Development of a Robust and Reusable Microreactor Employing Laser Based Mid-IR Chemical Imaging for the Automated Quantification of Reaction Kinetics

A robust, reusable microreactor coupled with laser based mid-IR chemical imaging and automated analysis is reported, for the first time, with its application to monitor and quantify fast organometallic chemistry in flow. We have investigated the subsecond organometallic addition reaction between lithium diisopropylamide and phenyl isocyanate in order to define and tune microfluidic system parameters such as residence time using physical system constraints (flow rate, reactor volume) to aid process development. The selectivity of mid-IR video rate capture of the flow response of reactants and product enabled the qualitative assessment of mixing properties. Furthermore, we report a minimally supervised automated image analysis toolbox that generates concentration as a function of residence time enabling the calculation of reaction rate constant, k, using hyperspectral data cubes. Finally, we report the reproducibility of quantification precision by measuring the rate constant, at three different flow rates with three replicates for each flow rate. These findings show the potential value of the microreactor particularly when coupled with automated mid-IR transmission analysis for the study of flow chemistry at the micron scale, assisting in the understanding of the reaction kinetics and mixing properties and enhancing the value of the chemical imaging based, automated quantification of microfluidics.