Anjani K. Bhatt

Environmentally benign chlorination and bromination of aromatic amines, hydrocarbons and naphthols

A simple and efficient procedure for chlorination and bromination of aromatic amines, hydrocarbons and naphthols by the action of aqueous hydrohalic acid and hydrogen peroxide is described. This environmentally clean and safe procedure involves in situ generation of the active halogen and its uncatalyzed reaction with the substrates in this study.

Asymmetric catalytic epoxidation of styrene by dissymmetric Mn(III) and Ru(III) chiral Schiff base complexes synthesis and physicochemical studies

Some dissymmetric Mn(III) and Ru(III) chiral Schiff base complexes derived from 1R,2R(−)1,2-diaminocyclohexane with 3-acetyl-4-hydroxy-6-methyl-2-pyrone and salicylaldehyde, 5-chloro-5-methoxy-and 5-nitrosalicylaldehyde have been synthesized. The characterization of the complexes was accomplished by microanalysis, IR, UV-Vis, CD spectroscopy, conductance measurements, magnetic susceptibility, optical rotation and electrochemical studies. The asymmetric epoxidations catalyzed by the complexes were examined with styrene using the terminal oxidant, iodosylbenzene to assess the stereoselectivity in the epoxidation of styrene by changing substituents on the catalyst. In all cases the R form of the catalyst resulted in S(−) form of the product as a dominant enantiomer. Optical yield of the resulting epoxide was determined by GLC using chiral capillary column/1H NMR using Eu(hfc)3 as a chiral shift reagent.

Kinetics and mechanism of epoxidation of cyclohexene and cyclooctene with potassium hydrogen persulphate catalyzed by aquoethylenediaminetetraacetatoruthenate(III) complex ion in water-dioxane medium

Abstract The kinetics of oxygenation of [(EDTA)Ru III (H 2 O)] − to [(EDTA)Ru v (O)] − by KHSO 5 was studied spectrophotometrically by following the appearance of characteristic peak of [(EDTA)Ru v (O)] − (ϵ 393 max = 8000) at a fixed pH of 6.0 and ionic strength 0.2 M (NaCiO 4 ). The time course of subsequent oxygen transfer from [(EDTA)Ru v (O)] − to cyclohexene and cyclooctene was investigated by following the decrease in the characteristic oxo peak at 393 nm as a function of substrate concentration and temperature (30–50 °C) at a constant pH of 6 and ionic strength 0.2 M (NaC1O 4 ). Activation parameters for both the oxygenation of [(EDTA)Ru III (H 2 O)] − to [(EDTA)Ru v (O)] − and oxygen atom transfer from [(EDTA)Ru v (O)] − to cyclohexene and cyclooctene were determined and probable mechanisms for both reactions proposed.

Synthesis of the complex [RuVO(edta)]− and its application in the oxidation of saturated substrates by oxygen atom transfer reaction

Abstract Oxidation of cyclohexane and cyclohexanol with Ru(edta)(O) − was studied spectrophotometrically by following the disappearance of the oxo peak of the complex Ru V (edta)(O) − at constant pH 5.0. The reaction rate was found to be first order with respect to oxo complex. The rate of oxidation increases with increasing substrate concentration and reaches a limit at high substrate concentration. Rate and activation parameters are in accordance with the mechanism proposed for the oxygen atom transfer reaction from high-valent Ru V (edta)(O) − complexes to saturated hydrocarbons.

Investigations into the nitric acid mediated dehalonitration of halophenols

A reaction of nitric acid with bromophenols and iodophenols results in substitution of the halogen with a nitro group. The study indicates moderate reactivity for bromophenols and iodophenols, while chlorophenols were found to be sluggish in this reaction.

Synthesis, crystal structures and competitive complexation property of a family of calix-crown hybrid molecules and their application in extraction of potassium from bittern

A family of calix-crown hybrid molecules containing calix[4]arene and crown-5/6, either at lower rim or at both upper and lower rims, have been synthesised, characterised and their competitive complexation property towards alkali and alkaline earth metal ions in aqueous media have been investigated. The competitive metal ion extraction study, carried out with equimolar mixture of Li+, Na+, K+, Mg2+, Ca2+ and Sr2+ in aqueous media, revealed that the amount of K+ extracted is remarkably high compared to other metal ions. Complexation with K+ has been investigated by 1H NMR, association constants and thermodynamic parameters have been determined by isothermal calorimetric study. The molecular structures of one of the receptors and two of the K+ complexes have been established by single crystal X-ray study. One of the receptors formed bimetallic complex and it exhibited interesting polymeric network structure with bridged picrate anion. These receptors have been applied for extraction of metal ions from bittern.