Spectroscopic and Conductometric Analyses of Ninhydrin and Threonine Reaction in Double-Headed Geminis

In our work, spectroscopic and conductometric analyses of the ninhydrin (Nin) and threonine (Thr) reaction were investigated in the aqueous micellar system. To perform the study in the micellar system, double-headed geminis with different flexible methylene chain length were chosen as surfactants. Rate constants, k_ψ, were observed by varying different parameters, viz., [Nin], [Thr], pH, and temperature in geminis using UV–vis spectroscopy. The study obeyed unity- and fractional-order dependencies on [Thr] and [Nin]. To check the efficacies of geminis, kinetic runs were performed at several [geminis], that is, below and above the critical micellar concentration (cmc) of these surfactants. Surfactants at a concentration less than the cmc are capable of catalyzing the reaction over aqueous medium and follow the order 16-4-16 > 16-5-16 > 16-6-16. k_ψ values noted at varying concentrations of gemini surfactants, thus, were scrutinized by the pseudo-phase model of micelles. Experimental outcomes of the current study are used to evaluate various constants and parameters and discussed by proposing a reasonable reaction mechanism.