Isopropanol → Formaldehyde

Participants

Reaction Steps

The catalyst is removed using tris-(hydroxymethyl)phosphine (“THMP”) which is prepared by adding 245 g of tetrakis-(hydroxymethyl)phosphonium chloride (1.03 mol, Strem) and 500 mL of isopropyl alcohol (IPA) to a 2 L round-bottomed flask, degassing the mixture with nitrogen for 20 minutes, slowly adding 64 g (1.03 mol, 90% purity, Aldrich) of potassium hydroxide over 30 minutes to the vigorously stirring solution, while under a nitrogen atmosphere, and, after the potassium hydroxide has been added, stirring the reaction for an additional 30 minutes. This reaction is exothermic, and produces THMP, formaldehyde, potassium chloride, and water. The catalyst is then removed using the THMP by adding 25-100 mol equivalents of THMP per mole of ruthenium catalyst, stirring vigorously at 60-70° C. for 18 to 24 hours, under nitrogen, adding degassed water or methanol (˜150 mL/L of reaction mixture) and vigorously stirring for 10 minutes, and centrifuging the mixture for phase separation. The oil may have to be heated to remove the residual water or methanol. The aqueous phase will contain small amounts of IPA, formaldehyde, and potassium chloride, and will need to be purged or cleaned for recycling.

Provenance & Evidence