of Heat and Pressure upon the Paraffins. 



189 



olefine. The distillate was then treated with aqueous potash to remove 

 the free bromine, and when colourless the hydrocarbon was decanted, 

 dried, and distilled over sodium; it boiled almost entirely between 

 65° and 70°, by far the greater portion coming over at 67-68°. It was 

 analyzed with the following results : — 



0-1440 grin, hydrocarbon gave 0*2095 grin, water; the carbon deter- 

 mination was lost. 



Calculated. Found. 



C 6 83-72 — - 



H u 16-28 16-16 



100-00 



Two determinations of its specific gravity made by means of different 

 bottles gave : — 



(1) 0-6620 at 19°-5, and 



(2) 0-6641 at 18°. 



Compared with water at the same temperature, Pelouze and Cahours 

 found 0-669 at 16° for the hexane boiling at 68° obtained from American 

 petroleum. Hexane from suberic acid, boiling at 69°-5, according to 

 Dale, has a specific gravity of 0*6617 at 17°- 5 ; this agrees with that of 

 (5 hexane obtained from mannite, viz. 0*6645 at 16°*5. Schorleininer 

 found 0*678 at 15°*5 for the hydride from cannel coal, which agrees 

 perfectly with that obtained by Williams for the same hydride prepared 

 from boghead coal, viz. 0*6745 at 18°. On the other hand, Schorlemmer 

 has found that the hexane prepared from mannite is probably identical 

 with that obtained for secondary hexyl iodide by the action of zinc and 

 hydrochloric acid, and with the dipropyl obtained from primary hexyl 

 iodide, for which he found the specific gravity 0*6630 at 17°; and these 

 are probably identical with the hexane of Pelouze and Cahours obtained 

 from petroleum, and with the hydride found by Schorlemmer in cannel 

 oil, all being normal hydrocarbons with the constitution 

 CH 3 — CH~-CH 2 ~-CH — CH 2 —CH 3 . 



The brominated hydrocarbon left in the flask after removing the 

 hexane was then distilled : it commenced to boil at about 190° ; the ther- 

 mometer gradually rose to 195°, and nearly the whole of the liquid 

 distilled over below 205°. As the compound showed signs of decompo- 

 sition on boiling, hydrobromic acid being continuously evolved during 

 the distillation, a considerable amount of tarry matter remaining in the 

 flask, it was impossible to fractionate it further. It was purified, how- 

 ever, by distillation in a current of steam ; it was nearly colourless, and 

 on analysis yielded numbers agreeing with the formula C 6 H 12 Br 2 . 



0*8950 grm. of the bromide gave 1*3570 grin, silver bromide and 

 0*0090 grm. reduced silver. 



Calculated. Found. 



Br , 65-57 65-28 



b2 



