Kinetic study of the metal-dipeptide complex with ninhydrin facilitated by gemini (m-s-m) surfactant micelles

Abstract

the three Gemini (m-s-m; m (head group) = 16 and s (spacer) = 4, 5, 6) surfactants have been synthesized and their impact on reaction of zinc(ii)-glycylleucine complex ([Zn(ii)-Gly-Leu] +) and ninhydrin were studied at temperature (343 K) and pH (5.0) using spectroscopic method. Influence of several factors, viz., [Zn(II)-Gly-Leu] + , [ninhydrin], temperature and pH were also carried out on title reaction in geminis. Rates of reaction are the first-order path in concentration of [Zn(II)-Gly-Leu] + complex and fractional order path in concentration of ninhydrin. The catalysis of gemini 16-s-16 surfactant micelles was investigated below and above their critical micelle concentration (cmc) value and detailed elaboration were provided in the text. In the present case, rate constants, k ψ , increased on increasing geminis ([gemini] are below their cmc, region I) and stayed nearly constant (region II). The shape of (region I and II) surfactants ([gemini] = 0 to 400 × 10 −5 mol dm −3) are similar to a cetyltrimethylammonium bromide, CTAB (single hydrophilic head group and hydrophobic part). Later, a sharp increment in rate was observed with higher [gemini] (region III, (Fig. 5). The study was catalyzed and accelerated quite enough by geminis (at concentrations below their cmc) compared to aqueous. An appropriate mechanism has been proposed for accounting for the distribution of reactants between aqueous and micellar pseudo phases. Resulting kinetic data were used to determine the binding constants of micelle-substrate (K B) and micelle-ninhydrin (K nin).

Mixed micellization study of dodecyltrimethylammonium chloride and cetyltrimethylammonium bromide mixture in aqueous/urea medium at different temperatures: Theoretical and experimental view

“…The observed cmc and ideal values of cmc, cmc id for pure surfactants (DTAC & CTAB) and their mixed systems are viewed in Tables 1-3. In aqueous solution, the value of cmc of individual CTAB was found to be 0.91 mmol·kg −1 at 298.15 K viewing a fine agreement with formerly accounted value, [8,25] and the cmc of value of individual DTAC was achieved 3.54 mmol·kg −1 at 298.15 K is also found to be sound conformity with the earlier reported value. [27] It is also a recognized reality that the longer the hydrophobic portion of the surfactant, the lesser is their cmc value.…”

“…The values of excess free energy of micellization (ΔG ex ) expound the nonideality of the mixed micellization between the studied amphiphiles. [28,[60][61][62][63][64][65][66][67]…”

“…In the different applied field, the mixture of surfactants is used instead of single surfactant because of the better electrical and micellar properties of the mixed micelle as compared with the micelle of single surfactant. [8][9][10] It is renowned that industrial surfactant systems are a mixture of dissimilar chemical varieties, for example, another surfactant or an amphiphile, electrolytes, dyes, or fillers.…”

Micellization behavior of cationic and anionic surfactant mixtures at different temperatures: Effect of sodium carbonate and sodium phosphate salts

“…Again, by the combination of different types of surfactants, the mixed micellization was also reported in the literature. [9,10] Actually, mixed micelles have a stable electric structure as compared with individual micelle and thus show better micellar properties. [11,12] Though there is a possibility to precipitate when cationic and anionic surfactants are mixed together in equimolecular ratio due coulombic attraction between two oppositely charged particles, the mixed micelle is formed when one of the surfactants is taken in excess.…”

Investigation of mixed micellization study of sodium dodecyl sulfate and tetradecyltrimethylammonium bromide mixtures at different compositions: Effect of electrolytes and temperatures

“…In the applied fields, surfactant mixtures are more applicable as compared with the individual ones. Mixed micelles have better micellar properties and electrical stability [10][11][12] which is the outcome of the synergistic interaction amongst the surfactants. [13,14] In our body, there are some hydrophobic lipid molecules which are water-insoluble that must be absorbed in aqueous medium that can be performed by means of aggregation formation with water-soluble lipid molecules illustrating the importance of mixed micellization.…”