Deep Eutectic Solvents (OTC Ionic Liquid)

Alcoholysis of ethylene carbonate with ethanol will yield diethyl carbonate. Ethylene carbonate is commercially available but it can be made from ethylene glycol (ethane-1,2-diol) and urea. Although Ethylene carbonate is a great solvent for ionics too... There is mention of this in the forum elsewhere also google yields useful hits too...

Edit: Never mind..dumb question

[Edited on 7/23/2008 by FrankRizzo]

So it appears the eutectic is 0.67 moles of FeCl3 to 0.33 moles of CaCl2, or on a weight basis, about 3 grams of ferric chloride for one gram calcium chloride
This is apparently a surprisingly simple ionic liquid.



[Edited on 26-4-2012 by AndersHoveland]

Giver of bad advice, indeed :

Mole fraction FeCl3 = 0.67,

Thus 0.67 * 162.2 / (0.67 * 162.2 + 0.33 * 111 ) = 0.748 or multiply by 100 % = 74.8 weight %.

With 162.2 g/mol the molecular mass of FeCl3 and 111 g/mol the molecular mass of CaCl2.

Quote: Originally posted by barley81

It is likely that Anders changed his comment when he was corrected by blogfast25.

I hereby find the defendant not guilty.

Dann2

[Edited by Dann2 on 1 May]

Quote: Originally posted by AndersHoveland

It would not have been possible for me to alter the date of my post after I had altered it.

Then there's only one possible explanation...

Time travel JK

As part of my long-running experiment to obtain neodymium metal from magnets, I've started investigations into deep eutectic solvents inspired by this thread and some additional searching. You can find my latest progress on this project over at the neodymium thread, here: http://www.sciencemadness.org/talk/viewthread.php?tid=14145&...

====================

The liquid I wanted to start with was choline chloride / urea at a 1:2 mole ratio. I purchased both chemicals from eBay - the choline chloride (CC) as fairly damp transparent crystals, and the urea in prill form. The CC has a rather strong, disagreeable smell to it that reminds me of triethylamine. I didn't bother drying it this time, but I put a portion in a dessicator for future use.

I ground 8.0g urea down to a powder in a mortar and pestle, and loaded this into a screw-top test tube. I then scooped 9.5g CC into the tube on top of the urea. Stoichiometrically, I only needed 9.3g but I wanted to add a little excess to help account for the water it's obviously absorbed.

This setup initially looked like this:


I then took this outside and gently heated with a propane torch, moving the tube in and out of the flame to reduce hot spots and prevent any decomposition. In retrospect, I should have put the urea on top of the CC instead since it has a lower melting point. As it was, the urea melted first and I had to slosh it around a bit to dissolve the CC sitting on top of it. Once everything was liquid, I stopped heating.

After cooling, an interesting thing happened: two layers of crystallization!


You can see it had solidified on the top and bottom, but left a small band of liquid in the middle. I suspected that this happened because I did not mix the liquid well enough, and while it formed enough of a mixture to be liquid while hot, it was not close enough to the eutectic point to stay liquid at room temperature. So the top layer would be CC-rich eutectic and the bottom layer would be urea-rich, while the middle was "just right."

I then took the test tube and heated again until molten. This time I used a glass rod to stir everything around and mix thoroughly. Upon cooling, it stayed liquid!



The liquid is very viscous, similar to syrup. The little black bits floating around are from when I hit the CC with the torch a little too hard and burnt a small bit of it.

I look forward to experimenting with electrodeposition of metals with these types of solvents. It sounds like the CC / glycerol mixture may be more suitable for this, but that's what experimentation is all about. More to come!

Help with ionic liquids

An interesting development: After making this a week ago and letting it sit in my lab, lots of needle crystals have formed in the liquid.



Perhaps I didn't get the ratio of the components quite right?

Quote: Originally posted by MrHomeScientist

An interesting development: After making this a week ago and letting it sit in my lab, lots of needle crystals have formed in the liquid. Perhaps I didn't get the ratio of the components quite right?

