Sciencemadness Discussion Board - ethanol purification by aluminum ?

ethanol purification by aluminum ?

kazaa81 - 6-8-2007 at 12:08

hi,

I've heard that denaturated alcohol (ethanol) can
be purified (or maybe just precipitate its dye)
if aluminum turning are used?

anyone aware of that? I'm getting no
success while trying it.

thank you all

12AX7 - 6-8-2007 at 13:19

No. If nothing else, you would need some acid or base to disrupt the aluminum's oxide layer anyway.

You might be thinking of calcium or other alkali metal turnings used to dry solvents such as ethanol (not the best as it slowly forms ethoxide with such basic elements) and ethers.

Tim

bio2 - 6-8-2007 at 13:42

I suppose one could form the ethoxide with amalgamated
Al then decompose that but there are other better ways
to dry or purify EtOH.

vulture - 6-8-2007 at 13:47

Ethanol is bound to contain some acetic acid, so that could start a reaction...

Is Aluminiumethoxide soluble in ethanol anyway? If not, the precipitate could indeed cause removal of the dye through some sort of flucculation process.

kazaa81 - 6-8-2007 at 14:09

Quote:

Originally posted by vulture
If not, the precipitate could indeed cause removal of the dye through some sort of flucculation process.

being just aluminum and ethanol, I think that's what is supposed to happen. Anyone got experience in this?

S.C. Wack - 6-8-2007 at 14:31

No one can be bothered to read Armarego and Perrin, which gives the outline and ref? Maybe it (both 4th and 5th eds.) never really existed and so can't even be searched for, like most every other post here more than a couple months old.

16MillionEyes - 6-8-2007 at 14:45

So basically the whole procedure is add some aluminum turnings sit back and watch? How do you know (say) that the reaction has happened or not (any specific color, thermal change etc)?

kazaa81 - 6-8-2007 at 15:29

Quote:

Originally posted by S.C. Wack
No one can be bothered to read Armarego and Perrin, which gives the outline and ref? Maybe it (both 4th and 5th eds.) never really existed and so can't even be searched for, like most every other post here more than a couple months old.

huh ?

as far as I know, the dye will precipitate on the bottom of the solution, leaving colorless alcohol.

S.C. Wack - 6-8-2007 at 15:38

That gives the reference on the purification of ethanol by Al!
Know what? There is no dye in any of several brands of denatured alcohol here!
How are we supposed to know how to purify the alcohol in your hands?

kazaa81 - 6-8-2007 at 16:00

Quote:

Originally posted by S.C. Wack
That gives the reference on the purification of ethanol by Al!
Know what? There is no dye in any of several brands of denatured alcohol here!
How are we supposed to know how to purify the alcohol in your hands?

Do you know how much is for a copy of Armarego and Perrin latest edition?

Damn, no dye? Then who knows what's solved in there...That's another thing

to keep in mind while disinfecting wounds in hydrogen peroxyde shortage

bio2 - 6-8-2007 at 20:19

..."Is Aluminiumethoxide soluble in ethanol anyway?"........

I don't know but I do know that the methoxide is not very soluble in MeOH and precipitates out.

Easy to decompose also just a little water and some heat.

indigofuzzy - 6-8-2007 at 20:32

Ok, if I'm reading right, we're trying to purify denatured alcohol? Where I live, denatured alcohol is ethanol mixed with methanol to make it unsuitable for drinking. Other localities or nations may vary.... The downside is, I'm not 100% sure how to get the methanol out. I don't know if they form an azeotrope that would make distillation not work.

kazaa81 - 7-8-2007 at 01:40

Quote:

Originally posted by indigofuzzy
Ok, if I'm reading right, we're trying to purify denatured alcohol? Where I live, denatured alcohol is ethanol mixed with methanol to make it unsuitable for drinking. Other localities or nations may vary.... The downside is, I'm not 100% sure how to get the methanol out. I don't know if they form an azeotrope that would make distillation not work.

read carefully

...we're talking about a specific method used in alcohol purification, the one which uses aluminum turnings to precipitate dyes out of solution.

S.C. Wack - 7-8-2007 at 01:42

Quote:

Originally posted by kazaa81
Do you know how much is for a copy of Armarego and Perrin latest edition?

That would be the 5th. Yes. Free.

