General procedure for the synthesis of 4,4,4-trifluorobutyric acid from ethyl 4,4,4-trifluorobutyrate: a mixture of 123 g of potassium hydroxide, 900 mL of methanol, and 80 mL of water was slowly added to 160 g of ethyl 4,4,4-trifluorobutyrate under the cooling of an ice-water bath and stirring was maintained. The reaction mixture was continued to be stirred for 12 hours at room temperature. After completion of the reaction, the reaction solution was concentrated under reduced pressure to give a residue. The residue was partitioned between water and ether. The ether layer was separated and washed once with water; the aqueous layer was combined with the previously separated aqueous layer. To the combined aqueous layer, ice-cold 10% hydrochloric acid solution was added and the pH adjusted to 1. Subsequently, the acidic aqueous solution was extracted three times with ether. All ether layer extracts were combined, washed twice with brine and dried with anhydrous magnesium sulfate. After filtration, the filtrate was evaporated under reduced pressure to give 131 g of 4,4,4-trifluorobutyric acid in 98% yield.1H-NMR (CDCl3, internal standard TMS) δ values (ppm): 2.52 (m, 2H), 2.67 (t, 2H).
