158 
Similar ketoformulae for the 2.3 oxynaphtoïc-acid are already 
found in the literature *). 
Further we investigated still : 
SCHÄFFER-salt, G-salt, 
SO*Na 
pee DAP RE 
ieee | 
BO ONG es 
M.W. = 246 M.W. = 348 
and also 
sodium p. phenol sulphonate. 
gon: 
The sodium 2.6. naphtol sulphonate has been investigated as 
technical SCHÄFFER-salt and also as a purified one prepared in the 
laboratory by sulphonation of g-naphtol. 
To determine the percentage of the technical product this was 
titrated by means of diazotated p. nitraniline according to the 
method in use in the technical control-stations of the dye-manufac- 
turies*). In this way we found the percentage 76.4. The purified 
preparation when dried gave a loss in weight of 11,4°/,. In the 
dried substance we made a sulphate-ash-determination. Having made 
the calcutation for Na, we found from this 9,1 °/,. (Theor. 9.35 °/,). 
From the observations combined in table VII we see, that 4 
milligram-molecules of the pure ScHAFFER-salt bind just as much 
alkali as the corresponding quantity of the technical product. 
88,6 
If the pure salt behaved as a monobasic-acid, just can 49,55 cm 
N. KOH would have been found. In reality we find 3,7 em* 0,93 
N. KOH = 3,4cem’N. As the titration gave for the percentage of 
the technical product 76,4, it is probable, that the technical product 
in question is made impure by substances which can bind alkali, 
but which under the circumstances of the titration with diazo-solu- 
tions, cannot form colours. As might be expected the ScHärrer-salt 
could not bind an acid in a hydrochloric medium. 
1) R. Mörvau, Berichte d. Deutsch Chem. Gesellsch. 28, 3100 (1895); 
M. ScHépr, Idem 29, 265 (1896); F. Friepr, Sitzungsber. der Akad. der 
Wissenschaften, Mathematisch-Naturwissensch. Klasse, Wien, 119, 731(1910). 
4) R. Mörvau and H. Bucrerer, Farbenchemisches Praktikum. 
EE ———— ee ee 
