[Calafalas]

Hi chemistry friends,

I'm currently working on a reaction to produce the following polymer: Cyclopentadiene functionalized polyketone.

I start with polyketone as a reagent and I should end up with the reaction product together with the solvent (THF) and water with NaOH.



My question is as following: How can I separate my reaction product from the THF/water ?
Do you think that is will be insoluble in THF/water, so I can use simple filtration? Or should I use a different solvent to extract the polymer ?

[Doc Oc]

I have questions about your synthetic route.

1) How are you planning to selectively attack one ketone over the other?

2) If you are going to use the cyclopentadiene anion, how will you keep that from being quenched by the H2O?

[Calafalas]

I see that some more information is needed than I have given:

The reaction is carried out by just using THF as a solvent. It is just my guess that the cyclopentadiene anion attacks at the polyketone monomer with the least steric hinderance. This should be the ketone without a methyl-sidegroup -> hence the position of the cyclopentadiene group.

Only after the reaction, I want to add water, so that the O^- (the former ketone group) reacts with a hydrogen ion to form the alcohol group.

That is why I end up with the product together with THF/Water.

[Doc Oc]

Well that makes more sense in regards to the water, but I still don't think you will get any control over the selectivity of the nucleophilic attack.  More than likely you'll end up with a mixture of products, but try it on a small scale I suppose and see.

As for the workup, your compound looks very greasy even with the alcohol and ketone groups, you should have no problem isolating it through a liquid liquid extraction.

[Calafalas]

Thank you very much for your reply.
It is very propable that you are right about the selectivity. But it does not really matter in my case: I just want the cyclopentadiene groups attached.

Do you think toluene, for example, will extract the reaction product?

[Doc Oc]

Toluene would probably work, but it's a pain in the ass to rotovap off because of its high boiling point.  Diethyl ether or ethyl acetate would probably work just fine.

[Calafalas]

Tried to repricipitate the reaction mixture in water. Filtration doesn't seem to work however.. only for about 5 ml. Then it stops.
Any tips for this ?