Mahesh K. Dalal

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.

Preparation characterization and catalytic activity of polymer supported Ru(III) complexes

Abstract Chloromethylated styrene-divinyl benzene copolymer with different types of cross-link was treated with glycine for the introduction of the ligand. The polymer modified with ligand was kept in contact with RuCl 3 to form the metal complex on the surface of the polymer. The catalysts thus prepared were characterised by techniques such as IR, UV-Vis reflectance spectroscopy and DTA-TG analysis. Other physico-chemical properties such as surface area, moisture content, bulk density and swelling were also studied. The morphology of the catalysts was observed by scanning electron microscope. The catalysts were tested for the hydrogenation of nitrobenzene as a model reaction. The influence of various parameters such as concentration of catalyst and substrate, temperature and different solvents on the rate of the reaction has been studied.

Surface characterization and catalytic activity of polymer-anchored Ru(III)–schiffbase complex

Abstract A polymer-anchored Ru(III)–schiffbase complex was synthesized by chloromethylation of styrene-divinylbenzene copolymer with 14% cross-linked (AM-24) followed by sequential attachment of ethylenediamine and salicylaldehyde and finally, treatment with an ethanolic solution of metal salt. It was characterized using various techniques such as FTIR, reflectance UV–Vis spectroscopy, SEM, Electron Spin Resonance (ESR), ESCA and TGA. Various other physico-chemical properties such as bulk density, surface area, moisture content and swellability in different solvents have also been studied. Catalytic activity of the synthesised complex was investigated for hydrogenation of styrene and oxidation of benzylalcohol. Reaction kinetics was studied by varying different parameters. Results were compared with that of unbound metal complex and higher catalytic activity was found in case of supported catalyst. Catalytic behaviour under repeated catalytic cycles was studied. A probable reaction mechanism has been proposed.

Hydrogenation of 1-hexene using polymer supported Pd(II) complex catalyst

Abstract Polymer supported Pd(II) complex catalyst was synthesised by chloromethylation of styrene-divinylbenzene copolymer (XAD-2), with sequential attachment of ethylenediamine and salicylaldehyde, followed by treatment with an ethanolic solution of palladium chloride. The synthesised catalyst, named 2PS, was characterised by various techniques, such as UV-vis reflectance spectroscopy, IR, SEM, TGA and ESR. Other physico-chemical properties, such as surface area (by the BET method), moisture content, bulk density and swelling by different solvents, have been studied. The catalytic activity of the catalyst was investigated for hydrogenation of 1-hexene by varying different parameters, such as temperature, amount of the catalyst and concentration of 1-hexene.

Preparation, properties, and catalytic application of polymer-bound Ru(III) complexes

Abstract Styrene-divinylbenzene copolymer with 2 and 5% crosslinking was chloromethylated by HCl and HCHO using AlCl3 as the catalyst. Polymer-bound Ru(III) complex catalysts were synthesized by sequential attachment of 1,2-diaminopropane to the copolymer beads followed by treatment with a metal salt. The catalysts were characterized by using various techniques: FT-IR, SEM, EPR, NMR, ESCA, TGA, and UV-Vis reflectance spectroscopy. Other physicochemical properties were determined: surface area by the BET method, swelling studies with different solvents, and moisture content. The catalytic behavior of the prepared catalysts was tested for hydrogenation of cyclohexene as a model reaction. The influence on catalytic behavior of various parameters was studied: temperature, concentration of catalyst and substrate, quantity of solvent, and the use of various solvents. The recycling efficiency of the catalysts was also studied. A probable reaction mechanism is proposed.

