What Are the Products of Chlorinating Diphenylether with Cl2 and FeCl3?

[metalmagik]

Homework Statement

Show the product(s) of chlorination (Cl2, FeCl3) of diphenylether

Homework Equations

None

The Attempt at a Solution

My solutions manual shows products with Chlorine in the para position, and then the ortho position, with a note saying (followed by disubstitution)

I'm really just looking for some clearing up to this answer. I understand that the oxygen in diphenylether is an ortho/para director, therefore placing Chlorine in the ortho and para position. However, I just assumed this would happen on both phenyl rings. Does it depend on exactly how much Cl₂ is provided?

 

[chemisttree]

Yes it does matter how much chlorine is present. The question didn't ask about exhaustive chlorination, did it?

 

[metalmagik]

Nope! It simply put Cl₂/FeCl₃.

So if given that on a test it's best to assume only monosubstitution? Maybe noting possible disubstitution if more reagent is present?

 

[chemisttree]

That's the way I'd play it.

 

[DeeNos]

I would like to provide a more detailed explanation of the products of chlorination of diphenylether. The reaction between diphenylether and chlorine gas (Cl2), in the presence of iron(III) chloride (FeCl3) as a catalyst, can result in the formation of different products depending on the reaction conditions.

Firstly, the oxygen atom in diphenylether is an ortho/para director, meaning that it directs the incoming chlorine atom to the ortho and para positions on the two phenyl rings. This is due to the lone pairs of electrons on the oxygen atom, which can interact with the pi electrons of the phenyl rings and stabilize the intermediate carbocation formed during the reaction.

In the presence of FeCl3 as a catalyst, the reaction can proceed via either an electrophilic aromatic substitution (EAS) or a free radical substitution mechanism. In the EAS mechanism, the FeCl3 acts as a Lewis acid, coordinating with the oxygen atom and enhancing its ability to stabilize the carbocation. This can result in the formation of para-chlorodiphenylether as the major product, with a smaller amount of ortho-chlorodiphenylether formed as a minor product due to steric hindrance.

On the other hand, in the free radical mechanism, FeCl3 can also act as a source of chlorine radicals, which can abstract a hydrogen atom from the phenyl rings and form a chlorine-substituted radical. This radical can then undergo further reactions to form a mixture of ortho and para isomers of chlorodiphenylether. The exact ratio of ortho to para isomers will depend on the reaction conditions and the amount of FeCl3 used.

In conclusion, the products of chlorination of diphenylether can vary depending on the reaction conditions and the mechanism of the reaction. However, the major product is typically para-chlorodiphenylether due to the ortho/para directing effect of the oxygen atom and the coordination of FeCl3. Further studies and experiments can provide more insight into the exact mechanism and products of this reaction.