The general procedure for synthesizing 2,2-difluoropropionic acid from ethyl 2,2-difluoropropionate was as follows: referring to Example G38, ethyl 2,2-difluoropropionate (1.2 g, 8.8 mmol) was dissolved in ethanol (26 mL), followed by the slow addition of 2N aqueous sodium hydroxide solution (26 mL). The reaction mixture was stirred at 0 °C, then gradually warmed to room temperature and continued stirring for 14 hours. Upon completion of the reaction, the reaction mixture was acidified to pH < 7 with 2N hydrochloric acid and then extracted with ether. The organic phases were combined, dried over anhydrous sodium sulfate and subsequently concentrated under reduced pressure to give 2,2-difluoropropionic acid (0.90 g, 92% yield). The product was an oil with the following 1H-NMR (CDCl3) data: δ 1.85 (3H, t, J = 19.0 Hz), 6.21 (1H, br s).
