Bromination reactions using elemental bromine in micro reactors have not been reported so far. To get a broad overview about the potential of micro chemical processing in the case of bromination, three different reactions covering different syntheses tasks were investigated: the bromination of toluene with competing side-chain and core substitution, the bromination of thiophene with competition of single and multiple substitution and the high-temperature (up to 230 deg C) side-chain bromination of m-nitrotoluene. All reactions were performed thermally without adding catalyst, irradiation and using solvents. Different micro mixers and tube sections were used depending on the specific required reaction conditions. Micro reactor processing thereby addresses the following aspects: transformation of batch in continuous processing, avoidance of solvents, safe processing, increase of space-time yields, and influence of process conditions on selectivity and yield and fast experimentation.
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