Viswanathan Balasubramanian

Bio: Viswanathan Balasubramanian is an academic researcher. The author has contributed to research in topics: Catalysis & Palladium. The author has an hindex of 2, co-authored 2 publications receiving 10 citations.

Synthesis, Characterisation of Polymer-Supported Palladium-2-Methylimidazole Complex Catalyst for the Hydrogenation of Aromatic Nitro Compounds:

Abstract: A polymer-​supported palladium-​2-​methylimidazole complex was synthesized and characterized by various physicochem. methods. The complex was successfully used as a catalyst for the hydrogenation of nitrobenzene and its derivs. under ambient conditions. Results reveal that the electronic as well as the steric effects of the substituent control the rate of hydrogenation of the nitro group in the studied nitro compds. The kinetics of hydrogenation and the reusability of the catalyst were also studied.

A new force field model of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and acetonitrile mixtures.

Abstract: Recently, we introduced a new force field (FF) to simulate transport properties of imidazolium-based room-temperature ionic liquids (RTILs) using a solid physical background. In the present work, we apply this FF to derive thermodynamic, structure, and transport properties of the mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM][BF4], and acetonitrile (ACN) over the whole composition range. Three approaches to derive a force field are formulated based on different treatments of the ion–ion and ion–molecule Coulomb interactions: unit-charge, scaled-charge and floating-charge approaches. The simulation results are justified with the help of experimental data on specific density and shear viscosity for these mixtures. We find that a phenomenological account (particularly, a simple scaled-charge model) of electronic polarization leads to the best-performing model. Remarkably, its validity does not depend on the molar fraction of [BMIM][BF4] in the mixture. The derived FF is so far the first molecular model which is able to simulate all transport properties of the mixtures, comprising RTIL and ACN, fully realistically.

The Partial Hydrogenation of 1,3-Dienes Catalysed by Soluble Transition-Metal Nanoparticles

Abstract: The partial hydrogenation of 1,3-dienes is a structure sensitive reaction that is typically catalysed by classical heterogeneous (heterotopic) or homogeneous (homotopic) catalysts. Recently, soluble transition-metal nanoparticles (M-NPs), particularly palladium and gold-based systems, have emerged as an efficient alternative. Here, we review the current state of the techniques for the partial hydrogenation of 1,3-dienes by M-NPs and conclude that, from the reactivity point of view, these materials possess heterotopic-like and homotopic-like characteristics. They are heterotopic-like because the relative concentration of the monoalkene with respect to the diene does not affect the product selectivity and their catalytic performance is affected by their physical properties (such as size and shape). Furthermore, they are easily recoverable, with long catalytic lifetimes. Additionally, as homotopic systems, their reactivity can be tuned by using an appropriate organic stabiliser, which displays substrate-selective levels that are not observed for classical heterotopic catalysts.

Reduction of olefins, nitroarenes and Schiff base compounds by a polymer-supported [2-(2′-pyridyl)benzimidazole]palladium complex

Abstract: 2-(2′-Pyridyl)benzimidazole (PBIMH) was functionalized onto chloromethylated polystyrene beads crosslinked with 6.5 % divinylbenzene, and this solid support was then reacted with Na2PdCl4 in methanol. The functionalized beads were then activated using sodium borohydride. The resultant polymer-supported [2-(2′-pyridyl)benzimidazole]palladium complex (PSDVB–PBIM–PdCl2) and its activated form were characterized by various physicochemical techniques. XPS studies confirmed the +2 oxidation state of palladium in the supported complex. The activated complex was found to catalyse the hydrogenation of various organic substrates including olefins, nitro and Schiff base compounds. Kinetic measurements for the hydrogenation of cyclopentene, cyclohexene and cyclooctene were carried out by varying temperature, catalyst and substrate concentration. The energy and entropy of activation were evaluated from the kinetic data. The catalyst showed an excellent recycling efficiency over six cycles without leaching of metal from the polymer support, whereas the unsupported complex was unstable as metal leached out into the solution during the first run.

Epoxidation of alkenes using inorganic polymer of silica zirconia molybdate as catalyst

Abstract: Silica zirconia sulfate was prepared by sol–gel copolymerization of the sulfated zirconium octanoxide and tetraethylorthosilicate (TEOS). Active polymer oxidation catalysts were obtained by introducing sodium molybdate into the polymer by a ligand exchange reaction. The prepared inorganic polymer designated as SZ-Mo was characterized by FT-IR, SEM, XRD, N 2 sorption isotherms, and ICP techniques. It was found that SZ-Mo successfully catalyzes the epoxidation of cyclooctene, cyclohexene, trans -stilbene, and norbornene with 22–95% conversion and 60–100% selectivity. The dependence of the SZ-Mo catalytic activity to the amount of adsorbed Mo within the polymer as well as the study of catalyst stability during the course of reactions will be described in this presentation.