Studies on Melamine. IV : The Reaction Mechanism of the Formation of Melamine from Dicyandiamide

(1) In the case of preparing melamine from dicyandiamide in presence of liquid ammonia under pressure, the formation of guanidine as an intermeiate product was proved by isolating it as its picrate. (2) In the above case, dicyandiamide was therefore dissociated into cyanamide, which was fixed as guanidine by coexisting ammonia. The formation of melamine was assumed to be due to the polymerization of the three moles of cyanamide produced through guanidine or to the combination of cyanamide and dicyandiamide. The author wishes to express his hearty thanks to Professor Kotaro Shimo for his kind guidance and also to offer his best thanks to Mr. Tadashi Yamaguchi for his help in the experiments.