You might want to find out what is in your alcohol and what you want it for. If you ask random questions you will get random answers, like use aluminum.

kazaa81 - 7-8-2007 at 01:50

Quote:

Originally posted by S.C. Wack

Quote:

Originally posted by kazaa81
Do you know how much is for a copy of Armarego and Perrin latest edition?

That would be the 5th. Yes. Free.

You might want to find out what is in your alcohol and what you want it for. If you ask random questions you will get random answers, like use aluminum.

Where can I get one? Thank you for your fast reply.

Seems like in EU, these denaturants are used :

to every 100 liters of EtOH are added:

Tiophene: 125 g.
Denatonium benzoate: 0,8 g.
25% solution w/w of C.I. Reactive Red 24 (red dye): 3 g.
Methyl ketone 2 liters (I think that's MEK, 2-butanone).

The denaturing power of denatonium benzoate is always astonishing :cool:

not_important - 7-8-2007 at 06:49

Quote:

No azeotrope, just difficult to separate because of the relative closeness of the boiling points of methanol and ethanol or the ethanol-water azeotrope. Most people don't have the equipment to do the fractional distillation required, certainly not to the point of completely removing the methanol.

Dyes and other large molecules are fairly easy to remove by distillation, some of the hydrocarbon additives can be difficult because of close boiling points or formation of azeotropes.

While absorbing the dyes onto Al(OH)3 might work, you're still likely going to need to do a distillation, in which as the Al(OH)3 might just be extra work unless it is a product of reacting aluminium with the water with the intent of drying the alcohol.

Is "Tiophene" actually thiophene? Thiophene forms an azeotrope with ethanol, and generally needs to be removed through chemical reaction.

kazaa81 - 7-8-2007 at 07:50

Quote:

Originally posted by not_important

Dyes and other large molecules are fairly easy to remove by distillation, some of the hydrocarbon additives can be difficult because of close boiling points or formation of azeotropes.

While absorbing the dyes onto Al(OH)3 might work, you're still likely going to need to do a distillation, in which as the Al(OH)3 might just be extra work unless it is a product of reacting aluminium with the water with the intent of drying the alcohol.

Is "Tiophene" actually thiophene? Thiophene forms an azeotrope with ethanol, and generally needs to be removed through chemical reaction.

I once observed that boric acid did "bleach out" EtOH dye, and
yes I think it is Thiophene, not tiophene.

woelen - 7-8-2007 at 10:39

In the Netherlands, we have something called 'spiritus', and it always has a deep blue color and a terrible smell. I'm not sure what is in it. The bottle only says that it contains 85% ethanol, but the other ingredients are not listed. Anyone here, who knows this blue 'spiritus' and what is in it?

vulture - 7-8-2007 at 13:48

I've distilled the stuff over a vigreux column and although the colour is gone, the smell stays, even after a second distillation.

It has a somewhat mint like smell, but very intense and almost unbearable.

not_important - 7-8-2007 at 18:03

Quote:

Originally posted by woelen
In the Netherlands, we have something called 'spiritus', and it always has a deep blue color and a terrible smell. I'm not sure what is in it. The bottle only says that it contains 85% ethanol, but the other ingredients are not listed. Anyone here, who knows this blue 'spiritus' and what is in it?

this?

http://nl.wikipedia.org/wiki/Spiritus_%28alcohol%29

85% ethanol,
10% water,
3% methanol,
1% acetone
1% pyridine - stinks
blue dye.

16MillionEyes - 7-8-2007 at 18:17

The rite aid rubbing alcohol lists:
70% Ethyl Alcohol (by volume)
Acetone
Denatonium benzoate (I see it's also present for the alcohol Kazaa posted, any particular purpose known other than to avoid consumption?)
Methyl Isobutyl ketone
Purified water

If you ask me this seems like a hectic job to purify. Any ideas?

16MillionEyes - 7-8-2007 at 18:22

Never mind about the Denatonium. I found the answer and possibly the answer for what someone else asked about a stinking smell:
"To help prevent this, Denatonium is often added to give the substance an extremely bitter flavor. Substances such as Pyridine help to give the mixture an unpleasant odor, and emetic (vomiting) agents such as syrup of ipecac may also be included."

The_Davster - 7-8-2007 at 18:30

Mine:
95% EtOH
camphor
diethylbenzyl benzoate
diethyl phthalate

kazaa81 - 24-8-2007 at 14:38

I left denaturated ethanol (pink-purple) with some
aluminum foil turnings for a week in a vial.

