I bought a red bottle of isopropyl gas-line water remover.  Knowing full well that it must be distilled - strait out of the bottle it's yellow gunky nastiness.(Maybe to prevent the isopropyl alcohol from 'salting out' into a seperate layer from the water that one intends to remove from the fuel system, in the event that there are any dissolved solids in the water).
Bought without thinking much of it instead of the
HE*T brand red isopropyl fuel line water remover, I got a generic one called
J*hnsen's brand red isopropyl fuel line water remover.
It was crystal clear out of the bottle.
It evaporated leaving no residue.
Once placed on heat, my lab thermometer went strait up to 82°C.  This was something I have never been able to achieve when salting out+ drying rubbing alcohol, and oh man I sure have tried.

Just thought I'd share this goodie.

How do you dry isopropyl alcohol? This might save me ordering an expensive reagent grade botle.

It salts out for one, then separate and distill over either CaO or the Alkali metal glycoxides

It depends on how it were done, but if the CaO powder were added to the Isopropyl alcohol while being magnetically stirred for a few hours to get rid of all of the water present, I bet  it wouldn't be a problem.  However, if you were to say add the CaO to the flask, and than pour in the alcohol and allow it to sit without agitation -- than you'd probably end up with a  solid chunk in the bottom of the flask. 

Yes IPA forms an azeotrope with water, you could just break the azeotrope with something -- perhaps benzene as they do with ethanol?
Wouldn't the pure/dry IPA be the first to boil off, leaving the azeotrope mix in the flask? You would not get much, I think the azeotrope is rather high so I don't think this is really a viable option.

if your going to bee needed lots of dry isopropyl, you may want to invest in a set of 4a molecular sieves. its not difficult to reactivate them and you can use them quite a few times. cheaper than buying salts to dry your alcohol... you can expect each on to remove about .25 grams of water.

there is a patent for the drying of isopropyl alcohol to bee used in the production of semi-conductors that may bee interesting:

United States Patent 5868906

A method for the on-site reprocessing of isopropyl alcohol used in semiconductor manufacturing, to generate an ultradry and ultrapure isopropyl alcohol. This ultradry and ultrapure isopropyl alcohol is produced through a pervaporation step, followed by double distillation. In the first distillation step, an autonomous azeotropic self-stripping distillation column is used to produce an ultradry and partially purified isopropyl alcohol. In the next step, the isopropyl alcohol is distilled in an overhead product distillation column, to produce an ultrapure and ultradry isopropyl alcohol. Alternatively, if the feed isopropyl alcohol contains less than 2000 ppm water, the pervaporation step may be omitted.

The resulting isopropyl alcohol has between a high of 100 parts per million (ppm) and a low of 0.1 ppm of water in the isopropyl alcohol. It also has zero particles per milliliter of a size larger than 2.0 microns, zero to 2 particles per milliliter of a size of 0.5 micron to 2.0 microns, zero to 30 particles per milliliter of a size between 0.1 microns and 0.5 microns, an unspecified number of particles per milliliter below 0.1 microns, 1 part per trillion (ppt) to 1 part per billion (ppb) of any specific trace impurity such as metals, anions, and cations, and 10 ppt to 10 ppm of any other specific trace organic substances.

seems a little out of reach for the home chemist. especially when you get to the line:
"2. The method of claim 1, wherein the first distillation column comprises eleven to forty theoretical distillation plates."

there are also other methods that utilize NaA zeolite to dry isopropyl.

thats about all that i can think of for super-dry alcohol...

Doesn't IPA form an azeotrope with water? If so you could just distill off the low boiling fraction, and what's left should be nearly pure.

Iknowit, thanks for the reference on alternatives. I picked up several of the red bottles to find the stuff contaminated. I thought it was some kind of oil, but whatever it is, it isn't worth it.

ISO + Water = 80°C
ISO = 80 = 82°C


Before I found these red bottles, I never saw that thermometer go past 80°C.