I bought it from user adpy-chemistry. He doesn't have any items for sale currently, and if there isn't anything else on eBay right now then I don't know what to tell you. Just keep checking every now and then and everything shows up eventually!

Now that it's been over a year, I suppose I should update on what happened to the liquid from my last post It ended up clearing nicely and has remained liquid this whole time. So it looks like drying the choline chloride and intimately mixing the reagents before melting them together is the way to go.

You have pretty generous poultry farmers in your region.
ChCl although very cheap is almost impossible to get a hold of...does anybody know a substitute?

[Edited on 9-4-2015 by gatosgr]

That sounds like the best option right now. I don't actually have a vacuum adapter for distillation though, as due to some quirks of glassware obtaining I only have a graham condenser and a 180 degree adapter so that the setup ends pointing down.

I will make sure to update when I finally make a DES, as I have plans for a sodium chloride cell that I think would be most entertaining. Unfortunately I will not be able to continue with the process for another week as school gets really crazy this time of year

Well regardless of how ridiculous this sounds you can make a cheap vacuum pump from an injection maybe you can lower the boiling point a bit although I havent calculated the pressure needed.

https://www.avs.org/AVS/files/10/1043c4c6-597a-498f-a45d-7f1...

thank me later

[Edited on 5-5-2015 by gatosgr]

[Edited on 5-5-2015 by gatosgr]

Quote: Originally posted by gatosgr

That's good news although you can use thrimethylglycine instead of choline chloride which is a supplement and easy to find. You are right about this method I found it here: http://www.pharmacopeia.cn/v29240/usp29nf24s0_m17300.html The page says you can dry it at 120 C for 2 hours. [Edited on 2-5-2015 by gatosgr]

Quote: Originally posted by Arun2642

Quote: Originally posted by gatosgr   That's good news although you can use thrimethylglycine instead of choline chloride which is a supplement and easy to find. You are right about this method I found it here: http://www.pharmacopeia.cn/v29240/usp29nf24s0_m17300.html The page says you can dry it at 120 C for 2 hours. [Edited on 2-5-2015 by gatosgr] Where did you find that trimethylglycine could be used as an alternative to Choline Chloride, I just tried making a DES with trimethylglycine 1:2 urea and trimetylglycine 1:1 urea. Both crystallized well above room temperature. The method I used was to melt the urea in an erlyn-myer flask, add the trimetylglycine, and swirl and reheat until it all formed a homogeneous solution. Is there a different procedure I should follow?

Quote: Originally posted by DeIonizedPlasma

I am having trouble understanding what you mean, deltaH. Choline chloride decomposes fairly easily and I feel that this would easily decompose it into fishy trimethylamine. Also, if it is getting viscous but there is still water, when you ultimately cool it down there will still be water in your batch of crystals. I suppose you could try vacuum filtration of this to remove as much liquid water as possible from the precipitate...

The amount of trimethylamine that comes off is very little (less than a couple percent?), it's a minor contaminant (although it smells horrible)... and I'm still here

[Edited on 7-12-2015 by deltaH]

The problem is that in time it will start stinking again, one of the big problems with my choline soaps I could make fresh stuff that smelled fine, but after a couple of weeks...

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]

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.

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]

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.

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.

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 AlCl<sub>3</sub> version behaves differently though.

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?

No results yet, but some pretty pictures with color changes.

I made the type 4 DES today on a 1/10 mol scale. Molar ratio 1:2 KCr(SO4)2:urea is 499g:120g, or at 1/10 scale 49.9g:12g
To this will add 20% water and boric acid to 0.1M. Per calculations that means 12.7g of a 2.5% boric acid solution that will bring both the required water and the boric acid.

Pictures below.



Chrome alum purple at the bottom, urea white on top.




1 minute in microwave, it started melting and changing color.




Another minute in microwave, it became really hot and it almost completely melted. Some alum crystals were stubborn. Nice emerald color. Consistency of syrup.




After cooling down a few minutes, in natural light. It became much thicker, like honey. Too bad I can't show the consistency in pictures.




