Water → 3,4,4-Trifluoro-3-butenoic acid

A mechanically stirred 12 L glass reactor clad with a jacket cooled with tap water was charged with 100 mL of acetone and 100 mL of Jones reagent. A solution of 3,4,4-trifluoro-3-buten-1-ol (850 g, 6.75 mol) diluted to a total volume of 5.0 L in acetone was added simultaneously with 5.0 L of Jones reagent via a twin head peristaltic pump capable of of a pump rate ca. 120 mL/min. A reaction temperature of 51°-54° C. was maintained by adjusting the pump rate and the tap water cooling flow. Following the addition (45 min), the mixture was allowed to cool to 35°-40° C. over 30-60 min. The reaction mixture was transferred to a separatory funnel and layers separated. The upper layer was washed once with brine and concentrated. The lower layer was diluted with water (500 mL) and extracted with dichloromethane (3 L). The dichloromethane extract was combined with the above residue, washed with brine and dried over magnesium sulfate. Evaporation of the solvent gave 613 g (65%) of the desired product as a green oil.