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. 



0-Amidopropiqnic acid, CH 2 (^H 2 )CH 2 .CO.OH. Is 

 obtained, like alanin, from j3-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 H 5 O.C1. Liquid. Boiling 

 point, 80. 



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

 point, 96-98. 



Propionyl iodide, C 3 H 5 O.I. Liquid. Boiling 

 point, 127-128. 



Propionylamide, C 3 H 5 O.N"H 2 . Colorless prisms, 

 fusing at 75-76. 



4. Butyric Acids. 

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



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 



