Hydrochloric Acid → 3-Phenoxybenzoyl chloride

Participants

Reaction Steps

In a well ventilated hood, a mixture of m-phenoxy benzoic acid (200 g, 0.933 mole) (Aldrich) and thionyl chloride (105 mL, 1.44 moles) was placed in a one liter, round-bottomed flask. The flask was fitted with a magnetic stirring bar (or mechanical stirring bar for larger quantity preparation) and a reflux condenser with calcium chloride drying tube, which was attached to an exit tube, for evolved hydrogen chloride and sulfur dioxide, leading to a gas absorption trap. The mixture was heated on a heating mantle cautiously at first until a brownish-green solution was obtained (about 11/2 hours). The resulting solution was then heated gently for an additional 11/2 hours. The resulting brown solution was then cooled, and excessive thionyl chloride was distilled off at 40° C. To the resulting oil was added toluene (75 mL), and the solution was evaporated to remove a small amount of thionyl chloride. Addition and evaporation of toluene (75 mL) was repeated once more. The resulting acid chloride was then dissolved in 100 mL of tetrahydrofuran (THF dried over molecular sieves 3A), and ready to use freshly for reaction.

Provenance & Evidence