[priyoX]

Is it possible to run a column chromatography without a solvent? I have a liquid methyl methacrylate solution that has inhibitor in it. I want to remove this inhibitor by using alumina as the stationary phase. But I'm not using a solvent, I'm simply pouring the liquid on a bed of alumina in a fritted column. I'm not seeing any yellow bands (as I'm supposed to see) from the inhibitor being absorbed by the alumina. I don't know if what I'm getting out the column is indeed inhibitor-free. Am i missing a step? Or doing something incorrectly? Any help is much appreciated, I am stuck on my looong process at this frustrating step

[wildfyr]

yep, that works perfectly well for removing inhibitor. Its the best, easiest method in my book. You can tell its inhibitor free because it barely shows a spot on TLC, while the stuff with inhibitor shows a spot quite obviously. Just force it all through the column with air until the alumina is dry. I've used this technique with virtually every commercial monomer (styrene, MMA, nbutyl acrylate, etc) and never had a problem.

[Arkcon]

Is it possible to run a column chromatography without a solvent?

Well, no, not really.

I have a liquid methyl methacrylate solution that has inhibitor in it. I want to remove this inhibitor by using alumina as the stationary phase. But I'm not using a solvent,

Well, its just going to sit on the alumina without any liquid ...

I'm simply pouring the liquid on a bed of alumina in a fritted column.

Oh.  You're using the solvent the sample is dissolved in as an elution solvent.  Go for it, if you have enough solvent.

I'm not seeing any yellow bands (as I'm supposed to see) from the inhibitor being absorbed by the alumina. I don't know if what I'm getting out the column is indeed inhibitor-free.

It would depend on what the inhibitor is, why its supposed to be yellow, and if whatever it is, has greater affinity for alumina than for its solvent.

Am i missing a step? Or doing something incorrectly? Any help is much appreciated, I am stuck on my looong process at this frustrating step

Where did you hear of this process, how did you develop this process, are all questions we can ask.  What does the inhibitor ... urm ... inhibit?  Does it inhibit a reaction the active you want undergoes?  Because purifying the inhibitor away, in an open column, with plenty of air and surface area, will very likely make that reaction happen -- polymerization, oxidation, etc, those may end up locked onto the alumina, or otherwise lost.

[wildfyr]

Arkcon, this technique is typically used to purify small amounts (tens of mL) of acrylic monomer immediately before use in a free radical or controlled radical polymerization (like ATRP). The inhibitor (almost certainly BHT or MEHQ) prevents autopolymerization during long storage. Methyl methacrylate, as well as most common monomers, is stable for weeks at room temperature on the bench without inhibitor.

When stored without inhibitor in large scales, autopolymerization can result in thermal runaway, which is why typically only small amounts are purified by neutral alumina plug or distillation. Another approach is just to add more radical initiator which will consume the inhibitor then begin the reaction, but this is not an optimal method.

I agree that calling this column chromatography is a misnomer, this is simply flashing monomer through a plug of alumina.

OP, to clear things up, this is how I would perform this very simple technique. Take a small fritted column, add a about 5 cm of neutral alumina to it, then pour your pure monomer on top. Add air pressure and collect the disinhibited monomer from the bottom. Thats all. Its not a real column. I've done this with cotton as a frit in a pasteur pipette before, its foolproof.