thors.lab - 9-11-2020 at 09:29
Hi,
I heard from the grapevine that straight chain acyl chlorides like propionyl chloride can be produced using TCCA and the respective aldehyde in DCM. I
haven't been able to find any writeups confirming this route though. Any thoughts?
Big if true.
Thanks
clearly_not_atara - 9-11-2020 at 12:04
It's highly unlikely. The same reaction is well-known for benzoyl and alpha-quaternary chlorides (think pivaloyl). However the rxn side-product is HCl
which catalyzes the alpha-chlorination of aldehydes, the aldol condensation, and the polymerization of aldol products. As such, the likely product of
rxn of propanal + TCCA in DCM is a polymeric tar.
However, a similar rxn might be possible with e.g. Br2 in tetra due to the suppression of ionic rxn mechanisms. Extremely anhydrous conditions are
essential but may not be sufficient.
[Edited on 9-11-2020 by clearly_not_atara]
thors.lab - 10-11-2020 at 00:45
Disappointing but interesting, thanks.
Prepic - 10-11-2020 at 08:33
I've always planned to eventually get around to try and make acyl chlorides from the corresponding aldehyde as described in "Trichloroisocyanuric
Acid: a Versatile and Efficient Chlorinating and Oxidizing Reagent"(linked below).
At least according to the article, aliphatic and aromatic aldehydes were successfully converted to their acyl chloride derivatives in DCM after
several days at room temperature.
I may be speaking under correction but I believe the TCCA would react with the aldehyde to form isocyanuric acid and the acyl chloride derivative
without releasing HCl.
So I hate to repeat the question, especially after receiving a response from a member far more educated than myself, but does this reaction really
posses no hope?
Attachment: Trichloroisocyanuric Acid a Versatile and Efficient Chlorinating and Oxidizing Reagent .pdf (1.6MB)
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