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How to "Salt Out"

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Salting out is a process that can be used to dehydrate Isopropyl alcohol, i.e., separate it from water in an azeotropic solution. Dehydrated Isopropyl is useful as a fuel by itself and in helping to determine the right amount of catalyst to add when making bio-diesel fuel.

Removing water also increases the Isopropyl alcohol's ability to:

> melt ice off your frozen windshield
> dissolve water in gasoline
> burn cleaner when used as a standalone fuel
> provide your pet with an invigorating rub after his next bath, which is curiously strong enough (dry enough) to dislodge stubborn ticks and fleas
> serve as a powerful pet or human wound antiseptic
> wash out those wax filled ears
> save you big $$$ (dough, ka-ching, moola, etc.) think money*

(*99.9% Isopropyl Iso-Heet at auto stores runs around 18.25 cents per ounce. 99.9% Isopropyl made from salting out 50%-91% generic retail brand Isopropyl runs around 6.73 cents per ounce. That is a savings of over 63%. If you use it to dry your gasoline then be sure to remove the residual salt using the addendum method.)

What you need:

- bottle of 50% to 70% Isopropyl alcohol
- a wide mouth glass jar and lid, or other leak and Isopropyl proof container
- a pound of non-iodized table salt
- a turkey baster with a reduced size nozzle
- an empty bottle equal in size to the bottle of Isopropyl alcohol.
 
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Step 6: Extract the Isopropyl alcohol

Use the turkey baster to extract the top layer, which will be the Isopropyl alcohol.
Pbyrd7 days ago
This is probably a rather ignorant question, but I'm assuming any sort of non-iodized salt would suffice? I have non-iodized sea salt, so I'm assuming this would work fine, but I wanted to make absolutely sure.
J@50n4 years ago
just wondering, is this the same as denatured alcohol?
alhewy J@50n19 days ago

No, "Isopropyl Alcohol" is the working name for the chemical compound 2-propanol (C3H7OH) usually mixed with water to about a 70% purity. "Denatured alcohol" is the working name for ethanol (C2H5OH) that's got nasty additives in it. They add impurities to deter people from drinking it... but I guess some hobos will always go for the cut-price booze, even to their own poor health :)

Qcks4 years ago
Just gonna add...
If you're having issues with salt residue in your isopropyl, you can limit the solubility of the Sodium Chloride by doping the isopropyl with sodium hydroxide prior to salting it.

This has the advantage of having a solvation effect with the salt and the base (Sodium Hydroxide competes with Sodium Chloride for solvation with the water because both have a sodium cation). Any residual hydroxide compound should burn clean.

The biggest downside is that you might begin to push your isopropyl to undergo a synthesis reaction, but due to it's shape that's not very likely (that is to say, it's stearically hindered, and thus, unlikely to undergo any synthesis reactions).
lpkid1057 Qcks3 years ago
Love the pedantic organic chemistry guy here.
JAMdown lpkid10572 months ago

Why you insulting him? He is answering someone's question and giving a good practical answer.

dmars3 months ago

Does anyone know a good way (cheap, not too involved manual labor) to get the salt out of the alcohol? I'm using it in an antique alcohol lamp, one that has a longish chimney, and the salt comes up the wick in rather huge quantities. It's a pretty orange while it's burning, but after it completely burns there's a solid crust on the end of my wick and the flame goes out. I have to trim the wick and relight it about every 15 minutes. Salted out IPA (isopropyl alcohol) with the salt somehow gone would be perfect!

