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Udayakumar VELU Alexander STANISLAUS Gayathri VIRUPAIAH Shivakumaraiah Viswanathan BALASUBRAMANIAN 《催化学报》2011,32(2):280-285
A polymer-supported palladium-imidazole catalyst was used to catalyze the hydrogenation of various olefins under mild conditions. The rate of hydrogenation was studied. The effects of factors such as substrate concentration,catalyst concentration,partial pressure of hydrogen and temperature on initial rate of reaction of selected olefins were investigated. A mechanism for the reaction was proposed from the rate equation. The effects of the solvent and structure of the olefin on the rate of hydrogenation were investigated. The catalyst showed good reusability without any leaching of metal from the support. The homologous analog of the polymer-supported catalyst could not be used as catalyst for the hydrogenation of olefins in methanol because there was precipitation of the metal during reaction. 相似文献
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H.N. Chandrakala B. Ramaraj Shivakumaraiah Siddaramaiah 《Journal of Physics and Chemistry of Solids》2014
We investigated the influence of lithium potassium zirconate (LiKZrO3) nanoparticles on the electrical properties and structural characteristics of poly(vinyl alcohol) (PVA) films. PVA/LiKZrO3 nanocomposite films were prepared by casting of aqueous solutions with varying LiKZrO3 content (0.5, 1.0, and 2.0 wt.%). The dielectric constant (ε′), dielectric loss (ε″), AC conductivity (σac), dielectric loss tangent (tan δ), and electric modulus (M′ and M″) of the nanocomposite films were measured over a range of frequencies at ambient temperature. The results show increases in σac and M′ with frequency, whereas ε′, ε″, and tan δ decreased with increasing frequency. The films were also characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) techniques. DSC and XRD revealed the nature of LiKZrO3 nanoparticle interaction with the PVA matrix. TGA analysis revealed an increase in thermal stability of the nanocomposites with increasing nanoparticle concentration. Scanning electron microscopy confirmed uniform dispersion of LiKZrO3 nanoparticles in the PVA matrix. 相似文献
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Shivakumaraiah D'souza Joyce Q. Reddy Yerrappagari C. Gayathri Virupaiah Nanje Gowda Nadur M. 《Transition Metal Chemistry》2004,29(2):113-120
[Pd(cod)(cotl)]ClO4 (cod = 1,5-cyclooctadiene, cotl = cyclooctenyl, C8H13
–) undergoes substitutions with multidentate N-heterocycles: 1,3-bis(benzimidazolyl)benzene (L1), 1,3-bis(1-methylbenzimidazol-2-yl)benzene (L2), 2,6-bis(benzimidazolyl)pyridine (L3) and 2,6-bis(1-methylbenzimidazol-2-yl)pyridine (L4) to yield mono/binuclear complexes: [Pd(cotl)(L1)(OClO3)], [Pd(cotl)(L)]ClO4 (L = L2 or L3) and [Pd(cotl)2(L4)](ClO4)2. Dihalobridged binuclear complexes [PdX(cotl)]2 (X = Cl or Br) undergo halogen bridge cleavages with the multidentate N-heterocycles to form binuclear complexes of the type [PdX(cotl)2L] (X = Cl or Br; L = L1, L2, L3 or L4). The complexes were characterized by elemental analyses, 1H-, 13C-n.m.r., i.r., far-i.r. and FAB-mass spectral studies. 相似文献
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