Faculty Publications
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Item Synthesis of copper graphene nanocomposite by amino functionalization and their catalytic applications(Elsevier Ltd, 2019) Anuma, S.; Badekai Ramachandra, B.R.A heterogeneous catalyst containing copper nanoparticle covalently immobilized on the surface of amino functionalized graphene oxide i.e., (CuAMSGO complex) for studying the catalytic activity of Suzuki cross coupling of substituted aryl halides with phenylboronic acids. The yield of the product was 93% analyzed using GC. Under the optimized conditions, the catalyst was able to retain its activty upto 4 regenerative cycles with a metal leaching of 1.34% determined using ICP-AES analysis. The high activity of catalyst is ascribed to good synergistic effects of copper nanoparticle and the amino functionalized graphene oxide. High yield, environmentally benign, easy work-up procedure and easy seperation of catalyst are some of the important features of this protocol. © 2019 Elsevier Ltd. All rights reserved.Item Nanographene sheet immobilized transition metal complexes for C-C coupling reactions(Science Publishing Corporation Inc ijet@sciencepubco.com, 2018) Anuma, S.; Badekai Ramachandra, B.R.Transition metal Schiff base complexes covalently immobilized on the surface of amino functionalized graphene sheet to catalyze C-C coupling reaction is reported. Graphene sheet which synthesized using mechanical exfoliation and then by differential oxidative reduction phenomenon of graphite. The schiff base ligand is prepared using aldehyde and amino groups containing compounds which further treated with metal salts to form metal complexes. The as-synthesized metal complexes was then incorporated into amino functionalized nanosheets which are characterized using different spectrochemical techniques. The catalytic investigation of the asprepared catalyst were done by the cross coupling of aryl halides and aryl boronic acids to form biaryls as product in C-C cross coupling reaction. The yield of the products were high and selective which were analyzed using Gas chromatography technique. The advantage of this catalyst is high stability, recyclability easy recovery of catalyst, environmentally benign and mild reaction condition. © 2018 Authors.Item Copper complex with N-,O- architecture grafted graphene oxide nanosheet as a heterogeneous catalyst for Suzuki cross coupling reaction(Taiwan Institute of Chemical Engineers, 2019) Anuma, S.; Mishra, P.; Badekai Ramachandra, B.R.We report a straight forward synthesis of a heterogeneous catalyst by covalently immobilizing copper Schiff base complex on the surface of amino functionalized graphene oxide (AGO) for the Suzuki coupling of substituted aryl halides with arylboronic acids. The as-synthesized complex and subsequent catalyst were characterized for their structural features using suitable techniques. The analysis confirmed that the Cu bound to Schiff base (L) ligand via bi(N-,O-) linkage and Cu-L immobilization on AGO was due to its amino functionality. The catalyst exhibited excellent yield of 94% for Suzuki coupling reactions as analyzed by gas chromatography. The catalyst was recycled for 5 successive reactions with insignificant loss in efficiency. ICP-AES analysis showed the catalyst retained 87.5% of its active metal center after 5th iteration. High yield, environmentally benign, easy work-up procedure, easy separation of catalyst and mild reaction conditions are some of the important facets this catalyst offer. © 2018 Taiwan Institute of Chemical EngineersItem Polypyrrole functionalized Cobalt oxide Graphene (COPYGO) nanocomposite for the efficient removal of dyes and heavy metal pollutants from aqueous effluents(Elsevier B.V., 2021) Anuma, S.; Mishra, P.; Badekai Ramachandra, B.R.A cobalt oxide graphene nanocomposite functionalized with polypyrrole (COPYGO) having a heterogenous porous structure was synthesized using hydrothermal method. Microscopic imaging of the COPYGO surface revealed its highly porous and ordered features. The adsorption performance of the COPYGO composite was systemically investigated for Methylene Blue (MB), Congo red (CR) dyes and toxic lead (Pb(II)) and Cadmium (Cd(II)) metals. These were selected as they are the common pollutants in industrial wastewater. The COPYGO was found to be thermally stable up to 195 oC with a specific surface area of 133 m2 g?1. Experimental data indicates that the COPYGO follows Langmuir and Temkin adsorption isotherm. The COPYGO was efficient in removing MB (92.8%), CR (92.2%), Pb(II) (93.08%) and Cd(II) (95.28%) pollutants at pH 7.2, 5.0, 5.5 and 6.1 respectively from the simulated effluents. The maximum adsorption capacity (Qmax) observed for MB 663.018 mg g-1, CR 659.056 mg g-1, Pb(II) 780.363 mg g?1 and Cd(II) 794.188 mg g?1 pollutants. The thermodynamic analysis of the COPYGO indicates that the adsorption is endothermic and spontaneous in nature. COPYGO showed very high efficient removal rate for the pollutants in simulated effluents which guaranteed its benefits and efficacy in industrial wastewater treatment. © 2021 Elsevier B.V.