No abstract

The kinetics of oxidation of cyclanols, viz., cyclohexanol, cyclopentanol, cycloheptanol and cyclooctanol by quinaldinium fluorochromate has been studied in aqueous acid medium at 313 K (±0.1 K). The cyclanols were converted to the corresponding cyclic ketones. The order of reaction was found to be one with respect to oxidant and fractional with respect to the substrate and hydrogen ion concentrations. Increase in the percentage of acetic acid increases the rate of reaction. The reaction mixture shows the absence of any free radicals in the reaction, which has ruled out the possibility of a one-electron transfer during the addition of acrylonitrile. The reaction has been studied at four different temperatures and the activation parameters were calculated. From the observed kinetic results a suitable mechanism was proposed. The relative reactivity order was found to be cyclohexanol < cyclopentanol < cycloheptanol < cyclooctanol. This was explained on the basis of I-strain theory.

In the present work, the effect of Mn doping in Zinc Chromite (ZnCr2O4) and particle size reduction on catalytic and photocatalytic degradation performance have been evaluated. The pristine Zn1−xMnxCr2O4 (x = 0 to 0.03) nanoscale samples are synthesized through a hydrothermal approach. The synthesized catalysts are characterized by XRD, HR-SEM, HR-TEM, catalytic, and photocatalytic degradation analyses. X-ray diffraction analysis results confirmed the formation of the ZnCr2O4 structure and its phase purity, crystallite size, and Mn dopant effect. The surface morphology and particle size of Zn1−xMnxCr2O4 samples are evaluated by SEM and TEM measurements. The textural properties of ZnCr2O4 samples are identified by the surface area analysis. The catalytic performance of Mn-doped ZnCr2O4 samples reveals superior catalytic performance compared to pristine ZnCr2O4 in benzaldehyde and carbonyl compound productions. Under UV irradiation, an excellent photocatalytic degradation efficiency of 89.66% for Zn0.97Mn0.03Cr2O4 catalyst with methylene blue has been obtained.

Zinc chromite (ZnCr2O4)-based nanoparticles have various exceptional properties that make them suitable for use in a variety of fields, including chemistry, medicine, energy, the environment, industry, and information. In this work, nanocrystalline ZnCr2O4 has been effectively synthesized with a distinct fuel by microwave-assisted solution combustion method. The XRD results reveal a single-phase high pure formation of nanoscale ZnCr2O4. The ZnCr2O4 samples are further characterized by scanning electron microscopy, transmission electron microscope, UV–Vis absorption spectroscopy, and vibrating sample magnetometer. The results reveal that modifying the fuel precursors in the combustion technique played an impact on the particle size, bandgap energy, magnetic properties, and reaction time of the ZnCr2O4 preparation. The average particle size of the various samples ranged from 18.6 to 13.9 nm with various fuels. The significance of this study is the tuning effect of optical and magnetic properties of ZnCr2O4 by using various fuel precursors.