58 THE BUTYRIC ACID GROUP. 



Butyr amide, H 2 N.C 8 H 7 O 2 , is obtained from butyrate of oxide 

 of ethyl when acted on by ammonia ; it forms colourless crystalline 

 tablets, which resist the action of the atmosphere ; it communicates 

 a taste which is at first sweetish but afterwards bitter; it fuses at 

 115, and at a higher temperature sublimes without change; it is 

 soluble in water, alcohol, and ether ; by anhydrous phosphoric acid 

 it is converted into butyronitrile, C 8 H 7 N, whose theoretical 

 formula, according to Kolbe, must=C 6 H 7 .C 2 N. Butyronitrile 

 is an oily fluid, with an agreeable, somewhat aromatic odour; its 

 specific gravity is 0'795, and its boiling point 118'5 ; treated 

 with potassium it yields cyanide of potassium, hydrogen, and 

 certain carbo-hydrogens. 



Aldehyde of butyric acid, C 8 H 7 O.HO, has hitherto only 

 been found by Guckelberger,* in the products which are obtained 

 by the action of peroxide of manganese and sulphuric acid on albu- 

 minous or gelatinous substances. It is a colourless fluid, its specific 

 gravity is O8, and its boiling point 68 ; it is slightly soluble in 

 water, but dissolves freely in alcohol and ether ; it soon becomes 

 acid when exposed to the air ; it reduces solutions of the silver-salts, 

 and, like aldehyde of acetic acid, it yields with ammonia a crystal- 

 lisable compound, H 3 N. C 8 H 7 O. HO + 10 aq. 



Butyrate of glycerin has been prepared by Pelouze and Gelis,t 

 by gently heating butyric acid and glycerin with concentrated sul- 

 phuric acid, and separating the new compound from the mixture 

 by means of water; or by passing hydrochloric acid gas through a 

 mixture of butyric acid and glycerin ; on the addition of water it 

 separates as a yellow oil, soluble in concentrated alcohol and ether, 

 which, when treated with caustic alkalies, again resolves itself into 

 butyric acid and glycerin. Whether this body be identical with the 

 butyrin (butyrate of oxide of lipyl) occurring in the fat of milk 

 but not yet isolated, cannot at present be decided, since no elemen- 

 tary analysis of it has been instituted. 



Preparation. Butyric acid, which was originally discovered by 

 Chevreul in the products of the saponification of butter, is also 

 formed when Jhis substance becomes rancid, and occurs amongst 

 the products of decomposition when oleic acid is submitted to dry 

 distillation, and especially when it is acted on by fuming nitric acid ; 

 it is likewise produced from non-fatty nitrogenous matters, as albu- 

 men, fibrin, and gelatin, during their putrefaction or their decom- 

 position by strong oxidising agents ; and, contrary to expectation, 



Ann. d. Ch. u. Pharm. Bd. 64, S. 46 if. 

 t L'Institut. No. 494. 



