Hydrazodicarbonamide prepn. from urea and hydrazine - or hydrazine hydrate in aq. medium with heating using excess water

摘要

Hydrazodicarbonamide (I) is prepd. by reacting urea with hydrazine (hydrate) in an aq. medium at 105-140 degrees C under 1.2-3.5 bar pressure. (I) is an intermediate in prepn. of azodicarbonamide, used as a blowing agent in prodn. of rubber foams and expanded plastics. The conversion is quantitative, mother liquor is free from by-prods. and can be rejected without causing pollution or it can be recycled, the reaction mixt. can be used directly as starting material for oxidn. of (I) to azodicarbonamide.