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Sep23-10, 01:34 PM
I think people are making this out to be way more complicated than it is.
The ethanol burns first partially because it can vaporize and better mix with air, and partially because it coats the paper. Ethanol rapidly evaporates, and it's much easier to ignite as a gas than as a liquid as it's better mixed with oxygen in the air. It's also all about surface area - the combustion reaction only takes place at the surface of anything. Therefore, if your paper is covered in ethanol, the ethanol must first burn away before the paper can start reacting with the air and also burn.
This also has nothing to do with autoignition, I'm not sure where that's coming from. Autoignition temperature is the temp. at which the material will ignite spontaneously, without any ignition source. Since we are talking about dipping paper in ethanol and intentionally lighting it on fire (not gradually heating it to high temperature), autoignition doesn't come into play here.
Which is what I tried to explain too...