Looking for some solubility info...

[jpsmith123]

Hello,

I'm wondering, does anyone have any info on the solubility of NaCl and/or KCl in diethylene glycol and/or ethylene glycol? Thanks.

[Charles Owlen Picket]

You MIGHT be able to find some from major manufacturers/distributors of glycol products to medical facilities or research. A good place to start would be those large business to business web sites that are chemical specific.

[jpsmith123]

Thanks for the thought, but I already tried that...unfortunately with no luck.

[nbk2000]

Knowing WHY you are asking the question goes a long way to answering it.

[jpsmith123]

I recently saw something in a patent about a novel electropolishing solution that would supposedly work on many different metals, including titanium (the main object of my interest). IIRC, the preferred formula was KCl and ethylene glycol, although NaCl could be substituted for KCl, and diethylene glycol for ethylene glycol. In light of this, I was curious about the solubilities of these salts in the various glycols.

[nbk2000]

Best way to find out is to buy the materials and mix it up yourself.

If it's a patent, surely they've included information on the ratios, right? Or a reference to something?

[megalomania]

One of the books published by CRC press might have what you are looking for. I am blanking on the title (not the Handbook of Chemistry and Physics, which might also have it), it is one of those physical properties books on solubilities.

Today I heard a chemist recite an anecdote about Edison: Edison asked his assistants to find out the volume of a lightbulb. They went to work measuring the bulb with rulers and calipers, and used all the fancy engineering equations, but every one of them had a different answer. Edison then proceeded to snip the end off a bulb, fill it with water, and measure the volume by dumping it in a beaker.

The moral of the story is sometimes an experiment can be very simple, and nbk2000 already suggested the best answer to the problem, do the solubility tests yourself and you will have an answer. Measuring solubility is not hard to figure out.

[Bugger]

Here is the CRC Handbook Of Chemistry, 87th edition:

http://rapidshare.com/files/16522356/CRC_Handbook_Of_Chemistry___Physics-87thEd_CRC-PDF-2006-7_.zip
92,362 Kb

I downloaded the International Critical Tables a year or two ago. They would certainly have the solubility data for salts in glycols you require, if the CRC Handbook does not. You could try looking for it on Google as a rapidshare.com download (include "rapidshare.com/files" and "International Critical Tables" in double quotation marks in the search string), or as a BitTorrent download (include torrent and "International Critical Tables" in the search string).

[jpsmith123]

The patent is US6835300. I already tried a quick test with NaCl and KCl using glycerin and propylene glycol as solvents, to no avail. (It didn't look like anything dissolved, and the solution measured infinite resistance with my cheapo digital meter).

I just bought some diethylene glycol (OTC as Sterno "wick chafing fuel"), and I'm preparing a test with that.

If this can be made to work, I can see some potential use as a surface preparation for titanium, prior to cobalt oxide plating (for use as a perchlorate anode).

[tranquillity]

I think you may need something like a crown ether http://en.wikipedia.org/wiki/Crown_ether which are specifically designed to improve solubility of salts in organic solvents. Each crown ether has a preference to a specific cation so you would need to make a decision about KCl or NaCl.

http://www.freepatentsonline.com/4435582.html details the synthesis of 18-crown-6 which targets potassium ions.

[jpsmith123]

That's the first I've ever heard of a "crown ether". Sounds interesting, but as I recall, the patent didn't mention anything else as being required. I'll try the DEG with NaCl and then KCl tomorrow and see what happens.

[nbk2000]

Patents often leave out the important details, to confound potential copy-cats.

[jpsmith123]

Just in case anyone's interested, I tried diethylene glycol with NaCl and KCl and had no luck; i.e., it appeared that nothing dissolved, and the liquid had no measurable conductivity. I think nbk2000 may be correct - some important detail was left out of the patent.