Reaction Cycling for Kinetic Analysis in Flow

A reactor capable of efficiently collecting kinetic data in flow is presented. Conversion over time data is obtained by cycling a discrete reaction slug back and forth between two residence coils, with analysis performed each time the solution is passed between the two. In contrast to a traditional steady-state continuous flow system, which requires upward of 5x the total reaction time to obtain reaction progress data, this design achieves much higher efficiency by collecting all data during a single reaction. In combination with minimal material consumption (reactions performed in 300 mu L slugs), this represents an improvement in efficiency for typical kinetic experimentation in batch as well. Application to kinetic analysis of a wide variety of transformations (acylation, SNAr, silylation, solvolysis, Pd catalyzed C-S cross-coupling and cycloadditions) is demonstrated, highlighting both the versatility of the reactor and the benefits of performing kinetic analysis as a routine part of reaction optimization/development. Extension to the monitoring of multiple reactions simultaneously is also realized by operating the reactor with multiple reaction slugs at the same time.