Iron Powder (Aldrich, -325 mesh)
Acetic acid
Distilled water
Anhydrous acetone (Aldrich, subsequently degassed)

A mixture of acetic acid (90 ml) and water (90 ml) was added to a 250 ml Schlenk vessel and was deoxygenated by bubbling N₂ though the solution for 20 min. A 500 ml round bottomed flask with Schlenk-type side-arm was connected to a dual manifold vacuum line and charged with Iron powder (25 g) and a magnetic follower. The vessel was placed under an atmosphere of argon or dinitrogen via three pump/refill cycles. The acetic acid and water mixture was then slowly added to the Iron powder via cannula using Schlenk technique while allowing evolved H₂ gas to escape (a needle in the septum was used for this purpose). The reaction mixture was stirred at ambient temperature for a further 1 h. The reaction mixture was then heated and stirred at reflux (115 °C) for 8 h under N₂ before cooling to RT. The reaction mixture changed from clear with a grey solid to a dark grey/brown solution. An inert atmosphere frit containing celite filter aid was fitted with a 250 ml Schlenk collecting vessel containing a large magnetic follower. The reaction mixture was transferred to this frit via a wide bore cannula and the solution was filtered remove unreacted Iron powder. The resulting pale brown solution was evaporated under reduced pressure - with the assistance of a magnetic stirrer - using a liquid nitrogen-cooled pre-trap to give an off-white solid. This solid was further dried under vacuum for 24 h. The Schlenk vessel was then removed to a glove box where the solid was scraped from the sides of the vessel and ground up to a fine powder. Under Schlenk conditions, dry freshly degassed acetone (100 ml) was added to the solid via cannula and the solution was stirred vigorously. This was then transferred via wide bore cannula to a clean frit to isolate a grey white solid. This solid was washed on the frit three times with dry acetone (3 × 50 ml) until the filtrate was colourless. The white solid was then dried under vacuum for 24h and collected and stored under inert atmosphere. Yield: 43.8 g, 46.5%.

A similar method using slightly different Schlenk techniques is detailed here.