After adding the boric acid solution and stirring for a few minutes. All dissolved. Same color. Much less viscous, similar to molten ice-cream.

I'll let it rest for a day or two (principally because I lack time to continue now) then onto electrolysis.





[Edited on 29-7-2018 by stamasd]

I don't know. So far I've only experimented with types of DES that don't use choline (type 4). In fact until today I didn't even have choline chloride... and then the mail came with my bag of choline.

Urea is also slightly hygroscopic but not deliquescent. With the type 4 using urea I have noticed however somewhat the opposite problem. I think that if exposed to air, some of the water that is brought in as crystallization water of the alum evaporates, and that is one of the factors that leads eventually to the solidification of the DES. I have noticed that a previous sample of a similar DES to the one above (that one was made with 1:1 alum to urea) after less than a day had become very viscous at the surface, almost making a "skin" at the top. And then it started becoming a solid mass from the top down. That's why I think there was evaporation at play.

[Edited on 30-7-2018 by stamasd]

Quote: Originally posted by BaFuxa

Note on Type IV DES using urea as hydrogen bond donor : the urea decomposes fairly quickly. Once I used a MgCl2-Urea DES and everything started smelling ammonia when I heated it up to about 150-200°C.

FWIW there was no ammonia smell while making the DES above (urea-chrome alum) nor since. Perhaps it's a better idea not to heat urea-containing solutions until it decomposes.

A little (belated) update on my chrome alum/urea/boric acid/water liquid above. I stuffed it in a drawer and it stayed there for a few months. I did get around yesterday and test it in an electrolysis experiment. Using a stainless steel anode, a copper cathode, electrode area about 1cm^2 each, 10ml electrolyte, electrode distance average 2cm, adjustable power supply.

First observation, it does conduct electricity but much less than a saline/water solution. To achieve a current 0.1A I had to crank the voltage to about 9V. That's an impedance of 90 ohms, vs 5-10 ohms for a similar saline cell.

Second, I did get chrome deposited but not great. The deposit is uneven, with areas of copper still showing through, and in places the deposit is heavy, dark gray and dull (the copper cathode was thoroughly cleaned beforehand). OTOH the deposition is fairly quick, in less than 1 minute I got the deposit as above and further electrolysis time (up to 10 minutes) didn't improve on it. Using a lower current of 30mA resulted in a similar deposit forming in about 5 minutes, on which extra time (up to 30min) didn't improve.

Third, the chromium plating isn't great. It is reasonably adherent overall, but with weak spots where it can easily get dislodged by light polishing. Since the appearance of the deposit off the bath was quite ugly I tried to improve on it by polishing with a chromium oxide paste. Now, Cr2O3 is a pretty harsh abrasive, granted. But light rubbing of the paste over the plated area with only light pressure with the tips of my fingers removed large areas of the deposit. What was left is pretty strong and adherent and was not easily removed with extended polishing; its appearance is also very good and shiny after the extra polishing. But it only covers about 50% of the plated area, the remaining is gone.

No pics, I did not want to get chromium oxide onto my lens.

Not a complete failure, but also not very encouraging.

(edit) I did try higher current densities up to 200mA/cm^2 but that required higher voltages and led to significant gas generation with a lot of bubbling especially at the cathode, that's why I lowered it to 100mA/cm^2 and below; the plating obtained with the higher currents was also significantly worse with lots of pitting.

[Edited on 27-1-2019 by stamasd]

I forgot to mention in the post above that the liquid's impedance seemed to vary nonlinearly with the voltage. Actually I should say that the cell impedance varies nonlinearly (as I used physical electrodes with it, not perfect electrodes). When varying the voltage from 0V to 24V, initially no current passed up until 4V; at 5V the current was 0.01A; at 6V, 0.03A; at 9V, 0.1A; at 15V, 0.2A; at 24V, 0.3A.

Attaching a little quick-and-dirty chart.
Almost looks like the current profile for a diode.





[Edited on 28-1-2019 by stamasd]