Hydrochloric Acid → Hexafluoroacetone monohydrate

In a 100-ml three-necked flask was placed 6.52 g (14.8 mmol) of the 56.8% aqueous potassium 3,3,3-trifluoro-2-trifluoromethyl-2-hydroxypropionate solution prepared in Reference Example 1. To this mixture were added 1.7 g of 35% hydrochloric acid and 0.8 g of potassium hydrogencarbonate in this order, thereby adjusting the pH to 8. Subsequently, 24.0 g (32.3 mmol) of 10% aqueous sodium hypochlorite solution was added over one hour while heating the mixture at 40° C. in a water bath, followed by further stirring for 5 hours while maintaining the same temperature. The pH when the reaction was complete was 8. Hexafluoroacetone hydrate was obtained at a starting material conversion of 90% with a selectivity of at least 99%.