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Topic: Solubility of Large Molecules  (Read 6430 times)

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Offline realmjumper99

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Solubility of Large Molecules
« on: May 31, 2007, 02:26:30 PM »
I have a large molecule with polar groups but I can't seem to find any way of dissolving it.

The Molecule I am attempting to dissolve is OH(CH2)11S-S(CH2)15COOH
It is a solid and I can't seem to get it to dissolve in anything. The closest thing I have found is a paper that has the same alcohol but the other end is an 8 carbon alkane. They used chloroform which didn't work for me.

I have also tried hexanes, toluene, and triehtylamine. None of them worked and neither did water. Any help would be great thanks.


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Offline english

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Re: Solubility of Large Molecules
« Reply #1 on: May 31, 2007, 04:30:06 PM »
Have you tried sonication?
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Offline realmjumper99

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Re: Solubility of Large Molecules
« Reply #2 on: May 31, 2007, 07:56:59 PM »
yes i have tried sonication and heating it forms an oily substance
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Offline kiwi

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Re: Solubility of Large Molecules
« Reply #3 on: May 31, 2007, 08:08:35 PM »
isopropanol? it seems to have the right mix of polar/non-polar bits to dissolve a fair bit of stuff. or if you're really desperate, something also polar and long-chained like octanol? (beware, bp 195 deg C)
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Offline english

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Re: Solubility of Large Molecules
« Reply #4 on: May 31, 2007, 08:53:52 PM »
These situations kind of suck.  On the one hand you could sonicate or heat the mixutre (which you've tried sonication), but this could cause nasty side effects.

On the other, you're on a wild goose chase to find the right solvent.



The best way is really to try everything, except for those that don't seem plausible in the least.

Either that or consult another paper.  This could also result in a wild goose chase.  Wish there was a better way.   :-\


Sometimes waiting 24+ hours gives results.
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Offline Custos

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Re: Solubility of Large Molecules
« Reply #5 on: June 01, 2007, 03:17:51 AM »
What are you trying to dissolve it for? I find the trifluoroacetic acid is an excellent solvent but it may not be compatible with what you are trying to do. It works okay for nmr spectra.
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Offline P

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Re: Solubility of Large Molecules
« Reply #6 on: June 01, 2007, 06:23:57 AM »
Quote from: g_english on May 31, 2007, 08:53:52 PM

Sometimes waiting 24+ hours gives results.

Have you tried THF yet?  When I was working in the polymer labs THF dissolved pretty much everything that was possible if it wasn't too far cross linked.   I agree with the above statement  -  leave it soaking in THF for a couple of days - possibly with stirring or agitation of some kind or heat occasionally. Maybe try crushing and stirring from time to time after soaking.  Good luck.
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Offline realmjumper99

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Re: Solubility of Large Molecules
« Reply #7 on: June 01, 2007, 02:23:47 PM »
Thanks for the help everyone. Heating it in 1-octanol did the job.
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