ii9 



Hydrocarbons. 



Ocimene. C. J. Enklaar has subjected ocimene (the aliphatic 

 hydrocarbon which had already been examined by him several times) *), 

 and some of its derivatives, tho the action of ozone. 2 ) When ocimene 

 was ozonised in carbon tetrachloride solution there was formed an 

 oily ozonide of variable composition, possessing the properties of an 

 aliphatic ozonide. In addition there were formed products of decom- 

 position, which either separated out in the form of a sublimate, or 

 were kept in solution by the carbon tetrachloride. They were partly 

 of a crystalline, partly of a liquid, constituency. The liquid products 

 of decomposition appeared to consist of methylglyoxal ; the solid 

 products were made up of trioxy methylene (m. p. 164 to 166 ), 

 the polymer of formaldehyde, and of acetone peroxide (m. p. 13 1°). 

 When allo-ocimene was ozonised, trioxymethylene and acetone per- 

 oxide were likewise obtainable, but in this case the ozonide itself 

 appeared to be a combination containing less than 10 carbon atoms. 

 Dihydro-ocimene, C 10 H 18 , yielded an oily ozonide which was soluble 

 in carbon tetrachloride, but insoluble in petroleum ether. The single 

 ozonides were decomposed by water, in the course of which process 

 ocimene and allo-ocimene ozonides gave off dioxide of carbon. 

 The aqueous solution of the products of decomposition of ocimene 

 ozonide contained a polymer of methylglyoxal (as was shown by a 

 conversion into the proper substance), of which the phenylhydrazone 

 melted at 145 . Furthermore, the presence of acetone, acetic acid and 

 malonic acid could be proved. Probably, malonic aldehyde had also 

 been formed, the pronounced red coloration which was given with 

 ferric chloride, and the formation of a semicarbazone melting at 24 5 , 

 pointing to this conclusion. On the other hand, no lsevulic acid, 

 oxalic acid, or laevulic aldehyde could be detected. The following 

 decomposition products of allo-ocimene had been formed: acetone, an 

 aldehyde (phenyl hydrazone, m. p. 230 ), pyroracemic acid (phenyl hydra- 

 zone, m. p. 169 ), and very probably also malonic aldehyde. The 

 ozonide of the dihydro-ocimene yielded as products of decomposition 

 principally laevulic acid (b. p. 148 to 149 ° at 14 mm. pressure); 

 also acetone, acetic acid and probably lsevulic aldehyde and malonic 

 aldehyde. A determination of the molecular dispersion of the three 

 above-named hydrocarbons showed considerable deviations from the 

 values calculated. 



*) Report October 1904, 14; April 1906, 109; October 1907, 113: November 

 1908, 153. 



2 ) Recueil des trav. chim. des Pays-Bas 27 (1Q08 422. From a copy kindly 

 sent to us. 



