Vegetable oil should dissolve very nicely in gasoline. In the past, Iíve used gasoline to dissolve grease on a bicycle chain. This is entirely not recommended, as gasoline is flammable and explosive, and prolonged exposures to its vapors can be harmful. But itís a great solvent. Other solvents, like turpentine, are also flammable, and some, like benzene, are carcinogenic.
Gasoline is also very volatile -- it evaporates quickly at room temperature in air. You can take advantage of this and put your gasoline-oil solution in a tray or something and let it evaporate, taking extra caution to ventilate it well so that gasoline vapors do not build up to an explosive mixture, and to keep all sparks and flames away.
One problem with this is that gasoline has many component hydrocarbons of differing volatilities. It even contains paraffins (waxes). Even after most of it is gone, some bits may still be left. Iíd not try to put the remaining vegetable oil on my salad.
If your plan was to recover the gasoline and not the oil, you may want to re-condense the gasoline vapors somewhere else with a cooled condenser coil.
Extra bonus fun facts: Diesel fuel is a mixture of oil and gasoline -- you can do your own separation ("refining") in this way.
Soybean oil is commonly extracted from soybeans by grinding them up and dissolving the oil with hexane, a hydrocarbon, which is a component of gasoline. The hexane is evaporated, leaving the oil behind. The hexane can be re-condensed for recycling in the process. Itís better to use pure hexane than gasoline here because gasoline has all kinds of other stuff which may contaminate the oil.
(published on 10/22/2007)