Catanionic Reverse Micelles as an Optimal Microenvironment To Alter the Water Electron Donor Capacity in a S_N2 Reaction

Abstract

The effect of interfacial water entrapped in two types of catanionic reverse micelles (RMs) on the kinetic parameters of the S N 2 reaction between dimethyl-4-nitrophenylsulfonium trifluoromethanesulfonate (S +) and n-butylamine (BuNH 2) was explored. Two catanionic surfactants, composed of a mixture of oppositely charged ionic surfactants without their original counterions, were used to create the RMs. Thus, benzyl-n-hexadecyldimethylammonium 1,4-bis(2-ethylhexyl) sulfosuccinate (BHD-AOT) and cetyltrimethylammonium 1,4-bis(2-ethylhexyl) sulfosuccinate (CTA-AOT) were formed. Also, the wellknown anionic surfactant sodium 1,4-bis(2-ethylhexyl) sulfosuccinate (Na-AOT) was employed as a comparison. Our results showed an important catalytic-like effect of all RMs investigated in comparison with a water−benzene mixture, and the rate constant values depend on the type of surfactant used. Faster reaction in BHD-AOT RMs than in CTA-AOT and Na-AOT RMs was observed. This behavior was attributed to the strong interaction (by hydrogen bonding with AOT anion and ion-dipole interaction with BHD +) between the entrapped water and the BHD-AOT interface, which reduces the solvation capacity of water on S +. In CTA-AOT (and Na-AOT) RMs, the water−interface interaction is weaker and the electron pairs of water can solvate S + ions. In summary, the chemical structure of the counterion on the catanionic surfactant alters the interfacial region, allowing the progress of a reaction inside the RMs to be controlled.

Long-Chained Acidic Ionic Liquids-Catalyzed Cyclization of 2-Substituted Aminoaromatics with β-Diketones: A Metal-Free Strategy to Construct Benzoazoles

“…52,53 In addition, the long-chained ILs may exhibit surfactivity, lead to the formation of micelle, and affect the reaction. 54,55 In our continuing effort to develop acid-functionalized ILscatalyzed reactions, 48,51,53 a series of task-specific ILs derived from imidazole, pyrrolidine, and morpholine, especially with a long chain (Figure 2), were synthesized and applied to construct benzoazoles without any other additives (Scheme 1, path D). Interestingly, the functionalized ILs were much more efficient than simple TfOH, TsOH, and even traditional acidfunctionalized ILs without a long chain.…”

“…As a new class of materials, ionic liquids (ILs), which are composed of organic cations and inorganic/organic anions, are reported to possess unique features, such as high thermal and chemical stability, negligible vapor pressure, easy recyclability, and tunable properties. − Owing to the combination of the advantages of liquid and solid acids, acid-functionalized ILs offer a new direction to develop environmentally friendly acid catalysts and display superior performance in esterification, , alkylation, nitration, amination, and dehydration. , In addition, the long-chained ILs may exhibit surfactivity, lead to the formation of micelle, and affect the reaction. , …”

Biocompatible Solvents and Ionic Liquid-Based Surfactants as Sustainable Components to Formulate Environmentally Friendly Organized Systems

“…SAILs composed of the anionic 1,4-bis(2-ethylhexyl)sulfosuccinate surfactant have been prepared in the past. Two novel catanionic SAILs, benzyl-n-hexadecyldimethylammonium 1,4-bis(2-ethylhexyl)sulfosuccinate (BHD-AOT, Table 1 ) and cetyltrimethylammonium 1,4-bis(2-ethylhexyl)sulfosuccinate (C 16 TA-AOT, Table 1 ), were formulated [ 39 , 40 , 64 , 65 ]. Both have shown interesting properties as surfactants to create organized systems.…”

“…For example, BHD-AOT RMs offer less of an electron donor environment than CTA 16 -AOT. This result may have a tremendous impact and is very useful for their use as nanoreactors [ 39 ].…”

Influence of the AOT Counterion Chemical Structure on the Generation of Organized Systems

“…Organized systems are important and promising in the progress of various branches of modern science and technology. , For example, they are used as detergents in the industries of dyes, cosmetics, and pharmaceuticals . The existence of different microenvironments in these systems is one of the reasons for their applications in different areas, such as chemical catalysis, − enzymatic hydrolysis, − and nanoparticle synthesis, − among others . In this context, nanomedicine has become in recent years one of the most promising fields concerning the diverse applications of organized systems.…”