R.N. Ram

Bio: R.N. Ram is an academic researcher from Maharaja Sayajirao University of Baroda. The author has contributed to research in topics: Catalysis & Reaction mechanism. The author has an hindex of 13, co-authored 25 publications receiving 391 citations.

Oxidation of benzyl alcohol using polymer anchored Ru(III) complex as catalyst

Abstract: Polymer-anchored Ru(III) complex was synthesized by sequential attachment of ethylenediamine, salicylaldehyde and ruthenium chloride to chloromethylated styrene–divinylbenzene copolymer with 8% cross-linking. Synthesized catalyst was characterized by different techniques such as FTIR, reflectance UV-VIS spectroscopy, ESR, ESCA, SEM and TGA. Various physico-chemical properties such as moisture content, bulk density, surface area and swelling behaviour in different solvents were also studied. Catalytic activity of this catalyst was tested for oxidation of benzyl alcohol by varying the temperature of the system as well as concentration of substrate and catalyst. Values of energy of activation and entropy of activation have been evaluated from the kinetic data. A probable reaction mechanism has been proposed.

Catalytic oxidation by polymer-supported copper(II)-L-valine complexes

Abstract: Anchoring of an amino acid l -valine on cross-linked styrene–divinyl benzene was carried out in presence of a base. Reaction of cupric acetate with the polymeric ligand resulted in chelate formation with Cu(II) ion. The immobilized Cu(II) catalysts were characterized by elemental analyses, IR, UV-Vis, SEM, ESR and thermal analysis. Physico-chemical properties like surface area, apparent bulk density, pore volume, etc. have been determined. The supported Cu(II) complexes behave as versatile catalysts in the oxidation of various substrates such as benzyl alcohol, cyclohexanol and styrene in presence of t -butyl hydroperoxide as oxidant. The effect of reaction conditions on conversion and selectivity to products has been studied in detail. Preliminary kinetic experiments reveal that the Cu(II) complexes attached to polymer matrix can be recycled about four times with no major loss in activity.

Olefin epoxidation catalysed by Mn(II) Schiff base complex in heterogenised–homogeneous systems

Abstract: The polymer supported Mn(II) Schiff base complexes were prepared from crosslinked chloromethylated poly(styrene-divinyl benzene) copolymer beads by sequential modification into a Schiff base bearing ligand. These Schiff base bearing polymer on treatment with a solution of MnCl 2 ·2H 2 O gave the corresponding metal complexes. The polymer supported Mn(II) complexes were characterised by elemental analysis, FT-IR, diffuse reflectance, SEM and thermogravimetric analysis. Physicochemical properties such as surface area, bulk density and swelling behaviour in different solvents were studied. The catalytic activity of the supported metal complexes were studied in the epoxidation of norbornene and cis -cyclooctene using tert -butylhydroperoxide (TBHP) as the terminal oxidant. The influence of various reaction parameters such as temperature, solvent, substrate and catalyst concentration, on conversion and selectivity has been studied.

Synthesis and catalytic activity of Fe(III) anchored to a polystyrene–Schiff base support

Abstract: Cross-linked styrene-divinylbenzene copolymer was functionalized into bidentate Schiff base bearing ligands. Immobilization of iron(III) on to the polymer matrix resulted in the synthesis of catalytically active metal complexes. These supported catalysts were found to be effective in the epoxidation of cis-cyclooctene and styrene in presence of tert-butylhydroperoxide under mild conditions. The influence of various reaction parameters on conversion and selectivity to products of epoxidation has been discussed.

A study of synthesis, characterization and catalytic hydrogenation by polymer anchored Pd(II)-amino acid complexes

Abstract: l -Valine was anchored to 6% and 8% cross-linked poly(styrene-divinyl benzene) resin and its complex with palladium chloride was prepared. The newly synthesized catalysts were characterized by various techniques such as elemental analysis, FT-IR, DRS, SEM and TGA. Physico-chemical properties like surface area, swelling behavior in different solvents, bulk density, etc. have been determined. The polymer supported Pd complexes behave as versatile and recyclable catalysts for the hydrogenation of 1-octene, cyclohexene, acetophenone and nitrobenzene. Kinetics of hydrogenation of 1-octene has been investigated in detail. The influence of different reaction parameters on conversion and selectivity to products are reported.

Oxidation of Alcohols with Molecular Oxygen on Solid Catalysts

Abstract: ion from a primary OH group of glyc-erol. 223,231 A similar mechanism was proposed manyyears ago for alcohol oxidation on Pt/C, involving asecond step, the transfer of a hydride ion to the Ptsurface (Scheme 11). 8,87,237 We consider it more feasible that the rate-deter-mining step is the cleavage of the C-H bond at theR-carbon atom. A similar mechanism is now generallyaccepted for Au electrodes (Scheme 12). 238 Despite thestructural differences between Au nanoparticles andan extended Au electrode surface, there are alsosimilarities, such as the critical role of aqueousalkaline medium and the absence of deactivation dueto decomposition products (CO and C x H y frag-ments). 239,240 An important question is the nature of active siteson Au nanoparticles. Electrooxidation of ethanol onAu nanoparticles supported on glassy carbon re-quired the partial coverage of Au surface by oxides. 241 Another analogy might be the model proposed for COoxidation. 219,242,243 According to this suggestion, theactive site consists of an ensemble of metallic Auatoms and a cationic Au

Advances in Homogeneous and Heterogeneous Catalytic Asymmetric Epoxidation

Abstract: Laboratory for Advanced Materials and New Catalysis, School of Chemistry and Materials Science, Hubei University, Wuhan 430062, China,Laboratory of Natural Gas Utilization and Applied Catalysis, Dalian Institute of Chemical Physics of Chinese Academy of Sciences, Dalian 116023,China, and Jingmen Technological College, Jingmen 448000, ChinaReceived June 30, 2004