23 research outputs found
Zeolite (ZSM-5) as a Highly Efficient and Heterogeneous Catalyst for the Synthesis of β-Enaminones and β-Enamino Esters
No full textSeveral β-enaminones and β-enaminoesters have been synthesized in high yields from amine and β-diketone in the presence of Zeolite (ZSM-5) as a catalyst. This method is applicable to both cyclic and acyclic ketones with aromatic and aliphatic amines
Synthesis and characterization of a recyclable graphene oxide-surface- engineered copper(II) Schiff base complex: Catalytic application in synthesis of 1,2,3-triazoles and 2H-indazoles
No full textDevelopment of a Graphene Oxide-Supported N-Heterocyclic Carbene Copper(I) Complex as a Heterogeneous Catalyst for the Selective N-Monoalkylation of Amines
No full textA new N-heterocyclic carbene (NHC) copper(I) complex supported on graphene oxide (GO-NHC-Cu) was synthesised and thoroughly characterised by various instrumental techniques such as FT-IR, FT-Raman, PXRD, XPS, FESEM, EDX, HRTEM, TGA and ICP-OES. The catalytic activity of the supported complex was explored in the N-alkylation of anilines with alcohols under solvent-free and aerobic conditions to afford monoalkylated products in good to excellent yields (20 products, 83–96%). All products were isolated and characterised by 1H and 13C{1H} NMR spectroscopy. The catalyst was recuperated from the reaction mixture by simple filtration and reused for up to five successive cycles with insignificant loss in the catalytic activity. The control experiments showed that the reaction proceeded in aerobic conditions. The green chemistry metrics for the reaction were found to be fairly close to the ideal values: carbon efficiency (95.9%), E-factor (0.15), atom economy (92.14%), process mass intensity (1.15) and reaction mass efficiency (86.80%). The air stability, selectivity, recyclability of the catalyst, and the high yields of the products under solvent-free conditions are some of the salient features of the reported methodology
Unprecedented formation of a μ -oxobridged polymeric copper(II) complex: Evaluation of catalytic activity in synthesis of 5-substituted 1 H -tetrazoles
No full textThe reaction of CuCl2·2H2O with Schiff base ligand, 4-[(2-hydroxy-3-methoxybenzylidene)amino-1,5-dimethyl-2-phenyl-1H-pyrazol-3-one] (hmdpH), in 1:1 molar ratio led to a novel and unprecedented oxo-bridged polymeric copper (II) complex, [Cu(μ-O) (hmdp)]n. The complex was isolated as crystalline solid and characterized by FTIR, UV–visible and EPR spectroscopic techniques. The molecular structure of the complex was also determined by single crystal X-ray diffraction studies. The formation of the complex is unique and unprecedented in the sense that one of the CH3 group of the 4-aminoantipyrene unit of the Schiff base ligand is oxidized in situ to CH2OH, during the complex formation. The catalytic potential of the complex has been demonstrated in the synthesis of a series of 5-substituted 1H-tetrazoles via [3 + 2]-cycloaddition reactions of substituted benzonitriles and sodium azide in ethylene glycol
Recovery of Ag, Cu, Ni and Fe from the nitrate leach liquor of waste ICs
No full textNovel and simple flow-sheet has been reported to process integrated circuits (ICs) for effective recovery of
metals. The depopulated ICs from waste PCBs were pulverised, beneficiated and leached in nitric acid. From the
nitrate leach liquor, Fe was removed at pH 3.5, temperature 60 °C and air sparging. Subsequently, 99.99% Ag
was precipitated as AgCl using 5% NaCl in mixing time 10 min. Further, 99.99% Cu was extracted from the
filtrate using 20% LIX 984 N along with 2% isodecanol (ID) diluted in kerosene at pH 2.97, organic to aqueous
phase ratio 1 in 10 min, leaving Ni in the raffinate. From the obtained pure solutions, salts of Cu and Ni could be produced using evaporation technique. The developed hydrometallurgical process flow-sheet to recover valuables from the nitrate leach liquor of waste ICs has the potential to be commercialised after pilot/ scale-up trial validations
Chitosan-Supported Copper(II) Schiff Base Complexes: Applications in Synthesis of 5-Substituted 1H-Tetrazoles and Oxidative Homo-Coupling of Terminal Alkynes
No full textRecovery of Cobalt as Cobalt Sulfate from Discarded Lithium-Ion Batteries (LIBs) of Mobile Phones
No full textCobalt, an exceptional cathode material present in lithium-ion batteries (LIBs), is an essential element for the production of energy storage devices. But, the
lifespan of rechargeable batteries is decreasing day-by-day, which become obsolete after reaching their end of life. Therefore, an enormous amount of discarded LIBs are
generated. Keeping in mind the above, a novel approach has been made to selectively recover cobalt from sulfate leach liquor of discarded LIBs containing 1.4 g/L Cu,
1.1 g/L Ni, 11.9 g/L Co, 6.9 g/L Mn, and 1.2 g/L Li. Initially, Cu and Ni were extracted by solvent extraction techniques using 10% LIX 84-IC. Almost complete
precipitation of cobalt occurred from leach liquor at pH ~3 using ammonium sulfide solutions. Cobalt from the precipitated product was further dissolved in H2SO4 in
presence of H2O2 at elevated temperature. The leach liquor obtained was evaporated to get the cobalt sulfate with a purity of more than 98%
Room-Temperature In-Situ Design and Use of Graphene Oxide-SBA-16 Composite for Water Remediation and Reusable Heterogeneous Catalysis
No full textTemplate-free single pot synthesis of SnS<sub>2</sub>@Cu<sub>2</sub>O/reduced graphene oxide (rGO) nanoflowers for high performance supercapacitors
No full textA template-free one-pot hydrothermal route was adopted for the facile synthesis of SnS2@Cu2O/reduced graphene oxide (rGO) nanoflowers for supercapacitor electrode materials.</p
Recovery of Manganese and Cobalt from Discarded Batteries of Toys
No full textCompared to other electronic goods, life span of children’s toys is very less, which resulted in the generation of huge amount of batteries and environmental pollution. Initially, the batteries are discharged, dismantled, crushed, and physically beneficiated to get black powder, metallic fraction, and plastics. Further, the black powder of batteries was processed for systematic leaching studies and
found that 95.6% Mn and 86.05% Co were leached in 2 mol/L H2SO4 at 30 °C in 120 min using 10% H2O2 (v/v) as an oxidant, maintaining the pulp density 75 g/L. From the leach liquor, at pH 5–8 and above 12, the oxides of Co and Mn were
obtained, respectively. The developed process has potential to be transferred in an industry after scale-up studies
