Sulfuric Acid → 5H-Octafluoropentanoic acid

Participants

Reaction Steps

5.2 ml water, 19 ml MeCN, 0.34 g KBr, TEMPO (0.12 g), and 6 g of 2,2,3,3,4,4,5,5-octafluoro-pentan-1-ol were placed in a 100 mL glass flask equipped with a dropping funnel and stirrer. 45 mL of 15% (wt) aq. NaOCl buffered to pH 8-9 were added via the dropping funnel in 3 portions over two days while stirring at room temperature. Then concentrated sulphuric acid were added to render the reaction mixture acidic. (pH 1-2). The reaction mixture was extracted three times with diethyl ether and the combined organic phases were dried over magnesium sulphate. The solvent was evaporated to give a colorless liquid (8.98 g), which was distilled using a water pump (15 mmHg, 73° C.) to give 5.13 g of the acid. Yield: 80%. 1H NMR (CDCl3): 6.08 (tt, J=52 Hz, J=5.3 Hz, 1H); 8.6 (s, 1H); 19F NMR (CDCl3): −120.6 (t, J=9.2 Hz, 2F); −125.81 (m, 2F); −130.61 (m, 2F); −138.4 (dm, J=52 Hz, 2F).

Provenance & Evidence