Dibromomethane → Potassium Bromide

Participants

Reaction Steps

Into a 500mL three-necked flask equipped with a dropping funnel, condenser, thermometer and mechanical stirrer were charged 50 grams of methylene-1,2-dioxybenzene (MDOB), 50 grams of methylene dibromide (Me2Br2) and 20 grams of 34% aqueous potassium bromide. With stirring, an aqueous potassium tribromide solution--formed from 165 grams of 34% aqueous KBr and 65 grams of elemental bromine--was added slowly over a two-hour period during which time the mildly exothermic reaction kept the reaction mixture at or slightly below 30° C. Samples were taken when 25%, 50%, 75% and 100% of the aqueous KBr3 solution had been added in order to determine the extent to which monobromination to methylene-1,2-dioxy-4-bromobenzene (BrMDOB) and dibromination to Br2MDOB had occurred. Another sample was taken after stirring the final reaction mixture for 30 minutes. Gas chromatographic analysis of these samples gave the following results (expressed in terms of percentages of the designated materials present):

Provenance & Evidence