Effect of Quaternary Ammonium Gemini Surfactant Solution on the Rate Constant of the Ninhydrin–Lysine Reaction
Dileep Kumar, Javed Masood Khan, Mihalj Poša, Ajmal Koya Pulikkal, Bidyut Saha, Ajaya Bhattarai
Abstract
The effect of solutions of double-chained quaternary ammonium gemini surfactants (16- s -16, s = 4–6) was characterized on the rate constant of the ninhydrin (nin) and lysine (Lys) reaction using a ultraviolet–visible (UV–vis) spectrophotometer. Rate constant ( k ψ ) values were obtained at different geminis. However, k ψ values obtained at several geminis were displayed in the form of the k ψ –[gemini] rate profile, and the quantitative estimation of these results was elucidated employing a model of micellar catalysis referred to as pseudophase. The role of other experimental ingredients such as nin, Lys, pH, and temperature ( T ) was examined in geminis, and k ψ values as a function of these parameters were determined. Data treatment confirms a fractional order in [nin] and a unity order in [Lys]. Using conductometric evaluation, the critical micellar concentration (cmc) of pure double-chained gemini surfactants (16–6–16, 16–5–16, and 16–4–16) and presence of nin and Lys were recorded. Results of the present experimental value were used to determine micellar binding constants ( K A for Lys and K B for nin). The binding constants and second-order rate ( k m ) affect the solvent properties at the micellar surface and hence are taken into consideration and discussed.