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Author: Subject: Sodium ethoxide purification?
polymerizer87
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[*] posted on 20-7-2012 at 05:08
Sodium ethoxide purification?


Anyone have a good reference to literature or a textbook on purification of common laboratory reagents. I've acquired some rather old sodium ethoxide. Over time this stuff tends to form carbonates from all the co2 in the atmosphere.
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zoombafu
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[*] posted on 20-7-2012 at 05:18


Is it in an ethanol solution? or crystals?



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polymerizer87
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[*] posted on 20-7-2012 at 05:24


Crystals, it's been in a plastic bag sealed in a metal can for god knows how long. I want to attempt to purify it before I think about neutralizing it and dumping it out
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zoombafu
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[*] posted on 20-7-2012 at 05:30


Purification of Laboratory Chemicals

Well I know that if it contacts water in the air it forms NaOH.
According to the above link purification is not possible (or very difficult not sure which) and the author recommends preparing a new sample if one is needed.

[Edited on 20-7-2012 by zoombafu]




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smaerd
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[*] posted on 20-7-2012 at 07:17


Couldn't you dissolve in anhydrous ethanol with molecular sieves. Then add dry acetone to crash the sodium ethoxide? Then again you might as well make more at that point.

[Edited on 20-7-2012 by smaerd]




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edgecase
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[*] posted on 20-7-2012 at 09:40


Quote: Originally posted by zoombafu  

Well I know that if it contacts water in the air it forms NaOH.
According to the above link purification is not possible (or very difficult not sure which) and the author recommends preparing a new sample if one is needed.

[Edited on 20-7-2012 by zoombafu]


I believe it can be made by refluxing NaOH and anhydrous ethanol, maybe you could just add some ethanol and reflux for a couple hours, then distill off the ethanol? Depending what you want to make with it, the NaOH may not be a problem.

Here's a photo of some sodium acetate I made (from ethyl acetate), by refluxing anhydrous 2A ethanol with NaOH. I believe there was some sodium ethoxide (or possible methoxide) produced along side, since after exposing the residue to the atmosphere, it darkened and produced red spots higher up in the stillhead, which from what I read is characteristic of the ethoxide in contact with air/water vapour.
sodium_acetate_ethoxide.jpg - 70kB sodium_acetate_ethoxide2.jpg - 51kB
http://coplanar.net/gallery2/main.php?g2_itemId=324



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polymerizer87
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[*] posted on 26-7-2012 at 05:51


the color is on par with the material I have. Ill do a run through this weekend and see what happens.
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edgecase
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[*] posted on 26-7-2012 at 07:04


Quote: Originally posted by polymerizer87  
the color is on par with the material I have. Ill do a run through this weekend and see what happens.


Cool! I look forward to some feedback.

On thinking it through however, If the sodium ethoxide decomposes to NaOH and ethanol, the colour would be white. Therefore the product must be something else. Will that something else react with ethanol and NaOH to produce sodium ethoxide again? I suspect not but that would be a happy outcome.
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polymerizer87
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[*] posted on 26-7-2012 at 07:48


Ill do some monitoring with FT-IR I have a reference sample of some sodium ethoxide, and ill post the data after the purification attempt.
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Dr.Bob
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[*] posted on 26-7-2012 at 10:56


There was a previous thread (try the search engine) where Nicodem stated that you could crystallize NaOEt from acetone somehow to get "pure" NaOEt. I am not familair with that try, but you might want to search for the thread.
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madcedar
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[*] posted on 27-7-2012 at 07:55


This is the thread you want to read:
http://www.sciencemadness.org/talk/viewthread.php?tid=2656

It's as easy as ABC believe it or not.
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