HIGHLY SELECTIVE BROMINATION OF TOLUENE IN A BROMINE OXIRANE ZEOLITE SYSTEM

The liquid-phase bromination of toluene in a zeolite-bromine-oxirane s ystem has been studied. This system increases selectivity toward the p ara-bromotoluene isomer due to two factors: first,the oxirane deactiva tes the sites located on the external surface of the zeolite and, seco nd, a bromine-oxirane complex is formed that is less active and bulkie r than is bromine. Using this method, 98% pure para-bromotoluene can b e obtained. The catalyst system is deactivated rapidly, presumably due to epoxide polymerization.