Application Note 2. Photoinitiated thiol-ene coupling in flow
Application Note 1. Synthesis of Cookson’s diketone via intramolecular [2+2] photocycloaddition
Benefits Arising from the Unique Properties of the HANU-reactor
The HANU-reactor is a continuous flow reactor, designed and engineered in order to fulfil specific unmet needs in the flow reactor market.
The process channel is 2 mm in depth and contains a number of static mixing elements. These obstacles induce a continuous split-and-recombine of the process stream to aid in mass and heat transfer. The main factor influencing hydrodynamics, however, is the use of a pulsatile flow. Its oscillating behavior in combination with the static mixing elements ensures high local fluid velocities while the average net flow rate may be very low. As such, plug-flow behavior is obtained at every flow rate.
The process stream can efficiently be irradiated through the large borosilicate or quartz window. In addition, the dramatically improved degree of turbulence in the process channel ensures fast film refreshment at the window. As a result, slow photochemical reactions that require long irradiation times can be run without recirculating, ensuring control over the residence time distribution.
2) Visual inspection of the process stream
Chemists like to look into the reaction medium. The ability to visually inspect the process stream is an invaluable asset that aids in monitoring or understanding a process. As such, the user may discern liquid-liquid flow regimes, identify color changes, detect precipitation, etc.
3) Non-invasive inline reaction monitoring
The application of through-window spectroscopic analyses makes the reactor particularly useful for process development or integration in cGMP processes. Consequently, at every point of the process channel the composition of the chemical matrix can be monitored. For instance, the point where 100% conversion is reached can be easily detected and the flow rate adapted to optimize reactor performance.
4) Scalable (photo)chemistry
The reactor may be scaled-up by simply widening the process channel. This does not affect the specific irradiated area and if all other process parameters are kept constant, a seamless scale-up is obtained based on the laboratory process.
5) Multi-phase chemistry
The reactor is capable of handling both homogeneous and heterogeneous process streams, including liquid-liquid and liquid-solid systems. Liquid-liquid reactions are efficiently mixed and solids (heterogeneous catalysts, formed crystals, precipitates, etc.) are dragged through the reaction channel without settling.
6) Multi-purpose reactor for cGMP production
The reactor may readily be disassembled which permits the user to thoroughly clean the wetted parts.