[ggfdpmro] Turning gasoline into water

You are stuck on a desert island but with a large amount of gasoline.  Turn it into drinking water.

Arbitrarily disallow the straightforward idea of burning it, producing carbon dioxide and water vapor, then condensing the water vapor into liquid water.  If we had a way of condensing water vapor, we could have already extracted water from the ambient atmosphere.

Nevertheless, the best ideas I can think of are still(!) variations of the disallowed idea: Boil (using gasoline) ocean water and distill it, using more ocean water outside the still to cool and condense the vapor.  Build a dehumidifier powered by gasoline and condense water vapor from the ambient atmosphere.  We would need refrigerant: make ammonia?

Unknown is the difficulty of building a fuel cell to oxidize gasoline at lower temperatures.

Even if we re-allow the disallowed idea, it still(!) seems pretty tricky to capture the water vapor from combustion with high efficiency.  The flame needs a connection to the outside air to provide oxygen, but we need to prevent water vapor from exiting out that connection.  Similarly, we need to capture the water vapor but allow the carbon dioxide to vent away so it doesn't extinguish the flame.  This latter task can be done with a still, but I worry that the convoluted path of the hot gas through the still will induce the hot gases to try to escape some other way, perhaps through the oxygen inlet.

Previously: a small form factor.