Organophosphorus compounds. II. Interaction of dimethylphosphoramidic dichloride with hexamethylphosphoramide: Adduct formation and radical exchange

When an equimolar mixture of dimethylphosphoramidic dichloride and hexamethylphosphoramide is heated (120–200°), radical exchange (NMe2 for Cl) takes place and tetramethylphosphorodiamidic chloride is formed. This radical exchange follows a first‐order reaction at 120°. An equimolar mixture of the dichloride and the amide undergoes polymerisation at room temperature, and after 6–8 days solidifies to a crystalline mass. This mass appears to be a mixture of a salt‐like addition product of the dichloride and the amide approaching a hexameric state, and the unchanged dichloride and amide. On heating, it undergoes radical exchange with the formation of tetramethylphosphorodiamidic chloride which yields bisdimethylaminophosphonous anhydride (schradan) on treatment with potassium hydroxide in toluene1.