Sodium Hydroxide → 2-Chloro-5-(trifluoromethyl)benzoic acid

Participants

Reaction Steps

A solution of 570 g (2.77 moles) of 2-chloro-5-trifluoromethylbenzonitrile (1) and 1140 g (28.5 moles) NaOH in 2.3 L water was heated at reflux in a 12 L flask overnight. TLC (silica gel, 20% ethyl acetate-hexane with 1 drop acetic acid/10 ml solution) showed reaction was complete. The solution was cooled, diluted with 3.5 L ice water and extracted with 1 liter ether. The aqueous extract was cooled in an ice bath, acidified to pH 2 with cold 50% H2SO4 and extracted with four 1.3 liter portions of ether. The ether extracts were dried over Na2SO4 and evaporated and the residue was triturated with 1.2 liters hot hexane, cooled, and filtered to afford 615 g (9%) of 2-chloro-5-trifluoromethylbenzoic acid as white needles, m.p. 93°-94° C.

Provenance & Evidence