THE OXIDATION OF PHENOL. 151 



SUMMARY. 



1. Pure phenol remains colorless in the sunlight when in contact with 

 the indifferent gases, hydrogen, nitrogen and carbon dioxide. 



2. Pure phenol will become colored in the presence of oxygen. 



In the dark the rate is not appreciable at room temperatures. It 

 increases with rise of temperature, can be measured at 100°, and at the 

 boiling point of phenol is fairly rapid. 



In the sunlight the rate of coloration is rapid and increases directly 

 with the temperature. 



3. The cause of the color is oxidation. 



The principal products of the oxidation are quinol, quinone, and 

 catechol. Some carbon dioxide has been found. 



The principal colored compounds are probably quinone condensation 

 products. The formation of the intense red condensation product pheno- 

 quinone is probable. 



4. Active oxygen will unite with phenol with considerable ease and 

 rapidity. 



Ozone is very reactive. Quinol, quinone, catechol, glyoxylic acid, and 

 carbon dioxide have been identified among the products of the action 

 with ozone. No ozonide has been isolated. 



Oxygen liberated at the anode reacts with phenol. Quinone is one 

 of the reaction products. 



5. The experiments argue against the chemical activity of the oxygen 

 gas ions. 



6. The glass through which the sunlight acts upon phenol in the 

 presence of oxygen has an influence upon the rate of reaction. Glasses 

 having the most complete ultra-violet absorption retard the reaction in the 

 greatest degree. 



7. Ozone could not be detected in pure, dry molecular oxygen sealed 

 in a glass tube and exposed to the sun. 



8. The altitude of the sun, the thickness of the atmosphere through 

 which it acts, and the atmospheric conditions undoubtedly influence the 

 rate of the coloration of phenol. 



9. The methyl ether of phenol, anisole, is not colored by ozone or 

 oxygen and sunlight. 



The fixation of the labile hydrogen of phenol decreases the sus- 

 ceptibility of the compound to oxydizing influences. 



10. The reactivity of the phenol molecule is augmented by the absorbed 

 wave lengths at about A.=891 to 243 /n/x, and as far as has been observed 

 the same effect is produced by higher temperatures. The oxidation and 

 consequent coloration of phenol goes on under both influences. 



11. The purest phenol can gnly be distilled out of contact with oxygen. 

 Hydrogen has been employed in this work. 



