kclo4
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Why make methane from acetates?
Well I am not sure were to ask this but
Why does every one make methane from acetates and hydroxides when it would be easier and cheaper to make it from acetone and a water-soluble hydroxide
and water?
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BromicAcid
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Probably because acetates are widely avalible and the decarboxylation reaction is fairly reliable and produces good quantites of methane. How does
the reaction with acetone proceed exactly to produce methane, which kinds of yields?
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kclo4
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Well if you add sodium hydroxide to water then add that to acetone it bubbles about the equivalent of vinegar and baking soda so good I guess
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Polverone
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The water and NaOH grow hot when mixed together. When combined with low-boiling acetone, the mixture boils. Mixing together strong, room-temperature
NaOH solution with acetone does not show any immediate reaction. Neither does mixing acetone with dry NaOH. Both will discolor with the formation of
acetone condensation products after some time (delay depending on temperature and concentration).
PGP Key and corresponding e-mail address
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kclo4
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hmm I will test it better tomorrow why wouldn’t these work
(CH3)2CO + 2NaOH = 2CH4 + Na2CO3
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unionised
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Why would it work?
Just because an equation balances doesn't mean the reaction happens.
In fact, a different reaction takes place producing diacetone alcohol.
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kclo4
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Well stupid me did not think to analyze
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denatured
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I never heard of such a reaction, i think producing Methane in a convenient way can be done by dropping water on Aluminum Carbide.
Al4C3 + 12H2O ---> 3CH4 + 4AL(OH)3
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12AX7
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You'd think so, but the last time I synthesized some Al4C3 it didn't bubble at all. I've had bad luck with CaC2, too...
However, the yellow metallic crystalline lumps have decomposed entirely to a gray pile sitting on a paper in my room here, so oxygen and/or moisture
certainly do work away at it eventually.
Tim
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denatured
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I don't know what was wrong with me when i said that .... its all because of that ancient textbook.
It says "Another convenient laboratory method of preparing methane is by the action of water on aluminium carbide"
p59.Organic Chemistry - Pavlov Terentyev - MIR
Maybe it is easy way when you have cheap Al carbide but when 50 grams of it sold by 400 USD , things become ugly!
And now i may say acetate-hydroxide route is convenient ... but i am not sure(i have not tried it yet)
12AX7 did you really synthesized Al4C3 ?
as i know it needs extremely high temp. to combine carbon and Al.
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12AX7
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Ya, just arc-melt some aluminum onto some charcoal. It also sticks to the graphite arc rods, so be careful. 
Tim
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Danne123
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| Quote: | Originally posted by kclo4
Well stupid me did not think to analyze |
How do you analyze if a reaction takes place or not?
We haven´t learnt it yet in the chemistry class yet...
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sparkgap
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Apart from actually performing the reaction  , maybe compute its Gibbs free
energy? (Google for details)
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
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Danne123
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| Quote: | Originally posted by sparkgap
Apart from actually performing the reaction , maybe compute its Gibbs free
energy? (Google for details)
sparky (~_~) |
You are talking about a exothermic reaction.
But there can be two types of reactions exothermic and endothermic. How do you know that it won´t be a endothermic reaction? Since we don´t know if
there will be a reaction or not you can´t calculate "deltaH" or gibbs energy?
What is it called in english?
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neutrino
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The gibbs equation works regardless of whether the reaction is endothermic or exothermic.
In reality, dG doesn't help you much. An equation with a negative dG won't necessarily happen with any speed at STP (like the conversion of
diamond to graphite). A positive dG doesn't mean that the equation doesn't happen, either: it just means that the Keq of the equation is
below 1.
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Danne123
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| Quote: | Originally posted by neutrino
The gibbs equation works regardless of whether the reaction is endothermic or exothermic.
In reality, dG doesn't help you much. An equation with a negative dG won't necessarily happen with any speed at STP (like the conversion of
diamond to graphite). A positive dG doesn't mean that the equation doesn't happen, either: it just means that the Keq of the equation is
below 1. |
How do we know if there will be a reaction or not then? When the gibbs energy won´t help us. 
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