THE EED COLOR IN PHENOL. 363 



the reaction is not as simple as Kobn and Fryer or Rieliardson believe it to be. 

 He exclvided air by fl'orking in an atmosphere of carbon dioxide and found that 

 under these conditions the coloration -was still produced in the sunlight. He could 

 demonstrate no traces of hydrogen peroxide in the mixture. 



J. Walter "* finds that the presence of iron salts increases the production of 

 the red color. He attributes the coloration to the action of hydrogen peroxide. 



L. Reuter '° has observed that by adding sulphur dioxide to phenol it can be 

 kept colorless for an almost unlimited period. Since the discoloration of phenol 

 does not interfere with its application in medicine he recommends that, to avoid 

 accidents, all phenol be uniformlj^ artificially colored rather than treated with 

 preserving or decolorizing agents. 



ESPBEIMENTAL. 



The samples of j)lienol investigated were the purest crj'stallized products 

 which could be obtained from various manufacturers. In this climate, 

 \\'here the sun's actinic rays are so very intense, they assume a Ijrilliant 

 red color very cpiickly ; it is in fact difficult to preserve the white 

 crystals after a bottle has been opened. Exceptional opportunities are 

 here offered for the studj^ of reactions which are at least in part due to 

 the catalytic action of light rays. The prevailing temperature is 30° 

 and the variations are within rather narrow limits. Many of the reagent 

 bottles standing upon the shelves in a well-lighted laboratory give a 

 distinct reaction for hydrogen peroxide, and whenever tests for hydrogen 

 peroxide are to be made the reagents employed must be purified and 

 tested. Under these conditions appreciable amounts of the reaction 

 products under investigation are produced in the minimum of time. 



I have found that cpiinone, or a quinone derivative is the principal 

 colored compound formed, although during the oxidation of phenol to 

 quinone it is to be ex23ected that other substances will be produced. 



Cross, Bevan, and Heiberg,"" on oxidizing benzol with hydrogen peroxide, 

 found the products to be phenol, catechol, quinol, and quinone. Martinon "' 

 demonstrated that phenol when oxidized with hydrogen peroxide produced cate- 

 chol, quinone, and quinol. It is to be expected that the oxidation of phenol 

 will produce the ortho and para derivatives and no meta compounds.-- 



Quinone dissolves in phenol, producing a brilliant red solution. A 

 very small crystal dropped into liquid, colorless phenol reddens im- 

 mediately upon striking the phenol and is slowly dissolved, producing 

 the characteristic red solution. 



" j_ ggg^ Chem. Ind. (1899), 18, ,360. 



"""Hid (1905), 24, 686. 



-°Ber. d. chem. Ges. (1900), 33, 2017. < 



"■Bull. Soc. C'him. Paris (1885), 43, 155. 



==Tliiele, Ann. Chem. (Liehig) (1899), 306, 129. 