Here are two pictures about what happened :

with aluminum still in

without aluminum

So it seems like the dye was precipitated in some way

16MillionEyes - 24-8-2007 at 16:10

Yeah, it's clear enough there's a formation of a precipitate. I'm guessing that's only getting rid of the dye you've been talking about.

kazaa81 - 24-8-2007 at 16:27

I don't know if it's precipitating only the dye...however the reaction happened is quite unclear too.

12AX7 - 24-8-2007 at 16:46

Could be it's adsorbed onto alumina hydroxide.

Tim

kazaa81 - 24-8-2007 at 18:07

absorbed onto Al2O3 ?

That's would be a nice guess, if I didn't etch aluminum
with a little of aq. 15% NaOH before use...I don't know

16MillionEyes - 25-8-2007 at 06:15

Maybe the Aluminum Hydroxide formed while in solution somehow. I never really heard of Al2O3 as an absorber of dyes.

kazaa81 - 25-8-2007 at 06:55

Aluminum hydroxide is Al(OH)3...upon drying, it converts to Al2O3
that's seen in the classical gelatinous precipitation which occurs while
mixing aq AlCl3 with aq ammonia.

At this point I don't know if it would be better to place some Al(OH)3
in ethanol as it may bring further impurities, being water the first one.

[Edited on by kazaa81]

16MillionEyes - 25-8-2007 at 15:19

But how do you think the Aluminum Hydroxide formed while submerged in Ethanol?

kazaa81 - 25-8-2007 at 17:01

I'm not sure of that, but 12AX7 gave his idea...
Oxygen dissolved in ethanol or the hydroxyl group
CH3CH2OH ?

I will surely have to find some time for synth.
gelatinous Al(OH)3 and try its absorbing
ability.

16MillionEyes - 26-8-2007 at 04:49

But in order for the hydroxyl group to be ripped away one of these things happen:
-The CH3CH2OH dissociates but this isn't true (as far as I'm aware) because it's being hold in place by covalent forces rather than ionic.
-Aluminum pulls the hydroxyl group away from the ethanol but this would destroy the molecule (leaving who knows what) and render the experiment useless (if you are trying to isolate the ethanol.
Another option would be that the Al2O3 present on the surface of the foil or the aluminum itself reacts directly with the dye, whatever its nature.
Here's something I'd suggest doing. Test the precipitate to confirm the presence of aluminum ions and then one of the above reactions (or some other) will definitely have to be considered.

12AX7 - 26-8-2007 at 07:28

Hmm, I wonder if the aluminum could be chelated instead -- which would be very interesting, as removing the dye is then only a dash of AlCl3.6H2O away.

Alcohol isn't very acidic, but it does dissociate. The pKa is in the 20 range. The "salt" thus formed would be something like aluminum ethoxide, Al(CH3CH2O)3, with release of hydrogen. Such reaction occurs quicker with extremely basic things like hydrides and alkalis (sodium metal for example), but still much, much slower than with water, because the acidity is just so little. Since the acidity is less than water (pKa = 7), such "salts" instantly hydrolyze in water, making this impossible if any water remains in solution.

All of this is problematic because the surface layer on a chunk of aluminum tends to be unreactive, both in and of itself and by protecting against further corrosion. If the dye combines with aluminum ions, it could dissolve some, and would open the possibility of further attack.

Tim

kazaa81 - 27-8-2007 at 18:52

waiting to get some time for trying Al ions checking in the precipitate...
these are some ethanol purification procedures outlined on
"Purification of Laboratory Chemicals by W.L.F. Armarego C.L.L. Chai 5th edition"