BTW it's not HE3T brand red bottles "ISO-H3ET"
That stuff is yellow and gooey.

The 4a molecular sieve I bought works great on everything I've used it for. It's one incompatibility is alcohol. The manufacturer didn't say what happens if you add it to alcohol and I haven't tried it.
PP

your correct... thats my bad for suggesting from memory. i never heard that a 4a shouldnt bee used for drying alcohol, but after reading around a few chem sites, it looks as though a 3a would be needed to dry alcohols and other polar solvents.

Molecular Sieve Information

Type 3A molecular sieves should be used to dry dehydration solvents for electron microscopy. Most common solvents (acetone, ethanol, and methanol, etc.) need to be anhydrous for electron microscopy embedding work using epoxy resins, yet they have a tendency to pick up atmospheric water when bottles are opened. Molecular sieves are used to dehydrate the solvents used in the final stages of dehydration and embedding . Molecular sieves are typically zeolite compounds that strongly adsorb water and have carefully controlled pore sizes. While both the solvent and the water will adsorb strongly to the molecular sieve surfaces, the large surface area within the pores is only accessible to the smaller water molecules, so they are effectively removed from the solvent. From the table below it can be seen that water (1.93A) will enter that 3A pore size while acetone (3.08A) will largely be excluded. Water will be able to occupy the large surface area inside the pores and thus be removed. If the solvent could also enter the pores, it would compete with water for the surface area and there would be little or no removal of the water from the bulk solvent. Type 4A molecular sieve is not suitable for drying ethanol, methanol, or acetone since the pore size does not exclude these solvents. The Advanced Specialty Gas Equipment catalog lists Type 3A for drying ethanol and methanol.

you can add it to a bottle like that... that is how i have used them anyways. no body really ever told me how to use them.. i just assumed to throw them in the jar like any other drying agent.

industrial applications use something called a molecular sieve 'bed' which is just that, a layer of the beads that solvents pass thru...

imagine setting up for a filtering with silica sand... a large neck with a filter and an inch or two of sieves on top. the solvent is poured in the top and allowed to pass thru slowly... like no vacuum, just passing thru by gravity.

at least that is what i have seen in literature. i have yet to see actual instructions on use.

some companies manufacture a device like a filter for a water line that holds a cartridge of sieves. they change it when a certain amount of material passes thru... see one here, and look at the .pdf attached to the page on the right hand column and you will see they use it in line after the distillation, so that the ethanol condenses on the sieves or at least right above them...

hXXp://www.uop.com/adsorbents/7240.html

so i think any of these methods would work.

JACS 54 1445 (1932)

Note on the Preparation of Absolute Isopropanol
BY LEWIS E. GILSON
During several years of biochemical research the writer has found many instances where isopropanol could be substituted for ethanol in laboratory work. It is cheap and there are no restrictions governing its use; nor is it likely to be an object of theft. The commercial 91% azeotropic mixture was used instead of 95% ethanol and found to be fully equal or superior to the latter as a solvent or extracting medium. Absolute isopropanol was used in place of absolute ethanol.

Absolute isopropanol is easily prepared. The 91% grade is shaken with 10% of its weight of commercial flake sodium hydroxide, separated from the aqueous layer which forms, then shaken with a little more sodium hydroxide, decanted and distilled. The product obtained mixes with eight volumes of carbon disulfide, xylene or petroleum ether without the slightest trace of turbidity.

Dilute isopropanol can be concentrated by shaking with dry sodium chloride. Water is removed as a saturated layer of brine. The upper layer contains about 87% isopropanol and 2-3% of sodium chloride. While distilling, an additional quantity of brine separates. The distillate has so nearly the composition of the 91% azeotropic mixture that it can be used as such without further treatment. Or, after shaking the dilute isopropanol with sodium chloride and separating, it can be treated directly with sodium hydroxide and the absolute grade prepared.

One can use these techniques to recover and purify large amounts of aqueous isopropanol if one needs to    A zip file of the deja vu file of the note is attached