Flow Methodology for Highly Reproducible Bromination Reactions

Uniqsis has announced an application note that describes a continuous flow methodology for electrophilic bromination that offers excellent control of both temperature and mixing using a proprietary mixer chip, leading to a highly reproducible outcome.

Electrophilic bromination is a useful reaction in organic synthesis. However, when molecular bromine is used as the electrophile, under acidic conditions, it can be difficult to control both the exothermic addition and to prevent subsequent bis-bromination of the desired monobrominated product.

In application note 21** - the authors demonstrate that using a static mixer chip on a FlowSyn flow chemistry system to control both mixing and temperature - bromination becomes a titration and the reaction can be performed rapidly under elevated temperatures. The bromination could be performed in a coil reactor however the short reaction time of 30 seconds at 70°C makes it better suited to implementation in a chip. The authors suggest how the chip based bromination methodology could be straightforwardly scaled to 28g / hour by connecting a 5 ml HT-PTFE coil reactor in line with the mixer chip and increasing the flow rate to 13.2 ml/min.


The Uniqsis FlowSyn™ is a compact integrated continuous flow reactor system designed for easy, safe and efficient operation. The FlowSyn™ range includes models for performing single or multiple homogeneous or heterogeneous reactions, either manually or automatically. The range of chemistries that can be explored with Uniqsis’ integrated and modular flow chemistry systems grows ever wider and is exemplified by the growing number of applications published both in the academic press and in Uniqsis’ own application notes. Typical examples of flow chemistry applications include hydrogenation, nitration, bromination, metalation, molecular rearrangements and synthesis of compounds suchas dihyropyridine, indole, pyrazole, quinolinone and benzimidazole.