(CAS NO.1) is crystd by soln in hot MeOH (0.8mL/g), diltd with Et₂O and allowed to stand. Alternate crystns are from acetone, benzene, chloroform, dioxane, methyl acetate or from benzeneethyl acetate mixture (3:1 and 1:1). It has also been recrystd from hot water after treating with HCl-washed activated charcoal (which had been repeatedly washed with water until free from chloride ions), then crystd again from hot 50% aq. EtOH and finally twice from hot 95% EtOH. Final drying is in a vacuum desiccator over P₂O₅.

Acetamide is also purified by distn or by sublimation in vucuo. Also purified by recrystn twice from cyclohexane containing 5% (v/v) of benzene. Needle-like crystals separated by filtn, washed with a small volume of distd H₂O and dried with a flow of dry N₂.