How to "Salt Out"

Intro: 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.

STEP 1: Start by Adding the Table Salt

Fill the empty jar about 1/4 full with table salt

STEP 2: Add the Hydrated Isopropyl Alcohol

Fill the jar about 3/4 full with hydrated (50% to 70%) Isopropyl alcohol

STEP 3: Shake Contents Vigorously

Put the lid on the jar, close to seal the contents and shake jar vigorously to be sure the salt and water combine.

STEP 4: Let Gravity Separate the Contents

Place jar on a level surface long enough for the alcohol and salt water to separate (15 to 30 minutes).

STEP 5: Keep the Two Layers Separate

Open jar carefully so as not to remix the two layers.

STEP 6: Extract the Isopropyl Alcohol

Use the turkey baster to extract the top layer, which will be the Isopropyl alcohol.

STEP 7: Fill the Receiving Bottle

Fill a receiving bottle with the turkey baster Isopropyl contents.

STEP 8: Label Bottle

Label the bottle "Dehydrated Isopropyl Alcohol"

STEP 9: Use Your Dehydrated Alcohol

Use in an alcohol stove, lamp, torch, etc. or to give your pet a nice alcohol rub down.

STEP 10: Addendum

You may find that your salted out Isopropyl leaves a salt residue when it is burned. In many applications like a pocket stove the salt residue will continue to serve in the role of helping to separate the Isopropyl and the water when water intrusion occurs from dampness, rain or boil overs.

In other applications the salt residue may not be desired. To separate the salt residue from the Isopropyl use a homemade still. In this case your are not distilling an azeotropic solution of Isopropyl and water but rather separating a liquid from a dissolved solid.

The diagram below illustrates the required components for such a still.

Comments

[QiangX]

Thanks. Can this method be used to salt out 70% ethyl rubbing alcohol?

[mrsensenig2000]

Yes.

[steviefun691]

"Salting Out" isopropyl alcohol will NOT and i repeat will NOT give you anywhere near 99.9% ISO. at very best you may get 80-82%.

[essarrenn]

Yes. I got 81% only

[GeneR5]

Actually done this process. I started with 70%, salted out then tested with a hydrometer. My reading over 5 runs averaged 96%. Allowing for salt still in solution that gave me 92%-93%.

[junits15]

what happens if I use iodized salt?

[Mikie-z]

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.

[samuelx3]

quite a bit late but iodized salt really doesn't have that much iodine.

[dammat]

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]

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).

[DamithaN]

Silica won't react with IPA but it will absorb both water and the IPA

[Gourdhead]

They make screw-on filters like car oil filters using that very thing -- silica -- for gasoline dispensers! Or you can strain it through an unused baby diaper!

[botronics]

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.

[Broom]

botronics, think about it. You're asking if it will remove water from the methanol in vodka - so you can mix it with camphor, ammonium chloride, potassium nitrate, and WATER.

[spinney1963]

The alcohol in vodka is ethanol. Methanol is poisonous!

[botronics]

The water content of Vodka is too high for the Fitzroy Weatherglass formula. That why I need to get the water out before mixing it.

[Broom]

Oh! Thanks. Did not realize that.

[yzrider3000]

sounds like a illegal substance lol starts with a m

[Broom]

If you're hinting at "methanol", it's not illegal. If not... you need to put down the bong, because you're not making sense.

[fenomen09]

MgCl?