276 Researches respecting the radical of Benzoic Acid. 



t i 



By dissolving benzamide in a strong acid with boiling, it disappears, 



and in its place benzoic acid in crystals separates from the cooled 



solution, while an ammoniacal salt has formed. By employing hot 



concentrated sulphuric acid, the formed benzoic acid sublimes. If 



boiled with pure water, even for a considerable length of time, this 



change into benzoic acid and ammonia does not take place. 



The analysis of benzamide is easily effected by ignition with oxide 

 of copper. The relative proportion of nitrogen and carbon was as- 

 certained by the ignition of the substance "in vacuo" The ignition 

 tube was provided at one end with a thirty inch tube, the one end 

 dipping in mercury, and the other drawn out to a strong point, which 

 by means of a caoutchouc tube could be connected with the small 

 air-pump. 



The air was then exhausted, and as soon as the mercury had risen 

 in the tube to the height of some twenty seven inches, the point at 

 the other end of the ignition tube was closed by the blowpipe, and 

 the ignition was commenced. 



From these experiments it followed that nitrogen and carbon were 

 evolved in the proportion of one to fourteen. It yielded farther, 



Carbonic acid. Water. 



I. 0.400 grm. benzamide =1.012 . +0.208 



If. 0.489 " " =1.235 . +0.253 



Calculated from these, benzamide contains in one hundred parts, 



I. II. 



Carbon, . . 69.954 . . 69.816 



Hydrogen, . . 5.780 . . 5.790 



Nitrogen, . . . 11.563 . . 11.562 



Oxygen, . . 12.603 . . 12.832 



By volume these numbers give as the theoretical result, 

 14 atoms Carbon, . 107.0118 . . 69.73 



14 " Hydrogen, . 8.7360 . . 5.69 



2 " Nitrogen, . 17.7036 . . '11.53 



2 " Oxygen, , 20.0000 . . 13.05 



This composition clearly explains not merely the manner of the 

 formation of benzamide, but also its behavior with acids and potassa, 

 that is, its conversion into benzoic acid and ammonia. 



If 2 atoms of ammonia be added to the composition of chloride of 

 benzoyl, we obtain the formula ; 



14C+10H+2O+2CZ=chlorobenzoyl 



12H +4N= ammonia 



14C+22H+20+2C/+4N. 



