Abstract: 

Surfactant-based aqueous reactions provide a sustainable alternative to performing organic reactions in organic solvents. However, the underlying mechanisms behind this success are not understood, and current analytical techniques cannot examine the reaction under synthetically relevant conditions. To bridge this technique gap, we herein report a series of fluorescence microscopy developments, particularly in fluorescence lifetime imaging microscopy (FLIM), to differentiate chemical microenvironments in complex, multiphasic reactions. Our work demonstrates that the changing microenvironments under reaction conditions can neither be modeled nor predicted based on studying the behavior of the individual components alone. These developments and findings demonstrate the capabilities of FLIM to analyze multiphasic reactions under reaction conditions and during ongoing reactions to better understand these surfactant-based reactions and move beyond a screening-based approach to broaden the use and applicability of replacing organic solvents in organic reactions.