36 THE ROYAL SOCIETY OF CANADA 



CôH8,CioHi6, C15H24, C20H30 and C25H4o- It will be shown presently 

 that this is in reality so. We have made oxygen derivatives of such 

 molecules from rubber by means of free oxygen, by hydrogen peroxide 

 and by potassium permanganate. Upon action with bromine, no 

 matter in what manner depolymerization should occur, the final 

 product should have the percentage composition C5H8Br2 or CioH]6Br4. 

 Likewise, the hydrochloric acid addition product should have the 

 composition CsHsHCl or CioHi6.2 HCl. It explains the ready forma- 

 tion of dipentene from rubber and the production of dinitro cumic 

 acid, so closely related to dipentene, observed by Ditmar. 



An apparent objection is found in the action of ozone on rubber. 

 At first sight it would seem that since the sole products of the decom- 

 position of the ozonide of rubber, as Harries claims, are laevulinic 

 aldehyde, laevulinic aldehyde peroxide and laevulinic acid, that the 

 possibility of the presence of any group other than dimethyl cyclo 

 octadiene is excluded. Upon closer examination, however, this 

 objection does not seem to be valid. Harries prepared the diozonide 

 of rubber by the action of ozone upon a chloroform solution of rubber. 

 This ozonide was precipitated from solution and washed. The possi- 

 bility is not excluded, that in the preparation of this ozonide in the 

 pure state, other oxygen products of the action were removed. Unless 

 I have overlooked the statement I can find no mention of a quantita- 

 tive yield of doHieOe having been obtained from a known weight 

 of rubber. What appears to have been obtained was a quantitative 

 yield of the products of decomposition of the purified diozonide. 

 Dingman, in this laboratory, endeavoured to determine quantitatively 

 the yield of diozonide obtainable from a known weight of rubber 

 made by Harries method, drawing ofï the adhering solvent and 

 precipitant in a vacuum at room temperature. However, he was 

 unable to get constant weight, as the diozonide decomposed under these 

 conditions, and so no decision could be reached. 



Since writing this my attention has been drawn to a paper by 

 Olivier (22) in which he has obtained the same result, viz., impossi- 

 bility to obtain constant weight of diozonide. Moreover, Olivier 

 found that he could obtain no constancy of the molecular weight of 

 the so-called diozonide by the freezing point method using benzene 

 as solvent. The values varied from 558 to 869 for moderate treat- 

 ment with ozone and from 321 to 487 for the product purified after 

 excessive treatment with ozone. Olivier comes to the same conclusion 

 that there is no proof that Harries diozonide is a homogeneous com- 

 pound. And unless this diozonide of the constitution given is the sole 

 product of the action of ozone then Harries constitution is not valid. 



