The usefulness of various quantum chemical algorithms (semiempirical, HF, DFT) for predicting the energy and geometry of transition states of polar pseudocyclic processes was analyzed using the example of a model cycloaddition process between (Z)-C,N-diphenylnitrone and (E)-2-phenyl-1-nitroethene. These studies clearly recommend the ωB97XD functional in 6-311+G(d) basis set as the relatively most precise tool for studying the mechanisms of polar pseudocyclic processes.

Batch adsorption and desorption kinetic experiments of fenitrothion on clay soil and sandy clay loam soil indicated that the equilibration time was approximately 30 hours. The kinetics of adsorption and desorption exhibited two distinct stages: a rapid process in the initial stages followed by a slow process. The pseudo-first-order model followed by the Elovich kinetic model fit the experimental adsorption and desorption data quite well, with high values of R2 and low values of ∆qe% and SSE. Accordingly, the pseudo-first-order model is most suitable for describing the adsorption and desorption kinetics of fenitrothion on clay soil and sandy clay soil. Pseudo-second-order model type-1 and type-2 models fit the experimental adsorption data; however, these models cannot be used to describe desorption kinetics. Moreover, the modified Freundlich model has limited applicability, and the intraparticle diffusion kinetic model cannot describe the kinetics of the adsorption and desorption of fenitrothion on clay and sandy clay loam soils.

In the present work the synthesis of 4-phenyl-2, 6-di (thiazol-2-yl) pyridine copper chloride (abbreviated as Cu-DTPy) complex using copper (II) chloride and 2, 6-di (thiazol-2-yl) pyridine has been carried out. The complex has been specified by UV-Vis, FT-IR, CHNS and ESI-MS methods of analysis. The synthesized copper complex has been used as catalyst in the oxidation of p-aminophenol using hexacyanoferrate (III) ions as an oxidant in aqueous alkaline medium by kinetic-spectrophotometric method. This experimental work was carried out at optimum pH 11.0 and temperature 25ºC. The variation of effect of concentration of p-aminophenol (abbreviated as PAP), hexacyanoferrate (III) ions, and Cu-DTPy catalyst on reaction rate has been studied. Thermodynamic parameters such as free energy of activation, activation energy, enthalpy and frequency factor have been evaluated with the change in rate of the reaction at four disparate temperatures i.e. 25-40ᵒC. The oxidation products have been identified by FT-IR and ESI-MS spectroscopic analytical techniques. The major product of this reaction is NN’-bis-(p-hydroxyphenyl)-2-hydroxy-5-amino-1,4-benzoquinone di-imine. Thus, this method is highly efficient and environmentally safe to remove PAP from polluted water resources.

Kinetic study of oxidation of toluidine blue (TB+) by periodate was carried out in aqueous medium and also in the cetyl trimethyl ammonium bromide (CTAB) reverse micellar medium. In both the media reaction obeys first order kinetics with respect to each of the reactants. In the reverse micellar medium, the reaction is forty times faster compared to aqueous medium under identical experimental conditions. The pronounced acceleration is accounted for by the lower micro polarity and the concentration effect present in the bound water of reverse micelles. In CTAB reverse micellar medium, the pseudo first order rate constant (k’) of the reaction is almost constant at all values of W, {W=[H2O]/[CTAB]} indicating that the reaction takes place on the micellar surface and results were explained by modified Berezin pseudo phase model..

Kinetics of the oxidation of primary aliphatic alcohols has been carried out using phase transferred monochromate in benzene. Tetrabutylammonium bromide (TBAB) and tetrabutylphosphonium bromide (TBPB) are used as phase transfer catalysts (PT catalyst). The reaction shows first order dependence on both [alcohol] and [monochromate ion]. The oxidation leads to the formation of corresponding aldehyde and no traces of carboxylic acid has been detected. The reaction mixture failed to induce the polymerization of added acrylonitrile which rules out the presence radical intermediates in the reaction. Various thermodynamic parameters have been evaluated and a suitable mechanism has been proposed.