[boswell] the constitution OF RUBBER 37 



Olivier expresses the belief that in spite of the detailed researches of 

 Harries not much progress has been made in the determination of the 

 constitution of rubber. 



However, even supposing the transformation of rubber into 

 CioHieOe does occur quantitatively, this would not constitute a decisive 

 objection to the above formula. 



. For the action of ozone is of an exceedingly violent sort and must 

 result primarily in a very thorough depolymerization of the whole 

 rubber molecule. It is not inconceivable that the five resulting 

 isoprene residues might rearrange themselves to form a diozonide 

 of dimethyl cyclo octadiene. Each pair of isoprene residues might re- 

 combine to form the single diozonide thus : 



Ç//J pj 



G //p~~ CH^ C — (^Hp CHp — CH — C — CM p 



I ' I 



I +20s 



CH^ — C ^ CH — Crf2 



0-0-0 



(^O-O 

 CHs-C^ — CH-CH^^ 

 ^^3 CHx 



Experimental. 



However probable this constitution which I have devised may 

 appear, from the facts which I have just briefly reviewed, more 

 conclusive evidence is desirable indicating the existence of a C25H40 

 nucleus in the rubber molecule. The experiments which have been 

 carried out by my students (A. Hambleton, R. R. McLaughlin and 

 R. R. Parker) were performed in an endeavour to prepare derivatives 

 of rubber by the mildest kind of action, in order to avoid as much 

 as possible the depolymerization of the rubber molecule. Oxidations 

 by means of a water solution of potassium permanganate, a water 

 solution of hydrogen peroxide, oxygen of the air, the action of iodine 

 and of iodine with hydrogen peroxide were employed. 



Oxidation by Potassium Permanganate — Experimental Work by A. 

 Hambleton. 



The rubber for these experiments was prepared by extracting 

 about 200 g. of para rubber, cut up into small pieces, with hot acetone. 

 The acetone was poured off frequently and fresh acetone added. 

 This was continued for eight days, when the extract was found to 

 leave no residue or evaporation. The excess of acetone sticking to 



