How to turn acetaldehyde into acetic acid using one of the five chemicals on the list?

Question

It's easy to see $X$ is $\ce{H2O}$: water turns acetylene into acetaldehyde.

But what can turn acetaldehyde into acetic acid?

I checked: $\ce{NaOH}$ would turn it into sodium acetate, $\ce{CuO}$ would not react (you'd need $\ce{Cu(OH)2}$), ethanol would turn it into either an acetal or hemiacetal.

Would acetaldehyde react with formic acid to produce acetic acid? I tried to google for it, and found no mention.

Would water in the presence of a heat source somehow react with acetaldehyde? I googled and discovered that it might form hydrates, not acetic acid.

So I'm at a loss. If you consider the question too easy, you could give just a hint.

I don't think it's a stretch to think that two copper(II) reagents would both do the trick, considering one is essentially just the hydrated form of the other... — Zhe, Apr 24 '17 at 13:41
https://chemistry.stackexchange.com/questions/50642/can-oxidation-of-ethanol-by-copperii-oxide-yield-copperi-oxide-as-one-of-the — Nilay Ghosh, Apr 24 '17 at 14:25

score 5 · Accepted Answer · answered Apr 24 '17 at 13:43

5

Oxidation of aromatic aldehydes to acids by air oxidation catalysed by CuO is reported in Molecules 2008 13 948

None of the other reagents can oxidise aldehyde to acid.

answered Apr 24 '17 at 13:43

Waylander

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Acetaldehyde isn't aromatic. – Pritt says Reinstate Monica Apr 24 '17 at 13:45
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I know!! But given that CuO oxidises aromatic aldehydes it is not such a stretch to think it probably will oxide acetaldehyde. Plus none of the other options look even remotely right – Waylander Apr 24 '17 at 14:01
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This paper says that acetaldehyde gives high yield of acetic anhydride when copper salts are used as catalyst. – Nilay Ghosh Apr 24 '17 at 14:35
Perhaps, but remember that we are supposed to solve the conceptual difficulties, not eliminate options like in a competitive examination. However I agree that $\ce{CuO}$ has a better chance of oxidizing. – Pritt says Reinstate Monica Apr 24 '17 at 16:01
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A friend who teaches chemistry has just said to me that CuO will first turn into Cu(OH)2 and only then the reaction will proceed. I don't know whether that's true. – CowperKettle Apr 25 '17 at 12:21

How to turn acetaldehyde into acetic acid using one of the five chemicals on the list?

1 Answers1