Hydrolysis Reactions of Two Benzoyl Chlorides as a Probe to Investigate Reverse Micelles Formed by the Ionic Liquid-Surfactant bmim-AOT

DIB, NAHIR; FALCONE, R. DARIO; GARCÍA-RÍO, LUIS

JOURNAL OF ORGANIC CHEMISTRY

AMER CHEMICAL SOC

Año: 2020 vol. 85 p. 15006 - 15014

0022-3263

In this work, two hydrolysis reactions were used as a probe to investigate the properties of reverse micelles (RMs) formed by the ionic liquid-surfactant 1-butyl-3-methylimidazolium 1,4-bis-2-ethylhexylsulfosuccinate (bmim-AOT). The results were compared with those found for RMs generated with sodium 1,4-bis-2-ethylhexylsulfosuccinate (Na-AOT). As external nonpolar solvents, n-heptane (n-Hp), isopropyl myristate (IPM), and methyl laurate (ML) were used. Thus, the effect of changing the Na+ cation by bmim+ was analyzed, as well as the impact of the replacement of a conventional external nonpolar solvent by biocompatible solvents. The kinetics of the hydrolysis reactions of 4-methoxybenzoyl chloride (OMe) and 4-(trifluoromethyl)benzoyl chloride (CF3) were studied. The results indicate that the replacement of the Na+ counterion by bmim+ in AOT RMs alters the rates of reactions carried out in them and produces changes in the reaction mechanism. In bmim-AOT RMs, the bmim+ cation is located between the surfactant molecules; this has an important influence on the reaction intermediates´ stability and, therefore, in the reaction rates and mechanisms. Also, the results indicate that when IPM is used as an external solvent instead of ML or n-Hp, interfacial water molecules have larger nucleophilicity due to the higher interface penetration of IPM.