Sciencemadness Discussion Board - How pure is denatured alcohol?

How pure is denatured alcohol?

achem500 - 4-8-2012 at 19:02

I've been looking for an OTC source of relatively pure ethanol, is hardware store "denatured alcohol" above 95%? Any help is appreciated.

Sublimatus - 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.

achem500 - 4-8-2012 at 22:07

Thanks. Everclear looks like the next best option.

hyfalcon - 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.

Pyro - 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.

weiming1998 - 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.

Endimion17 - 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.

MR AZIDE - 5-8-2012 at 10:22

Quote: Originally posted by weiming1998

Quote: Originally posted by hyfalcon

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.......

hyfalcon - 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.

ScienceHideout - 5-8-2012 at 13:33

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

weiming1998 - 6-8-2012 at 04:31

Quote: Originally posted by MR AZIDE

Quote: Originally posted by weiming1998

Quote: Originally posted by hyfalcon

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.

liquidlightning - 10-8-2012 at 00:20

Yep, SLX denatured alcohol is 45/50/5 ethanol/methanol/methyl isobutyl ketone.

Vargouille - 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

Mailinmypocket - 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.

edgecase - 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.

triplepoint - 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.

unionised - 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.

BromicAcid - 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'.

Antimony Pentafluoride - 15-8-2012 at 19:46

Denatured alcohol is designed to be extremely difficult to purify through distillation.

achem500 - 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.

Pyro - 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

DieForelle - 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.

DieForelle - 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.

BromicAcid - 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]

DieForelle - 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.

DieForelle - 28-8-2012 at 12:07

Here we go, everything you could possibly want to know about this particular bureaucracy:
http://www.lyondellbasell.com/techlit/techlit/Brochures/Ethy...

Looks like flavoring manufacturers have to buy taxed alcohol, but can get most of the taxes back if they have the proper record keeping (somewhat bizarre) Still trying to figure out what the impact on someone like SAFC would be though, who, it seems to me, could theoretically manufacture/distill the alcohol they need in whatever form on premises under the $1000 "producers tax" and as long is it was consumed/destroyed in the production of something else, would not have any additional taxes to pay. Seems like it would be cheaper than worrying about 20 different denaturing formulas and which would be the best to use.

Dr.Bob - 28-8-2012 at 13:01

I think that she is stating, correctly, that if you use denatured ethanol for a reaction or to clean your workspace then you don't need to account for it all, just like buying denatured alcohol at the store.

Universities and businesses are "supposed" to account for every last drop of the untaxed, non-denatured, but I think most universities and larger businesses are given a lot of slack in the auditing of the records. However, the ATF may not be so kind or liberal to individuals or smaller companies. But it is legal for individuals to make distill untaxed ethanol for personal use as a fuel, provided you pay the highway taxes on it and get a permit. You can brew beer and wine as well, but if you distill for consumption, then they get upset, although there are numerous companies that sell very nice equipment to distill your biofuel to very high quality.

I think that if you use ethanol in flavorings to be consumed that you actually may have to use taxed ethanol for that purpose, since it is being consumed. Otherwise, some creative company would create food flavorings which were rum flavored or beer flavored and try to skip the tax that way. The ATF/taxman is way ahead of people there. However, medicines can use untaxed ethanol, such as for mouthwash, tincture of iodine, and cough syrups. And those purposes typically use 95% ethanol, as they usually add water anyway.

Lastly, most ethanol for fuel usage is created as absolute ethanol, as water is bad in fuel, but they must denature it before shipping for fuel use, as diversion would be too big a problem. Normally this is done by adding methanol and kerosene to each batch. But almost no one uses benzene azeotrope to dry ethanol now, most large biofuel plants use either alumina or molecular sieves to remove the water and then regenerate the column with steam heat to boil off the water under vacuum. That is one reason why using ethanol as fuel is so expensive and energy intensive. That would be a good purpose for solar thermal heating, but very few plants use it as best as I can tell, as they want to make fuel 24/7, even when the sun is not shining.

DieForelle - 28-8-2012 at 13:39

Right, the flavoring (or pharmaceutical) companies have to document that the products they make with the taxed alcohol actually become flavorings or pharmaceuticals, and not flavored alcoholic beverages! Then they get $12.50 of the $13.50 of taxes paid per gallon back.

Mouthwashes use a 1% menthol formula, but the TTB actually regulates those more carefully in some respect than plain taxed 200 proof ethanol, because they consider it purifiable. An entity can only buy a limited amount without getting a permit detailing what they do with it.

The key point to all of it is they don't really care what you do with it, as long as there's no way it gets diverted to beverage use in untaxed form. Even research labs or flavoring manufacturers who don't want to bother getting permits can certainly buy taxed 200 proof alcohol without a permit if they want. But $13.50 a gallon is a crushing overhead and presumably very few entities actually buy it that way.

BromicAcid - 28-8-2012 at 14:21

Quote: Originally posted by Dr.Bob

I think that she is stating, correctly, that if you use denatured ethanol for a reaction or to clean your workspace then you don't need to account for it all, just like buying denatured alcohol at the store.

You hit the nail right on the head with that one. They prefer denatured solvents because then you don't have to account for every drop.

mr.crow - 28-8-2012 at 16:16

This thread is as good as any to post in

I recently purified some ethanol from the drug store. Rubbing alcohol contains ethanol, ethyl phthalate, denatonium and camphor. Yuck!

