Faculty Publications

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    Magnetically retrievable nickel hydroxide functionalised AFe2O4 (A = Mn, Ni) spinel nanocatalyst for alcohol oxidation
    (Springer Nature, 2016) Bhat, P.B.; Badekai Ramachandra, B.R.
    Ultrasmall nickel hydroxide functionalised AFe2O4 (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 m2 g?1 was achieved for ferromagnetic MnFe2O4 and 100.50 m2 g?1 for superparamagnetic NiFe2O4, 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 MnFe2O4 and NiFe2O4. Higher conversion rate was observed for nickel hydroxide functionalised NiFe2O4 compared to MnFe2O4. 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. © 2015, The Author(s).
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    A Liquid Derivative of Phosphotungstic Acid as Catalyst for Benzyl Alcohol Oxidation in Water: Facile Separation and Stability of Benzaldehyde at Room Temperature†
    (Wiley-Blackwell, 2017) Bhattacharjee, R.R.; Thangamani, S.; Mal, S.S.
    Polyetheramines belong to a class of green di-block copolymer with ethylene oxide and propylene oxide moieties along with terminal amine functionality. The polymers are biocompatible and show temperature dependant phase separation properties. Herein, we report the effect of a polyetheramine (Jeffamine®) on the catalytic properties of a well studied polyoxometalate catalysts, phosphotungstic acid (PTA). The catalytic reaction chosen for the test is the hydrogen peroxide-mediated oxidation of benzyl alcohol (BzOH). Modification of PTA with Jeffamine® (PTA-Jeffamine®) resulted in a solvent-less liquid-like material accessible to a wide range of solvents. The PTA-Jeffamine® catalyst was observed to enhance the conversion of BzOH compared to that of pristine PTA and facilitated easy separation of benzaldehyde (BzH) and catalyst from reaction mixture. Stability of synthesized BzH was studied with gas chromatography attached with mass spectrometry (GC-MS). Synthesis of the catalyst is cost-effective and scalable due to easy availability of the individual components and nature of the synthetic protocol. UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscopy (FE-SEM) were used to characterize the catalyst. Surface tension experiment, FE-SEM, ICP-MS and controlled experiments were performed to understand the effect of Jeffamine® in the catalytic process. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim