Chromic acid oxidation of hexitols in the presence of 2,2′‐bipyridyl catalyst in aqueous micellar media: A kinetic study

Abstract

In aqueous H 2 SO 4 media, chromic acid oxidation of hexitols (D-sorbitol and D-mannitol) to their corresponding aldohexoses in presence and absence of 2,2 -bipyridyl (bipy) have been studied under the experimental conditions, [hexitols] T [Cr(VI)] T and [bipy] T [Cr(VI)] T (subscript T stands for the total concentration). Under the conditions, both the slower uncatalyzed and faster bipy-catalyzed paths go on simultaneously. The monomeric species of Cr(VI) has been found to be kinetically active in absence of bipy whereas in the bipy-catalyzed path, the Cr(VI)-bipy complex has been found to be the active oxidant. Both the paths show first-order dependence on [hexitol] T and [Cr(VI) ] T . The uncatalyzed path shows a second-order dependence on [H + ]. The bipy-catalyzed path is first order in [bipy] T . These ratedependence patterns remain the same in the presence of externally added surfactants. Sodium dodecyl sulfate (SDS), an anionic surfactant, has been found to accelerate both the uncatalyzed and bipy-catalyzed paths while N-cetylpyridinium chloride (CPC), a cationic surfactant, shows the rate-retarding effect for both the uncatalyzed and bipy-catalyzed paths. The observed micellar effects have been rationalized by considering the distribution of the reactants between the aqueous and micellar phases in terms of the proposed reaction mechanism.

Removal of hexavalent chromium by an aromatic alcohol

“…Benzyl alcohol is a volatile component of flower of a night blooming plant Gaura drummondii [8] and strawberry leaves [9]. The present investigations have been carried out in micro-heterogeneous systems to substantiate the proposed reaction mechanism as we carried out for other systems [10][11][12][13][14][15][16][17]. Effects of electrolytes are studied to support the proposed reaction mechanism.…”

Studies on the Kinetics of Oxidation of 4-Oxo-4-phenylbutanoic Acid by Benzimidazolium Fluorochromate in the Presence of Oxalic Acid in Acetic Acid-Water Medium

“…This new compound is more efficient for quantitative oxidation of several organic substrates and has certain advantages over similar oxidizing agents in terms of the amount of oxidant and solvent required, short reaction times and high yields. Among the different chelating agents [14][15][16][17][18][19] that promote Cr(VI) oxidation of different types of organic substrate, oxalic acid is quite important [20][21][22][23] .…”

Micellar Effects on Vanadium(V) Oxidation of Lactic Acid in Aqueous Acid Media: A Kinetic Study

“…This has prompted the present study. Micellar effects have appeared as a powerful probe to support the identification of reaction mechanism for different transition metal ions and these micelles also behave as cellular membranes [7][8][9][10][11][12][13][14].…”