MANUFACTURE OF HYDRAZINE SULFATE FROM UREA

Hydrazine sulfate is prepared by treating urea with sodium hypochlorite and sodium hydroxida solution in the presence of gum or gelatin, followed by neutralization with sulfuric acid. 160g sodium hydroxide is dissolved in 900 ml of water, 800g ice is then added. Chlorine gas is passed into the solution under a temperature of 0—5℃, until the pH value of the solution is 9—10. A suitable sodium hypochlorite solution is obtained (solution A). 6g gum is dissolved in 60 ml of hot water in an evaporating dish, to which 120g urea and 400 ml sodium hydroxide solution (containing 160 g NaOH)are dissolved. After cooling to 0℃, solution A is poured in with agitation. This mixture is heated as rapidly as possible to 60—80℃ and cooled down to 5—10℃, neutralized with 400 g of H₂SO₄ (50% w/w). Coolad to 0℃, to remove sodium sulfate by filtration. To the filtrate 400g of H₂SO₄ (50% w/w) is added again as before, the hydrazine sulfate is then crystallized out, and is collected by filtration. The crude product is purified by recrystallization from boiling water (decolorlized with charcoal). Yield of chemically pure hydrazine sulfate 164—180g, melting point 254℃ with decomposition.