202 Dr. A. W. Hofman on the Organic Bases 



to 1 



lemon-yellow precipitate, which is characteristic of chlorin- 

 doptic acid ; sulphate of copper gave a purple violet deposit, 

 partially soluble in alcohol. The salts of lead and chloride of 

 mercury produced white precipitates. The formation of chlo- 

 rindoptic acid from cyanol is not surprising, as the two bodies 

 contain an equal number of equivalents of carbon ; the hydro- 

 gen is partly replaced by chlorine and partly given off with 

 the nitrogen as ammonia. 



One atom of cyanol, two atoms of water, and six atoms of 

 chlorine contain the elements of one atom of ammonia, three 

 atoms of hydrochloric and one atom of chlorindoptic acid. 



1 atom of Cyanol C 12 H 7 N 



+ 2 atoms of Water .... H 2 G 2 



+ 6 ... Chlorine .... Cl e 



C 12 H 9 N0 2 C 

 1 ... Chlorindoptic acid . 

 + 3 ... Hydrochloric acid . 

 + 1 ... Ammonia . . . 



'C 12 H 9 N0 2 C1 6 

 If anhydrous cyanol be heated with strong hydrochloric 

 acid, and a considerable quantity of chlorate of potash added 

 to the boiling mixture, a violent reaction ensues, whereby 

 chloranil, contaminated with a red resinous substance, is ob- 

 tained. This matter may be separated from the chloranil by 

 boiling in alcohol. When the alcoholic solution is subjected 

 to distillation, and till the spirit has passed over, a small por- 

 tion of chloranil sublimes out of the melting mass. Hydro- 

 chloric acid is then evolved, and in the neck of the retort a 

 crystalline substance condenses, which presents the odour and 

 all the characteristics of chlorindoptic acid. 



This body is Erdmann's* chlorated chlorindoptic acid 

 (chlorophenussic acid of Laurent). Erdmann obtained it also 

 as a secondary product in the preparation of chloranil. 



Its formation is perfectly explicable, since its constitution 

 differs from that of chlorindoptic acid, by two more atoms of 

 its hydrogen being replaced by chlorine. 



Action of Bromine upon Cyanol. — I have not yet been able to 

 prepare the bromindoptic acid (Laurent's bromophenissic 

 acid). The action of bromine upon cyanol is very different 

 from that of chlorine. When bromine water is added to a 

 hydrochloric solution of cyanol, a white precipitate with a 

 slight tinge of blue falls, which quickly assumes a crystalline 

 aspect. None of the other oily bases present a similar reac- 

 tion. This compound is not however bromindoptic acid, but 

 * Erdmann's Journ. B. xxii. p. 257. 



