Abstract
For the purpose of exploring the mechanism for the formation of guanylmelamines from dicyandiamide in the presence of acid catalyst, the following three reactions were carried out ; reaction of dicyandiamide at 40°C, reaction of phenyldicyandiamide, and reaction of phenyldicyandiamide-cyanamide mixture.
It was observed that guanylmelamines were formed from dicyandiamide at 40°C, and that diguanylmelamine was obtained in higher yield than monoguanylmelamine, in contrast to our previous experiments carried out at 70-100°C.
Phenyldicyandiamide gave two types of phenylguanyltriazines ; they were 2-amino-4-anilino-6- (ω-phenylguanidino) -1, 3, 5-triazine and 1-phenyl-2-amino-4-imino-6- (ω-phenylguanidino) -dihydro-1, 3, 5-triazine.
On the other hand, phenyldicyandiamide-cyanamide mixture reacted to form 2-amino-4- (α-phenylguanidino) -6- (ω-phenylguanidino) -1, 3, 5-triazine. These results showed that the formation of guanylmelamines from dicyandiamide is consistent with the following four reactions ; formation of dicyandiamide linear dimer, cyclization of the linear dimer, degradation of dicyandiamide to cyanamide, stepwise addition of cyanamide to the linear dimer and cyclization of the linear intermediates.
