996-70-3

light yellow-green liquid with an unpleasant

Impurities include tetramethylurea, dimethylamine, tetramethylethanediamine and tetramethyloxamide. It is washed with water while being flushed with nitrogen to remove dimethylamine, dried over molecular sieves, then passed through a silica gel column (previously activated at 400o) under nitrogen. De-gas it in a vacuum line by distillation from a trap at 50o to one at -70o. Finally, it is stirred over sodium-potassium alloy for several days. [Holroyd et al. J Phys Chem 89 4244 1985, Wiberg Angew Chem Int Ed Engl 7 766 1968, Beilstein 4 IV 167.]