A UV–visible and conductometric studies on the analyses of valine and ninhydrin reaction in aqueous-surfactant solutions of dicationic geminis (n-s-n type)

Abstract

The influence of surfactants (represent the respective length of alkyl and tail chain referred to as gemini) was investigated on rate constant (kψ) of valine (Val) and ninhydrin. Also, the effect of other experimental parameters that includes reactant’s concentration (Val and ninhydrin), pH and temperature was performed and examined. Via UV–visible method, the absorbance of different solutions was recorded at fixed time intermissions and kψ was estimated by employing a computer-based procedure. The values ofkψ obtained at varied concentrations of gemini n-s-n (n = 16; s = 4–6) surfactants show an infrequent behavior (plotted askψvs. [gemini]). In the plot, kψ data rises gently at surfactant concentration far smaller related to cmc-value (Segment I) and formerly attains virtually unaffected behavior (Segment II, up to 400 × 10-5 mol dm−3). To end, we perceive a quick variation in kψ beyond 400 × 10-5 mol dm−3 (Segment III). Dicationic geminis improve the study, excellently, at [n-s-n] slighter than cmc over monomeric CTAB. However, quantitative treatment of such results achieved in dicationic gemini surfactant solutions was made by an appropriate model of micellar activity recognized as pseudo phase. Critical micelle concentration (cmc) of dicationic geminis (n-s-n type) with reactants has been determined at two different temperatures 303 K and 353 K using conductometric analysis. A reasonable reaction mechanism concerning the present study is provided. Additionally, some other reaction factors (binding and rate constants) were evaluated and discussed.