110 PROCEEDINGS OF THE AMERICAN ACADEMY. 



tion to show that they contained unsaturated hydrocarbons (Am. Chera. 

 Journ., 16, 92). 



Upon returning to these distillates, it was found that some of them 

 had undergone a marked change. Those collected at certain tempera- 

 tures, — especially at 44°-45°, seventh distillation, 50 mm.; 70°-71°, 

 twenty-second distillation, atmospheric pressure; 97°-98°, tenth distilla- 

 tion, atmospheric pressure; 118°-119°, tenth distillation, atmospheric 

 pressure, — corresponding in part to the boiling points of well-kuown 

 hydrocarbons of the ethylene series C n H 2n , had deposited in considerable 

 quantities heavy dark red oils, evidently products of polymerization. 

 Some of the polymerized oils were found to contain as much as 8 per 

 cent of sulphur, although polymerization took place in oils containing 

 not more than 1.5 per cent of sulphur. It was interesting to observe 

 that distillates on either side of those from which the heavy oils separated 

 remained unchanged and were scarcely more discolored than when they 

 were first distilled. That the distillates below 150° contain sulphur 

 compounds with a peculiar odor, attacking the eyes and in other respects 

 different from the series C n H. 2n S described above, has been apparent since 

 the first distillatiou of these oils, although these peculiar compounds are 

 evidently present in much smaller proportions than the others. 



All these fractions, as well as those above 150°, united with bromine 

 with explosive violence, and with the evolution of great heat. The 

 bromine addition products, however, were found to be so unstable that it 

 was impossible to purify them by distillation even in vacuo. They de- 

 composed rapidly even on standing with the separation of hydro- 

 bromic acid. In ascertaining the composition of these hydrocarbons we 

 have, therefore, relied on the more stable addition product obtained with 

 hydrobromic acid, which had the further advantage that, having no action 

 on the sulphur compounds, the latter need not be removed before heating 

 with the acid. 



Hexylene. 



For the identification of hexylene, the small quantity of the fractions 

 70°-80°, twenty-second distillation, atmospheric pressure, were put to- 

 gether, and a portion was heated to 120° during five hours with fuming 

 hydrobromic acid. The product was washed, dried, and fractioned in vacuo. 

 On account of the higher boiling point of the bromide it was easy to sepa- 

 rate the addition product, and of the small quantity obtained, the greater 

 portion collected at 62°-65°, 50 mm. The boiling point of the bromide 

 under atmospheric pressure could not be determined on account of its 