Ethanol [64-17-51 M 46.1, b 78.3O, d15 0.79360, d5 0.78506, n 1.36139, pKZ5 15.93. Usual
impurities of fermentation alcohol are fusel oils (mainly higher alcohols, especially pentanols), aldehydes,
esters, ketones and water. With synthetic alcohol, likely impurities are water, aldehydes, aliphatic esters,
acetone and diethyl ether. Traces of *benzene are present in ethanol that has been dehydrated by azeotropic
distillation with *benzene. Anhydrous ethanol is very hygroscopic. Water (down to 0.05%) can be detected by
formation of a voluminous ppte when aluminium ethoxide in *benzene is added to a test portion, Rectified spirit (95% ethanol) is converted to absolute (99.5%) ethanol by refluxing with freshly ignited CaO (250gL) for
6h, standing overnight and distilling with precautions to exclude moisture.
Numerous methods are available for further drying of absolute ethanol for making "Super dry ethanol". Lund
and Bjermm [Chem Ber 64 210 19311 used reaction with magnesium ethoxide, prepared by placing 5g of clean
dry magnesium turnings and 0.5g of iodine (or a few drops of CCl4), to activate the Mg, in a 2L flask, followed
by 50-75 mL of absolute ethanol, and warming the mixture until a vigorous reaction occurs. When this
subsides, heating is continued until all the magnesium is converted to magnesium ethoxide. Up to 1L of
ethanol is added and, after an hour's reflux, it is distd off. The water content should be below 0.05%. Walden,
Ulich and Laun [Z Phys Chem 114 275 19251 used amalgamated aluminium chips, prepared by degreasing
aluminium chips (by washing with Et20 and drying in a vac to remove grease from machining the Al), treating
with alkali until hydrogen was vigorously evolved, washing with H20 until the washings were weakly alkaline
and then stirring with 1% HgC12 soln. After 2min, the chips were washed quickly with H20, then alcohol, then
ether, and dried with filter paper. (The amalgam became warm.) These chips were added to the ethanol, which
was then gently warmed for several hours until evolution of hydrogen ceased. The alcohol was distd and
aspirated for some time with pure dry air. Smith [J Chem Soc 1288 19271 reacted 1L of absolute ethanol in a
2L flask with 7g of clean dry sodium, and added 25g of pure ethyl succinate 27g of pure ethyl phthalate was an
alternative), and refluxed the mixture for 2h in a system protected from moisture, and then distd the ethanol. A
modification used 40g of ethyl formate, instead, so that sodium formate separated out and, during reflux, the
excess of ethyl formate decomposed to CO and ethanol.
Drying agents suitable for use with ethanol include Linde type 4A molecular sieves, calcium metal, and CaH2.
The calcium hydride (2g) was crushed to a powder and dissolved in lOOmL absolute ethanol by gently boiling.
About 7OmL of the ethanol were distd off to remove any dissolved gases before the remainder was poured into
1L of ca 99.9% ethanol in a still, where it was boiled under reflux for 20h, while a slow stream of pure, dry
hydrogen (better use nitrogen or Ar) was passed through. It was then distd [Ruber Z Elektrochem 29 334
19231. If calcium was used for drying, about ten times the theoretical amount should be taken, and traces of
ammonia (from some calcium nitride in the Ca metal) would be removed by passing dry air into the vapour
during reflux.
Ethanol can be freed from traces of basic materials by distn from a little 2,4,6-trinitrobenzoic acid or sulfanilic
acid. *Benzene can be removed by fractional distn after adding a little water (the *benzene/water/ethanol
azeotrope distils at 64.9O); the alcohol is then redried using one of the methods described above. Alternatively,
careful fractional distn can separate *benzene as the *benzene/ethanol azeotrope (b 68.2O). Aldehydes can be
removed from ethanol by digesting with 8-log of dissolved KOH and 5-log of aluminium or zinc per L,
followed by distn. Another method is to heat under reflux with KOH (20g/L) and AgN03 (lOg/L) or to add 2.5-
3g of lead acetate in 5mL of water to 1L of ethanol, followed (slowly and without stirring) by 5g of KOH in
25mL of ethanol: after lhr the flask is shaken thoroughly, then set aside overnight before filtering and distilling.
The residual water can be removed by standing the distillate over activated aluminium amalgam for 1 week, then
filtering and distilling. Distn of ethanol from Raney nickel eliminates catalyst poisons.
Other purification procedures include pre-treatment with conc H2SO4 (3mL/L) to eliminate amines, and with
KMnO4 to oxidise aldehydes, followed by refluxing with KOH to resinify aldehydes, and distilling to remove
traces of H3P04 and other acidic impurities after passage through silica gel, and drying over CaS04. Water can
be removed by azeotropic distn with dichloromethane (azeotrope boils at 38.1O and contains 1.8% water) or
2,2,Ctrimethylpentane.
Rapid purification: Place degreased Mg turnings (grease from machining the turnings is removed by
washing with dry EtOH then Et20, and drying in a vac) (5g) in a dry 2L round bottomed flask fitted with a
reflux condenser (protect from air with a drying tube filled with CaC12 or KOH pellets) and flush with dry N2.
Then add iodine crystals (0.5g) and gently warm the flask until iodine vapour is formed and coats the turnings.
Cool, then add EtOH (50mL) and carefully heat to reflux until the iodine disappears. Cool again then add more
EtOH (to 1L) and reflux under N2 for several hours. Distil and store over 3A molecular sieves (pre-heated at
300' -350' for several hours and cooled under dry N2 or argon).

