THE RED COLOE IN PHENOL. 367 



following proportions were sealed in tubes and agitated in the sunlight 

 at about 30° for seven days. 



1. Phenol 1 dropj chloroform 1 cubic centimeter and water 5 cubic centi- 

 meters. 



N 



2. Phenol 1 drop, chloroform 1 cubic centimeter and — sulphuric acid 5 



cubic centimeters. 



N 



3. Phenol 1 drop, chloroform 1 cubic centimeter and — sodium carbonate 5 



cubic centimeters. 



In each case the tube was half filled with liquid, the remaining space 

 being occujjied hj air. After a few hours in the sun the chloroform layers 

 in each tube showed a yellow coloration. The aqueous layers in numbers 

 1 and S were colorless, while that in number 3 was slightly yellow. The 

 colors continued to deepen and at the end of one week, when the tubes 

 were opened, the chloroform was a deep yellow and in numbers 1 and 2 

 contained all the color, while in number 3 the yellow was equally 

 distributed between the two solvents. Quinone was found to be firesent 

 in every tube. The remaining portions were too small to work with 

 separately; however, a composite mixture of the residues was found to 

 contain catechol. It was to be expected in the tube number 3 that the 

 aqueous layer would also be colored for the reason that quinone in alkaline 

 solutions unites with oxygen to form more complex colored compounds, 

 some of which are soluble in water. 



A mixture of 5 grams of phenol, 100 cubic centimeters of chloi'oform, 

 and 200 cubic centimeters of purified water, which had an electrical 

 conductivity of 3.7X10"", was agitated in a liter bottle for eight days 

 at a temperature of 30° ±1°. The chloroform became yellow in one day 

 and after eight days was a yellow-brown. On treating portions of the 

 chloroform solution with sulphurous acid and distilling in steam until 

 the phenol was volatilized, the residual solution was found to contain 

 small c[uantities of quinol and catechol. The aqueous portion of the 

 reaction mixtures shows considerable quantities of hydrogen peroxide by 

 the titanic and vanadic acid tests and by the potassium dichromate and 

 aniline reaction of Bach.-' 



In view of Bach's criticism of the statements of Kohn and Fryer (that 

 the coloration of phenol requires oxygen, moisture and light rays), the 

 experiments of Bach, in which he excluded oxygen by working in an 

 atmosphere of carbon dioxide, were repeated and further extended by the 

 employment of two other gases, hydrogen and nitrogen. 



The experiments were carried on in sealed tubes and the necessary precautions 

 were taken to exclude all substances except those the presence of which was desired. 

 The hj-drogen employed was generated in a steady, rapid stream by the action of 



^Compt. rend. Acad. d. sc, Par. (1S94), 119, 1218. 



