To a reflux apparatus add a mixture of 14.8 g of phthalic anhydride, 60.1 g of urea, 50 mg of ammonium molybdate and 6.6 g of nickel(II) sulfate hexahydrate and heat in 180-200°C for 5 h with stirring. Cool the solution down and boil the mixture with 200 mL of 10 % HCl for 2 h in a reflux apparatus. Filter the mixture and reflux the dark powder with 200 mL of 2 N sodium hydroxide for 2 h, filter and wash the mixture. Then reflux the powder again with the HCl and filter, wash with water and dry the powder.
The powdered mixture
Heating the mixture
The filtered and washed product