kazaa81 - 31-8-2007 at 08:36

Waiting for checking the precipitate, I left a bottle full of
denatured alcohol (the heaviest dyed I could buy) with
the previously used aluminum strips...that's the result
after 6 days

6 days ago:

today :

closeup, showing reacted aluminum :

That last picture clearly show how aluminum is attacked, probably not as metal itself, but as oxide which is continuously produced and combines with the dye.

I dried some of the precipitate in the last experiment and it showed the presence of Al+3 ions.

jarynth - 30-8-2008 at 11:22

Given the relatively expensive and somewhat controlled nature of pyridine, a reasonable alternative OTC source could be its extraction from denatured alcohol. Then on to remove the other denaturants.

(I moved my post to the pyridine extraction thread

http://www.sciencemadness.org/talk/viewthread.php?tid=9717&a...)

[Edited on 30-8-2008 by jarynth]

Arrhenius - 30-8-2008 at 12:44

Aluminum does absorb dyes, as in the process of anodizing. If you soak your aluminum in some aqueous NaOH first, then rinse off the base in DI water, and then place it in the alcohol it may react a bit faster. As to why it gives you the precipitate, I can't say... It could be that some of the aluminum is dissolved (this is probable) and then reacts. I do know that most cars are not E85 ethanol compatible because they use lots of aluminum fuel parts.

16MillionEyes - 30-8-2008 at 20:34

Quote:

Rapid purification: Place degreased Mg turnings (grease from machining the turnings is removed by
washing with dry EtOH then Et20, and drying in a vac)

Kind of useless if you have to use dry ethanol in order to obtain dry ethanol when you don't have it (and want it) in the first place.

Assuming that Al2O3 is the sole responsible for this, would it be reasonable to assume that as it absorbs the dye it eventually "flakes off" due to inhibiting interactions with the metal layer below, and this in part would allow the actual metal layer to start to act on the alcohol making the ethoxide?

This paper talks about a similar process (using a catalyst but hey, it only lowers the activation energy, the free energy must be there from the beginning in the first place) with aluminum cans, ethanol, xylene as solvent and HgI2 as the catalyst claiming to get high purity aluminum ethoxide after careful processing. The paper It isn't free but you can see the abstract and preview anyway.
http://www.springerlink.com/content/j832762327374j6x/

chloric1 - 31-8-2008 at 05:00

That is very interesting kazaa! I kind of wish we had those denaturants in the alcohol over here!

Quote:

25% solution w/w of C.I. Reactive Red 24 (red dye): 3 g.

Now this has got my attention because of my limited experience with fibre reactive dyes. IRC Kirk talk about diazine fiber reactive dyes that actually reacted with natural fabrics cellulose. Apparently, the dye part is attached to a cyclic nitrogen diazine group that ha two active chlorides which interact with hydroxyl groups in the cellulose. With cotton, hemp, and other natural fabrics, Sodium carbonate is necessary as the pH has to be at least 10. Now aluminum with its oxide skin might behave simularly without the pH increaser. Although I would love a video of this reaction if you added a few prills of NaOH to it.

jarynth - 3-9-2008 at 08:31

Quote:

This paper talks about a similar process (using a catalyst but hey, it only lowers the activation energy, the free energy must be there from the beginning in the first place) with aluminum cans, ethanol, xylene as solvent and HgI2 as the catalyst claiming to get high purity aluminum ethoxide after careful processing. The paper It isn't free but you can see the abstract and preview anyway.
http://www.springerlink.com/content/j832762327374j6x/

Here it is:

[Edited on 3-9-2008 by jarynth]

[Edited on 3-9-2008 by jarynth]

Attachment: Al(OEt)3.pdf (596kB)
This file has been downloaded 1025 times

Panache - 30-9-2008 at 20:35

Vogel distilled denatured ethanol from a refluxing al amalgam to obtain 99.9%ethanol. I have actually done this and it works fairly well. you initially reflux the mix for sometime, say thirty minutes, the amalgam will consume the water first before it begins on the ethanol, at which point you distill some, discarding the first 50mL ass it has dried your glassware for you, empty the flask and voila.

i'm getting a strange sense i have posted this information already. hmm

anyway i'm fairly sure that in doing this most dyes will not distill over also.

jarynth - 8-10-2008 at 20:23

Quote:

Originally posted by kazaa81
That last picture clearly show how aluminum is attacked, probably not as metal itself, but as oxide which is continuously produced and combines with the dye.

