Sauron - 2-10-2007 at 07:12
The combination of phthaloyl chloride and chlorosulfonic acid has been found to directly convery carboxylic acid esters to acyl chlorides.
RC(O)OR -> RC(O)Cl
See attachment'
[Edited on 2-10-2007 by Sauron]
[Edited on 2-10-2007 by Sauron]
Attachment: jo01327a058.pdf (287kB)
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chemrox - 2-10-2007 at 20:56
Thanks for the post. I'm a little shakey on the application ... but it's good to know about it and have paper.
Sauron - 2-10-2007 at 21:26
Phthaloyl chloride is not too hard to make, benzotrichloride and phthalic anhydride in an autoclave for 20 hrs (overnight, giving very high yields of
both phthaloyl chloride and benzoyl chloride.
Chlorosulfonic acid, is easy, run dry HCl into oleum or preferably neat SO3. Exothermic, and dealing with oleum/SO3 and chlorosulfonic acid is always
an adventure.
Forget about the substrate in that paper. The reaction is a general one, so acetyl chloride from ethyl acetate, propionyl chloride from ethyl
propionate, and so on. Benzoyl chloride from ethyl benzoate. Only the acid group of the ester matters. The alcohol side can be anything.
I don't think this is going to replace benzoyl chloride, or TCT, but we have elborated how to make SO3 from ferric sulfate have we not?