Abstract
In the current work, the effect of dicationic gemini (16-6-16, GS-6; 16-5-16, GS-5 and 16-4-16, GS-4) surfactants on reaction between ninhydrin (Nin) and arginine (Arg) was performed at 353 K by UV-Vis spectroscopic technique. Study is accelerated and catalyzed, greatly, by gemini surfactants even at [gemini] smaller compared to their cmc-values. The rate constant (k(psi)) values are more in the dicationic gemini micellar medium over aqueous system and show the order of their catalyzing capabilities at all concentration as: GS-4 > GS-5 > GS-6, while reaction order always obeys same in both systems (i.e., first-order in [Arg] and fractional-order in [Nin]). k(psi) values against different amounts of geminis are plotted and a typical feature of rate profile (k(psi) vs. [gemini]) is analyzed quantitatively by micellar pseudo-phase model. Also, effects of temperatures, Arg, Nin and pH have been investigated on the condensation reaction between Nin and Arg. These reaction ingredients have affected the reaction, meaningfully, and their valuable impacts on the reaction have been discussed and revealed in the text. Thermodynamic quantities evaluated are effective more in geminis over aqueous. Conductometric technique was utilized to get the critical micellar concentration (cmc) of dicationic gemini (GS-6, GS-5 and GS-4) surfactants and their varied system in the presence of reactants. In addition, binding parameters (K-T for Arg and K-N for Nin) with dicationic gemini micelles were determined.