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

Abstract

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.

NiFe2O4nanoparticles: an efficient and reusable catalyst for the selective oxidation of benzyl alcohol to benzaldehyde under mild conditions

“… 38 Bhat et al reported the use of different ferrites for the oxidation of benzyl alcohol in an acetonitrile medium using H 2 O 2 as an oxidant at 80 °C for 7 h. The maximum conversion of 82.4% was attained with a nanofunctionalized NiFe 2 O 4 catalyst. 39 Nasrollahzadeh et al studied the performance of CoFe 2 O 4 NPs in the oxidation of benzyl alcohol to benzaldehyde using H 2 O 2 as an oxidant under solvent-free conditions. They acquired >99% conversion of benzyl alcohol to benzaldehyde at 110 °C for 5 h. 40 A careful investigation suggests that in the above reports either the catalyst system was prepared using a complex methodology or harsh conditions such as high temperatures or longer reaction time was applied for the desired conversion.…”

Advanced metal oxide-based nanocatalysts for the oxidative synthesis of fine chemicals

“…With the intension to design a magnetically retrievable nanocatalyst, the same research group fabricated nickel hydroxide functionalized spinel AFe 2 O 4 (A= Mn, Ni) nanocatalyst for the oxidation of aromatic alcohols to carbonyl motifs in presence of H 2 O 2 as the oxidizing agent 161 . The motive to devote attention towards soft ferromagnetic spinel ferrites are associated with their inherent features including high dispersion, less toxicity, excellent stability, low oxidation potential values etc.…”

Synergetic Effect of Calcium Doping on Catalytic Activity of Manganese Ferrite: DFT Study and Oxidation of Hydrocarbon

“…They observed the same trend in selectivity and conversion per unit time. Table 1 reflects the higher catalytic activity of Mn-ferrite and Ca-doped Mn-ferrite used for the oxidation of CH in solvent-free conditions compared to all reported catalysts being used for the oxidation of COH/RCOR [29][30][31]50]. Reaction progress (%) Fang & co-workers [49] performed electrocatalytic oxidation of CH to CHOH/RCOR using a functional electrocatalytic membrane reactor (ECMR) assembled with an MnO nanostructure that was loaded on a porous titanium membrane as an anode in a ternary system of CH, water and acetic acid.…”

“…They observed the same trend in selectivity and conversion per unit time. Table 1 reflects the higher catalytic activity of Mn-ferrite and Ca-doped Mn-ferrite used for the oxidation of CH in solvent-free conditions compared to all reported catalysts being used for the oxidation of COH/RCOR [29][30][31]50].…”