AJKOER
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Encouraging an naturally occurring electrochemical
Per this reference (see full paper at http://www.jim.or.jp/journal/e/pdf3/50/06/1433.pdf ). , the following corrosion reaction naturally takes place:
Al = [Al]3+ + 3 e as the anodic reaction.
and
2Et-OH + 2 e = 2 [Et-O]- + H2 as the cathodic reaction.
Anhydrous AlCl3 is added to the 99.5% Ethanol (Et-OH) to serve as the electrolyte.
My questions are if one added an external current, would the indicated reactions proceed more rapidly?
A more complex question is as a significant amount of water interferes with the chemical reaction (more precisely the reaction between Aluminum and
Ethanol), would a new electrochemical reaction take place removing the water so that the above reaction could proceed in any event?
Thanks for any input.
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Fantasma4500
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probably not the answer youre looking for, but i mean to understand that ethanol doesnt react with aluminium or aluminium oxide (or well not very
much)
i got some high conc. ethanol standing around from accidental destillation so to say, and i filled in aluminium foil (as methanol which was the
impurity i wanted gone) because aluminium foil have a layer of aluminium oxide on it, which methanol happens to react with going into H2O and CO2
but ethanol is a base, so as aluminium metal already reacts very slowly with water it would be plausible there would also be a reaction with ethanol
and aluminium..
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Metacelsus
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As to adding a current, I doubt the conductivity of ethanol (even with a few % water) is great enough for any appreciable current to flow. You could
try it, I guess, with aluminum as the anode.
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DraconicAcid
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Quote: Originally posted by Antiswat  |
but ethanol is a base, so as aluminium metal already reacts very slowly with water it would be plausible there would also be a reaction with ethanol
and aluminium.. |
Don't be fooled by the OH at the end of EtOH or CH3CH2OH- ethanol is less basic than water. In the proposed reaction, ethanol
is acting as an acid with a reactive metal (just like reactive metals react with water, and less reactive metals react with, say, hydrochloric acid).
This may be sped up with a current, but as Cheddite says, ethanol's a very poor conductor of electricity (unless you've got a lot of aluminum chloride
in there). You might make the aluminum more reactive by making an amalgam with mercury or gallium.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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AJKOER
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Draconic Acid:
Usually a small amount of water (just a couple of percent) stops the normal chemical reaction between the alcohol and Aluminum (true for
Aluminum/Methanol as well). Note,the reference paper I supplied indicates that heating the alcohol pushes the normal chemical (or is it the normal
electrochemical) reaction.
So, if unwanted H2O is present, would a electrochemical breakdown of the water in the Al/AlCl3/Ethanol cell occur with current? In other words, is it
your opinion that a current could eventually make the cited reaction proceed upon decomposition of the H2O?
[Edited on 4-4-2013 by AJKOER]
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DraconicAcid
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If unwanted water is present in the solution, it may react with the aluminum chloride, or it may react at the aluminum to passivate the metal (coating
it with aluminum hydroxide). Destroying it electrochemically might work. It might be easier just to add more aluminum chloride.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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AJKOER
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| Quote: Originally posted by DraconicAcid | | If unwanted water is present in the solution, it may react with the aluminum chloride, or it may react at the aluminum to passivate the metal (coating
it with aluminum hydroxide). Destroying it electrochemically might work. It might be easier just to add more aluminum chloride.
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Yes, adding the aluminum chloride would be easier if one has the anhydrous AlCl3 and not the hydrate.
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