Hetero-aromatic Nitrogen Base Promoted Cr(VI) Oxidation of Butanal in Aqueous Micellar Medium at Room Temperature and Atmospheric Pressure

摘要

The kinetics of the oxidation of butanal by chromic acid in aqueous and aqueous surfactant (sodium dodecyl sulfate, SDS, Triton X-100 (TX-100) and N-cetylpyridinium chloride, CPC) media have been investigated in the presence of a promoter at 303 K. The pseudo-first-order rate constants (k (obs)) were determined from a logarithmic plot of absorbance as a function time. The rate constants were found to increase with introduction of heteroaromatic nitrogen base promoters such as picolinic acid (PA), 2, 2'-bipyridine (bipy) and 1,10-phenanthroline (phen). The product, butanoic acid, was characterized by H-1-NMR. Three promoters PA, bpy and phen are used in combination with SDS, TX-100 and CPC surfactants showing an increase in the rate of oxidation compared to the unpromoted pathway. The mechanism of the reaction path has been proposed with the help of kinetic results and spectroscopic studies. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. The TX-100 and PA combination is suitable for butanal oxidation.