Gerhard fs Organic Chemistry. 179 



same relations as amide. Oxamide itself, might be viewed as 

 containing this substance. The ammonia gives two equivalents 

 ol its hydrogen to combine with the oxygen of the organic sub- 

 stance. Thus C 2 H L , 2 +2 NH. In other cases the whole of the 

 hydrogen of the ammonia is eliminated in the form of water, and 

 N alone remains combined with the residue. Three equivalents of 

 bitter almond oil and two of ammonia form one of hydrohenza- 



mide with the solution of three of water, 3C 7 H 6 0+2NH. 

 C 21 H I8 N 3 +3H 9 0. As N s here replaces 3 , MM. Millon 

 and Bin sail have been induced to consider the equivalent of ni- 

 trogen as two-thirds of the number generally adopted. The ex- 

 planation of all these difficulties is found in the fact that accord- 

 ing to the nature of the organic substances, ammonia loses one, 

 two or three equivalents of its hydrogen and leaves NH 2 , NH 

 or N only in combination. 



The amides of the monobasic acids are derived from one equiv- 

 alent of the acid and one of ammonia by the elimination of H 2 O ; 

 thus benzoic acid, C 7 H n 2 and NH,* benzamide C 7 H 7 NO 

 +H 2 0. The amides of the bibasic acids are formed in the 

 same manner from one equivalent of acid and two of ammonia 

 by the elimination of two of water. When but one equivalent 

 of ammonia enters into the reaction, an acid amide is obtained 

 which may be regarded as analogous to the coupled acids already 

 described, (p. 176.) The acid oxalate of ammonia C 2 H 2 2 , 

 MI 3 affords oxamic acid C n EL N0, + H o O. These acids are 



- — - — • r » r f r 



Monobasic in accordance with the law before given; (2+0) 

 **■!• When they or their salts are placed in contact with acids 

 °r an excess of caustic potash, they resume the elements of water 

 and regenerate the acid and ammonia. The same change takes 

 place when the acids are long boiled with water. 



The amides of some of the bibasic acids are formed in decern- 

 ing the ammoniacal salts by heat, and the amides of the other 

 acids may be obtained by the action of ammonia upon their ethers, 

 a process which will be again noticed. .Some anhydrides like 

 succjiiide and isatine combine with ammonia with the evolution 

 of water and the formation of a new amide. That of succinide 



called succinidam : it is neutral and contains the elements of 

 one equivalent of ammonia and one of succinic acid minus 3H 2 ; 

 7 the action of alkalies it regenerates succinic acid and ammo* 

 n,a - The number of amides which may be derived from a sm- 

 - r| e substance is often very great.* The amide acids themselves 

 taajr form amides { asparagine is the amide of aspartic acid, and 

 J v hen boiled with an alkali takes up H , O and loses ammonia 

 tanning aspartic acid, which is itself an amide. By the aid of 



is 



Jo!i5°i a notice of the amides of phosphoric acid, the reader is referred to this 

 urnal , 11 Series, vol. Hi, No. 7, p. 105. 



