[boswell] . THE CONSTITUTION OF RUBBER 41 



obtained. This was filtered off and washed with methyl alcohol, 

 ethyl alcohol and acetone and dried to constant weight at room 

 temperature under suction. This was again partially dissolved in 

 ether, filtered, precipitated and washed as before and dried to constant 

 weight. The substance was now analysed, giving the following 

 result: 



A sample of this compound, which had stood for some time in the 

 air, was partially redissolved in ether, filtered, precipitated, washed 

 and dried to constant weight. Analyses were as follows: 



This compound appears to be identical with the C25H40O2 com- 

 pound just described as one of the products of the oxidation of the 

 C25H40O compound in the air. 



This would indicate that a nucleus C30H48 occurs in the rubber 

 molecule and that the first product of oxidation is C30H48O. 

 This compound readily loses an isoprene group and becomes C25H40O. 

 In place of this CsHs group an oxygen then enters, giving the com- 

 pound C25H40O2. This is entirely in harmony with the above results. 

 It is also verified by the fact that in the hydrogen peroxide oxidation 

 of rubber a water soluble oxidation product, already referred to, is 

 formed which probably results from the oxidation of this isoprene group 

 which has been split off. Also Hambleton, in this laboratory, observed 

 that when rubber is oxidized by potassium permanganate in the 

 preparation of the C25H40O compound, there is a water soluble oxida- 

 tion product as well as considerable carbon dioxide formed. He 



