[mir]

Thank you very much, for all answers:

How do I isolate an activated phenol from glacial acetic acid?

I tried using a saturated solution of sodium bicarbonate, NaHCO3, to adjust the pH to pH 7-8. But still I fail to separate my product (which is 2,6-dimethoxy-3-hydroxy toluene) from the acetic acid. And while I do it, a lot of tars is formed (is that my product that is polymerizing?). The tars is dissapearing into the waterphase when i extract it with ethyl acetate. And when I have dried and removed the ethyl acetate, the residue smells glacial acetic acid - of course.

Other sources uses vacuum to remove the acetic acid. But I dont have a vacuum pump strong enough for this job, and the water aspirator vacuum is to weak: If I not just leave it on over the night or some days(?). Some other students used a warming pistol while they used vacuum. But the product is drying into the glassware in some way - I loose yield and no almost hope to get the glassware cleaned afterwards.

Some suggested using a strong alkali base like KOH, to bring the phenol and the glacial acetic acid into the water solution - and then acidify the water solution slightly to pH-8-9. But still I get the acetic acid when I extract it with ethyl acetate.

I could do a flash of the residues from the methods mentioned above. But that would require extra time. I hope to find an easier way to seperate the phenol from solution.

This reaction is a nightmare! Please help...

[russellm72]

Do you have access to HPLC?

[russellm72]

Do you have any idea about the boiling point of your product. If it is not volatile I would spin down the AcOH then take it down from toluene a few times which will azeotrope your AcOH off quite nicely. Then spin down from DCM/hexane and give a pump in a dessicator if you need to. Are you going to react the stuff further?

R.

[mir]

The boilingpoint is about 200 degrees celsius (although it has a low melting point its an oil in roomtemperature).

What do you mean with "spin down"?

I dont have access to HPLC.

[russellm72]

200 oC should be Ok. I mean concentrate in vacuo or rotary evaporate when I say spin down.

R.

[Dude]

How about just adding cold water to the mixture and filtering the phenol?  The solubility of the phenol should be much lower than the solubility of acetic acid.

[russellm72]

Good idea but depends on the scale your on. Can always try a portion it wont hurt

[mir]

Thank for all good advices. I cant believe I didnt think of azeotropes before, hehe.

I will use that washing procedure with water before Im doing GC of the reaction.

If you wonder what reaction Im doing, you can look up this article:

 Title: Efficient and green telescoped process to 2-methoxy-3-methyl-[1,4]benzoquinone
Author(s): Gonzalez RR, Gambarotti C, Liguori L, Bjorsvik HR
Source: JOURNAL OF ORGANIC CHEMISTRY 71 (4): 1703-1706 FEB 17 2006
ISSN: 0022-3263

Or

 Title: Synthesis of methoxy-substituted phenols by peracid oxidation of the aromatic ring
Author(s): Bjorsvik HR, Occhipinti G, Gambarotti C, Cerasino L, Jensen VR
Source: JOURNAL OF ORGANIC CHEMISTRY 70 (18): 7290-7296 SEP 2 2005
ISSN: 0022-3263