Certain New Derivatives in the Aromatic Series. 191 



The compound which appeals most strongly to the practical color- 

 ist was the derivative obtained when Bronner's and the Schcellkopf 

 acid were joined. This dye was a red which had very remarkable 

 powers of sustaining the prolonged action of the acids used in 

 bleacheries ; this gives the dye a commercial value which is not 

 small ; further, the dye was very resistant when exposed to the 

 sunlight. 



*o' 



Action of Bromine on the Dyes of the Azo Group. 



YI. This group of experiments was carried out with the desire 

 of proving whether the presence of bromine in the dyes of the Azo 

 Group was detrimental or not. The halogens are essential in the 

 production of certain colors, namely, bromine in the production of 

 Eosine from Fluoresceine, and Phloxine from di-chlor-fluoresceine ; 

 iodine in changing Fluoresceine to Erythrosine ; and the di-chlor- 

 fluoresceine to Rose Bengale. In general the results of the trials 

 seem to indicate that bromine alters the color to the orange side of 

 the red, and gives, as a rule, an undesirable hue. 



The writer here wishes to express his sense of the many obliga- 

 tions he is under to Professor C. Loring Jackson, without whose 

 encouragement and counsel the experiments would not have reached 

 a successful termination. 



The experiments resolved themselves into the making of a series 

 of chemically pure dyes, and then constructing analogous dyes, 

 which carried bromine in the molecule. 



The first dye manufactured was Sudan I, and the corresponding 

 dye which was made with bromine was, 



The two colors have the same formulae, with the exception that 

 one holds the three atoms of bromine. The dyes are readily made; 

 in the case of the Sudan I, aniline is diazotized in the usual manner 

 with sodic nitrite in an acid solution, and coupled with naphtol. 

 For the bromated compound, tri-brora-aniline was made by draw- 

 ing vapors of bromine through an acidulated solution of aniline 

 hydrochloride, and the precipitated tri-brom-aniline was filtered off, 

 washed, and dried. After diazotization, it was coupled with naphtol, 

 and the dye immediately resulted. The colors are red and orange- 

 red. 



