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Author: Subject: Deep Eutectic Solvents (OTC Ionic Liquid)
zts16
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[*] posted on 8-12-2015 at 20:25


Quote: Originally posted by deltaH  
I used to think the same as you, but then I tried it...

The boiling does smell fishy because in the beginning, the trimethylamine that's initially in there (typical of commercial samples) boils off, but later it doesn't smell fishy and the freshly crystallised crystals don't smell fishy at all either. It's only upon aging that the characteristic odour develops again.

For all intent and purposes, the crystals are dry except for trace water. If you do it, you will see.

I think the viscous liquid is molten choline chloride. I didn't measure the temperature, but it was @#!%! hot at the end (gas burner on full with a large skillet pan over the flame). Luckily I had a hunch that it was dry and so turned off the gas. I was pleasantly surprised when cooling that everything solidified into a crystal mass.

My point... you CAN simply just boil it down, so long as you know where to stop it. Anyway, if you stop it too early and it's too 'wet' when cooled, just turn up the heat and heat some more.
Then how is it that when a few months ago I decided to try drying some damp reagent grade ChCl using medium heat on a hotplate at my school, it burnt black within a few minutes and made the entire classroom smell like a burning fish market? (to the despair of the AP chemistry class I was sharing the room with)



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deltaH
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[*] posted on 8-12-2015 at 21:19


Because yours was probably near the end point of what I made. I stopped mine just before it got very hot and presumably would start decomposing. When it cooled, the liquid solified into a slightly damp mass of white odourless crystals. If I had continued to heat this, it would likely have burnt too, I simply acted on a gut feeling not to heat further. Turns out at that point most of the water was gone.

Due the extreme hygroscopic nature of ChCl, I would think that what you see as 'damp' crystals, is in fact a very small amount of total water (or perhaps ethylene glycol). What I mean, let's say saturated ChCl is 80% solution (thumb-sucked) and let's say that your crystals are dampened by 5% saturated solution, so the water causing the apparent dampness is just 20%*5% = 1% overall!

Finally, this IS very stinky! I did my boiling outside and slowly so as to limit the stink. No doubt some decomposition occurs in the process, but the product was pure enough for my needs, white crystalline and odourless... at least for a while.

I made very nice choline soap with it, the only problem is that after a while, my soap bars went from being odourless to very fishy, which made me really sad because it worked very well otherwise, i.e. it made a beautifully mild and gentle soap.





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deltaH
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[*] posted on 8-12-2015 at 21:29


Quote: Originally posted by DeIonizedPlasma  
Quote: Originally posted by MrHomeScientist  
I'm going to have to try that some time;my choline chloride smells awful! I thought that was just a property of that compound.


No, sadly choline chloride just likes to undergo a Hoffman degradation into trimethylamine (wonderful fishy smell), water, and ethenol/acetaldehyde from what I can find. Mechanism picture attached, taken from Electrochemical decomposition of choline chloride based ionic liquid analogues. Given that it requires the hydroxide rather than the chloride, I think it may be happening due to trace presence of water. I couldn't find more mechanisms on the degradation, but I wonder if there isn't one that would occur in anhydrous ChCl. Perhaps someone should attempt to seal some choline chloride with negligible water content and leave it out for a while to test if it produces trimethylamine.


[Edited on 9-12-2015 by DeIonizedPlasma]


I noticed that the hydroxide degraded when preparing my soap. In an early experiment, I simply dissolved my NaOH directly into my 75% ChCl solution letting it get hot as well. This was bad, it seemed to degrade rapidly and the solution turned yellow-orange!

I had the idea that removing water might prevent this, so I proceeded to dry my ChCl solution by the method described before, then dissolving the ChCl into 1.5 mol. equivalents (off the top of my head, check the choline soap thread) 100% glycerine and only then added and blended the NaOH. This was better behaved and didn't yellow much, at least in the time it took to make the soap.

Unfortunately, the soap still formed trimethylamine in time when used, possibly because it gets wet. Water might be speeding up the process.

[Edited on 9-12-2015 by deltaH]




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[*] posted on 3-7-2016 at 22:20


Trimethylglycine also decomposes to trimethylamine but not very much.



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[*] posted on 2-8-2016 at 07:27


To those interested in RTILs (Room Temperature Ionic Liquids), the following book has been published recently: "Ionic Liquid Properties - From Molten Salts to RTILs"
http://link.springer.com/book/10.1007%2F978-3-319-30313-0
The last chapter is over 70 pages, and is all about RTILs.
I don't have full access, but maybe some mad scientists do.
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[*] posted on 2-8-2016 at 10:08


Quote: Originally posted by Bezaleel  
To those interested in RTILs (Room Temperature Ionic Liquids), the following book has been published recently: "Ionic Liquid Properties - From Molten Salts to RTILs"
http://link.springer.com/book/10.1007%2F978-3-319-30313-0
The last chapter is over 70 pages, and is all about RTILs.
I don't have full access, but maybe some mad scientists do.




Attachment: Ionic Liquid Properties_ From Molten Salts to RTILs.pdf (3.5MB)
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[*] posted on 8-9-2016 at 09:25


I can not receive the eutectic solvent when using AlCl3 (anhydrous) and urea, Who can tell me why?
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[*] posted on 8-9-2016 at 09:46


Magic elves?

Need more details from you. No one can give a meaningful answer with no information to go on. Tell us what exactly you did and where it went wrong.
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[*] posted on 8-9-2016 at 09:58


Quote: Originally posted by MrHomeScientist  
Magic elves?

Need more details from you. No one can give a meaningful answer with no information to go on. Tell us what exactly you did and where it went wrong.


The mole ratio is 1:1, N2 protection and nothing happened at room temperature, so I increased to 120oC, but only white powder can be found. Thanks.
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[*] posted on 8-9-2016 at 11:48


I'm just speculating, but urea doesn't melt until 130 C so you may not have heated it enough. Also ensure your aluminum chloride is really anhydrous; a difficult task if not in a professional lab. A nitrogen blanket is a good idea.

When I made the urea / choline chloride liquid, I melted the whole contents of the test tube with a propane torch. No precise temperature control. Maybe the AlCl3 version behaves differently though.
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[*] posted on 8-9-2016 at 12:07


Quote: Originally posted by MrHomeScientist  
I'm just speculating, but urea doesn't melt until 130 C so you may not have heated it enough. Also ensure your aluminum chloride is really anhydrous; a difficult task if not in a professional lab. A nitrogen blanket is a good idea.

When I made the urea / choline chloride liquid, I melted the whole contents of the test tube with a propane torch. No precise temperature control. Maybe the AlCl3 version behaves differently though.


Thank you. I have tried higher temperature than 130 C, the white smoke on the top of tube exhibits the sample evaporated. Maybe my AlCl3 has not high purity, I will try again after vacuum drying. Thanks.
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[*] posted on 6-7-2017 at 06:49
Type II DES (Choline Chloride with MgCl2.6H2O)


Has anyone able to synthesize type II DES ? I had tried every molar ratio according to journals ranges from 1:1 to 2:1 (MgCl2.6H2O:Choline Chloride). It seems like the products i got are always in milkish color (as shown in the attached photo) even though they are in liquid form at room temperature. Any idea to resolve this? :(


20170706_120216.jpg - 1.5MB
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