I added some NaOH to it in a jug and after about a month it turned a putrid red color (aldol condensation with camphor). Denatonium should be destroyed and phthalate hydrolyzed. Then distill 2/3 of it for pure ethanol. Obviously not for drinking!!!

This method should be able to purify most denaturants (except methanol of course)

marko - 31-8-2012 at 02:46

Hey mr. crow. I have the same rubbing alcohol.

Going from the govnt's denatured alcohols law, this is denatured alcohol "DA-2O", which is:

95% ethanol, denatured with (per litre):
2.5mL diethyl phthalate -- (why?)
7mg denatonium
0.4g camphor ( for smell? I can't really smell it. Maybe is enough to be cooling on skin?).

Oh - I can kinda smell the camphor on skin once the alcohol evaporates... has slight cooling feel also.

I wouldn't think camphor or DEP would come over on distillation? why bother with the lye?

Anyway, if yours is weaker than 95%, this type would be a better starting point... (I think I've seen 70% and 50% variations)

I was thinking I'd use it for fuel or cleaning or so, but I don't really like the idea of leaving phthalate film on things. I don't know. Wonder if the denaturants burn clean.

Could be a cheap reagent for someone if separated, certainly cheaper than everclear.

(also, for cleaning/fuel - half price of strong isopropyl, and probably cheaper than methanol... healthier too)

mr.crow - 31-8-2012 at 08:00

Hey thanks for the composition! I must have used way too much NaOH. I wanted to be sure it was all gone, they chose it so simple distillation isn't good enough

They put mineral oil in IPA rubbing alcohol so the skin still has lubrication. Maybe that's what the DEP is for.

In Quebec you can get Alcool. Who would want to drink this shit?

zed - 11-9-2012 at 13:31

The small college that I used to work for, had endless problems with the ATF. If you use even a gallon of un-taxed ethanol per year, a suspicious control agent may visit you multiple times per year. Our agent was perpetually telling us we were using too much ethanol. Even when we clearly hadn't used any at all. It comes with the territory.

It was such a hassle, that our lab techs employed denatured ethanols, when they shouldn't have. Thus, our thin layer chromatography experiments never worked right. Change the polarity of your solvent, and your solutes may not elute in the order they are supposed to. Bother.

If you are a small fry, it is easier to buy taxed ethanol, and thus exempt yourself from regulation. If you are able to use denatured ethanol without ill-effect on your process....fine. If not, pay the tax.

The production of beverage grade ethanol, without a permit, and without paying the tax, may be construed as a crime in the U.S..

Arthur Dent - 12-9-2012 at 04:31

Quote: Originally posted by mr.crow

In Quebec you can get Alcool. Who would want to drink this shit?

I believe it is mostly used to prepare drinks and other alcoholic beverages. Some pro winoes use it straight or with some water. But for chemical purposes, it is food grade, so it should be quite pure chemically. I guess that the last 6% water could be salted out...

Robert

SM2 - 12-9-2012 at 05:39

Can't say for certain. Many variations in different brands/makes. One might use mainly denatonium benzoate (which wont hurt you at all if you drink it's just bitter.) Others use mixtures, including methanol. From what I hear, the methanol in anything <%10 is not a problem as ethanol is the only known antidote to methanol poisoning,

Lavacol is the brand I always grew up with, and it contained methyl isobutyl ketone. Jimmy Carter let us all brew beer. Brewing a few gallons moonshine for personal use only doesn't seem to be a far stretch.

Dr.Bob - 14-9-2012 at 11:51

Quote: Originally posted by Fennel Ass Ih Tone

Can't say for certain. Many variations in different brands/makes. One might use mainly denatonium benzoate (which wont hurt you at all if you drink it's just bitter.) Others use mixtures, including methanol. From what I hear, the methanol in anything <%10 is not a problem as ethanol is the only known antidote to methanol poisoning,

Lavacol is the brand I always grew up with, and it contained methyl isobutyl ketone. Jimmy Carter let us all brew beer. Brewing a few gallons moonshine for personal use only doesn't seem to be a far stretch.

The government has tables of what is in different types of denatured alcohols, many called SD mixes. Just look in the BATFE website for details. Most will cause you to throw up or get violently ill, but some can kill you.

And methanol, even under 10% is certainly quite toxic to humans, at amounts larger than about a ml, even mixed with ethanol, which is used in poisoning cases as an antidote to help overwhelm the liver enzymes that oxidize methanol to formaldehyde. But that is an equilibrium reaction, and only helps, it does not protect against the damage of formaldehyde, which is bad for the eyes, nerves, and DNA, for starters. Please don't encourage people to drink denatured alcohol, it can easily cause blindness, and often does when mixed with illegal moonshine, as happened recently in Czech. where 28 people were poisoned by bad alcohol.

Also, ethanol is not the only antidote, there are pharmaceutics that block the liver enzymes for the oxidases as well, they are often used by ER doctors as well as vets as well for dogs that drink antifreeze. Fomepizole is one such compound.

ElectroWin - 4-10-2012 at 11:08

Quote: Originally posted by marko

95% ethanol, denatured with (per litre):
2.5mL diethyl phthalate -- (why?)
7mg denatonium
0.4g camphor

...
I was thinking I'd use it for fuel or cleaning or so, but I don't really like the idea of leaving phthalate film on things. I don't know. Wonder if the denaturants burn clean.

according to the CDC, diethyl phthalate gives off irritating fumes or toxic gases when burned in open flame...
http://www.cdc.gov/niosh/ipcsneng/neng0258.html