[koral]

Hi All,
First time, I will do Column Chromatography for eluting Acrylonitrile from its inhibitor MeHQ.
I have some questions coming to my mind to be sure about I do correct.

I will use activated alumina as stationary phase, and pour slurry of Alumina in column.
Then, Lets say i have a solution of 10g Acrylonitrile in 50 ml solvent.
I pour the solution in column, and open the valve, and let some solution to flow down.
Simultaneously, i will add more solvent from top, and continue to collect liquid from bottom.

- Should I finish this process until no solvent remains in stationary phase ?
- or Should I leave some solvent covering the stationary phase ?

- After this process, can I collect %100 of the 10gr Acrylonitrile at bottom, or will be any loss in stationary phase.
As i guess, if i leave some solvent with stationary phase, there will be some amount of Acrylonitrile dissolved in the solvent there.
So, this can cause a small fraction of Acrylonitrile loss.

- If I let all solvent to flow out (no liquid remains in stationary phase), will any inhibitor MeHQ flow out with solvent ?
or MeHQ always sticks to the Alumina in column ?

I am appreciated for your answers.

Regards.

[marquis]

This is a very dangerous step to take.  The mehq is there for a very good reason.  Do not proceed down this road.

[wildfyr]

Marquis, I disagree. For 50 mL of monomer it's perfectly safe to remove the inhibitor. I would say for short terms it's safe to many of liters, and long term up to a 500 mL should be fine.

Koral whenever I do this I just use neat monomer and push it all through with air pressure. No big deal, and you don't have remove the solvent at the end. You lose a little bit, but most monomers are quite cheap

[koral]

Hi, Thanks for answers.

So, my purpose is to remove MeHQ inhibitor prior to polymerisation of the monomer.

Wildfyr, I would like to get %100 of (10 gr) Acrylonitrile monomer back. Because, I will add co-monomer for polymerisation. So, monomer to comonomer weight-to-weight ratio should be in optimum level. I guess should be 95/5. So, if i lose some monomer during chromatography, it can result in deviation from optimum ratio.

So, i was planning to remove all the solvent by draining through stationary phase. Maybe, that can minimise the monomer loss.

Regards.

[wildfyr]

It doesn't matter if you lose some as long as your aren't running the column right into the reaction. Just do more than you need into a flask, then weight it out precisely from the flask into another container and dump that into the reaction. Acrylonitrile is about as cheap as chemicals come, I really suggest my method instead of trying to column (really its just a little plug that's needed) it quantitatively. Weigh out purified monomer.

Many monomers, such as acrylonitrile, are quite volatile, so if you were planning to rotovap off the solvent that will be a source of error.