Purification of N,N-Dimethylformamide (DMF)
The middle fraction is collected, degassed (seven or eight freeze-thaw cycles) and redistd under as high a vacuum a possible. Rapid purification: Stir over CaH 2 (5% w/v) overnight, filter, then distil at 20mmHg. Store the distd DMF over 3A or 4A molecular sieves. For solid phase synthesis, the DMF used must be of high quality and free from amines.