I left about 1sqm kitchen Al foil (duly cut up in ~1sqcm pieces) in 250ml of my denatured alcohol in a loosely capped jar. The Al wasn't attacked in the least after 10+ days. Your pink stuff must contain something interesting... what's the pH?

kazaa81 - 10-10-2008 at 11:53

@jarynth: why did you leave if loosely capped? I don't think gases are produced, and in this way you let EtOH evaporate.

Dunno about the pH, but the denaturants/colorants have been listed some posts ago in this thread

Ephoton - 14-10-2008 at 03:34

yep Panache beat me too it that's how I do it. add some hg salt and you not only loose the denaturant but also dry the ethanol at the same time

jarynth - 14-10-2008 at 11:56

Quote:

Originally posted by kazaa81
@jarynth: why did you leave if loosely capped? I don't think gases are produced, and in this way you let EtOH evaporate.

If the Al gets oxidized, then H2 is produced. But this would have been too good to be true.

ycheff - 26-10-2008 at 01:29

Try to purify ethanol by pinch of KMnO4. Decantation - in a week.

HydroCarbon - 26-10-2008 at 07:21

Quote:

Originally posted by __________
But in order for the hydroxyl group to be ripped away one of these things happen:
-The CH3CH2OH dissociates but this isn't true (as far as I'm aware) because it's being hold in place by covalent forces rather than ionic.
-Aluminum pulls the hydroxyl group away from the ethanol but this would destroy the molecule (leaving who knows what) and render the experiment useless (if you are trying to isolate the ethanol.
Another option would be that the Al2O3 present on the surface of the foil or the aluminum itself reacts directly with the dye, whatever its nature.
Here's something I'd suggest doing. Test the precipitate to confirm the presence of aluminum ions and then one of the above reactions (or some other) will definitely have to be considered.

If it did happen a double bond would most likely form between the carbons and make ethylene, which would be quite obvious as it's a gas.

12AX7 - 26-10-2008 at 09:20

Ethanol's proton comes off about as easily as water's. That is to say, ethoxide has nearly the same pKa as the hydroxide ion. The hydroxyl is much harder to remove, C-O bonds are stronger.

Tim

Tsjerk - 26-10-2008 at 12:10

To come back onto the spiritus sold in the Netherlands, I was able to purify it to 99% with the last percent as a bit of methanol, acetone and a trace of water (0,1%). This was checked with a GC.

I first did a destillation over a 30cm vigreux colom with a couple of drops H2SO4 to protonate the pyridine. Discarded the first 10%, to get rid of most methanol. I captered the middle 80%. The bleu dye didn't come over.

Then dried with MgSO4 and then refluxed over grignard grade magnesium turnings (about 10-15g) for a couple of hours followed by a second destillation, again captured the middle 80% after which I did a GC to come with the earlier stated purity.

I got 600-700ml ethanol out of 1L spiritus, which costs about 1,50 euro's, very economical if I may say.

[Edited on by Tsjerk]

vulture - 26-10-2008 at 15:07

Quote:

I got 600-700ml ethanol out of 1L spiritus, which costs about 1,50 euro's, very economical if I may say.

If you didn't have to pay for the electricity, the cooling water, the other chemicals and the manhours involved, then yes.

Tsjerk - 27-10-2008 at 05:34

Well, the magnesium turnigs cost about 25 euro for 500gr at Fisher so that is 0,75 cents but this amount of magnium can be used for a lot more alcohol. The MgSO4 doesn't cost much and is re-used almost indefinitly.

Water is in a closed circuit, so it is'nt used. Ice comes out of a refrigerator which is turned one anyway.

About the electricity I don't know what it costs but it can't be more than 2 euro's.

If you see the work done as a hobby manhoures should be forgot.

So that makes about 7 euro's a liter 99% ethanol, with a price that gets lower if you make larger batches. Normally I pay 9,50 for a liter of 96% denatured ethanol.

Ps. price of sulferic isn't counted in because it's about a milliliter or less.