Exploring the role of mixed micelles and promoters for alcohol oxidation: A green catalytic approach and insights into micellar chemistry

Abstract

Oxidation of 1-butanol at 30 °C was carried out using chromic acid in an aqueous medium, employing pseudo 1st order reaction conditions. The resultant 1-butanal was isolated through fractional distillation. Surfactant micelles, acting as tiny templates or nano-reactors, play a vital role in generating nano-structured materials with desired attributes. These micelles have shown promise as effective catalysts, including mixed anionic-nonionic micelles like SDS-TX 100. In the pursuit of enhancing the rate of oxidation, micelle catalysts were tested in conjunction with various promoters. Astonishingly, these combinations displayed an impressive rate acceleration. To validate the products and interactions, comprehensive analyses were conducted using techniques such as IR, NMR, and UV. The formation of mixed micelles was also established through DLS analysis. Interestingly, among the catalytic paths, mixed micelles combined with 2, 2́-Bipyridine (Bpy) promoter exhibited the highest oxidation rate, overshadowing other combinations. Further insight was gained by observing the rate constants: kobs (SDS) > kobs (TX 100) and kobs (Phen) > kobs (Bpy) > kobs (PA) for promoted reactions in single micelle catalysis. For SDS micelles and mixed micelles, the order was kobs (Bpy) > kobs (Phen) > kobs (PA), whereas in TX 100 micelles, it was kobs (Phen) > kobs (Bpy) > kobs (PA).