Green and Efficient: In Situ Oxidation Kinetics of Some Tailor-Made γ-Styrylpyridinium Dyes in Aqueous Medium Using the β-CD-CTAP Complex

Abstract

β-CD-CTAP (β-cyclodextrin-cetyltrimethylammonium permanganate) complex, a novel functionalized oxidant, has been used to investigate the oxidation kinetics of some water-soluble γ-styrylpyridinium dyes containing a trans-double bond. In absence of acid or base catalysis and in neutral medium, the in situ oxidation process successfully demonstrates the potential of β-CD-CTAP complex as a green oxidant, in contrast to earlier reports on permanganate reagents. β-CD lends a supramolecular catalysis during the reaction due to its noncovalent interaction with CTAP. Substituent effect, reaction coefficient, deuterium isotope effect, effect of β-CD concentration, and the values of thermodynamic parameters help in proposing suitable mechanisms for the oxidation process. Proportionate variation of the rate constant values with the concentration of CTAP demonstrates the absence of any reverse micellization phenomenon of the oxidant, in contrast to earlier findings.