(1) Weigh 1.2188 g (0.0058 mol) of citric acid and 1.3932 g (0.0231 mol) of urea, dissolve in 60 ml of deionized water, and ultrasonicate for 10 min to ensure adequate mixing; (2) Transfer the mixed solution to a reaction vessel and place it in an oven preheated to 185 ℃, and maintain the reaction in hydrothermal conditions for 2 h; after completion of the reaction, cool naturally to After the reaction was completed, it was cooled naturally to room temperature to obtain a dark green solution; (3) the above solution was placed in a constant temperature water bath at 60 ℃, and 98% sulfuric acid was added dropwise slowly under magnetic stirring to adjust the pH of the solution to 2-3; at this time, a large number of yellow solids were precipitated, and the solution was centrifuged at 12,000 rpm for 10 minutes, the supernatant was discarded, and the precipitate was washed with deionized water for several times and drained; finally, the yellow precipitate was dried in the oven at 60 ℃, and citrazinic acid was obtained, with a yield of 85.18%. The yield was 85.18%.
