Polysialate
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Ethanol partial drying additive?
If working with a crude distillation apparatus (no temperature control, just heats til boiling and stops once distillate hits a given volume) getting
a perfect 95% azeotrope is not really doable. However, with multiple crude distillations yields ~80% ethanol pretty quickly.
My question is what could be added to the 80% ethanol pre-distillation to help it get to 95% even when distilling at overheated conditions? Perhaps
adding a bunch of adhydrous MgSO4? Or CaCl2? Or MgCl2?
I'm not sure what would hold the water best through the heat, if any of those.
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Texium
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Thread Moved
25-10-2022 at 12:47 |
Fery
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K2CO3. K3PO4. K4P2O7. Not sure whether they concentrate upto 95%.
https://www.kci.go.kr/kciportal/ci/sereArticleSearch/ciSereA...
Be careful with K2CO3 which is sometimes sold as K2CO3 . 1,5 H2O. Anhydrous is better.
[Edited on 25-10-2022 by Fery]
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Polysialate
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Wow, thanks! I didn't know it was possible to salt out ethanol, much less with something as easy/cheap as potassium carbonate.
In case others are wondering the full paper is available on sci-hub under the following DOI http://dx.doi.org/10.1016/j.jiec.2017.07.006
That led me down a rabbit hole of the Hofmeister series. Apparently the tribasic citrate ion might be better than carbonate. From experience I know
that trimagnesium citrate really likes water, and has no problem solidifying as an amorphous, resinous hydrate. Might be something workable there by
letting magnesium oxide react with citric acid in the water/ethanol mix.
Also learned that lixivium is a word (meaning a solution of wood ash), that would make for a contentious scrabble win.
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Fery
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MgO + citric acid would produce extra water. Kitchen / food grade citric acid is monohydrate which introduces extra unwanted water.
You can buy cheap and not extra pure K2CO3 . 1,5 H2O in shops for home soap producers, but they sell sesquihydrate - you can dehydrate it by heating.
Using anhydrous K2CO3 would improve your yield by not adding extra water into the mixture.
I used K2CO3 to dehydrate allyl alcohol and I was able to recover a little of alcohol from water phase, but only a little, most of it was in organic
phase. For isopropanol I used kitchen NaCl which is much weaker dehydration agent and I recovered alcohol from water phase too, but NaCl does not work
with ethanol. I did not dehydrate ethanol yet, I produced azeotrope by Hempel column + Rashig rings + variable reflux ratio head.
I used K2CO3 and KOH for salting out dioxane but that is ether. NaOH for pyrrolidine but that is a secondary cyclic amine. I remember using NaOH to
remove denaturing shits from commercial ethanol (methylethylketone by aldol condensation).
Using K2CO3 for allyl alcohol was quite tedious and long lasting method, later I used azeotropic distillation which was faster and better. Also
instead NaCl for IPA I would use column distillation but I did not yet have the glass equipment when salting out using NaCl.
column distillation of ethanol into azeotrope:
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...
salting out isopropanol using NaCl;
https://www.sciencemadness.org/whisper/viewthread.php?tid=14...
allyl alcohol salting out using K2CO3 and dehydration into anhydrous by azeotropic distillation using Dean-Stark trap apparatus:
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...
[Edited on 26-10-2022 by Fery]
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Mateo_swe
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What about Cu salts?
I dont remember exactly what Cu salt, but its one of the more common ones.
Its used to make anhydrous ethanol so it might be worth looking into.
I know there is youtube videos about it.
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