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How to "Salt Out"

How to \"Salt Out\"
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 1Start by adding the table salt

Start by adding the table salt
Fill the empty jar about 1/4 full with table salt
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175 comments
1-40 of 175next »
Nov 7, 2010. 9:30 AMh0meIandsecurity says:
hahahaha, funny
Oct 29, 2008. 5:47 PMemergencydpt.com says:
You could put the salt on your margarita for a scientific buz...or was the alcohol in the water?
Jan 9, 2010. 5:54 PMversusterminus19 says:
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 ;))
Aug 23, 2010. 2:14 PMnathanielg says:
I have read that if you drink isopropyl alcohol it can cause blindness or even death.
Oct 16, 2010. 7:21 AMbinnie says:
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.
Feb 7, 2010. 11:37 AMQcks says:
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).
Jul 5, 2010. 1:46 PMlpkid1057 says:
Love the pedantic organic chemistry guy here.
Sep 3, 2009. 2:29 PMjunits15 says:
what happens if I use iodized salt?
May 20, 2010. 5:41 PMMikie-z says:
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.
Nov 16, 2008. 8:30 AMdammat says:
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.
Jun 26, 2009. 3:26 PMBroom says:
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).
Oct 20, 2009. 6:00 AMAerospaced says:
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. 
Oct 18, 2009. 11:14 PMpatmccock says:
i used 91% isoproply alcohol and it wont work why is that?
Oct 20, 2009. 4:47 AMDrCoolSanta says:
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
Oct 6, 2009. 8:44 PMspark master says:
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
Oct 6, 2009. 8:37 PMspark master says:
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.
Sep 27, 2009. 4:02 PMJ@50n says:
just wondering, is this the same as denatured alcohol?
Aug 12, 2009. 10:15 AMPyrotechnic-Robot says:
slurp slurp bubble bubble gurgle gurgle haha very nice.
Jun 9, 2009. 7:18 PMBerkin says:
What happens if you use iodized salt?
Aug 7, 2009. 9:26 PMlilpepsikraker says:
KA-BOOOOOOOOOOOOOOOOOOOM!
Aug 12, 2009. 8:34 AMBerkin says:
I doubt that.
Mar 9, 2008. 8:02 PMWeissensteinburg says:
Why is it 91% alcohol, and not 100?
Jun 29, 2009. 2:37 AMomnibot says:
Found it!
The reason why alcohol is never 100% is *drum roll* is that hydrogen bonding causes pure ethanol to be hygroscopic to the extent that it readily absorbs water from the air.
Mixtures of ethanol and water form an azeotrope at approx. 89 mole-% ethanol and 11 mole-% water or a mixture of about 96 volume percent ethanol and 4 % water at normal pressure and T=351 K. This azeotropic composition is strongly temperature- and pressure-dependent and vanishes at temperatures below 303 K. Wikipedia
Mar 10, 2008. 11:03 AMomnibot says:
I believe that alcohol can not be 100% at one atmosphere and room temperature. Being a gas it needs to be in a solution or it would evaporate.
Jun 26, 2009. 3:48 PMBroom says:
"Being a gas" - ??? Alcohol is a liquid at one atmosphere & room temperature (STP). Maybe you mean that it has high volubility - it evaporates quickly.
Jun 29, 2009. 2:32 AMomnibot says:
It seems you're right, I had it mixed up with something else with those properties.
Mar 10, 2008. 7:06 PMfour_eyes954 says:
also people would start drinking it like ddum @$$es americans are, im from america and i can still see it happening. good were stupid
Jul 19, 2009. 6:34 PMvestie says:
Wow. I really hope you come to find that America is a group of relatively educated people.
Mar 10, 2008. 3:19 AMWeissensteinburg says:
You know what? I think I misunderstood part of the instructable. I read it as your salted out alcohol was 91%. Sorry.
Mar 10, 2008. 1:42 PMWeissensteinburg says:
Yep, that was it. Thanks for clearing it up.
Mar 10, 2008. 9:16 AMchuckr44 says:
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.
Jun 26, 2009. 3:46 PMBroom says:
Another great insight! You rock!
Apr 19, 2008. 9:18 AMsimplestatic says:
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.
May 31, 2009. 2:16 PMgenius245 says:
For a second I thought you said "jetpack fuel" lol
Aug 15, 2008. 6:45 AMchuckr44 says:
Isopropyl is not a preferred fuel for backpackers because it leaves carbon on the cooking pot. That's why methanol is preferred.
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