VANADIUM WITH PETROLEUM AND ASPHALT 309 



3. One-tenth gram solid sodium vanadate, 0.2 gram solid sodium sul- 

 phide, and 15 cc. saturated solution of carbon dioxide were brought together. 

 A bulkjf, dark brown precipitate formed almost immediately, but it re- 

 quired six weeks standing to effect complete settling. The precipitate 

 was a sulphide of vanadium. 



4. Solutions of sodium vanadate and sodium hydroxide, and elementary 

 sulphur were mixed thoroughly'. No precipitate formed even on long 

 standing. But on passing carbon dioxide through such a mixture the so- 

 lution became turbid within ten minutes. The precipitation was very 

 slow and it did not really begin to settle out until after about two days. 

 The product was vanadium sulphide. 



5. Sodium vanadate solution was added to a solution of stick sulphur 

 in benzine; no precipitate was formed on standing two days. Carbon 

 dioxide in solution was then added, without a visible reaction taking place. 

 Oil passing hydrogen sulphide into the mixed solutions a dark brown 

 precipitate formed immediately. 



Reactions involving -petroleum* 



6. Five cubic centimeters of the stock solution of sodium vanadate 

 was mixed thoroughly with sulphur bearing petroleum that had been di- 

 luted with kerosene oil (2 cc. petroleum to 20 cc. kerosene). The density 

 of the undiluted petroleum made accurate observations very difficult. 

 No change was observed after the mixture had stood for two days. It 

 was then boiled with a reflux condenser for an hour. A slight precipitate 

 was formed, but this contained no vanadium. 



7. This experiment was a repetition of (6) except that 0.1 gram finely 

 powdered sulphur was added. No different results were obtained. 



8. This was also a repetition of (6) except that 5 cc. of twentieth- 

 normal sodium hj'droxide solution was added. No different results were 

 obtained. 



(6) NaVOs aq. + Sulphur bearing petroleum ] yielded no precipitate 



(7) NaVOs aq. + Sulphur bearing petroleum -f- Sulphur \ containing vana- 



(8) NaVOs aq. + Sulphur bearing petroleum + NaOHaq.J dium sulphide. 



9. Petroleum and sodium vanadate solution were mixed as well as pos- 

 sible and hydrogen sulphide was passed into the mixture. There resulted 

 a very finely divided precipitate that was extremely difficult to filter. 



*The oils used in this investigation contained less vanadium than could be de- 

 tected by the test applied after the reactions. 



