174 PROCEEDINGS OF THE AMERICAN ACADEMYo 



Petroleum decane boils at 163°, and its specific gravity at 20° is 0.7479. 

 lu a similar reaction using amjl bromide, Grimshaw * obtained a decane 

 boiling at 168°, under 751 mm. Either the normal bromide must have 

 been used in this reaction giving normal decane, or the boiling point of 

 the product is too high. 



Kormal hendecaue (or undecane) was prepared by KrafFt f from the 

 aldehyde raulenol by the same reaction that he used for decane. Its 

 boiling point is given as 194°.5 under 760 mm., and the specific gravity as 

 0.7411 at 20°. Since the boiling point, 196°-197°, and specific gravity, 

 0.7581, of petroleum hendecane and the formula of this body, C11H24, 

 determined by its molecular weight, correspond so closely to normal hen- 

 decane. it has doubtless the same form. As already explained, the higher 

 specific gravity may be due to a small proportion of a naphtene. 



The formula C12H26, which represents the petroleum hydrocarbon 

 boiling at 214°-216°, is supported by that of normal dodecane which 

 Krafi't t obtained by the reduction of laurinic acid. Normal dodecane 

 boils at 214°. 5, atmospheric pressure, and its specific gravity at 20° is 

 0.7511. The specific gravity of petroleum dodecane was found to be 

 0.7729. 



Relation between Specific Gravity and Chemical Compo- 

 sition OF Petroleum Distillates. 



One interesting result of the examinations described in this paper, and 

 other papers of this series, is the relation between the chemical composition 

 of the individual hydrocarbons and the density of the crude oils from 

 which they were prepared. Pennsylvania petroleum with the lowest spe- 

 cific gravity, 0.80-0.82, is composed below 220° of the hydrocarbons 

 C„H2„+2- Ohio oil. next higher in the scale of specific gravity, 0.82-0.85, 

 still contains below 220°, as its principal constituents, hydrocarbons of 

 the same series. As the density increases, in the Canadian oil, specific 

 gravity 0.85-0.88, the series C„Ho„_^.2 represents the principal constitu- 

 ents up to and including decane, boiling point 173°, the higher members 

 having the composition C„H2„. But oils with higher specific gravity, 

 such as a South American petroleum, specific gravity 0.941^0, described in 

 another paper of this serie-, contain only hydrocarbons of the series C„H2„, 

 and in Caucasus petroleum, specific gravity 0.88, Markownikoff and Oglo- 

 bine found as the principal constituents the naphtenes, series C„H2„. 



* Ber. der deutsch. chem. Gesellsch., X. 1602. t Loc. cit., 1698. 



t Ibid., X. 1697. 



