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ShadowWarrior4444
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Deep Eutectic Solvents (OTC Ionic Liquid)
Deep Eutectic Solvents have had a bit of my attention for quite some time, the applications are quite intriguing. They are also exceedingly easy to
make at home with cursory access to a nutrition store. The prime compositions of this type of solvent usually use Choline Chloride, though literature
seems to indicate that any "clunky organic molecule" will work. (Quaternary amine chlorides are much preferred, usually paired with an a hydrogen
donor to form the solvent.)
Notable properties:
Choline Chloride+Urea has an MP of 12C
CC+Glycerol at -35C
CC+Phenol at -40C
These solvents are electrically conductive, can dissolve cellulose, and many metal salts in large quantities. DES can also dissolve metal
oxides and carbonates.
I personally have made and prefer the CC+Glycerol variety, and have recently been testing its stability in various environmental conditions. So far,
the formulation has remained unfrozen and unchanged for 6 months at -15C. The current formulation I am using contains a bit of water due to the
hygroscopic nature of CC, though dehydration of the CC before hand may make a very useful anhydrous solvent.
Due to its ability to dissolve a wide variety of salts, as well as its electrical conductivity, I have been considering it for use in an attempt to
produce metallic sodium from electrolysis of a sodium salt in an unreactive anhydrous solvent as mentioned in:
http://members.aol.com/bromicacid/sodium/14.jpg
http://members.aol.com/bromicacid/sodium/15.jpg
A versatile solvent such as this may provide very unique opportunities to the home chemist.
(Note: I have also added the solvent to a collagen based gelatin before gelling. It has remained stable at 5C for 6 months as well.)
Useful reference:
http://www.rsc.org/Education/EiC/issues/2005_Jan/salty.asp
[Edited on 5-15-2008 by ShadowWarrior4444]
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-jeffB
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Me too! Me too!
I actually ordered a couple of Kg of USP choline chloride, mostly for this sort of experimentation. You can apparently deposit aluminum from salts
dissolved in these mixes, and I wanted to see just how far along the electromotive axis I could go.
Unfortunately, choline chloride is EXTREMELY hygroscopic, in fact deliquescent. Leave some crystals scattered on an exposed surface and they'll
quickly become droplets, even when the relative humidity is fairly low. I was easily able to make an aqueous solution containing 1g of choline
chloride per ml. I think it's pretty darn close to "miscible in all proportions" with water.
The choline chloride I got was in the form of caked crystals. The papers I've seen talk about recrystallizing it from anhydrous ethanol, which I
don't happen to have on hand, but may be able to get through my place of work.
I made the 2:1 molar eutectic with urea. It formed easily, but after sitting sealed at room temperature for a day or so (well above 15C), white waxy
discs started to form at its surface -- it looked for all the world like it was starting to get moldy. Within a few days, most of the mix had
solidified. I reheated it and everything went back into solution, but the phenomenon repeated upon cooling. Within a week or so, the entire mass had
solidified.
I suspect I'm seeing this because there was too much water in the mix, and there's some component that freezes out of the ternary system. FWIW, my
mix didn't do a darn thing to cellulose in the form of absorbent paper.
I intend to try the glycerol (and maybe ethylene glycol) mixes as well, but I think I'd better pursue choline chloride dehydration first.
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12AX7
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What are the redox potentials for those solvents? I think you're going to have quite a problem bringing metallic sodium or elemental chlorine into
contact with them. For instance, tetramethylamine hydroxide (or was it ethyl or butyl?) cannot be prepared pure, one of the alkyls breaks off. I
forget what the reaction is called, but a cursory review of said chemical should find it.
Tim
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ShadowWarrior4444
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| Quote: | Originally posted by -jeffB
I made the 2:1 molar eutectic with urea. It formed easily, but after sitting sealed at room temperature for a day or so (well above 15C), white waxy
discs started to form at its surface -- it looked for all the world like it was starting to get moldy. Within a few days, most of the mix had
solidified. I reheated it and everything went back into solution, but the phenomenon repeated upon cooling. Within a week or so, the entire mass had
solidified. |
I had used a 1:1 ratio of glycerol to choline chloride, as is described in the literature, though 2:1 mixtures are also mentioned. It may be
advantageous to attempt a series of mixtures, from 1:1 to 2:1 with urea, conducting a melting point test on each one, as well as stability tests. It
should melt at 12C when the optimum ratio has been reached.
