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JJay
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JJay Makes Anhydrous Ethanol
I started distilling some denatured alcohol today. I'm not terribly concerned about removing small quantities of denaturant (certainly not trying to
make food grade alcohol), but I wanted to make the ethanol anhydrous and reasonably pure so it can be used in organic reactions. I definitely don't
want any residues on evaporation. Since I don't have any benzene, I'm going to remove the water using molecular sieves.
On the topic of legality, I am pretty sure that distilling denatured alcohol for purposes of preparing a chemical reagent is completely legal in my
jurisdiction. Also, I'm pretty sure it won't be feasible to completely remove all denaturants. And in any case, no one will be permitted to drink the
product.
So I started up a simple distillation with 250 mL of cheap denatured alcohol in a boiling water bath. Around 100 mL of liquid distilled out at 66-68
C. That seemed oddly different from the conditions under which ethanol distills, so I checked the SDS... this brand of denatured alcohol is 60%
methanol and 30% ethanol! Unfortunately, I already bought a gallon of it.... Aside from not buying this brand of alcohol again, it looks like I am
going to distill through column to strip the methanol fraction and then distill out the ethanol, and doing multiple fractionations would probably
help....
IMHO, selling a more-than-half methanol solution as denatured alcohol is false advertising, but I'm probably going to have to let it slide for now. So
I'm going to do a little fractionation....
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arkoma
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turbo yeast + white sugar + ten days= 25% ethanol. Fractional disty with a Vigreux column and 95% EtOH is easily achievable. Side bonus is it is
quite safe to (ahem) drink. Costs about $12US for the ingredients, theoretical yield 1.25 US gallons 95%.
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JJay
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Well, this setup is for separating methanol and ethanol. I considered adding a sulfuric acid trap, but I highly doubt that the alcohol is anhydrous.
I'm distilling into a sep funnel so I can easily split fractions. I'd be reluctant to say that anything that is home distilled is safe to drink.
[Edited on 4-11-2015 by JJay]
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woelen
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Methanol is quite useful as well, both as a solvent and as a reactant.
If you use molecular sieves, then you need the 3Å (0.3 nm) variant. This absorbs water, but ethanol molecules are too large to be absorbed. A 4Å
sieve cannot be used, an ethanol molecule also fits in the pores of this material and hence this sieve does not exclusively absorb water.
[Edited on 4-11-15 by woelen]
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JJay
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Quote: Originally posted by woelen  | Methanol is quite useful as well, both as a solvent and as a reactant.
If you use molecular sieves, then you need the 3Å (0.3 nm) variant. This absorbs water, but ethanol molecules are too large to be absorbed. A 4Å
sieve cannot be used, an ethanol molecule also fits in the pores of this material and hence this sieve does not exclusively absorb water.
[Edited on 4-11-15 by woelen] |
Right, I have 3A molecular seives. I am thinking about picking up some 4A for removing methanol and ethanol from other solvents.
Anhydrous methanol is easy to obtain, but I'm planning on keeping the methanol too.
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arkoma
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moonshining is quite a tradition here in the south. gave my boss a quart for his 45th wedding anniversary. have consumed LOTS of my own "product"
with no ill effects
*edit*
and a glass disty rig removes any worries of heavy metal contamination
[Edited on 11-4-2015 by arkoma]
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JJay
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The first drops came over at around 64, and the temperature has been climbing since. Right now it is around 74. I'm going to collect the fraction
below 78 to be further refined as methanol and the fraction above 78 to be further refined as ethanol. I'm storing the fractions in mason jars 
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arkoma
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excellent book on home ethanol production
*edit* KEEP A FIRE EXTINGUISHER CLOSE BY
*edit* the music stand is a sweet idea. props!
[Edited on 11-4-2015 by arkoma]
[Edited on 11-4-2015 by arkoma]
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JJay
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It would be nice to have a cow-type distillation adapter for doing anhydrous distillations.
