[Bibinou]

Hello,

Why can't we use an ether as sovant while making a friedel craft acylation?

Thx

[victor]

I think that ether will make a bond with carbonyl group from acyl halide and thus making it become an ester and alkyl halide...That's only my hypothesis, please correct if I'm wrong. I can say like this because of pairs of free electron from O atom in ether and C carbonyl which obtain positive partial charge.

[lavoisier]

I'm not really sure about victor's mechanism. Ethers are said to be quite unreactive, so I wouldn't expect them to attack a carbonyl.

My guess about the reason why ethers are unsuitable for FC acylation is that they would coordinate the Lewis acid, making it unavailable for coordinating the acyl halide (or anhydride).
For the same reason, side reactions like ether cleavage may be expected (ethers are known to be cleaved by strong acids like HI, so...).

The most common solvents for FC are: excess aromatic hydrocarbon if possible, nitrobenzene, CS2 (nice one!), chlorinated solvents, because they are all unreactive towards both the Lewis acid and the acyl halide / acyl halide-Lewis acid complex.

[mkaplan4]

CS2 is nice, if you like the smell of rotten eggs....non reactive aromatics such as toluene, or any of the xylenes work well. It really depends on the temperature you need to make the reaction occur at.