 characteristic of the CH 2 stretching of aminopropylg roups.…”

“…Previously,w er eported the preparation of ah ydroformylation catalyst through the immobilization of Rh nanoparticles (NPs) on am agnetics upport, the surface of whichw as functionalized with propylamino bis(methylenediphenylphosphine) ligands. [17] The aminopropyl moiety grafted into the support surface( silica-coated magnetite) was phosphinomethylated to give terminal diphenylphosphine groups that interacted with Rh NPs. This interaction allowed the immobilization of catalytically active Rh specieso nt he surface and prevented metal leachingu nder hydroformylation conditions.…”

Green Synthesis of Rhodium Nanoparticles that are Catalytically Active in Benzene Hydrogenation and 1‐Hexene Hydroformylation

“…[47] The formation of soluble active species during hydroformylation was reported for Rh NPs stabilized by tetraoctylammoniumb romide. [48] We have previously reported excellent chemoselectivity to aldehydes at av ery high activity of the Rh catalyst in hydroformylation performed under water and solventless conditions. [49][50][51] Herein, we present an ew,s imple, and green methodo fR h NP synthesis by the reduction of rhodiums pecies,R h(acac)(-CO) 2 ,R h 2 (OAc) 4 ,a nd RhCl 3 ,i na na queous medium, in thea bsence or in the presence of PVP or PVAp olymers as stabilizing agents.…”

Copper Immobilized on Isonicotinic Acid Hydrazide Functionalized Nano‐Magnetite as a Novel Recyclable Catalyst for Direct Synthesis of Phenols and Anilines

“…It is worth mentioning that nanocomposites have wide varieties of applications in various fields, such as supporting catalytic nanoparticles, drug delivery (in treating hyperthermia of cancer cells), and catalytic activity for cross‐coupling reactions ,. Herein, we have tried to design and introduce a heterogonous and magnetic‐nanoparticles catalyst having advantages like being environmentally friendly, economical, very active, possessing simple separation, and also reusability and recovery ability abilities . Magnetic nanoparticles (MNPs) which provide an active surface for the adsorptions of metal and ligand, which supported catalytic systems.…”