Bromochloromethane is prepared commercially from dichloromethane:
The latter route requires aluminium trichloride as a catalyst. The bromochloromethane is often used as a precursor to methylene bromide.1
Dagani, M. J.; Barda, H. J.; Benya, T. J.; Sanders, D. C. "Bromine Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a04_405. ISBN 978-3-527-30673-2. 978-3-527-30673-2 ↩