Alcohol concentration , and use

when you distil alcohol(ethanol) you cannot get above ~95% because it forms a low boiling aeziotrope at 95.4% and condenses at that %. The only way to remove the water is to absorb it via a drying agent. You can apply this to denatured ethanol as long as the denaturant is tolerated by the shellac and makes no surface problems. zeolite 3A can be used to dry it. After drying you can heat the zeolite to 130C to remove the water, but take care, it will have some alcolhol in there too and can start a fire in any enclosed over or heating box, so outside and well vented

I ain't no chemist, but I thought it was relatively easy to get 199 proof alcohol. It's getting the last 1 proof that's hard to do. From what I heard, the alcohol has to be mixed with benzene, which sucks up the last bit of water.

Anyway, you can purchase 200 proof (100%) ethyl alcohol on the web from several chemical supply houses. I use it for Martini... Uh, mixing with dyes for laser work.

Yes, you can use a distillation process to co-distil alcohol with benzene, but benzene is a flammable carcinogen, so I steered him towards chemical dehydratoirs and sieves.

http://www.ethanolindia.net/molecular_sieves.html

I concur. Who in their right mind wants to work with benzene if they don't have to. That's why I suggested he just by the stuff. It's cheaper than a good bottle of scotch.

May be the cheaper and safe way to get rid of the small percentage of water in alcohol is to distill it with calcium oxide, on a water bath with a reflux condenser. All alcohols are hygroscopic and it is necessary to ensure that the alcohol, after distillation, is not exposed to the atmosphere.

Hi vermin. There is a big difference between alcohol proof and alcahol by volume (ABV). Most industrial alcohol is quite high in pecentage of alcohol to water, being about 90% ABV. This means that it is 90% alchol and 10% water. Drinking spirit is somewhere between 35 and 45& ABV. I used to distil my own fire water, but I never got higher than 96% ABV. It is possible to get higher by triple distilation, but as soon as you expose it to the atmosphere it absorbs water. Spencer.

If you are buying 200 proof ethanol, trust me, it's denatured and "toxic" for ingestion. The only other route is to get a gov't permit to purchase 200 proof (absolute) alcohol, or pay the taxes. The "pure ethanol" they sell in package stores (selling liquor) is 95 % and you'll pay a hefty tax per quart/liter. The ethanol itself is quite inexpensive. In the U.S., the plan is to plant more acres of corn since the 1940s. The additional is dictated by a move to increase the addition of 10 % ethanol to gasoline, where the ethanol is obtained from corn (or biomass). I believe (someone correct me, please) that most vehicles in Brazil are run on ethanol. Take that, OPEC! Now, when one drives thru/past the extensive corn fields in the mid-western U.S., there is likely a fermentation or chemical plant right on the property, to produce ethanol from the corn.

Yes, 100% (200 proof) ethyl alcohol is available from chemical companies without having to deal with revenuers. I have a couple of bottles of it sitting (tightly closed) in my refrigerator right now. And I can assure you that I would never try drinking the stuff...

Hey! Where did my keyboard and monitor go! Who turned out the light! Are we having a black out! Who am I?!

Hi Vermin - this raises a question I've wondered about from time to time. I know % proof is always about 2 x % ABV, but is it exactly 2 x, by definition, or for some other reason?

I believe "proof spirit" was originally defined as the strength at which gunpowder wetted with it would just burn. But it doesn't seem likely that was 100% proof, as I'd expect that to be well above the burning limit, since spirits at ~ 40% ABV burn OK on their own. Also it would be OK for strengths > burning limit (keep trying successive dilutions till limit reached, then multiply up), but not so easy for lower strengths.

Any comments? Cheers.....Codey

I've heard basically the same thing about proof versus %. I think the roots of proof date back to trying to explain to a cowboy what 45.37% alcohol meant. Much easier to multiply by two and just tell them "it's 91 proof. Of course, there are several drinking concoctions that are stronger than 100 proof (50%).

Also, there is a reaction between different substances (gun powder) and ethyl alcohol as the purity climbs. I was warned not to get my aluminum powder anywhere near my 200 proof alcohol. If the two get together, the aluminum starts pyro-type oxidizing that won't stop until one or the other reactants run out!

Thanks Vermin, I checked on Wiki and it refers to the gunpowder test but surprisingly (to me) the burning limit is 57.15% ABV. So proof on this basis is ~ 1.75*ABV (100/57.15)

But it also says in US proof is now defined as 2*ABV.

Codey

I still like my cowboy story

"Is that thar a 10 gallon hat or a 3.8 liter hat?"

That must be a pin headed cowboy. 10 US gallons = 38 litres??

Dang! Busted for my own stupidity!!!

Uh, yeah. It was a really tall hat.

AAAAH , it may be time to close this thread , it appears that some may be inbibing in the subject matter.

Jon

What makes you think that? Hic!

Just a WAG!

To achieve the best dissolution of shellac flakes you want to use denatured alcohol which is water free. BEHKOL, a brand name, is a good choice. I love working with shallac flakes and by their degree of refinement, you can achieve nearly colorless results. Many woodworkers think shellac is an old-fashioned finishing technique but it actuall brings out more of the woods natural beauty than coatings (like poly) which only coat the wood for the light reflection effect. Also, water based analine dyes are my choice for the coloration of wood replacing stains which I gave up on many years ago. Try this link for alcohol and flakes:http://www.woodworker.com Good luck, Max

The distinction needs to be made, and it has been referenced in the previous posts, the difference of pure ethyl alcohol and other forms including denatured. The application here is for denatured, since it is not suitable (actually it can really mess you up and basically kill a person) and is relatively readily available for purchase.

Guest's post about the 200 proof ethyl alcohol purchase is almost correct, at least from what I have come to understand. Yes, you must apply for and receive a permit that must be supplied to the vendor when ordering but the government (FDA or DEA, I'm not sure which) doesn't just hand them out to anybody since it is used in drug manufacturing. It isn't even an option to just buy it and pay the tax.

All that being said, denatured alcohol is what is needed for the application in question so it just becomes a question of where to find a quality product which I believe another post provided a link for.

There are dozens of denaturants created for the chemical process industries that make the alcohol taste bad/make you vomit, yet allow each process to proceed without the denaturant ruining the reaction and cannot easily be distilled/adsorbed out.

Some processes cannot tolerate denaturants and are bought under the aforementioned permit procedure. Mouthwash cannot tolerate poisonous denaturants, so it uses ethanol, but the flavors added make consumption of a large amount hard to do and a de factor denaturant. Cough syrups do this as well.

Winos and Alkies have trained themselves to drink lots of these materials for the high

You should be able to get alcohol at most any hardware store, but I think it is Isopropyl - will that work? You shoudl be able to get really close to 100% alcohol, and it isn't that expensive/

Thanks for all the input , this will help dilute my confusion in the subject.

Jon

Please do yourself a favor if you're into wood working, check out Lee Valley Tools, sign up for their catalogs and check out the site... I have bought flakes from them. Excellent company with superior products.

Domestic 'methylated spirit' is historically used to prepare shellac. It's available relatively inexpensively at most hardware outlets and ironmongers.

I use Behlen's Bekhol from Woodcrafter's, Highland Hardware(both Mail order) or a local supplier. It is somewhat expensive but so is the furniture ect. that I make.

has anyone thought about freeze distillation to remove the water from the alcohol? it is quite simple, pour it in a shallow dish like a baking pan, stick it in the freezer and then skim off the ice. repeat until no ice forms.

Yes, Freeze distil works, but you must boil it all over first or you get all the residue in the alcohol phase. Fusel, dead yeast protein, etc.

That is the poor mans high octane beer