A kinetic and mechanistic study of oxidation of L-lysine by diperiodatonickelate(IV) in aqueous alkaline medium

1470-1475The kinetics of oxidation of L-lysine by diperiodatonickelate(IV) (DPN) in aqueous alkaline medium at a constant ionic strength of 0.60 mol dm-3 has been studied spectrophotometrically. The reaction shows first order in diperiodatonickelate(IV) and less than unit order dependence each in lysine and OH- ion concentrations. The addition of periodate retards the reaction, while the product nickel(II) do not show any significant effect on the reaction rate. An increase in ionic strength and decrease in dielectric constant of the medium decreases the rate. A mechanism based on experimental results is proposed. The constants involved in the mechanism are evaluated. The activation parameters with respect to slow step of the mechanism are computed and discussed

Kinetics and mechanism of oxidation of arsenic(III) by quinolinium dichromate(QDC) in aqueous perchloric acid

388-393The kinetics of oxidation of arsenic(III) by quinolinium dichromate(QDC) has been investigated spectrophotometrically over a wide range of arsenic(III) concentrations in aqueous perchloric acid medium and at a constant ionic strength. As the arsenic(III) concentration varies, from lower concentration region to higher one, the order with respect to [arsenic(III)] changes from first to zero order. In all the regions of the [arsenic(III)], the reaction is first order in [oxidant] and less than unit order in [acid] . Increase in [perchloric acid] accelerates the reaction rate. The added products, chromium(III) and arsenic(V) do not significantly affect the reaction rate. A suitable mechanism is proposed and the involved reaction constants have been evaluated. Activation parameters have also been calculated

Hexacyanoferrate(III) oxidation of antimony(III) in aqueous acetic acid

231-234The rate of hexacyanoferrate(III) oxidation of antimony(ill) in 50% aq. acetic acid (v/v) in the presence of H+ and Cl- ions is considerably accelerated with increase in [H+] and [CI-] as well as increase in acetic acid content of the medium. The experimental results indicate that the reaction occurs mainly between H2Fe(CN) and SbCl

Investigation of binding behaviour of procainamide hydrochloride with human serum albumin using synchronous, 3D fluorescence and circular dichroism

Interaction of procainamide hydrochloride (PAH) with human serum albumin (HSA) is of great significance in understanding the pharmacokinetic and pharmacodynamic mechanisms of the drug. Multi-spectroscopic techniques were used to investigate the binding mode of PAH to HSA and results revealed the presence of static type of quenching mechanism. The number of binding sites, binding constants and thermodynamic parameters were calculated. The results showed a spontaneous binding of PAH to HSA and hydrophobic interactions played a major role. In addition, the distance between PAH and the Trp–214 was estimated employing the Förster's theory. Site marker competitive experiments indicated that the binding of PAH to HSA primarily took place in subdomain IIA (Sudlow's site I). The influence of interference of some common metal ions on the binding of PAH to HSA was studied. Synchronous fluorescence spectra (SFS), 3D fluorescence spectra and circular dichroism (CD) results indicated the conformational changes in the structure of HSA

Mechanism of oxidation of hexamine by quinoliniumdichromate (QDC) in aqueous perchloric acid

459-465The kinetics of oxidation of hexamine by quinoliniumdichromate (QDC) has been investigated spectrophotometrically in aqueous perchloric acid medium at constant ionic strength. The reaction is first order with respect to oxidant and reductant. Increase in perchloric acid concentration increases the reaction rate and order with respect to acid concentration is nearly two. The added products chromium(III), formaldehyde and oxime do not have any significant effect on the rate of reaction. Increase in ionic strength and decrease in dielectric constant of the reaction medium increases the rate of reaction. A suitable mechanism is proposed and the constants involved have been obtained. The activation parameters were evaluated with respect to slow step of the mechanism and discussed