[HailoMan]

I am currently performing a solubility test of a compound in solvents listed below. However, I am concerned that the test will be affected by the moisture uptake by the solvents from the air. As I do not have access to a glovebox in my lab, I just have to accept that these solvents will take up moisture.

Does anyone has any suggestion as to how I can quickly measure the moisture content in these solvents? Also, does anyone have a rough idea as to how much water gets absorbed by the solvents I list below (is it percent range or ppm range?). Thank you in advanced.

Solvent list:
Ethanol
Isopropanol
Methanol
Ethyl acetate
Cyclohexane
Tetrahydrofuran (THF)
Mesitylene
N,N'-Diethylformamide
Dimethyl formamide (DMF)
Dimethylphthalate
Acetylacetone
Dimethyl sulfoxide (DMSO)
N-Methyl-2-Pyrrolidone (NMP)
Tetremethylurea
1,3-Dimethylimidazolidin-2-One (DMI)
Gamma-Valerolactone (GVL)
1,4-dioxane

[jaspevacek]

I'm afraid that I don't have much good news here, except to compliment you on your insight that moisture uptake from the atmosphere is a real concern.

The equilibrium value for water in many of these (the alcohols for instance) is infinite - they will keep soaking up water without stopping, while for something like the cyclohexane, it would be in the ppm range.

The rate for uptake is depends on numerous factors including RH, air flow rate, surface area, temperature...

Not an easy problem at all to face.

[Arkcon]

For the water miscible solvents, the number can be quite high, several percent before the rate of diffusion slows down.  Others often have a few ppm moisture as an impurity..  There are a number of analytical methods for checking the moisture content of solvents -- for example, GC or Karl Fischer titration.  You can also scrupulously dry your solvent, with a drying agent and use it quickly, or purchase anhydrous solvent from the manufacturer, but that can get pricey -- especially given your long list.  Do you really need to test them all?  For example:  methanol, ethanol, and isopropanol?  For some compounds (admittedly, not every case) these should give similar results.  Can you use the structure of your compounds as a hint?

[HailoMan]

Thank you for the response.
I do not necessarily have to have anhydrous solvents, as long as I have information about the water content. I will look into Karl Fischer titration in more details, but currently I am planning to use NMR to determine the water content (though I'm unsure how complicated it is going to get).

I am actually testing the solubility of the compound in various solvents to determine its Hansen solubility parameters (http://www.hansen-solubility.com/). That is why I am testing a few solvents that may be seemingly similar (e.g. methanol, ethanol and isopropanol. They actually have quite different Hansen parameters). The recommended solvent list (by Charles Hansen) have 40+ solvents and as is, I have significantly cut down the number of solvents that I am trying.

[acsudhamsu]

1.how to determine moisture content in ethanolic hydrochloride(high concentrations) ?
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[curiouscat]

1.how to determine moisture content in ethanolic hydrochloride(high concentrations) ?
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