1865.] of the Series C n lI 2R+y 465 



series exhibits cases of absolute isomerism, can only be definitely decided 

 by obtaining from different sources perfectly pure hydrocarbons, having 

 the same composition. But unfortunately only a few of the hydro- 

 carbons can be obtained perfectly pure, and still fewer of these possessing 

 the same composition can be derived from different sources. This is seen 

 by a glance at the following Table, containing those alcohol-radicals and 

 hydrides which have been obtained with certainty in a pure state. 



Boiling-points, Boiling-points. 



C H 8 Methyl. Hydride of ethyl. 



G; H 10 Ethyl. 



C 3 H ]2 Hydride of Amyl .... 30 



C 6 H u Ethyl-butyl 62 Hydride of hexyl * . . 69'5 



C 7 H 16 Ethyl-amyl 90 Hydride of heptyl f . . 99 



C 8 H 18 Butyl 108 



C 9 H 00 Butyl-amyl 132 



C 10 H 2 " 2 Amyl ..." 158 



C 12 H 2C Hexyl (caproyl) 202 



For the purpose of examining the question of the identity or the 

 isomerism of these hydrocarbons, I selected methyl-hexyl and hydride of 

 heptyl, obtained from azelaic acid, comparing the properties of these bodies 

 with ethyl-amyl, as described in my last communication. 



(1) Methyl-hexyl. 



Methyl-hexyl (methyl-caproyl) has already been prepared by \Vurtz 

 by the electrolysis of a mixture of acetate and oenanthylate of potas- 

 sium, but he has obtained it in a small quantity only, and in a very 

 impure state J. I adopted the same method, and am able to confirm all 

 that Wurtz has stated. Although I employed several ounces of cenanthy- 

 late of potassium, only a very inconsiderable quantity of an aromatic oil 

 was obtained, which, in order to isolate the hydrocarbon C 7 H, 6 , was first 

 distilled with concentrated sulphuric acid, by the action of which sulphu- 

 rous acid was evolved and a black charry matter separated out. The oily 

 distillate was well washed and further purified by means of nitric acid, 

 caustic potash, and sodium, as described in my former papers, and then 

 the small quantity of methyl-hexyl separated by fractional distillation from 

 hexyl, C ]2 H 26 , which latter hydrocarbon is formed in by far the greatest 

 proportion. 



Methyl-hexyl boils at 89-92C., and has the specific gravity 0-6/89 

 at 1 9 C. The analysis gave the following numbers : 



0-2002 substance gave 0'6150 carbonic acid and 0'2900 water. 

 Calculated. Found. 



C 7 84 83-78 



H 10 _16 16-14 



100 99-92 



* Dale, Journ. Chem. Soc. New Ser. ii. p. 258. t Ibid. 



I Ann. de Chim. et de Phys. 3 scr, xliv. 296. 



