Methanol attacks aluminum oxide?

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Offline lightarrow

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Methanol attacks aluminum oxide?
« on: 22/01/2009 12:19:46 »
wiki says that CH3OH attacks some metals, e.g. aluminum:
http://en.wikipedia.org/wiki/Methanol
Quote
One of the drawbacks of methanol as a fuel is its corrosivity to some metals, including aluminum. Methanol, although a weak acid, attacks the oxide coating that normally protects the aluminium from corrosion:

    6 CH3OH + Al2O3 → 2 Al(OCH3)3 + 3 H2O

The resulting methoxide salts are soluble in methanol, resulting in clean aluminum surface, which is readily oxidized by some dissolved oxygen. Also the methanol can act as an oxidizer:

    6 CH3OH + 2 Al → 2 Al(OCH3)3 + 3 H2

This reciprocal process effectively fuels corrosion until either the metal is eaten away or the concentration of CH3OH is negligible. Concerns with methanol's corrosivity have been addressed by using methanol compatible materials, and fuel additives that serve as corrosion inhibitors.
My question is: is that really true or it's more a legend? How the heck methanol attacks aluminum oxide?

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Offline Bored chemist

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Methanol attacks aluminum oxide?
« Reply #1 on: 22/01/2009 19:12:04 »
I think that the reaction would be, at best, very slow except in the presence of some acid or base to form an aluminuim salt or an aluminate.
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Offline lancenti

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Methanol attacks aluminum oxide?
« Reply #2 on: 23/01/2009 15:49:10 »
http://cat.inist.fr/?aModele=afficheN&cpsidt=15593271

If that link is correct, then I would go with Myth since if you can study it adsorbing onto the surface, that means it doesn't react spontaneously. Then again, you probably still could but it'd be pointless since it'd be a kinetics-like experiment rather than anything else.