Suresh M. Tuwar

Bio: Suresh M. Tuwar is an academic researcher from Karnatak Science College. The author has contributed to research in topics: Reaction rate & Detection limit. The author has an hindex of 8, co-authored 36 publications receiving 217 citations.

Kinetics and Mechanism of the Oxidation of Vanillin by Hexacyanoferrate(III) in Aqueous Alkaline Medium

Abstract: The title reaction was investigated in aqueous alkaline medium. A first-order dependence in hexacyanoferrate(III) concentration and a fractional order in both vanillin and alkali were obtained at the concentrations studied. The added product, hexacyanoferrate(II), had a retarding effect on the rate of reaction. Ionic strength and dielectric constant of the reaction medium have little effect on the reaction rate. The effect of temperature on the rate of reaction has also been studied and activation parameters have been evaluated. A mechanism based on the experimental results is proposed and the rate law is derived. The reaction constants are calculated and used to regenerate the kobs values, which are compared with the experimental values.

Mechanism of Oxidation of L-Histidine by Heptavalent Manganese in Alkaline Medium

Abstract: The kinetics of oxidation of L-histidine by manganese(VII) in aqueous alkaline medium at a constant ionic strength of 0.05 mol dm-3 was studied spectrophotometrically. The reaction between permanganate and L-histidine in alkaline medium exhibits 2:1 stoichiometry (KMnO4: L-histidine). The reaction is of first order in [KMnO4], less than unit order in [L-histidine] and [alkali]. Decrease in the dielectric constant of the medium decreases the rate of reaction. Effect of added products and ionic strength of the reaction medium have been investigated. The main products were identified by spot test and I.R. A mechanism involving the free radical has been proposed. In composite equilibrium step L-histidine binds to MnO4- species to form a complex(C). The reaction constants involved in the different steps of mechanism are evaluated. The activation parameters with respect to slow step of the mechanism are computed and discussed and thermodynamic quantities are also determined.

Handbook of Chemistry and Physics

Abstract: There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Silver Nanoparticle−Reactive Oxygen Species Interactions: Application of a Charging−Discharging Model

Abstract: The silver-nanoparticle-catalyzed decomposition of hydrogen peroxide (H2O2) in pH 9.5 bicarbonate buffer is investigated here with attention given to (i) the mechanism of decomposition, (ii) the role of superoxide in mediating silver nanoparticle re-formation, and (iii) the effect of nanoparticle size on decomposition rate. Silver nanoparticles (AgNPs) of average size between 25.0 and 69.4 nm were synthesized via the reduction of Ag+ [the dominant Ag(I) species present] by photochemically produced superoxide at pH 9.5 and characterized by UV−visible spectroscopy and dynamic light scattering. The ability of these particles to catalytically decompose H2O2 was examined by measuring the decay of H2O2 and the approach to steady state in AgNP and Ag+ concentrations. Additionally, the generation of superoxide on reaction of AgNPs with H2O2 was monitored using a chemiluminescence-based method. The second-order rate constants for reaction between AgNPs and H2O2 correlated linearly with their average particle size ...