Cationic Mixed Micelles as Reaction Medium for Hydrolysis Reactions

Abstract

The influence of cationic mixed micelles composed of quartenary ammonium surfactants on hydrolysis reactions has been studied in detail. The basic hydrolysis of Nmethyl-N-nitroso-p-toluene sulphonamide has been chosen as the reaction probe, while mixed micelles composed of lauryl trimethyl ammonium chloride and octadecyl trimethyl ammonium chloride with different molar ratios were studied as the reaction medium. The ion-exchange pseudophase model was used to fit the experimental results to obtain the kinetic and thermodynamic parameters of the reaction. The result show that the hydrophobic character of the mixed micelles drives the association of the substrate to them, leading to a local increase of reactant concentrations at the micellar interface and, therefore, to a catalytic effect. By tuning the molar ratio of the mixed micelles it is possible to control substrate binding affinity and thus the catalytic efficiency of the reaction medium.

Alkyl(C16, C18, C22)trimethylammonium-Based Herbicidal Ionic Liquids

“…37 Nevertheless, due to their unique, m u l t i f u n c t i o n a l p r o p e r t i e s , a l k y l ( C 1 6 , C 1 8 , C 2 2 )trimethylammonium halides have also been successfully applied as intercalating agents for layered silicates and their nanocomposites, 39−42 drag reducing agents for anionic polymer solutions, 43 emulsion viscosity stabilizers, 44 and basic hydrolysis catalysts via cationic mixed micelles. 45 This study describes a convenient synthesis methodology of biologically active ILs possessing a long-alkyl-chain quaternary ammonium cation. Furthermore, HILs comprising an alkyl substituent longer than C 18 in the cationa behenyl group (C 22 alkyl)were presented for the first time and their properties were compared with their homologuesalkyltrimethylammonium HILs with a shorter carbon chain (C 16 and C 18 alkyl).…”

Kinetics of alkaline fading of methyl violet in micellar solutions of surfactants: Comparing Piszkiewicz's, Berezin's, and pseudophase ion‐exchange models

“…The next step of using the PIE model is the estimation of ion‐exchange constant between counterion of surfactant and reactive ion. One of the methods for determination of the ion‐exchange constants is based on the study of the rate effect of inert salts, containing the same anion as in the cationic surfactant used . In our experiments, the reaction rate constants have also been determined at a constant CTAOH concentration (0.01 M) and variable NaBr concentrations within the range of 0–0.4 M. The results show that the rate constant decreases exponentially with the increasing in NaBr concentration (Figure ) in solution.…”

Aggregation and reactivity in aqueous solutions of cationic surfactants and aromatic anions across concentration scales

“…This challenge has been addressed by several groups, typically using reactions involving very low concentrations (~ 10 μM) of often neutral reactive chemical probes in combination with higher surfactant concentrations (~ 1-10 mM). For examples, see References [3,[16][17][18][19][20][21][22][23]. The combined efforts of multiple groups have now resulted in a good understanding of typical micellar binding sites and what these sites look like in terms of reaction medium for a wide range of surfactant systems.…”