Hydrogen Bromide → alpha-Hydroxyacetophenone

Participants

Reaction Conditions

Reaction Steps

About 13 parts of bromine was added with stirring to a mixture of 474.6 parts of acetophenone in about 640 parts of methanol, while the mixture was stirred and maintained at a temperature between 5°-10° C. Hydrogen bromide gas was then introduced into the mixture until bromine coloration disappeared, at which point an additional amount of bromine was added over a 2 hour period to make a total of 631.3 parts. There was then added 71 parts of water while the mixture was stirred and externally cooled for a period of about 30 minutes. An excess of about 2700 parts of water was then slowly added to effect the precipitation in the form of crystals of α-bromo acetophenone from the mixture. The crystals were decanted by means of a vacuum siphon, washed, then neutralized with a 20% sodium hydroxide solution and decanted to dryness. There was then added about 940 parts water, 1600 parts of methanol, 333 parts of sodium bicarbonate and a sodium formate solution prepared from 161 parts of 90% formic acid and sufficient sodium hydroxide to neutralize the acid. The mixture was heated at 60° C. with vigorous stirring for 7 hours after which time it was cooled to ambient temperature and filtered. Based on method of preparation and gas chromatographic analysis of the mixture there was produced α-hydroxy acetophenone in quantitative yields.

Provenance & Evidence