Hydrochloric Acid → 4-Hydroxy-4'-chlorobenzophenone

Participants

Reaction Conditions

Reaction Steps

510 g of aluminium chloride (3.82 M), then 3.5 l of dry methylene chloride, and, slowly, 430 g (4 M) of anisole are added to a 5-liter flask; the flask is cooled to maintain the temperature at about 25° C, and 600 g (3.44 M) of 4-chlorobenzoyl chloride is then added dropwise; the reaction mixture is next heated 6 hours under reflux, is left to cool to about 25° C, and the reaction mixture is poured onto 5 kg of ice and 0.5 l of concentrated HCl; the mixture is stirred well during this hydrolysis; the methylene chloride phase is decanted, washed once with water, and transferred to another 5-liter vessel. The methylene chloride is removed by evaporation and replaced in the flask by 2 l of chlorobenzene; a Dean-Stark apparatus is connected and the reaction mixture is refluxed to dehydrate the medium; when this operation is complete the mixture is cooled to approximately 50° C and 800 g (6 M) of aluminium chloride is added; the reaction mixture is heated 1 hour 30 minutes under reflux (very gentle reflux), and demethylation proceeds rapidly; the reaction mixture is cooled and poured onto 6 kg of ice and 0.5 l of concentrated HCl; the mixture is stirred for 1 hour 30 minutes and the precipitate is dried; the latter is washed with water, with methylene chloride, and then dried:

Provenance & Evidence