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Author: Subject: Dimethoxybenzene oxidation in storage?
RareEarth
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[*] posted on 27-5-2015 at 14:12
Dimethoxybenzene oxidation in storage?


I had about 500mL of of Dimethoxybenzene in storage for a few months and I went to measure some today and noticed the liquid had an amber color to it, opposed to the original clear color I remember it being. Did the methoxygroups oxidize to some extent? What sort of contamination should I expect to be present?
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Loptr
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[*] posted on 27-5-2015 at 14:27


I would imagine it would be pretty stable, especially since methoxy groups are used to protect the parent hydroxyl groups. There are procedures to cleave aryl ethers that use strong Lewis acids, so it's not like they should easily oxidize under storage conditions.

Is this something you prepared yourself? What were the storage conditions? Light? Temp?

This is only an assumption, though.

[Edited on 27-5-2015 by Loptr]

[Edited on 27-5-2015 by Loptr]
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RareEarth
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[*] posted on 27-5-2015 at 14:36


I actually had two samples of the dimethoxybenzene from two different suppliers, one was in a plastic bottle, the other in a glass, they both turned amber.

I just noticed the one in the glass bottle had more liquid in it and was a much clearer color, but with the same amber tint to it. I suspect since it did not have as much oxygen-room in the bottle, the oxidation was not as much, where as the first sample was almost 3/4 empty and a much darker color.

[Edited on 27-5-2015 by RareEarth]
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ledob86
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[*] posted on 27-5-2015 at 15:55


Did you thought about photodegradation/peroxide forming in the presence of oxygen ?
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RareEarth
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[*] posted on 27-5-2015 at 15:57


Quote: Originally posted by ledob86  
Did you thought about photodegradation/peroxide forming in the presence of oxygen ?


Peroxides are a possibility, but would that not be the oxidation I referred to?

Photodegradation is not possible considering they were stored in total darkness.
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ledob86
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[*] posted on 27-5-2015 at 16:05


If you talk about months storage, i think it could be possible a radicalar process has been initiated before storage and then continued. The Sigma MSDS don't tell about particular storage conditions.


>> If you purify it by distillation, watch if remains some tar, it could be a polymerization product. Or you can do a TLC if you have...

[Edited on 28-5-2015 by ledob86]
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