(Note: Found in journal article 3: "The DES of particular interest is a 2:1 molar mixture of Urea to Choline Chloride.")
Finding information on the redox potential of these ionic liquids hasn't been particularly easy, mainly papers that require purchase come up, and not
all may be useful. Some I have come across:
Electroless deposition of metallic silver from a choline chloride-based ionic liquid: a study using acoustic impedance spectroscopy, SEM and atomic
force microscopy
http://www.rsc.org/publishing/journals/CP/article.asp?doi=b7...
Application of ionic liquids to the electrodeposition of metals
http://www.rsc.org/publishing/journals/CP/article.asp?doi=b6...
148 U.S. Department of Energy Journal of Undergraduate Research
http://www.scied.science.doe.gov/SciEd/JUR_v7/pdfs/Chemistry...
Replicated here: http://www.scied.science.doe.gov/scied/Abstracts2006/chem.ht...
Ion transfer processes at ionic liquid based redox active drop deposited on an electrode surface
http://www.rsc.org/publishing/journals/CC/article.asp?doi=b5...
[Edited on 5-15-2008 by ShadowWarrior4444]
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woelen
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I am quite sure that certain not too reactive metals can be deposited from these solutions, but I have severe doubts on alkali metals, earth alkali
metals and aluminium. E.g. glycerol is an alcohol and this reacts with those metals by formation of a glycerolide (sp?) anion and hydrogen:
2ROH + 2Na --> 2RO(-) + Na(+) + H2
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-jeffB
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| Quote: | Originally posted by woelen
I am quite sure that certain not too reactive metals can be deposited from these solutions, but I have severe doubts on alkali metals, earth alkali
metals and aluminium. E.g. glycerol is an alcohol and this reacts with those metals by formation of a glycerolide (sp?) anion and hydrogen:
2ROH + 2Na --> 2RO(-) + Na(+) + H2 |
I'll have to go back and refresh my memory from the papers I pulled. I think the aluminum deposition was done from the choline/urea mix, but I'm not
positive. I was also reading a survey of ionic liquids, and I might be remembering one of the aluminum chloride-quaternary ammonium mixes.
Here's one abstract claiming that choline chloride/urea lets you electrodeposit zinc onto magnesium, which is challenging to say the least in an
aqueous environment:
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi...
What I'm remembering, fuzzily, is that the potential window for electrodeposition from these mixes is much wider than from aqueous solutions, thus
broadening the range of metals that you can electrodeposit. I agree that it's unlikely we'd be able to plate an electrode with potassium, but I
wouldn't be surprised to find lithium within reach. If the choline chloride/miscellaneous organic mixtures don't support it, the eutectic mixes with
anhydrous ZnCl2 and the like might, and they're still well within amateur reach. The need to exclude moisture is beyond my technical skill at the
moment, but it shouldn't be that much harder than running a challenging Grignard.
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franklyn
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Wikipedia cites a supplier which cites various reference papers here _
http://www.scionix.co.uk/index.php?option=com_content&vi...
Method for Dissolution of Metal - U.S. patent 5120523
Application of Ionic Liquids and Microwave
Activation in Selected Organic Reactions
http://herkules.oulu.fi/isbn9789514287190/isbn9789514287190....
.
[Edited on 18-5-2008 by franklyn]
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vulture
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I know someone who is doing research on ionic liquids for use in electrochemistry with rare earths. As these have quite high reduction potentials, the
redox window of these materials tends to be fairly high.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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panziandi
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I remember reading a paper about side reactions of N,N'-dialkylimidazolium based ionic liquids undergoing reduction reactions under electrolysis
conditions. Much like H+ forms H2 Im+ forms Im2 or something like that, I shall try to find a ref for it. That is what made me look into solvents
which dissolve ionic compounds but are themselve not ionic. one class of solvent which screams out are the organic carbonates such as ethylene and
propylene carbonates. I have several solvents to try and will trial out different anions to see which salts are most soluble also.
