underground - 25-11-2018 at 11:34
Searching on SM about DPT i found this.
synthesis of DPT：
Configured with 50 ml of concentrated nitric acid (98%) + 20 ml of concentrated sulfuric acid mixture solution was cooled to 0 ° C, and added slowly
with stirring 25 g of sulfamic acid, and to keep the temperature below 5 ° C. Added portionwise methenamine dinitrate 27g after 20min was added under
stirring during the temperature not higher than 15 ° C, maintained at 5-10 ° C for 40 min, after which the reaction mixture was slowly heated to 30
° C. The heating was stopped after the temperature will continue to rise slowly.When the temperature reached 40 ° C, the water bath was cooled to 35
℃, this process is repeated several times, the temperature no longer rises after the 30 ° C incubation 1h, during the reaction solution becomes
viscous, after sufficiently cooled to 0 to 5 ° C, poured into 250mla pre-frozen 10% aqueous ammonium nitrate solution, and then slowly added NaHCO3
was adjusted to pH 6, and filtered to give the product DPT, water washed. The yield is said to more than 90%.
Has anyone ever tried it ? The synthesis looks easy to do and i believe that a nitrate salt/h2so4 mix can be used instead of concentrated HNO3 .