High performance magnetic separation of gold nanoparticles for catalyticoxidation of alcohols

Oliveira, Rafael L.; Kiyohara, Pedro Kunihiko; Rossi, Liane M.

doi:10.1039/b916825g

Cited by 141 publications

(75 citation statements)

References 67 publications

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“…In the oxidation of less reactive 2-octanol, the present catalytic system gave a better yield of 78% with 100% selectivity compared to RuO 2 -FAU catalytic system (Table 7, entry 3) [28]. Moreover, less reactive cyclopentanol was also converted into cyclopentanone in better yield of 70% whereas Au/Fe 3 O 4 @SiO 2 -catalyzed reaction gave only 42% yield (Table 7, entry 4) [50]. The rRuO 2 /MWCNT catalytic system showed comparatively lesser yields when compared with the commercial Ru/Al 2 O 3 catalytic system [30].…”

Section: Versatility Of Ruo 2 /Mwcntmentioning

confidence: 87%

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Nanostructured RuO2 on MWCNTs: Efficient catalyst for transfer hydrogenation of carbonyl compounds and aerial oxidation of alcohols

Gopiraman

Babu

Karvembu

et al. 2014

Applied Catalysis A: General

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Multiwall carbon nanotubes (MWCNTs)/ruthenium dioxide nanoparticles (RuO 2 NPs) composite was prepared by a straightforward 'dry synthesis' method. After being well characterized, the prepared composite was used as a nanocatalyst (RuO 2 /MWCNT) for the transfer hydrogenation of carbonyl compounds. The excellent adhesion of RuO 2 NPs on the anchoring sites of MWCNTs was confirmed by TEM and Raman analyses. The weight percentage (7.97 wt%) and the chemical state (+4) of Ru in RuO 2 /MWCNT was confirmed by EDS and XPS analyses, respectively. It was found that the RuO 2 /MWCNT has a higher specific surface area of 189.3 m 2 g -1 . Initially the reaction conditions were optimized and then the scope of the catalytic system was extended with a wide range of carbonyl compounds. The influence of the size of RuO 2 NPs on the transfer hydrogenation of carbonyl compounds was also studied. The RuO 2 /MWCNT is highly chemoselective, heterogeneous in nature, reusable and highly stable. Owing to the high stability of the used catalyst (u-RuO 2 /MWCNT), it was further calcinated at high temperature to obtain RuO 2 nanorods (NRs) hybrid MWCNTs. Then the hybrid material was used as a catalyst (r-RuO 2 /MWCNT) for the aerial oxidation of alcohols and the result was found to be good.

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Section: Versatility Of Ruo 2 /Mwcntmentioning

confidence: 87%

“…At the lower reaction temperatures (27,50 and 70C), the reactions were very slow, which gave very poor yield ( …”

Section: Optimization Of Reaction Conditionsmentioning

confidence: 99%

Nanostructured RuO2 on MWCNTs: Efficient catalyst for transfer hydrogenation of carbonyl compounds and aerial oxidation of alcohols

Gopiraman

Babu

Karvembu

et al. 2014

Applied Catalysis A: General

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“…The material obtained is far superior in terms of morphology control and particle size than those prepared before and has been applied in our group as a support for a variety of applications in drug delivery, separation of enzymes and catalysts. [53][54][55][56][57][58] Another interesting feature is that the thermal stability of the magnetite nanoparticles was increased after the coating with a layer of silica. The pure magnetic nanoparticles loose the magnetic properties after thermal treatment (500 °C, 2 h, air), while the silica-coated magnetite preserved its magnetic properties.…”

Section: Coating Magnetite With Silicamentioning

confidence: 99%

“…58 The Au NPs were prepared by thermal reduction in air and by hydrogen reduction at mild temperatures of the gold species attached to the magnetic support. Interestingly, the mean particle size of the supported Au NPs was similar, ca.…”

Section: Gold Catalystsmentioning

confidence: 99%

Recent advances in the development of magnetically recoverable metal nanoparticle catalysts

