304 Unversity Geological Survey of Kansas. 
HYDROCARBONS OF THE SERIES CnHoniz. PARAFFINS AND ISOPARAFFINS. 
All hydrocarbons of this series are saturated.??2 
1. Gases.?48 
Five gaseous saturated hydrocarbons are found dissolved in 
petroleum whose molar weights are 16, 30, 44, 58 and 58, cor- 
responding to the formule CH:, C2Hs, C:Hs, CsHw and C:H«, 
respectively. In percentage composition also they agree theo- 
retically with these formule. According to our modern 
theories of structural chemistry there should be two isomers of 
the formula C:H», but no isomers of lower molar weight. All 
the gaseous hydrocarbons, therefore, that are theoretically pos- 
sible in this series, occur in petroleum. The first of these is 
methane, or marsh-gas, the principal constituent of natural 
gas. The others, ethane, propane, butane and isobutane, occur 
in relatively small quantities. 
2. Liquids. 
_ Liquid saturated hydrocarbons corresponding in percentage 
composition and in molar weight to all possible empirical for- 
mule from C;sH», pentane, to CuwHu, hexadecane, have been 
isolated from Pennsylvania petroleum. They range in density 
between 0.626 at 0° to 0.7925 at 20°, and in boiling-point be- 
tween 37° and 275°. The number of isomers theoretically pos- 
sible within these limits is very great; so great that in many 
cases the difference in boiling-point between the different 
chemical individuals may be only a fraction of a degree, so that 
their separation by means of fractional distillation is impossi- 
ble. 
3. Solids. 
With only three exceptions, all the members of the paraffin 
series having molar weights corresponding to the empirical 
formule from CvH« up to C»Hez have been found in petro- 
leum. The three exceptions, heptacosane (CH), triacon- 
tane (C»He) and tritriacontane (CsHe) have been found in 
paraffin obtained from German brown coal.?44 These hydrocar- 
bons range in melting-point between 10° and 76°, and the spe- 
cific gravity of the highest member reaches 0.805 at 80°. It is 
probable that further research will reveal the presence of still 
242. A saturated hydrocarbon is one that is not capable of uniting with more 
hydrogen. An unsaturated hydrocarbon may unite with hydrogen to form a satu- 
rated hydrocarbon. Ex. C,H,+H,—C,H,. 
243. Ronalds, Jahresbericht der Chemie, 1865, 507, c.f. Jour. Amer. Chem. ‘Soc. 
80, 142; 1908. 
244, Krafft. Berichte d.d. chem. Ges. 40, 4779; 1907. 