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arkoma
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can't get anhydrous EtOH through distillation. dreaded azeotrope
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JJay
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There's still a good bit of alcohol distilling, but it looks like I am going to get 100 mL tops of 78+ C fraction from about 600 mL of Klean Strip
denatured alcohol.... While I could slow down the distillation and use temperature controlled baths to get larger higher fractions, that's pretty
disappointing.
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JJay
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Right, but once it's already anhydrous, it can be kept that way by distilling it in anhydrous conditions (which would involve a device such as a
sulfuric acid trap or perhaps a calcium chloride tube).
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arkoma
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| Quote: Originally posted by JJay |
Right, but once it's already anhydrous, it can be kept that way by distilling it in anhydrous conditions (which would involve a device such as a
sulfuric acid trap or perhaps a calcium chloride tube). |
what need to distill a pure/anhydrous product?
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JJay
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I need to prepare some products that can only be produced in anhydrous conditions.
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JJay
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I am now collecting the fraction that distills over 78 C. It smells like vodka 
It looks like I'll probably get around 100 mL. I started with about 600 mL... that's a pretty lousy yield, but I guess it isn't too bad considering
that I started with only about 200 mL of ethanol in solution. Of course, it still requires further purification, so this is going to be some very
expensive anhydrous ethanol.
[Edited on 4-11-2015 by JJay]
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JJay
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I ended up getting only about 40 mL of high-boiling fraction.... I can and probably will try to recover more ethanol from the low-boiling fraction
before further purifying the high-boiling fraction. Right now I am storing the fractions in 1 qt. mason jars that are clearly labeled as POISON. I
think I might want to make more fractions and mix fractions....
[Edited on 4-11-2015 by JJay]
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aga
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The yeast dies well before 25% - it's poisoned in it's own ethanol excreta.
Around 10%~15% should be used as a workable estimate unless you can directly measure the ethanol with a refractometer, or do a titration.
Using a Vigreux column should get you at or near the 96% azeotrope.
Maybe use a 'Thumper' if you have not got a Vigreux column.
http://www.sciencemadness.org/talk/viewthread.php?tid=61566
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JJay
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| Quote: Originally posted by aga |
The yeast dies well before 25% - it's poisoned in it's own ethanol excreta.
Around 10%~15% should be used as a workable estimate unless you can directly measure the ethanol with a refractometer, or do a titration.
Using a Vigreux column should get you at or near the 96% azeotrope.
Maybe use a 'Thumper' if you have not got a Vigreux column.
http://www.sciencemadness.org/talk/viewthread.php?tid=61566 |
Interesting idea... but a thumper wouldn't help much for eliminating methanol. Actually, I think using one would be counterproductive.
I have a Vigreux, pictured above. I wonder if maybe I should pack it with glass beads and see if I can get a better division between fractions.
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JJay
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Ethanol can be titrated with what... sodium dichromate..?
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Detonationology
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A much better option to figure out the % alcohol
is by it's density (i.e. a hydrometer).
[Edited on 11-4-2015 by Detonationology]
“There are no differences but differences of degree between different degrees of difference and no difference.” ― William James
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JJay
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True... but how to determine methanol concentration....
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aga
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Also included in the 'Thumper' thread :-
Attachment: ethanol titration.pdf (166kB)
This file has been downloaded 539 times
I'm sure you're right.
Analytical chemistry techniques are just for idiots.
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Metacelsus
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Gas chromatography is what's usually used, but that's generally out of reach for the amateur. You might be able to buy an enzymatic test kit.
[Edited on 4-11-2015 by Cheddite Cheese]
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JJay
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It is theoretically possible to calculate the concentration of MeOH, EtOH, and H<sub>2</sub>O after measuring density and doing a
titration, but tables with the density of various concentrations would be required.
[Edited on 4-11-2015 by JJay]
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aga
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Strange you got SM and no Google power.
Logically i'd remove the MeOH and EtOH fractions as best i could to eliminate the majority of water.
Then i'd start with separating the MeOH and EtOH from each other.
That's just me.
Us druknen idiots think the Wrong way most of the time.
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