Boosting Lewis Acid Catalysis in Water‐in‐Oil Metallomicroemulsions

Abstract

A study on the effect of sodium bis(2‐ethylhexyl)sulfosuccinate‐based metallomicroemulsions on the Lewis acid‐catalyzed hydrolysis of the ester 2,4‐dinitrophenylpicolinate is reported. For a given amount of metal (Ni2+), the presence of these colloidal systems increases the catalytic efficiency of the Lewis acid approximately 1000 % over that found in bulk water. This finding is justified on the basis of the highly localized confinement of the catalyst at the aqueous interface of the microemulsion. In addition, the obtained results indicate that the encounter of the ester with the metal catalyst is significantly favored in the presence of this metallo‐functionalized microreactor. The mathematical model developed herein also allows an accurate determination and prediction of the influence of the metallomicroemulsion composition on the catalytic effect on the reaction rate. The results obtained lead to the development of similar reaction systems involving the application of metal Lewis acid catalysts such as carbon–carbon bond‐forming reactions.

Sulfonatocalixarene Counterion Exchange Binding Model in Action: Metal‐Ion Catalysis Through Host‐Guest Complexation

“…p-sulfonatocalixarenes and 2,4-dinitrophenyl picolinate were available from previous studies undertaken in our laboratory. [28,38,43] The kinetic experiments were triggered by injection of 30 μL of 5 mM stock solution of 1 in acetonitrile into a quartz cuvette containing 3 mL of an aqueous solution with all the remaining reactants. Hydrolysis reactions were followed by monitoring the UV/Vis absorbance of 1 at 405 nm at 25°C.…”

Enhancing the Exploitation of Functional Nanomaterials through Spatial Confinement: The Case of Inorganic Submicrometer Capsules

“…In light of these results, one may infer that a similar approach could be exploited when dealing with inorganic hollow nanostructures. Thus, silica nanocapsules could be engineered for the accumulation of catalysts, giving rise to high local concentrations as in the classical colloidal approach . In this way, cooperative effects aroused from the high degree of contact between the metal complexes could be addressed.…”