Dibromomethane

At ambient temperature, dibromomethane solidifies around 0.61 GPa. The crystal structure strongly suggests both interhalogen and hydrogen-halogen interactions. Dibromomethane is prepared commercially from dichloromethane via bromochloromethane: The latter route requires aluminium trichloride as a catalyst. The bromochloromethane product from either reaction can further react in a similar manner: In the laboratory, it is prepared from bromoform using sodium arsenite and sodium hydroxide: Another way is to prepare it from diiodomethane and bromine. Dibromomethane is used as a solvent, gauge fluid, and in organic synthesis (often as H-NMR internal standard). It conviently converts polyols (such as catechols) to their methylenedioxy derivatives, and bromomethylenates enolates. It is a much cheaper precursor to a Simmons-Smith-type reagent than diiodomethane.