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achem500
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[*] posted on 4-8-2012 at 19:02
How pure is denatured alcohol?


I've been looking for an OTC source of relatively pure ethanol, is hardware store "denatured alcohol" above 95%? Any help is appreciated.
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[*] posted on 4-8-2012 at 19:35


Look up the Material Safety Data Sheet (MSDS) for whichever products you might consider buying.

By definition, denatured alcohol will never be pure ethanol.

As an example, S-L-X Denatured Alcohol by Klean-Strip is about half and half methanol and ethanol, with methyl isobutyl ketone as a denaturant. As far as I'm aware, separation is a major pain in the ass, if not impossible.

You might get MEK Subsitute, ethyl acetate, and cleave that to ethanol and acetate. Otherwise, ferment sugar and distill, or just find some Everclear.
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achem500
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[*] posted on 4-8-2012 at 22:07


Thanks. Everclear looks like the next best option.
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hyfalcon
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[*] posted on 5-8-2012 at 02:51


Ethanol will still have an azotrope at 95% with water making up the other 5%. You have to jump through hoops and hurdles to get that last 5% to go then you're not left with pure ethanol then due to the contaminates from breaking the azotrope.

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Pyro
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[*] posted on 5-8-2012 at 04:03


well,
I can buy 99% in my area, in an art restoration shop along with: THF, toluene, xylene, MEK, zinc salts, potassium salts, sodium salts, and many more. you should look for one of those in your area.




all above information is intellectual property of Pyro. :D
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weiming1998
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[*] posted on 5-8-2012 at 04:14


Quote: Originally posted by hyfalcon  
Ethanol will still have an azotrope at 95% with water making up the other 5%. You have to jump through hoops and hurdles to get that last 5% to go then you're not left with pure ethanol then due to the contaminates from breaking the azotrope.



Not really. In large quantities, dry ethanol is made by azeotropic distillation with benzene, but what I always find handy when I need dry ethanol (synthesis of aluminum ethoxide, for example) is to use a drying agent like anhydrous copper sulfate. It absorbs enough water for it to be pretty much anhydrous. Copper sulfate is not soluble in ethanol, so contamination is minimum.

Anyway, methylated spirits are fairly pure sources of ethanol suited for most purposes. The methylated spirits that I use contains 95% ethanol (rest water/denaturing agent). It is certainly not a 50:50 mix of methanol and ethanol.
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[*] posted on 5-8-2012 at 05:05


If you need pure ethanol without heavy metal contamination, use quicklime for drying. It's best to heat slaked lime above 600 °C.



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MR AZIDE
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[*] posted on 5-8-2012 at 10:22


Quote: Originally posted by weiming1998  
Quote: Originally posted by hyfalcon  
Ethanol will still have an azotrope at 95% with water making up the other 5%. You have to jump through hoops and hurdles to get that last 5% to go then you're not left with pure ethanol then due to the contaminates from breaking the azotrope.



Not really. In large quantities, dry ethanol is made by azeotropic distillation with benzene, but what I always find handy when I need dry ethanol (synthesis of aluminum ethoxide, for example) is to use a drying agent like anhydrous copper sulfate. It absorbs enough water for it to be pretty much anhydrous. Copper sulfate is not soluble in ethanol, so contamination is minimum.

Anyway, methylated spirits are fairly pure sources of ethanol suited for most purposes. The methylated spirits that I use contains 95% ethanol (rest water/denaturing agent). It is certainly not a 50:50 mix of methanol and ethanol.



Is Aussie meths purple, due to added methyl violet?, and have they added pyridine as a denaturant as well.??

I have distilled Bartoline Methylated spirits, which contains about 92 -95 % ethanol, less than 5% Methanol, and less than 1% pyridine and methyl violet.

From 70 ml portions I was distilling, about 65 ml boiled over at 76 'C, and stopping the collection at 78'C when the last 5 ml left in flask, another fraction of a few ml begins to come over at 81 to 83 'C, which has a much stronger sickly sweet smell.
Evaporation of the last portion in the distilling flask yields some small amount of methyl violet, which is a very small range pH indicator incicating from pH 0 ti 1.6 ish.......

