Structure of Simpler Organic Compounds. 103 



instead of the original cyanate, an isomeride separated. 

 This reaction affords also a classical example of the 

 phenomenon of isomerism. Ammonium cyanate is obtained 

 by the double decomposition of ammonium sulphate and 

 potassium cyanate. Potassium cyanate can be obtained 

 by the oxidation of potassium cyanide with lead oxide 



It is of interest to note that all these substances were 

 regarded as of inorganic nature, and for this reason the 

 synthesis of urea, a typical animal product, by the above 

 method aroused at the time of its discovery considerable 

 interest in the scientific world. 



The change from ammonium cyanate to urea may be 

 represented by the equation 



NH 2 

 NH^OC'N OC 



In ammonium cyanate only one nitrogen is directly united 

 to a carbon atom, whereas in urea two nitrogen atoms are 

 so united. The urea is generally synthesized by mixing 

 solutions of potassium cyanate with ammonium sulphate, 

 and evaporating the mixture to dryness. The intermediate 

 product, ammonium cyanate, is not isolated, but the urea 

 is extracted directly from the dried mass by alcohol. 

 Now the constitution of urea is known from various facts. 

 Acid chlorides and esters on treatment with ammonia give 



C, as stated above, to acid amides. Urea can be prepared 

 n similar derivatives of carbonic acid. If this latter 

 acid be represented by the formula 



OH 



it should form an ester and acid chloride (by the substitu- 

 ion of two hydroxyl groups) of the formulae 



