ON THE PRESENT POSITION OF THE CHEMISTRY OF RUBBER. 253 



130° C. Its molecular weight was found by Raoult's method to be about 

 600 and its formula CjoHjoNgOic. On oxidation of this nitrosite with 

 nitric acid a dark yellow powder having the composition CaoHaiNsO,,, 

 was produced, as well as oxalic acid and an oil containing apparently an 

 aliphatic nitro-acid. When potassium permanganate was used as the 

 oxidising agent, the products consisted of a mixture of fatty acids, 

 principally oxalic and succinic acids. 



By passing a rapid current of unwashed nitrous fumes into a solution 

 of rubber in moist benzene a yellow compound, C00H30NCO14 (nitrosite c) 

 was the result. This decomposes at 160° C, and gives on oxidation 

 similar compounds to those obtained from nitrosite b. 



In a second paper on this subject ^ Han-ies stated that if 

 the nitrous acid used was previously dried, by passing it through 

 phosplioric oxide, only nitrosites a and c were formed, the one 

 described as /) having been produced by oxidation. He had previously 

 passed his nitrous fumes overCaCU to dry them, chlorine and nitroso- 

 chloride.had been formed and oxidation had occurred. 



An interesting observation made by Harries is that myrcene, the 

 C,oHi6 hydrocarbon from Bay oil, on heating to 300° for four hours, 

 is partly converted into dimyrcene, C.^qHso, boiling-point 1G0° to 300° 

 (13 mm), and by the action of nitrous fumes on this compound a 

 nitrosite, CaoHsoNrPu, is produced apparently identical with nitrosite c 

 obtained from rubber. 



These results seemed to confirm the opinion that rubber was an 

 unsaturated open-chain hydrocarbon. 



Action of Nitrogen Dioxide. 



In 1902 2 Weber found that on passing dry nitrogen dioxide gas, 

 obtained by heating lead nitrate, into a solution of Para caoutchouc 

 in benzene, a coherent amorphous mass separated out, which, on the 

 removal of benzene and washing with alcohol, was obtained as a 

 dark yellow powder. The product was further purified by dissolving in 

 acetone and afterwards precipitating with water. A straw-coloured 

 powder was the result, which on analysis gave figures corresponding to 

 the formula C,,|Hi(-,N204. Subsequent investigators,^ however, were 

 unable to isolate a compound of this composition ; the substances generally 

 obtained more nearly approximated to the formula CioHi.^NaOy. A 

 compound having this composition and possessing similar properties to 

 Weber's compound has been prepared by Harries by another method and 

 named nitrosite c. 



Weber proposed the preparation of the ' dinitro caoutchouc ' as a 

 quantitative method for the estimation of pure caoutchouc in commercial 

 samples and manufactured articles. 



Action of Ozone. 



The study of the effect of the treatment of rubber with ozone has, 

 in the hands of Prof. C. D. Harries, not only provided us with a new 

 and interesting class of indiarubber derivatives, but has also contributed 



' Ber., 35 (1902), 44, 29. * -»«•-, 35. 1917. 



' Harries, Ber., 1905, 87-90, and Alexander, Ber., 38 (1905), 181-84. 