DrSimons6 months ago
Nice instructions, I'll try adding more salt (had tried this previously with mixed results, but I didn't use nearly as much salt). One thing: BE CAREFUL if you decide to distill anhydrous IPA, let alone fuel, as hinted in the intro. If you are gonna do that, make sure you use a hot plate or other electric heat source, i.e no open flame. Probably don't even try it with gasoline, unless you want to read about yourself on the local news (as a ghost).
botronics1 year ago
Can this work with Vodka? I need pure ethanol for making a Fitzroy Storm Glass. Which is a mixture of camphor, ammonium chloride, potassium nitrate, water and ethanol.
Just tried this, stove works much better thanks! I put the Isopropyl in the same container. Crossed out the fifty percent and wrote 'much higher'.
ironLes41 year ago
can you use a salt subtitute
hahahaha, funny
You could put the salt on your margarita for a scientific buz...or was the alcohol in the water?
Isopropyl alcohol is definitely not something you want to drink. Not all alcohols get you drunk, as far as I know ethanol is the only one that does it without some pretty nasty side effects (although hangovers aren't too fun ;))
I have read that if you drink isopropyl alcohol it can cause blindness or even death.
most alcohols actually cause blindness, and ethanol is really the only alcohol thats safe to drink (not that its that safe eh ;D ) most other alcohols cause blindness in really small quantities, and theyr all very lethal poisons.
junits154 years ago
what happens if I use iodized salt?
Most likely reason why people say to not use iodized salt is because it has iodine which can either A) make I2 which is non polar and may mix with alcohol as apposed to the water or B) could make a iodo-*suffix* compound.
Only speculation from a hobby chemist though.
dammat5 years ago
Wouldnt silica gel work to remove the water? I found an experiment online that somehow used silica in a distillation column to remove the water. The water vapor is easil absorbed by the silica gel. Silica will retain up to 40% of its weight in water. Seems like a good idea to me. Otherwise I would research how its manufactured on a larger scale.
Broom dammat4 years ago
Seems to me the problems are: 1. You'd need 2.5x the weight of water in silica gel - that's a fair amount, and salt is easier to come by. 2. Is silica gel soluble in isopropyl alcohol? If so, it wouldn't work at all. 3. Does silica gel absorb isopropyl alcohol? If so, it wouldn't work at all. Seems to me table salt is the better solution (no pun intended).
You could use lime to do the same thing. When I was growing up, my dad taught me this trick.
Take some ordinary dry wall and bake it in a toaster oven OUTSIDE. The paper on the outside may burn off. The lime left behind will be completely dried out. Take the lime and crush it into as fine of a powder as you can. Add it to your alcohol and mix thoroughly. Let it set over night and either re distill or  use a sepratory funnel to get the end product.
 We had a farm that had a large above ground gas tank for refilling our tractor. It would accumulate water and had to be dried out. 
patmccock4 years ago
i used 91% isoproply alcohol and it wont work why is that?
Thats what the product is suppose to be. If you use more dilute alcohol this will work. Just add some water to this and see :P
Methyl and isopropal can be absorbed through the skin, if you use it a lot it can have bad effects on you, rub downs with alks should only be with ethyl. They tell you now never rub your kid down with it . When I was a kid everyone knew to use rubbing alks for fevers. No Mas muchacha
isopropal is lousey for alcohol stoves, methyl is great , but ethyl is best (more btu's. Since we can drink it it is heavily taxed. Denatured alks are mixtures and can have ethyle and methyl and other crap. The other crap will soot pans and in some cases stinks like heck. Go to the site for S-L-X denatured alcohol, the stuff varies. GO to Minibull Designs.com and look for Tinny's fuel comparasons, it explains much. This is a great article/instructable. You could if you had equipment, or really cold cold streak, do cryogenic distillation. Put a few gallons in a drum freeze it to -20 for say a few days then let it 'warm to -10 few hours, then refreeze to -20, do this a few cycles and ice crytals will form on out sideof alcohol column. Well it does with hard apple cider. But you need those frigid upstate NY death by cold winters. Farmers could leave casks of hard cider freeze then pop a hole in the center and drain off the liquer. Not worth the effort though. Buy heet or Air Brake Antifreeze, pure methyl spirits, 98%. If you are lucky enough you may find a speed shop that sells it by the gallon out of a drum, (bring clean jug/can) 4-8 bucks a gallon. Sadly I can't find one by me. I enjoyed this piece I will re read later on in the week.
slurp slurp bubble bubble gurgle gurgle haha very nice.
Berkin4 years ago
What happens if you use iodized salt?
KA-BOOOOOOOOOOOOOOOOOOOM!
I doubt that.
chuckr446 years ago
I'd be interested if you used a beer-making specific gravity meter for alcohol, to measure the SG of the alcohol your produced. Is it closer to 90%? Is this method efficient? Thanks for a great instructable.
thinkahead (author)  chuckr446 years ago
You are welcome and thanks for the compliment. Just as I was getting ready to build a hydrometer it dawned on me that all I really need to do is to measure volume and weight. I have a good postal scale and volume is also pretty easy to measure with just kitchen wear. All measurements so far confirm 99-100% Isopropyl.
Another great insight! You rock!
Interesting process to know, but seems like a lot of work to get questionable purity IPA. I can currently get 99.99... technical grade isopropyl by the drum for roughly 7 cents an ounce(volume). Just find your local chemical company. They'll sometimes deliver at no extra charge too.
thinkahead (author)  simplestatic6 years ago
I'm guessing but most people would only use 99% Isopropyl for backpack fuel and purity can be asserted with a post-salting out distillation. If you camp every weekend this is no more than a 32 fl oz bottle of fuel per month. A 55 gallon drum contains 7040 fl oz which would last the every weekedn backpacker about 18.3 years and since the price of Isopropyl has increased by 50% in the last year buying a whole drum now might actually pay off down the road. No harm in posting the name of your supplier...
For a second I thought you said "jetpack fuel" lol
Isopropyl is not a preferred fuel for backpackers because it leaves carbon on the cooking pot. That's why methanol is preferred.
Why not just try some instant grits, they will absorb the water and leave you with nothing but good alcohol.
chotii5 years ago
I'm still not clear on how you re-use the salt. If you pour the salt water into a pan to evaporate, you end up with a crust of salt, maybe a half inch thick. This is not exactly going to make it easy to re-use. I suppose you could grind it up, but there must be a point of diminishing returns...? And if you don't re-use it, what do you do with it? Salt the driveway? Kill weeds you don't want to pull? Just throw it in the trash?
just crumble it up
morganw chotii4 years ago
when the water evaporates the salt crystallizes and is easily broken up
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