To a beaker immersed in an ice bath 12.8 g of cold acetic acid and 13 mL of cold water are added, slow addition of thick paste made from 74 g of zinc dust, 26 g of nitroguanidine and about 40 mL of cold water is started with vigorous stirring. The temperature should be maintained below 15°C upon addition, the mixture may be cooled down by an addition of ice. The mixture is then stirred for additional 8h, after which the solution is stirred at 40°C for 5 minutes, then the mixture is immediately filtered and washed with 60 mL of hot water. To the filtered solution 20 g of ammonium chloride is added until it dissolves, with stirring 22 g of sodium bicarbonate is added and the solution is placed in a refrigerator to crystallize the product out. The mixture is filtered and washed with 50 mL of cold water and 25 mL of cold ethanol. The crude product is recrystallized with hot ethanol.
Addition of the paste and stirring for 8h
Filtration of the mixture and washing
The product crystallized out from the solution
The pure crystallized aminoguanidine bicarbonate