METHYL SALICYLATE II. THE COLORATION OF METHYL 
SALICYLATE AND SOME ALLIED COMPOUNDS 
; IN THE SUNLIGHT. 
By H. D. Gisss,* R. R. WILLIAMS, AND D. S. PRATT. 
(From the Laboratory of Organic Chemistry, Bureau of Science, 
: Manila, P. I.) 
Quite accidentally, during the investigations of methyl] salicyl- 
ate by one of us, the details of which have appeared in other 
papers? relating principally to the hydrolysis of this ester, it was 
observed that it turned yellow in the sunlight while the corre- 
sponding ester of benzoic acid remained colorless. Very early 
in the work, a preliminary hydrolysis experiment was so placed 
that the direct sunlight fell upon the solutions, producing the 
color in the methyl] salicylate in a few hours. 
Since the literature concerning the coloration in the light of 
a simpler compound, phenol, was so misleading, this substance 
was first investigated and the cause of the phenomenon found to 
be the oxidation of the phenol to quinone.® 
It was at once suspected that the cause of the coloration of 
methyl salicylate might also be oxidation to a quinone, in fact, 
since salicylic acid splits off carbon dioxide under some circum- 
stances so easily, the coloration might be due to p-quinone itself 
through the oxidation of the phenol formed. This phase of the 
question was eliminated by the investigation of the splitting off 
“Associate professor of chemistry, University of the Philippines. 
* Part I. The separation of salicylic acid from methyl salicylate and 
the hydrolysis of the ester. This Journal, Sec. A (1908), 3, 101, and 
Journ. Am. Chem. Soc. (1908), 30, 1465; Part IJ. Solubility in water 
at 30°. This Journal, Sec. A (1908) 3, 857; Part IV. The saponification 
of methyl salicylate and methyl benzoate, by H. D. Gibbs and R. R. 
Williams, will follow. 
* The compounds which cause the red color in phenol. This Journal, Sec. 
A (1908), 3, 361; the oxidation of phenol; the effect of some forms of light 
and active oxygen upon phenol and anisole. Jbid. (1909), 4, 133. 
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