The Kinetics of the Hydrolysis of Urea and of Arginine

Fawsitt (1) and Werner (2) have studied the hydrolysis of urea by acids and by alkalies. They agreed in assuming that cyanate was an intermediate in the hydrolysis, but differed widely as to the details of the mechanism and as to experimental values for the velocity constants of the reactions involved.1 The reverse reaction, the synthesis of urea from ammonia and cyanate, has been investigated in some detail by Walker and his coworkers (3) and more recently by Warner and Stitt (4) and by Svirbely and Warner (5). The latter workers have concluded, on the basis of the effect of ionic strength on the velocity, that the reaction is one between ammonium and cyanate ions. Because of the unsatisfactory nature of the data on the kinetics of the hydrolysis of urea, we have reinvestigated the rates and mechanism of the reactions involved. We were chiefly interested in the hydrolysis by alkali, but the work was extended to include neutral and acid pH ranges.