Sub-Millisecond Mixing in a T-Mixer in the Turbulent Flow Regime: Quantitative Chemiluminescence-Based Analysis

Microreactors have been widely used in recent years for the development of new organic reactions and precise material synthesis, leveraging rapid mixing for reaction control. Among these, T-shaped mixers are widely employed due to their simple and cost-effective configuration. However, quantitative insights into mixing behavior in practical condition with high Reynolds number regime (Re>500) are limited. This issue becomes especially important when scaling up laboratory-scale reactors, where the impact of increased mixer diameter on mixing performance must be evaluated. In this study, we used a T-mixer of an equivalent diameter of 500 µm and measured mixing times under high flow rate conditions up to total flow rate of 160 mL/min using the chemiluminescence reaction of luminol. By using a larger diameter mixer, we achieved extremely short mixing times of 0.3 ms while keeping pressure loss to about 500 kPa. This mixing time is sufficiently rapid for utilizing short-lived intermediates in organic synthesis reactions. Our discovery provides practical guidelines for quick utilization of intermediates and high-throughput processes in organic synthesis reactions.