MABERY, — SULPHUR PETROLEUMS. 29 



HgClsR^Sj or in some other combination. This peculiarity has 

 occasioned us much trouble in purifying distillates above 200°. In 

 some of these products, hydric sulphide in the cold will not precipitate 

 the mercury; frequently it is only after prolonged action with the aid 

 of heat that the mercury can be completely removed. These sulphur 

 oils seem to possess the property of dissolving metals, metallic oxides, 

 and other compounds, which has been observed in other petroleums. 

 The action of paraffine oils on metals has been examined by 

 Macadam,* who finds that lead, solder, and zinc are quite readily, 

 tin and iron but slightly, affected. Some oils have a greater solvent 

 action than others, and Macadam attributes it to the hydrocarbons. 

 Engler f repeated the experiments of Macadam, and observed that 

 metals were not affected when air is excluded. It was therefore 

 inferred that acid compounds are formed in the oil by exposure to air, 

 and also metallic oxides, which are dissolved by the acids. Engler 

 does not attribute the solvent action to ozone. It is probable that the 

 purification of refinery distillates from the sulphur petroleums, by 

 agitation with an alkaline solution of plumbic oxide, depends, at least 

 in part, upon the solvent action of certain constituents of the oil. 

 Oxygen compounds, which are doubtless present in these oils, may 

 assist the action, as has been observed in other oils. This subject will 

 receive further attention when we reach the higher distillates. 



After removal of the sulphur compounds, each distillate for vapor 

 density determination was thoroughly agitated, first with concentrated 

 nitric, then with concentrated sulphuric acid, washed, and dried. 

 Finally, under a return condenser, it was heated for some time with 

 metallic sodium. 



From 41.5 kilos distilled in vacuo, at the end of the eighth dis- 

 tillation, the last seven under atmospheric pressure, the following 

 weights were obtained with much smaller quantities outside these 

 limits : — 



—55° 58 ^-62° 65^-68'^ 77^-83=' 



Grams 15 120 310 85 



As already mentioned, on account of loss from the diminished 

 pressure, as well as the unavoidable lo^s in any distillation, the 

 weights of the lower fractions collected in vacuo evidently cannot be 

 accepted as representing even approximately the quantities present ia 

 the crude oil. 



* Journ. Chem. Soc, 1878, p. 355. 



t Ber. der deutsch. chem. Gesellsch., 1878, p. 2186. 