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hyfalcon
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[*] posted on 5-8-2012 at 10:53


achem500 was talking about everclear which is drinking ethanol. That will be the 95/5 ratio of alcohol to water. I just wanted to make sure he was aware of that. The 99% denatured variety will have other contaminates that was used to break the azeotrope.
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[*] posted on 5-8-2012 at 13:33


MSDS sheets show that most denatured alcohols are around 50/50 ethanol/methanol.



hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!


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weiming1998
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[*] posted on 6-8-2012 at 04:31


Quote: Originally posted by MR AZIDE  
Quote: Originally posted by weiming1998  
Quote: Originally posted by hyfalcon  
Ethanol will still have an azotrope at 95% with water making up the other 5%. You have to jump through hoops and hurdles to get that last 5% to go then you're not left with pure ethanol then due to the contaminates from breaking the azotrope.



Not really. In large quantities, dry ethanol is made by azeotropic distillation with benzene, but what I always find handy when I need dry ethanol (synthesis of aluminum ethoxide, for example) is to use a drying agent like anhydrous copper sulfate. It absorbs enough water for it to be pretty much anhydrous. Copper sulfate is not soluble in ethanol, so contamination is minimum.

Anyway, methylated spirits are fairly pure sources of ethanol suited for most purposes. The methylated spirits that I use contains 95% ethanol (rest water/denaturing agent). It is certainly not a 50:50 mix of methanol and ethanol.



Is Aussie meths purple, due to added methyl violet?, and have they added pyridine as a denaturant as well.??

I have distilled Bartoline Methylated spirits, which contains about 92 -95 % ethanol, less than 5% Methanol, and less than 1% pyridine and methyl violet.

From 70 ml portions I was distilling, about 65 ml boiled over at 76 'C, and stopping the collection at 78'C when the last 5 ml left in flask, another fraction of a few ml begins to come over at 81 to 83 'C, which has a much stronger sickly sweet smell.
Evaporation of the last portion in the distilling flask yields some small amount of methyl violet, which is a very small range pH indicator incicating from pH 0 ti 1.6 ish.......



Yeah, some methylated spirits that I see at hardware stores are dyed, others aren't. I pick the ones that are not dyed. As for pyridine, I haven't done any analysis on it, but it doesn't smell anything like the rotten fish smell of pyridine described by other people. It smells like normal drinking alcohol, albeit with a more "solvent" like and slightly spicy smell.

Anyway, it's strange to see people say that methylated spirits is 50:50 methanol and ethanol. I haven't seen any like that. If I have, I would have bought it, because I lack a source of methanol.
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[*] posted on 10-8-2012 at 00:20


Yep, SLX denatured alcohol is 45/50/5 ethanol/methanol/methyl isobutyl ketone.
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[*] posted on 10-8-2012 at 03:49


And Crown Denatured Alcohol is worse for ethanol, better for methanol: 60-75% Methanol, 20-30% Ethanol and <10% ea. MIBK and IPA
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[*] posted on 10-8-2012 at 06:31


If you can find a local chemical supplier that supplies things like industrial cleaners, germicidals and things like urinal pucks and whatnot, they will often also have denatured alcohol. In my case the local supplier has what is called "2 A Alcohol, Denatured, Anhydrous"

The MSDS indicates that the only ingredients are:

Ethanol 85-90%
Methanol 15-10%
Ethyl Acetate <1%

In my experience the hardware varieties often contain several more ingredients as mentioned above, I havent tried to separate the methanol and ethanol though, but it works fine for my purposes.

alcohol.JPG - 165kB
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[*] posted on 11-8-2012 at 06:52


Quote: Originally posted by Mailinmypocket  
If you can find a local chemical supplier that supplies things like industrial cleaners, germicidals and things like urinal pucks and whatnot, they will often also have denatured alcohol. In my case the local supplier has what is called "2 A Alcohol, Denatured, Anhydrous"


Yes I have purchased this also, I believe the 2A is only in Canada, the regulations for denatured alcohol state the formulas for each class. In the USA, there are similar regulations, so if you can buy something in either of those countries, that states which denatured formula, you can lookup the composition on various government websites.

