Selection of Suitable Micellar Catalyst for 1,10-Phenanthroline Promoted Chromic Acid Oxidation of Formic Acid in Aqueous Media at Room Temperature

Abstract

ABSTRACT. In the present investigation, kinetic studies of oxidation of formic acid with and without catalyst and promoter in aqueous acid media were studied under the pseudo-first order conditions [formic acid]T >>[Cr(VI)]T at room temperature. In the 1,10-phenanthroline (phen) promoted path, the cationic Cr(VI) phen complex is the main active oxidant species undergoes a nucleophilic attack by the substrate to form a ternary complex which subsequently experiences a redox decomposition through several steps leading to the products CO2 and H2 along with the Cr(III) phen complex. The anionic surfactant (i.e., sodium dodecyl sulfate, SDS) and neutral surfactant (i.e., Triton X-100, TX-100) act as catalyst and the reaction undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation in the micellar phase. Whereas the cationic surfactant (i.e., N-cetyl pyridinium chloride, CPC) acts as an inhibitor restricts the reaction to aqueous phase. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. The neutral surfactant TX-100 has been observed as the suitable micellar catalyst for the phen promoted chromic acid oxidation of formic acid.

Combination of Sodium Dodecylsulfate and 2,2′-Bipyridine for Hundred Fold Rate Enhancement of Chromium(VI) Oxidation of Malonic Acid at Room Temperature: A Greener Approach

“…Oxidation is key reaction in organic synthesis and will likely play a significant role in the development of value added chemicals from biomass, which is a very much targeted area of scientists worldwide [1]. Among numerous oxidants chromium(VI) has frequently been employed as an oxidant in both preparative and analytical chemistry, where chromic acid [2][3][4][5][6][7][8], aqueous dichromate [9], chromyl chloride [10], chromyl acetate [11] and ditertiary butyl chromate [12] are important chromium(VI) compounds used in the oxidation of a wide variety of organic and inorganic substrates in solution. Kinetic studies of interaction of Cr(VI) with the organic acids appear to be important and thus have been intensively investigated.…”