SUNLIGHT UPON METHYL ALCOHOL. 63 
TABLE Il.—Mixtures of methyl alcohol, air, and water exposed to the sun- 
light in sealed tubes. 
Tube i Exposure. 
num- Contents of tubes. a 
Bes Tr From— Lo— 
1909. 1909. | 
I | 1cc. methyl alcohol, 10 ce. x sulphuric acid _-_-______- Aug. 10 | Dec. 21 | 
II | 1 ce. methyl alcohol, 10 ec. water -----....--_-----.---- Aug. 10 | Dec. 21 | 
Ill | 4 cc. methyl alcohol, 10 ce. water __....___.-_-_---_--__ Aug. 10 | Dec. 21 | 
1910. 1910. 
DVEiee 85 (6 00 SE nS a eo aa Oe ey Jan.128 | Jan.13> | 
| 
810 a. m. > 8 a.m. 
The methyl alcohol and all the reagents employed were care- 
fully tested for formaldehyde before the tubes were sealed, with 
negative results. At the end of the four months’ exposure, tubes 
numbered I, II, and III were found to contain formaldehyde. 
The amount was estimated at 1 to 5,000 in tube number I, less in 
number III, and least in number II. The tests employed, the 
milk and sulphuric acid method of Hehner, and the phenyl- 
hydrazine method of Rimini, both gave very strong, positive 
reactions. 
Tube number IV, after not more than six hours’ exposure to 
a bright sun on a day which was shown to be very actinic by 
the rate of decomposition of oxalic acid in presence of uranium 
acetate,?> contained a small quantity of formaldehyde. 
After these preliminary tests the methyl alcohol was purified 
as previously described and an extensive series started. This is 
recorded in Table III. 
In general, the tubes containing the highest concentrations 
of alcohol showed the greatest quantities of formaldehyde; that 
is, dilution reduces the speed of the reaction. The presence of 
sulphuric acid increases the rate of oxidation. 
Control tubes wrapped in tin foil and kept in the dark at room 
temperature failed to show the presence of formaldehyde. A 
control protected in the same way and kept in a steam bath at 
100° gave faint tests for formaldehyde by all three methods; 
the amount formed, however, was so small that there could be no 
doubt that the sunlight was the important factor. 
* Bacon, This Journal, Sec. A (1910), 5, 285. 
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