THE PHILIPPINE 
JOURNAL OF SCIENCE 
A. CHEMICAL AND GEOLOGICAL SCIENCES 
AND THE INDUSTRIES 
Vou. VII DECEMBER, 1912 No. 6 
THE ABSORPTION SPECTRA OF ORTHO- AND PARA- 
NITROPHENOL AND PARA-NITROSOPHENOL. 
NEW EVIDENCE OF THE QUINOID STRUCTURE OF THESE 
COMPOUNDS IN ALKALINE SOLUTION. 
By H. D. Gipps* and D. S. Pratt. 
(From the Laboratory of Organic Chemistry, Bureau of 
Science, Manila, P. I.) 
Baly, Edwards, and Stewart? described the absorption spectra 
of the three nitroanilines, the three nitrophenols, and p-nitroso- 
phenol, and from their investigations of these compounds in 
neutral, acid, and alkaline solutions conclude that, in alkaline 
solutions, they all exist in the quinoid form. Four years later, 
Baly, Tuck, and Marsden : entirely retract the first explanation 
of the color of the nitroanilines and the salts of the nitrophenols, 
and substitute the explanation that the change from a colorless 
compound to a colored one or a deepening of the color of a colored 
compound of this type is not due to any essential change in struc- 
ture, but merely to a shift of an absorption band from the invisible 
to the visible region of the spectrum, and is similar to the shift 
*Associate professor of chemistry, University of the Philippines, Manila, 
P. I. 
* Journ. Chem. Soc. London (1906), 89, 514. 
*Tbid. (1910), 97, 571. 
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