Ammonia → Monoguanidine phosphate

Participants

Reaction Conditions

Reaction Steps

Cyanoguanidine 336 parts (4.00 moles) is mixed with 603.2 parts (4.00 moles) of 65.0% phosphoric acid in a stainless steel beaker having a volume about four times that of the reaction mixture. The mixture is stirred with a spatula while maintaining the temperature at 25° C. The resulting smooth fluid slurry is heated in an oil bath from 25° to 90° C. in 0.35 hour when the slurry clears to a solution and boils vigorously. Within 2 minutes the boiling ceases and the liquid solidifies. To the solid carbamoylguanidine phosphate is added 1.9 parts (0.2%) of the polyoxyethylated propylene glycol block copolymer of molecular weight 1,045 identified in Example 1 as a viscosity reducer and foam controller. The heating is continued and at about 180° C. the solid begins to soften and at 190°-195° C. the cake begins to breakup with stirring. At about 200° C., the melt begins to foam (CO2 and NH3 evolution) and by 225° C. has become a uniform melt free of lumps with reduced foaming. The time required to heat from 90° to 225° C. is 1.3 hours. After 0.7 hour at 225° C. foaming has largely subsided. Heating at 225° C. is continued for an additional one hour. The beaker is then removed from the bath and cooled to room temperature. The product, a faint tan opaque glass has a pH of 6.5 (1% aqueous slurry), an amorphous solids content of 3.9% and a guanidine content of 47.9%. The conversion yield of cyanoguanidine to guanidine is 119.2% based on the stoichiometry, 1 cyanoguanidine→1 guanidine. The weight loss at 220° C. for 1 hour is 0.4%. The product is ground to a coarse powder in a Wiley Mill using a 6-mm screen.

Provenance & Evidence