Methods of Preparation of Urea Preparation and Properties
→ Wohler Method : Reaction of ammonium sulphate and potassium cyanate gives ammonium cyanate which on rearrangement gives urea.
→ Laboratory Method : In laboratory liquid ammonia react with carbonyl chloride or ethyl carbonate or ethyl urethane and give urea.
→ Industrial Method : Carbon dioxide and liquid ammonia react to form ammonium carbamate which decomposes at high pressure and high temperature to give urea.
→ From Cyanamide : At high temperature, calcium carbide reacts with nitrogen to form calcium cyanamide which on neutralisation with H2SO4 gives cyanamide which on hydrolysis gives urea.