You would definitely want to get one of the ones denatured with pure compounds, not a mix of stuff like gasoline or pine oils, good luck separating those out.

I have tried separating 2A Anhydrous, using a variable reflux head and 6ball snyder column, the methanol comes off first easily enough, and the ethyl acetate with high reflux ratio 10:1 seems to mostly come over first, the remaining bulk seems to have only the "grain alcohol" smell. I didn't do an exhaustive search for azeotrope data, and I certainly wouldn't drink it; I did go on to reflux with NaOH and was able to get sodium acetate, and sodium ethoxide, as an investigation of a way of furthur purifying.
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[*] posted on 12-8-2012 at 04:56


Weiming1998 wrote that methanol is not easily available to him. Weiming - do you have Heet brand automobile engine products available locally? They sell methanol as a gasoline additive (although not by name, you need to check the msds sheets of likely candidates). You also may have the same thing under a different brand name.
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[*] posted on 12-8-2012 at 08:47


Quote: Originally posted by ScienceHideout  
MSDS sheets show that most denatured alcohols are around 50/50 ethanol/methanol.


I doubt that.
Here are the first few that Google finds
http://www.hvchemical.com/msds/deal.htm

http://engineering.case.edu/thinkbox/sites/engineering.case....

http://www.sciencelab.com/msds.php?msdsId=9922820

Most are mainly ethanol.
And this
http://en.wikipedia.org/wiki/Denatured_alcohol
says it's essentially ethanol with additives. I'd feel that I had been defrauded if I bought denatured alcohol and it was mainly something else.
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[*] posted on 12-8-2012 at 09:21


Something amusing about denatured alcohol that I see a lot in industry. You can have a drum that says 99.5% ethanol (denatured) and look up the MSDS to find that it's only 95% ethanol with the remainder toluene or the like. The ethanol itself going in is 99.5% pure and they just don't count the toluene or the denaturant in that. Because of the tax on non-denatured (drinkable) ethanol, nearly everything we use is denatured so we have to carefully pick from a list of about 20 different kinds of denatured ethanols to find a denaturant that will not adversely affect the reaction. The non-denatured stuff sticks out, bright green drums and a large symbol on the side saying 'Kosher Grade'.



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[*] posted on 15-8-2012 at 19:46


Denatured alcohol is designed to be extremely difficult to purify through distillation.
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[*] posted on 17-8-2012 at 12:30


I might just use Everclear straight from the bottle. It is probably pure enough for my experiments. Magnesium sulfate is the only drying agent I currently have on my shelf, and I dried some in the oven the other day. It is only slightly soluble in ethanol, so it looks like the best option.
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[*] posted on 17-8-2012 at 17:05


you could distill everclear to 95% (if you only have 70% that is) depending on state laws. but since you will only be using, a little? you could distill it just before you use it, nobody would know, and you are not selling it or anything. so i think you would be ok. but do what you think is right



all above information is intellectual property of Pyro. :D
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[*] posted on 27-8-2012 at 17:46


Ah, good old EtOH.

