Nanoscale stirring at the liquid–liquid interface: the interfacial nano-vortexer actively converges immiscible biphasic reactants for enhanced phase-transfer catalysis

Abstract

Liquid–liquid biphasic reactions hold great promise for green molecular synthesis by leveraging mild chemicals and reaction conditions that are otherwise challenging in traditional single-phase chemistry. However, current interfacial reaction designs suffer from limited practicality due to the unsustainable use of high catalyst/reactant loadings and halogenated solvents to promote chemical reactions. Herein, we achieve efficient interfacial phase-transfer catalysis using green organic solvent by strategically positioning magnetically active nano-vortexers at the liquid–liquid boundary to effectively manipulate biphasic chemical species at the point-of-reaction. Using the interfacial nitration of phenol as a model reaction, the dynamic spinning of these interfacial nano-vortexers attains an optimal nitrophenol yield of ∼90% in just 2 hours. This superior performance represents up to a 200-fold enhancement in phase-transfer catalysis compared to control experiments involving a non-dynamic liquid–liquid interface or traditional homogenization methods. Comprehensive investigations underscore the importance of our design to actively converge and enrich reaction/catalyst species directly at the liquid–liquid interface, thus kinetically boosting phase-transfer catalysis even with the use of dilute concentrations of catalysts and/or chemical reagents. Our unique mass manipulation approach offers valuable insight into achieving efficient interfacial reaction/catalysis to create enormous opportunities in realizing greener chemistries for diverse chemical, environmental, and energy applications.