Rossi¹,

Garcia²,

Vono³

2012

J. Braz. Chem. Soc.

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O objetivo deste Account é fornecer uma visão geral de nossas atividades atuais de pesquisa, as quais envolvem a síntese e modificação de nanomateriais superparamagnéticos para aplicação na área de separação magnética e catálise. Primeiramente, uma introdução ao magnetismo e à separação magnética é feita. Em seguida, estratégias sintéticas que têm sido desenvolvidas para gerar nanopartículas superparamagnéticas revestidas esfericamente por sílica e outros óxidos, com destaque a sistemas bem caracterizados e preparados por metodologias que geram amostras de elevada qualidade e que, a princípio, podem ser produzidas em maior escala, são discutidas. Uma série de catalisadores magneticamente recuperáveis preparados em nosso grupo de pesquisa pela combinação única de suportes superparamagnéticos e nanopartículas metálicas é destacada. Este Account é concluído com observações pessoais e perspectivas neste campo de pesquisa.The aim of this Account is to provide an overview of our current research activities on the design and modification of superparamagnetic nanomaterials for application in the field of magnetic separation and catalysis. First, an introduction of magnetism and magnetic separation is done. Then, the synthetic strategies that have been developed for generating superparamagnetic nanoparticles spherically coated by silica and other oxides, with a focus on well characterized systems prepared by methods that generate samples of high quality and easy to scale-up, are discussed. A set of magnetically recoverable catalysts prepared in our research group by the unique combination of superparamagnetic supports and metal nanoparticles is highlighted. This Account is concluded with personal remarks and perspectives on this research field.

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“…Shi et al (2008) observed a maximum of 33 % conversion with 95 % selectivity for benzyl alcohol oxidation with free nano iron oxide. Researchers have explored different ways to enhance catalytic activity for alcohol oxidation by impregnating ferrite with different supports (Polshettiwer and Varma 2009;Oliveira et al 2010;Kotani et al 2006;Zhang et al 2008;Bhat et al 2014;Bhat and Bhat 2015). The synthesized nanocatalyst provides an alternative inexpensive catalyst for efficient oxidation of alcohols.…”

Section: Catalytic Oxidation Of Alcoholsmentioning

confidence: 99%

Magnetically retrievable nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) spinel nanocatalyst for alcohol oxidation

Bhat

2015

Appl Nanosci

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Ultrasmall nickel hydroxide functionalised AFe 2 O 4 (A = Mn, Ni) nanocatalyst was synthesized by traditional co-precipitation method and was examined for oxidation of aromatic alcohols to carbonyls using hydrogen peroxide as terminal oxidant. A very high surface area of 104.55 m 2 g -1 was achieved for ferromagnetic MnFe 2 O 4 and 100.50 m 2 g -1 for superparamagnetic NiFe 2 O 4 , respectively. Efficient oxidation was observed due to the synergized effect of nickel hydroxide (bronsted base) on Lewis center (Fe) of the nanocatalyst. Catalyst recycling experiments revealed that the ultrasmall nanocatalyst can be easily recovered by external magnet and applied for nearly complete oxidation of alcohols for at least five successive cycles. Furthermore, the nickel hydroxide functionalised ultrasmall nanocatalyst exhibited higher efficiency for benzyl alcohol oxidation compared to Ni(OH) 2 , bare MnFe 2 O 4 and NiFe 2 O 4 . Higher conversion rate was observed for nickel hydroxide functionalised NiFe 2 O 4 compared to MnFe 2 O 4 . Ultrasmall magnetic nickel hydroxide functionalised nanocatalyst showed environmental friendly, greener route for the oxidation of alcohols without significant loss in activity and selectivity within successive runs.

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High performance magnetic separation of gold nanoparticles for catalyticoxidation of alcohols

Cited by 141 publications

References 67 publications

Nanostructured RuO2 on MWCNTs: Efficient catalyst for transfer hydrogenation of carbonyl compounds and aerial oxidation of alcohols

Nanostructured RuO2 on MWCNTs: Efficient catalyst for transfer hydrogenation of carbonyl compounds and aerial oxidation of alcohols

Recent advances in the development of magnetically recoverable metal nanoparticle catalysts

Magnetically retrievable nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) spinel nanocatalyst for alcohol oxidation

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