Polymer anchored palladium(II)-diaminopropane complexes: synthesis and catalytic behaviour

Abstract Styrene-divinylbenzene copolymer with 5% and 15% cross linked were synthesised by suspension polymerization, chloromethylated and treated with 1,2-diaminopropane for the introduction of the ligand. The polymer beads modified with ligand was kept in contact with PdCl 2 to form the metal complex on the surface of the polymer. The catalysts thus prepared were characterized by various techniques such as FTIR, reflectance UV–vis spectroscopy, SEM, EPR, TGA and ESCA. Physico-chemical properties such as moisture content, bulk density, surface area by BET method and swelling with different solvents were studied. The catalytic activity of synthesised catalysts was tested for hydrogenation of cyclohexene as a model reaction. Kinetic studies were carried out by varying different parameters. Energy of activation as well as entropy of activation was calculated. The recycling efficiency of the catalysts was also studied. A probable reaction mechanism was proposed.

Catalytic activity of polymer-bound Ru(III)-EDTA complex

Chloromethylated styrene-divinylbenzene copolymer was chemically modified with ethylenediaminetetraacetic acid ligand. Catalytically active polymer containing Ru(III) moieties were synthesized from this polymeric ligand. They were characterized using FTIR, UV-vis, SEM, ESR and TGA. Other physico-chemical properties such as bulk density, surface area, moisture content and swelling behaviour in different solvents were also studied. The polymer bound complex was used to study hydrogenation of 1-hexene ton-hexane under mild conditions. Influence of [1-hexene], [catalyst], temperature and nature of the solvent on the rate of the reaction was investigated. A rate expression is proposed based on the observed initial rate data. Recycling efficiency of the catalyst has also been studied.

Oxidation of cyclohexane using polymer bound Ru(III) complexes as catalysts

Publisher Summary Oxidation of hydrocarbons are required for functionalizing hydrocarbons to yield products that are either important in themselves or are intermediate en route to other chemicals. In fine chemicals, because of stringent ecological standards, more emphasis is given to oxidation by molecular oxygen or hydrogen peroxide in preference to nonenvironmental friendly metal oxides. The catalytic activity of transition metal ions has been reported to be low as such in homogeneous system, while an enhanced activity was observed when they were heterogenized by supporting on to a solid support. Research for viable polymer supported catalysts for laboratory and industrial oxidation reactions has received recent scientific interest. The main problem is the leaching of the metal ion from the surface of the support when it is immobilized by the use of the monodentate or nonchelating ligands. Catalytic activity of different heterogenized chelated metal complex catalysts for various hydrogenation reactions has been reported. Covalently attached polymer bound multidentate amines could be valuable starting material to synthesize polymer bound chelates and macrocycles. This chapter discusses the synthesizing of the polymer bound Ru (III) complexes, using 1,2-diaminopropane (DAP), as a ligand, and oxidation of cyclohexane under mild reaction conditions, using the catalysts. Polymer bound Ru(III)-DAP complexes were found to be stable up to 100°C. These catalysts were found to be effective for oxidation of cyclohexane under mild operating conditions. The rate of reaction was studied by varying different parameters and the order of reaction with respect to catalyst as well as substrate was found to be fractional for both the catalysts.

Catalytic activity of polymer-anchored Pd(II) Schiff base complexes: hydrogenation of styrene and oxidation of benzyl alcohol

Various crosslinked chloromethylated styrene-divinylbenzene copolymer was functionalised with schiff base by sequential treatment with ethylenediamine and salicylaldehyde. The polymer modified with ligand was treated with PdCl2 to form the metal complex on the surface of the polymer. These catalysts were characterized using various techniques such as FTIR, reflectance UV-vis spectroscopy, SEM, ESR, ESCA and TGA., Various other physico-chemical properties such as bulk density, surface area, moisture content and swellability in different solvents have also been studied. The catalytic activity was evaluated for hydrogenation of styrene and oxidation of benzyl alcohol. Reaction kinetics was studied by varying different parameters. Results were compared with that of unbound metal complex and higher catalytic activity was found in case of supported catalysts. Catalytic behaviour under repeated catalytic cycles was studied. A probable reaction mechanism has been proposed.