Hydrochloric Acid → Carbonic acid, compound with phenylguanidine (1:1)

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Reaction Conditions

Reaction Steps

To 98.2 g aniline (1.0 mol) is added 32% HCl until the pH of the solution reaches approximately 2.5; 95.2 g (0.83 mol) 32% HCl are required. The solution is heated to 87° C. and stirred while 93.0 g of a 50% aqueous solution of cyanamide (1.10 mol) are added over a period of 1 hour. Shortly before completion of the cyanamide addition, another 16.8 g (0.15 mol) 32% HCl are added. After 3 hours stirring at 87° C. the solution is cooled to 60° C. and added to a stirred suspension of 101.0 g (1.20 mol) sodium hydrogencarbonate in 170 ml water at 60° C. After cooling to 5° C., 127.6 g phenylguanidine hydrogencarbonate (dried at 45° C./100 mbar) are isolated (66.8% free base), representing a yield of 94.5% based on aniline. The melting point (decomposition) is 150° to 152° C.

Provenance & Evidence