VALERIC ACIDS. 95 



. ). A liquid very similar to butyric acid ; is, how 

 ever, more difficultly soluble in water (in 3 parts at the 

 ordinary temperature) ; boils at 153-154. 



Calcium isobutyrate, (C 4 H 7 2 ) 2 Ca + 5H 2 0, crystal 

 lizes in long prisms, and is much more easily soluble 

 in hot than in cold water. 



Silver isobutyrate, C 4 H 7 2 Ag, crystallizes from 

 hot water in lustrous laminse. 



Monobromisobutyric acid, C 4 H 7 Br0 2 = CH3 j- 



CBr.CO.OH. By heating isobutyric acid with bro 

 mine to 140. Colorless crystals, fusing at 45, not 

 volatile without decomposition. Becomes oily on 

 being mixed with water; over sulphuric acid in a 

 vacuum, it congeals again. But slightly soluble in 

 cold water, soluble in every proportion in hot water. 



5. Valeric Acids. 

 = C 4 H 9 .CO.OH. 



Of the four acids of this composition, which are 

 theoretically possible, only two are well known. 



1. Normal valeric acid, CIP.CH 2 .CH 2 .CH 2 .CO.OH. 

 Is prepared from butyl cyanide like propionic acid. 

 Is also obtained by the oxidation of the mixture of 

 alcohols from the amyl hydrides of petroleum. Color 

 less liquid, with an odor like that of butyric acid. 

 Boiling point, 184-185; specific gravity at 0, 

 0.9577. 



The barium salt (C 5 H 9 2 ) 2 Ba crystallizes in small 

 anhydrous laminse. 



2. Ordinary valeric acid (Isopropylacetic acid), 



CH.CH 2 .CO.OH. Is contained in the root of 



Valeriana and Angelica qfficinalis and of Athamanta 

 oreoselinum ; in the berries and bark of Viburnum 



