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Author: Subject: Where can I get relatively pure ethanol?
UnclearReactor
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[*] posted on 15-4-2015 at 10:22


Buy the cheapest vodka you can find. Absorb the water with an anhydrous salt (e.g. Copper Sulfate, Magnesium Chloride). Distill gently with a water bath; you don't even need a condenser if the tubing is long enough.
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[*] posted on 15-4-2015 at 10:41


I just use denatured ethanol I get from the hardware store. The MSDS says that it contains both ethyl and methyl alcohol, along with methyl isobutyl ketone.

The ethanol and methanol have too close of a boiling point to effectively separate, but the methyl isobutyl ketone has a boiling point of 117.5C, so it can be separated using fractional distillation since that is a 39.5 degree difference.

I don't mind methanol being a minor constituent, and if I wanted to, I could just remove the MIBK.

EDIT: What I do hate though is when the MSDS says that denatured ethanol could be anywhere from 0 to 50% methanol. You could take some measurements and figure out how much methanol was there, but the lack of a guarantee that you are actually being ethanol irks me.

[Edited on 15-4-2015 by Loptr]
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[*] posted on 15-4-2015 at 11:18


There is a guide (google the web to find it) to specially denatured alcohols that tells what the law says must be in each one. So if the MSDS says which SD it is (eg, SD 42), you can see what the level of MeOH is by law. In many states you can buy 95% EtOH in liquor stores as long as you don't mind paying the tax, which is a lot. I know one person who used to do that. You might have to ask for it, maybe say that you wish to make some extracts for flavoring agents or something. All the state cares about is that you pay the taxes, most of the time.
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[*] posted on 15-4-2015 at 17:03


I have 4 liters of reagent grade ethyl alcohol available from Fischer scientific if you are interested
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[*] posted on 15-4-2015 at 17:10


Quote: Originally posted by Steam  
Try buying a bottle of 95% everclear, you could dry it using standard methods for alcohols.
Maybe you could distill it over sodium?


I know this post is over a year old, I just didn't want any viewers to be misinformed. Although this is standard practice for some solvents, it won't work as well with with ethanol because ethanol reacts rather vigorously with sodium to form sodium ethoxide.
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[*] posted on 17-4-2015 at 20:31


Quote: Originally posted by gdflp  
Quote: Originally posted by Steam  
Try buying a bottle of 95% everclear, you could dry it using standard methods for alcohols.
Maybe you could distill it over sodium?


I know this post is over a year old, I just didn't want any viewers to be misinformed. Although this is standard practice for some solvents, it won't work as well with with ethanol because ethanol reacts rather vigorously with sodium to form sodium ethoxide.


Use 3A molecular sieves.
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[*] posted on 17-4-2015 at 20:44


Period.

Buy Ever-clear, and follow the above post.

It doesn't get any better than that.

You have to purge with nitrogen to store for long periods but you also have to purge to use it if you want 99% +




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[*] posted on 20-4-2015 at 19:40


Well, there are a few options for pure ethanol;

1. Go to a laboratory supplier and buy "absolute ethanol". Where I live (Australia) one must obtain a permit to obtain alcohol that has not been denatured. There is no problem in buying absolute ethanol that has been denatured (typically with denatonium benzoate/Bitrex). Denatured alcohol is therefore not suitable for use in any application where the end product may be consumed.
Cost: $20-30 / 2.5L bottle

2. Go to a liquor shop and buy high proof alcohol or rectified spirit. Here in Australia, this product is typically available as a product called "Spirytus", a Polish grain alcohol. It is 95% v/v ethanol and not denatured. You will need to use 3A molecular sieves and distillation to remove the last bit of water. Cost - $60-70/500ml - expensive but very useful for products that may be consumed later. I use it for extracting lemon oils in order to make Limoncello. Potent but tasty

3. Ferment your own alcohol from grain and distill using fractional distillation. You may need to distill twice or three times to get the constant boiling azeotrope which is also 95% ethanol. A little more difficult but in the long term it may be cheaper, depending on where you live.

4. Distill cheap & nasty white spirits. You can buy cheap vodka and distill it using very simple laboratory glassware. Recommend using a 1 or 2 litre flask, 200-300mm insulated fractioning column and efficient condenser to obtain a good yield of alcohol. May be cheaper than buying rectified spirit but risk of contamination from alcohol congers significantly increased if you use a spirit other than vodka.

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[*] posted on 20-4-2015 at 20:36


I buy Everclear (95%), distill it over CaO (burnt lime), then treat with 3A mole sieves. This has been suitable for some very finicky syntheses. See Vogel.

I don't see why you couldn't skip the burnt lime and go right to the mole sieves. Seems like I tried it and it didn't work as well.

I make my burnt lime by firing hydrated lime, Ca(OH)2, aka slaked lime. This is available dirt cheap by the pound at your neighborhood weed & feed store. Bring your own container or plastic bag.




