Eco-compatible zeolite-catalysed continuous halogenation of aromatics

A completely eco-compatible halogenation reaction of arenes has been developed allowing high conversions (>95%) of iodobenzene with nearly 100 kg iodobenzene converted per kg cat in one day. Several solid acids, zeolites being the most promising, have been successfully tested in the chlorination reaction of iodobenzene by using trichloroisocyanuric acid (TCCA), a green chlorination agent. H-*BEA zeolites were found to be the most active catalysts for this model halogenation reaction. A strong structureactivity relationship could be established by thorough characterisation (SEM, BET, XRD, FTIR) of various synthetic zeolites. Indeed, nano-sized *BEA zeolites and more specifically nanosponge-like *BEA crystals exhibited the highest catalytic performance with a conversion up to 100% and a selectivity toward monochlorinated products up to 98%. Finally, the gained knowledge was applied to set-up an eco-compatible continuous flow halogenation process of different aromatics catalysed by H-*BEA zeolites. Continuous iodobenzene chlorination reaction: experimental set-up and conversion acid site density dependence.