MABERY. 



CONSTITUENTS OP PETROLEUM. 



161 



A determinatiou of the specific gravity of this distillate at 20° gave 

 0.7770, a value somewhat higher than the specific gravity of the corre- 

 sponding Ohio distillate. For the removal of the aromatic hydrocarbons 

 to determine the boiling point of the principal constituent, all the frac- 

 tions 168°-173° were agitated and warmed with fuming sul[)liuric acid, 

 washed, dried, and the distillation continued until after a few repetitions 

 the fractions came together at 1G9°-170'^ (730 mm.), or under 7G0 mm., 

 and with the mercury column all in the vapor at 173°-174°. By this 

 treatment the specific gravity was reduced to 0.7614, and the percent- 

 ages of carbon and hydrogen changed in a proportionate degree : — 



I. 0.1545 gram of the oil gave 0.4810 gram CO2, and 0.2091 gram 

 H.,0. 

 II. 0.1446 gram of the oil gave 0.4485 gram CO2, and 0.1946 gram 



H,0. 

 III. 0.1678 gram of the oil gave 0.5204 gram CO., and 0.2246 gram 

 H2O. 



Although these results indicate t'le removal of a large portion of the 

 aromatic hydrocarbon, and analyses II. and III. were made of different 

 specimens with the action of the acid continued several hours, it is evi- 

 dent that the less hydrogenized body was not even then entirely re- 

 moved. In further confirmation of the presence still of this constituent, 

 one of the oils treated with the fuming acid was shaken with a mixture 

 of nitric and sulphuric acids. The solution became warm and an oily 

 nitro product separated above the acid. Since MarkownikofF preferred 

 purification of the Russian oil with sulphuric acid to avoid the formation 

 of objectionable nitro products, it was inferred that this acid should 

 remove completely the aromatic bodies. But in our experience 

 with American oils, complete purification cannot be reached with the 

 fuming acid alone. At first we relied on decomposition of the nitro 

 product with sodium ; but this required long digestions several times 

 repeated, and in Canadian distillates the residual hydrocarbon which 

 contained the nitrogen could not always be entirely removed, as 

 shown by analysis of a portion of crude distillate purified in this 

 manner : — 



VOL. XXXII. — IJ 



