188 Certain New Derivatives in the Aromatic Series. 



Of course, the dye when used is used in the form of its sodium 

 salt. The specimen attached is numbered No. 1. 



The next step in the research was the examination of Dahl's acid, 

 betanaphtylamine-sulphonic acid, CjgHgNH2(2)S03H(5). Dahl's is 

 already used for some of the dyes in commerce at the present time. 

 One of these is made by the linking of the diazotized Dahl's acid 

 with Neville and Winther's acid, naphtolsulphonic acid, 1 : 4, for 

 Pyrotin RRO Several new dyes were brought out of this Dahl's 

 acid: beta-Naphtol gave a red ;' naphtol-disulphonic acid, " G", 

 2:6:8, gave an orange ; its isomeric modification " R", 2:3:6, 

 gave a red; and then the Schoellkopf's, 1:4:8, gave the red which 

 was the most resistant. This again pointed to the Schoellkopf's 

 acid, as the most satisfactory to use, if fastness to light was desired. 

 The compound produced by the Dahl's and Schoellkopf's had the 

 proved constitution, CioHg(S03Na)N = N— CioH,(S03Na),.OH. A 

 sample numbered No. 3^ is annexed. 



The writer took up next Naphthionic acid. And it gave some 

 new derivatives, but again the Schoellkopf's acid was the best color 

 from the standpoint of the solidity to the action of the sunlight. 

 The sample of Naphthionic and Schoellkopf is numbered No. 4. 



All this seemed to indicate that the Schoellkopf's acid had some 

 very strong staying powers against light, and the Schoellkopf acid 

 itself next became the object of investigation. 



The Schoellkopf's acid has already been used for several dyes, 

 patented by the Schoillkopf Aniline and Chemical Co., of Buffalo, 

 N. Y. They are Wool-Scaidet B, where diazotized xylidine is used 

 with the Schoellkopf's acid; Buffalo Bubin, in which alpha-naphtyl- 

 amine is applied ; Groceine B, which is made from diazotized 

 amido-benzene; and Crocein SB, where amido-azo-toluol is utilized. 



The experiments which had been made seemed to lead directly to 

 the inference that when any naphtylamine-sulphonic acid was used 

 with the Schoellkopf acid, a dye would result which would be fast 

 to every common reagent. All the obtainable naphtylamine sul- 

 phonic acids were tried, and the results are appended. The weights 

 used and the method is given here; the statement is for all the 

 naphtylamine-sulphonic acids. Any naphtylamine-sulphonic acid, 

 of the general formula, CjoHg.NH^.SOgH, was taken, and 23.2 kilos, 

 were weighed, dissolved in water, and diazotized with 7 kilos, of 

 sodic nitrite and 12 kilos, of hydrochloric acid of twenty Baume ; 

 then 25.4 kilos, of the Schoellkopf's acid, which had been previously 



