A facile chemical precipitation method is used to prepare both lanthanum hydroxide [La(OH) 3 ] and neodymium hydroxide [Nd (OH) 3 ] nanopowders in an ambient temperature without the addition of any surfactants. Both rare-earth hydroxides nanopowders are characterized by X-ray diffraction and FE-SEM analysis. The supercapacitor performances of La(OH) 3 and Nd (OH) 3 electrodes are studied by cyclic voltammetry, electrochemical AC-impedance and galvanostatic charge-discharge studies. It revealed that Nd(OH) 3 electrode possesses a high specific capacitance (C sp ) than La(OH) 3 electrode. Hence, an asymmetric supercapacitor device is fabricated and denoted as Nd(OH) 3 j j AC in 6 M KOH as the electrolyte soaked in the electrospun poly(vinylidene fluoride) membrane as the separator, which exhibited an energy density of 18.8 Wh kg À 1 at a power density of 796 W kg À 1 .[a] S.
Electrochemically produced and regenerated cerium(IV) ions, by Ce 3+ /Ce 4+ , are well-known redox mediators and are used particularly as synthesis agents for the indirect oxidation of a side chain methyl group to the aldehyde group in substituted toluene. Detailed studies on indirect electrochemical oxidation of p-methoxytoluene to p-methoxy-benzaldehyde using ceric methanesulphonate were carried out. Under optimized conditions, the yield achieved was 65-78% for the oxidation with continuous recycling and electrochemical regeneration of ceric was achieved with a current efficiency of 70-85%. Purity of the product was also remaining consistent during recycling.
A green and efficient methodology has been developed for the construction of 2-[(1,3-diaryl-4-pyrazolyl)methylene]malononitriles, potent antioxidant molecules, in good to excellent yields in five minutes from 1,3-diarylpyrazole-4-carbaldehydes and malononitrile using PEG-400 and water at ambient temperature under catalyst-free conditions. The PEG-400 could be reused without appreciable loss in the yield. The methodology has been extended to the synthesis of a diverse range of homo/heteroaryl-based nitriles and acrylates, reflecting its versatility.Pyrazole-based chemical entities are one of the most important classes of nitrogen heterocycle possessing a diverse range of biological activities. 1 In continuation of our research on the synthesis of heterocycles and methodology development, 2 we initially synthesized 2-{[3-(4-bromophenyl)-1-phenyl-1H-pyrazol-4-yl]methylene}malononitrile (1a) and 2-{[3-(4-fluorophenyl)-1-phenyl-1H-pyrazol-4-yl]methylene}malononitrile (1b) from their corresponding aldehyde precursors and malononitrile using sodium ethoxide and ethanol with a view to evaluate their antioxidant activities (Figure 1). Since 1a and 1b showed good antioxidant properties in their preliminary screening, we decided to synthesize an array of 2-[(1,3-diaryl-4-pyrazolyl)methylene]malononitriles for further exploration of antioxidant and anticancer activities.Such an approach involving condensation between aldehydes and active methylene compounds, first reported in 1894, 3 can be effected using either a base or an acid. Various synthetic protocols include exploitation of zeolites, metal-based/encapsulated nanoparticles, ionic liquids, inorganic/organic bases, metal organic frameworks, ammonium salts, and mesoporous materials as catalysts. 4-6 We herein report a green and simple process for the construction of a diverse range of homo-/heteroaryl-based nitriles and acrylates.Reaction between 3-(4-bromophenyl)-1-phenylpyrazolecarbaldehyde and malononitrile was chosen as a model one in this study (Scheme 1, Table 1).
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