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[*] posted on 21-4-2015 at 19:18


Well, there are a few options for pure ethanol;

1. Go to a laboratory supplier and buy "absolute ethanol". Where I live (Australia) one must obtain a permit to obtain alcohol that has not been denatured. There is no problem in buying absolute ethanol that has been denatured (typically with denatonium benzoate/Bitrex). Denatured alcohol is therefore not suitable for use in any application where the end product may be consumed.
Cost: $20-30 / 2.5L bottle

2. Go to a liquor shop and buy high proof alcohol or rectified spirit. Here in Australia, this product is typically available as a product called "Spirytus", a Polish grain alcohol. It is 95% v/v ethanol and not denatured. You will need to use 3A molecular sieves and distillation to remove the last bit of water. Cost - $60-70/500ml - expensive but very useful for products that may be consumed later. I use it for extracting lemon oils in order to make Limoncello. Potent but tasty

3. Ferment your own alcohol from grain and distill using fractional distillation. You may need to distill twice or three times to get the constant boiling azeotrope which is also 95% ethanol. A little more difficult but in the long term it may be cheaper, depending on where you live.

4. Distill cheap & nasty white spirits. You can buy cheap vodka and distill it using very simple laboratory glassware. Recommend using a 1 or 2 litre flask, 200-300mm insulated fractioning column and efficient condenser to obtain a good yield of alcohol. May be cheaper than buying rectified spirit but risk of contamination from alcohol congers significantly increased if you use a spirit other than vodka.

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[*] posted on 11-6-2015 at 13:40


Quote: Originally posted by Magpie  
I buy Everclear (95%), distill it over CaO (burnt lime), then treat with 3A mole sieves. This has been suitable for some very finicky syntheses. See Vogel.

I don't see why you couldn't skip the burnt lime and go right to the mole sieves. Seems like I tried it and it didn't work as well.


Are you saying that when you tried directly treating Everclear (95%) with 3A mole sieves, it didnt work well? Meaning it didnt dry the everclear well? or didnt work well in some syntheses?

From what I read, static drying of 95% ethanol can be done with 3A sieves. I attached one of the papers.

Here are a few of them.
J. Chem. Tech. Biotechnol. 1984, 34A, 187-194 (static and column drying of 95% ethanol)
*J. Org. Chem., Vol. 48, No. 14, 1983

Thanks
TonyZ

* I noticed in an older thread, you referenced this paper regarding drying ethanol (which contains 1500ppm (0.15%) water).

Attachment: J. Chem. Tech. Biotechnol. 1984, 34A, 187-194.pdf (466kB)
This file has been downloaded 560 times

[Edited on 11-6-2015 by TonyZ]

[Edited on 11-6-2015 by TonyZ]
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[*] posted on 11-6-2015 at 14:43


Quote: Originally posted by TonyZ  

Are you saying that when you tried directly treating Everclear (95%) with 3A mole sieves, it didnt work well? Meaning it didnt dry the everclear well? or didnt work well in some syntheses?


I'm sorry but I can't remember.

IIRC, CaO will take the water down to 1%. So, if you use CaO first you reduce the load on the sieves by about 80%.




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[*] posted on 11-6-2015 at 17:27


It is so easy to ferment and distil your own alcohol. Sugar, water, yeast, a glass bottle, a vent top, and 5-6 days. Distil after fermentation is complete.. 95.6% ethanol if you have a good column and condenser.
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[*] posted on 11-6-2015 at 20:09


Easy? Sure. Practical? Not really. Legal? Almost certainly not, even if you can prove you didn't drink it.
I've done this a few times, and found it to be a big pain.
The most recent time I used turbo yeast, capable of withstanding alcohol percentages of up 18%. Let it ferment at room temperature for a week (twice as long as the package suggested). Distilled twice normally and then once with magnesium sulfate (I didn't need it to be more than 95%, otherwise I'd of used a stronger desiccant).
Overall time took a week and a day, the week doing nothing but the last day I spent about six hours monitoring several distillations. Yield was one liter of not very pure ethanol, containing at least 4% water and many trace organic impurities.
I could have gone to work that day and earned enough money to buy five liters of vodka (40%) or about one to two liters of everclear (95%).
The only application I can think of this being useful is for those who can't legally buy ethanol (because of either country, or age restrictions). However this is very, very rare these'a days. I had friends who bought me liquor to drink at age 14, and my parents would've done it if it was for chemistry purposes.
Regarding countries where it's illegal, I'm sure they have denatured alcohol, which works most of the time. Oddly I wasn't able to buy denatured alcohol under age either, probably because they think teens are really dumb and might drink it and die, (I wasn't planning on drinking it, I had in molotov cocktails in mind:P, turned out gasoline works fine though).




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