Employment and resurrection of surfactants in bipyridine promoted oxidation of butanal using bivalent copper at NTP

Abstract

A recent “Renaissance” has various fields of chemistry exploring processes that are more Earth-friendly One focus is to make kinetic experiments greener by applying modified methodologies for metal mediated oxidation kinetics mean while recycling the used reagents and catalysts after completion in greener aqueous media. Use of surfactants has been established as a green modification to conventional chemical transformation reactions. Here bipyridine, a hetero-aromatic notrogen base was employed as promoter in association with cationic, anionic and non-ionic surfactants for room temperature oxidation of butanal to butyric acid. Results are compared with unpromoted and uncatalysed Cu2+ (aq) oxidation (E 0 Cu 2+ (aq)/ Cu + (aq) = 0.15 V). All the reactions were performed under the pseudo-first-order kinetics at 30 °C. The determined pseudo-first-order rate constant (k obs) and half-life value (t 1/2) of all the reactions indicates that sodium dodecyl sulphate inhibits the reaction rate while N-cetylpyridinium chloride accelerates the same in the titled kinetic experiment. The suitable formal potential in the presence of bipyridine guides the reaction to follow faster kinetics. The yield of the final butyric acid from butanal were found to be satisfactory (see “Yield (approx) of butyric acid in different reaction systems”). The purity of the oxidized product was determined by specific gravity calculation after fractional distillation along with 1H-NMR and FTIR spectroscopic measurements. Formation of micelle in the kinetic study was proved by optical imaging and TEM studies; incorporation of active substrate and reagents in micellar core was found with DLS data.