To a beaker immersed in an ice bath 90 mL of fuming 99% nitric acid is added and cooled down to 10°C. While maintaining the temperature below 10°C an addition of 19 g of hexamine is started with stirring. After the addition, the mixture should be heated and stirred at 50°C for 10 minutes, the solution is cooled down to 10°C and poured into 400 mL of ice. After the mixture has settled for a time it is filtered, washed with 50 mL of water, 50 mL of saturated sodium carbonate solution and 100 mL of water. The white powder is recrystallized from warm acetone and stored in a tight container.
The nitrating acid
Addition of the hexamine
Heating and stirring in a water bath
The poured to the ice, the ice melted