94 BUTYRIC ACIDS. 



Ethyl butyrate. C 4 H 7 O.O.C 2 H 5 . Colorless liquid of 

 a pleasant odor, boiling at 119. 



Butyroacetic acid, CH 12 O, a remarkable com- 

 pound of butyric with acetic acid, is produced by the 

 fermentation of crude calcium tartrate. It forms salts, 

 but the free acid, when subjected to partial distillation, 

 is decomposed into equal molecules of butyric and 

 acetic acids. 



Substitution-products. Of each substitution-pro- 

 duct, in which one hydrogen atom is replaced by a 

 monovalent group, there are three modifications possi- 

 ble. Up to the present, but few of them have been 

 prepared, and their constitution is not well known. 



Monochlorbutyric acid, C 4 H 7 C10 2 . .By the action 

 of chlorine on butyric acid in the presence of iodine. 

 Fine, pliant needles. Easily soluble in hot water. 

 Fuses at 98-99, and sublimes at 80. 



A non-crystalline, viscid acid, isomeric with this, is 

 produced by the decomposition of chlorbutyryl chloride 

 with water. 



Monobrombutyric acid, C 4 II 7 Br0 2 (a liquid, which 

 does not congeal at 15 ; boiling at about 217, 

 not, however, without undergoing decomposition), and 

 dibrombutyric acid (colorless, long, thin prisms, fusing 

 at 45-48) are produced by heating butyric acid with 

 bromine. 



Amidobutyric acid, C 4 H 7 (^H 2 )0 2 . From mono- 

 brombutyric acid and ammonia. Small laminae or 

 needles, easily soluble in water, difficultly in alcohol, 

 insoluble in ether. 



2. Isobutyric acid, ^ 3 I CH.CO.OH. Is contained 



in the Carob bean (the fruit of Ceratonia siliqua). Is 

 obtained from pseudopropyl cyanide (p. 67) by heating 

 with alkalies and by the oxidation of isobutyl alcohol 



