6 RICHMOND. 



The acid layer, for the separation of the aromatic from the other 

 unsaturated hydrocarbons, was largely diluted with water, calcium car- 

 bonate added to slight excess, and the brown solution of calcium sul- 

 phonates separated from the precipitated calcium sulphate by filtration 

 and evaporated to dryness on a steam bath. 



An attempt to recover the benzene homologues by steam distillation 

 of the sulphonic acid salts in the presence of phosphoric acid alone * was 

 unsuccessful. 



Approximately 500 grams of the dry calcium sulphonates were mixed with 500 

 grams of glacial phosphoric acid, (specific gravity 1.715) and subjected to ex- 

 haustive steam distillation, but only about 5 cubic centimeters of oil were 

 recovered from a liter of aqueous distillate. The maximum temperature attainable, 

 namely, the boiling point of glacial phosphoric acid (130°), was insufficient to 

 cause hydrolysis of the sulphonic acids present. 



At this stage, about 200 grams of concentrated sulphuric acid were added to 

 the contents of the flask and the distillation continued. The temperature rapidly 

 rose to 140° and hydrocarbons began to distill freely. The temperature gradually 

 rose to 170°, at which point the distillation was practically finished. A total 

 volume of 148 cubic centimeters of oil, approximately 50 per cent of the unsaturated 

 hydrocarbons present in the crude oil, was obtained. The oil was washed with 

 water dried over calcium chloride and separated by distillation into the following 

 fractions : 



Per cent by 

 Initial boiling point, 130° volume. 



First fraction, 130° to 150° 25 



Second fraction, 150° to 200° 38.5 



Third fraction, 200° to 250° 17 



Fourth fraction, 250° to 300° 17 



Residue by difference 7.5 



Total 100.00 



Each of the above fractions was nitrated and the derivatives obtained showed 

 a close homologous series of aromatic hydrocarbons beginning with xylene, CgHn,. 

 Neither benzene nor tuolene nor any of the naphthalene series were found. 



THE KEFINED OIL. 



The oil remaining from the acid treatment, consisting of 70 per cent 

 of the original crude petroleum " by volume, was further refined by 

 thorough agitation with strong caustic soda, and then washed with water 

 and dried over calcium chloride. The specific gravity of the dry oil was 

 0.793 at 15° C, at which temperature it became somewhat cloudy, due 

 to the separation of solid hydrocarbons. At 0° C. it was quite viscous and 

 at — 5° it was completely solid. 



'Friedel and Crafts. Compt. rend. Acad. set. (1889) 109, 95. 



