Methanol → 4,4,4-Trifluorobutanoic acid

To 160 g of ethyl 4,4,4-trifluorobutyrate, a mixed solution of 123 g of potassium hydroxide, 900 ml of methanol and 80 ml of water was added under ice cooling and the mixture was further reacted at room temperature for 12 hours. After the reaction solution was concentrated under reduced pressure, the resulting residue was then partitioned between water and diethyl ether. The ether layer was extracted once with water and the water layer was combined with the aqueous layer which had already been partitioned. After adjusting the pH to about 1 by the addition of an aqueous 10% ice-cooled hydrochloric acid solution, the mixture was extracted three times with diethyl ether. The layers were combined and the combined ether layer was washed twice with saturated saline and dried over anhydrous magnesium sulfate. Then, the solvent was distilled off under reduced pressure to give 131 g of 4,4,4-trifluorobutyric acid (yield: 98%).