"Because of the tax on non-denatured (drinkable) ethanol nearly everything we use is denatured so we have to carefully pick from a list of about 20 different kinds of denatured ethanols"

Strange - who is "we"? At least when I worked in labs in the mid 90s, it was apparently quite easy to get to get the ATF or TTB or whoever's exemption if you were a legitimate research outfit. At least the university lab did, and the industrial lab. We used Pharmco USP 200 proof like windex in the pharma research lab. Wiped our lab space down with it at the end of every day. Everybody had their own bottle and if you needed another there was an unlocked cabinet with scores of pints of the stuff. A PI let a hot girl take some home once to spike her punch for a weekend party. Yes...those were freewheeling days. (lab closed down because the work was outsourced)

Here's a conundrum of mine: thinking of starting a small biz. making flavoring extracts. Until I have a business location, I will have to buy Everclear or GEM Clear to source EtOH. Everclear seems to be the more celebrated one in American folklore, but, interestingly, only GEM's label says "USP". And, I done swears tuh gawd, it tastes purer to me. (Believe it or not, I do not recreationally drink! True nerd here! Find the sensation of even slight inebriation to be horrible.) Surely, the use of the term "USP" on a label is governed...right? They can't just put it there for ornamental effect? I could just ask the GEM Clear distillery, but it seems production is handled by a shell company that is hard to reach. (Liability avoidance, one assumes. How sad) I have a vague understanding that people who repackage real USP grade ingredients, i.e., certain ebay sellers, are not supposed to call their product USP grade unless they actually repackage it in an FDA registered facility. But that's obviously not enforced. I could always test them for cogeners myself, if I really want to be OCD. There's a lab in California that will do those tests for anybody willing to pay; i.e., home vintners.







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[*] posted on 27-8-2012 at 17:59


Hmmmmm. I did find this:
http://www.usp.org/support-home/frequently-asked-questions/u...

Sounds like USP just sets the standard, it would be up to the FDA to enforce. Presumably they have many bigger fish to fry. But, indeed, if Gem Clear is labeled USP, it is legally obligated to meet the monograph.
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[*] posted on 27-8-2012 at 19:04


Quote: Originally posted by DieForelle  
Ah, good old EtOH.

"Because of the tax on non-denatured (drinkable) ethanol nearly everything we use is denatured so we have to carefully pick from a list of about 20 different kinds of denatured ethanols"

Strange - who is "we"?


Sigma Aldrich

Industrial use of ethanol is covered in CFR 27 sections 17, 20, 21, and 22. If we want to use ethanol without the tax then we have to account for every last drop. It's a pain in the butt, especially check out CFR22 Subsection G regarding the use of tax free alcohol. Of course all this is dependent on the industry, the final use, and if you want to avoid paying taxes in the first place. So the relevance of all these regulations can vary greatly. Still, by using the denatured these can be side-stepped.

[Edited on 8/28/2012 by BromicAcid]




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smile.gif posted on 28-8-2012 at 10:19


Wow! I'm shocked someone who works for the mighty Sigma Aldrich is allowed to reveal that here. It's good they bother to be above board, I suppose, but, really who's going to know? (I guess the point is with a large corporation of 1000s of employees, someone IS going to know something, and then everyone else could be in deep doo-doo.) I'll try not to bother you will all the questions I could bother you with :)

But I still find the context of your comment somewhat mystifying. If you work in the manufacturing side of things, surely to perform certain manufacturing or purification steps, you'd need to start with completely pure EtOH, and that such use would be permitted by law? I highly doubt the ethanol being carted around the midwest on railcars to go into our gasoline, for example, is taxed or denatured, and that certainly counts as a manufacturing/industrial use. (although it might not be safe to consume if it is denatured as a byproduct of its manufacturing, like containing too much benzene or something) Oh well...I think for the point of this thread, our twin perspectives show both sides of the story on the use of this material. I do find it interesting the CFR appears to list no exception for flavoring manufacturers. It's very hard to believe McCormick is having to pay tax on the tonnes of EtOH they must use every year. OTOH, it does end up getting "consumed" however indirectly. I have a contact in the flavoring industry so I might ask him about that. And the exemptions seem to keep saying "research laboratories"...maybe as a manufacturer, what you do cannot be considered research anymore? But that would be odd because your products are only supposed to GO to research facilities.

So I can only assume you are saying, to manufacture substance X, you have to start with denatured alcohol and somehow perform additional purification steps on X to eliminate the byproduct of any side-chain reactions that occur due to the denaturants? If you're permitted to clarify, please do.
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