92 BUTYRIC ACIDS. 



Hard, fascicular needles, soluble in 5 parts cold water, 

 more easily in hot water and alcohol. When carefully 

 heated it sublimes ; when rapidly heated it decomposes, 

 yielding ethylamine and carbonic anhydride. It com 

 bines, like glycocol, with bases, acids, and salts. 



/3-Amidopropionic acid, CH 2 (OTI 2 )CH 2 .CO.OH. Is 



obtained, like afanin, from 0-iodopropionic acid. Color 

 less, transparent, oblique rhombic prisms. Easily solu 

 ble in water, but slightly in absolute alcohol. When 

 heated it fuses and decomposes, carbon being deposited. 

 When very carefully heated to 170 it sublimes par 

 tially in needles. 



The remaining derivatives of propionic acid are pre 

 pared in the same manner as the corresponding deriva 

 tives of acetic acid. 



Propionyl chloride, C 3 IPO.C1. Liquid. Boiling 

 point, 80. 



Propionyl bromide, C 3 II 5 O.Br. Liquid. Boiling 

 point, 96-98. 



Propionyl iodide, C 3 IPO.I. Liquid. Boiling 

 point, 127-128. 



Propionylamide, C 3 IPO.NH 2 . Colorless prisms, 

 fusing at 75-76. 



4. Butyric Acids. 

 C 4 H 8 2 =C 3 H 7 .CO.OII. 



Theoretically there are two acids of this composition 

 possible (p. 75). Both are known. 



1. Normal butyric acid (butyric acid of fermen 

 tation), CH 3 .CH 2 .CH 2 .CO.OH. Is contained in a great 

 many animal juices, and in the form of the glycerin 

 ether in butter. Is produced by the oxidation of nor 

 mal butyl alcohol and, in small quantity together with 

 acetic acid and other acids, by the dry distillation of 



