evildrome
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Alternate route to dry ethanol
I recently bought some gallium to muck about with gallium/aluminium amalgam.
Having reacted it with TSDA (ethanol) to make aluminium triethoxide it occurred to me that adding excess TSDA would destroy any water in the ethanol
(by consuming the aluminium triethoxide)
https://www.youtube.com/watch?v=PqDU6DsYr98
You'd need to do the math to work out ideal proportions but its a route to dry ethanol that doesn't involve metallic sodium.
Thoughts?
[Edited on 11-8-2014 by evildrome]
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hyfalcon
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Ethyl acetate/Sodium hydroxide still seems easier to deal with to me anyway.
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DJF90
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Anhydrous ethanol is best made by distillation from magnesium
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evildrome
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Horses for courses. If you've got gallium but don't have either ethyl acetate or magnesium its a way forward.
I agree though that magnesium sounds like an easier route.
I've never tried 3A sieves but would like to. The price on Ebay UK appears to be GBP 20 per kilo plus £8 post.
That sounds quite pricey.
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gdflp
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Couldn't you just reheat them to reactivate them? If that was the case, then it's fairly cheap compared to buying anhydrous ethanol.
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evildrome
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Yes, they're recoverable which is very attractive.
I might just bite the bullet & get some.
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papaya
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Always wanted to try CaC2 as a drying agent, will it work?
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Pyro
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sounds like a bad ides, liberationg relatively large amounts of highly flammable gas from a flammable liquid...
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Burner
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Quote: Originally posted by gdflp  | | Couldn't you just reheat them to reactivate them? If that was the case, then it's fairly cheap compared to buying anhydrous ethanol.
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Regeneratong the molecular sieve beads or pellets is easy, especially if you have access to a vacuum oven and a good mechanical pump. The powder is
much more difficult to regenerate.
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- Isaac Asimov
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TheChemiKid
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I would use everclear as my alcohol source (if it is legal where you live), and distill over molecular sieves (not the powder).
That method is relatively cheap, and the sieves are regenerable.
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arkoma
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short question----stoichometric amounts of NaOH and EtAcetate=Sodium acetate and 200 proof booze?
Because I have both, mua-ha-ha
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Magpie
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Working definitions (mine):
1. Everclear = distilled spirits = 95% ethanol
2. Commercial absolute ethanol = 99% ethanol
3. "Super dry" ethanol = 99.9% ethanol
Without a Karl Fischer apparatus or other instrumentation it is hard to determine when your ethanol is "super dry." But if you have had good success
with it in those reactions that require it, then it is likely "super dry," I would think.
There is a paper* that provides the results of several methods for making "super dry" ethanol. The method par excellence was 3A mole sieves.
But the starting point for all these tests was 1500ppm (0.15%) ethanol. My concern is that I don't know if you can go right from Everclear to "super
dry" with just the 3A sieves. I think some on this forum have recommended against trying this. Taking their advice I went from Everclear to
"absolute" by distilling over burnt lime (CaO). I caught the distillate in a receiver loaded with the 3A sieves. The "super dryness" of my product
was verified by a successful reaction which required it.
I put this information out FYI, not as anything dogmatic. I'm simply relaying my experience for your consideration. In theory I don't know why one
couldn't go directly from Everclear to "super dry" using the proper amount of 3A mole sieves.
*"Desiccant Efficiency in Solvent and Reagent Drying. 7. Alcohols," by Burfield and Smithers, J. Org. Chem., 1983,
48, 2420-2422
[Edited on 12-8-2014 by Magpie]
The single most important condition for a successful synthesis is good mixing - Nicodem
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