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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: 4nnie on December 15, 2013, 01:22:17 PM

Title: Aldehyde and carboxylic acid
Post by: 4nnie on December 15, 2013, 01:22:17 PM
What product would you expect in a reaction of an aldehyde and a carboxylic acid?
It is in my questionaire for an exam, so I'd like to find out what the teacher wants me to do here.

I honestly cannot find anything anywhere. It's not an oxidation, I found lots about that...

My thoughts so far:

The only thing I could come up with was a hemiacetal... although that might be wrong. I know carboxylic acid is not alcohol, but there is an -OH group in there, that could be a nucleophile... so could it happen theoretically, meaning that the equilibrium is far on the left. (?) It could be a hemiacetal even with the oxygen on a double bond, could it?
Or is there some srewed up way we could get an aldol out of there...
or any other ideas??
Thank you in advance!
annie
Title: Re: Aldehyde and carboxylic acid
Post by: Hunter2 on December 15, 2013, 01:46:17 PM
Think about mesomer aldehyds with alkeneole
Title: Re: Aldehyde and carboxylic acid
Post by: 4nnie on December 15, 2013, 03:35:29 PM
?

So what you are suggesting is that the aledyde can turn into an alkeneole and therefore I have an alcohole and carboxylic acid and could get an ester?
Title: Re: Aldehyde and carboxylic acid
Post by: Hunter2 on December 16, 2013, 02:19:43 AM
yes correct.

How to make Vinylacetate?
Title: Re: Aldehyde and carboxylic acid
Post by: 4nnie on December 16, 2013, 12:46:31 PM
Ok. Thank you. That makes sense :)

But one can generally say that this is a very unlikey reaction, because the aldehyde is far more on the aldehyde side, and alkeneoles turn into aldehydes again, but it is possible, that is the point.

And just for the record: Why is the hemiacetal even more unlikely? Because the OH-group is stabilized through the resonance of the double bonded oxygen. And that tones down its nucleophilic properties, correct? Is that why carboxylic acids are not as reactive as alcohols?
Title: Re: Aldehyde and carboxylic acid
Post by: AlphaScent on December 16, 2013, 08:08:40 PM
Even though mesomer is a term that can be used.  Resonance is the proper, english terminology.  By Alkenole do you mean enol? I am having trouble following.