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vulture
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Diethylcarbonate is used in lithium batteries, so it should posses a very large electrochemical window.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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ShadowWarrior4444
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| Quote: | Originally posted by vulture
Diethylcarbonate is used in lithium batteries, so it should posses a very large electrochemical window. |
Is Diethyl Carbonate produced in a method analogous to Dimethyl Carbonate? ('catalytic oxidative carbonylation of methanol with oxygen') [Pietro Tundo
and Maurizio Selva (2002). "The Chemistry of Dimethyl Carbonate". Acc. Chem. Res. 35 (9): 706-16. doi:10.1021/ar010076f.]
Or must it be produced using Phosgene as detailed here: METHOD OF MANUFACTURING ALKYL CARBONATES
It also should be noted that the lithium battery solvent seems to be a chlorinated diethyl carbonate mixed with propylene carbonate in a range from
2-75%:
Chlorinated diethyl carbonate solvent for battery
[Edited on 5-18-2008 by ShadowWarrior4444]
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panziandi
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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... 
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franklyn
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I am very much interested in using choline chloride solvation for anhydrous electrolysis,
but I am stymied in obtaining it. You would think that a nutritional supplement for livestock
and poultry should be easier to get than in 25 kg bags,
http://www.nutrimart.com/Bulk/Nutraceuticals.htm
and these are usually only 50 to 60 % content the balance being silica so you're buying
sand besides. The alternative is to buy it from a Chemical company but for what they
charge one could buy it in the big 25 kg bag.
http://www.coleparmer.com/catalog/productsearch.asp?search=c...
Another has it at more reasonble cost but won't deliver to a P.O.Box or residence.
http://www.usbweb.com/category.asp?cat=121&id=13410
The most common available form however is the bitartrate as the B4 vitamin, I suppose
treating with muriatic acid would produce the chloride but why go to the trouble since
it is already availble as a solution http://www.lef.org/newshop/items/item00541.html
http://www.amazon.com/Choline-Chloride-oz-Vitamin-Research/d...
containig 116 grams in a pint bottle. The problem then is how to dehydrate deliquescent
material into a dry powder. It melts with decomposition at just over 300 ºC so it may be
safely boiled to reduce the water volume then salting out by freezing the remainder.
CRC only indicates solubility in alchohols, but I found this added data online :
[color=darkgreen]- Freely soluble in water(1:4.5),slightly soluble in alcohol(1:90) and acetone. Soluble in
chloroform and insoluble in ether - [/color]So partitioning with cloroform or some other
chlorocarbon solvent may be a possibility. I am open to ideas or suggestions or if you
have a lead on a source send a private message.
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-jeffB
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| Quote: | Originally posted by franklyn
The problem then is how to dehydrate deliquescent
material into a dry powder. It melts with decomposition at just over 300 ºC so it may be
safely boiled to reduce the water volume then salting out by freezing the remainder.
CRC only indicates solubility in alchohols, but I found this added data online :
[color=darkgreen]- Freely soluble in water(1:4.5),slightly soluble in alcohol(1:90) and acetone.
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I'm not sure what temperature they had in mind for that 1:4.5 figure -- I think the real ratio is more like 1:0.45. I've made up some of mine as a
nutritional supplement in a 1g/ml aqueous solution. Weigh out 50g (quickly, because it's gaining weight from atmospheric moisture while you work!),
drizzle a few ml of water onto it, stir it while it "melts" into syrup, top off to 50ml. I generally have to microwave it up to maybe 40 C to get the
last few crystals to dissolve, but once that's done it's stable at refrigerator temps (<5C).
I don't think it would be worthwhile to try to recover it from the LEF solution, and I think they preserve (contaminate) theirs with sodium benzoate
anyhow. I used to get a 200g/l solution from Twinlab as a supplement, but I think that had pantothenic acid in the mix as well, and in any event they
discontinued it years ago. Check your PM for the source I use now.
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not_important
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| Quote: | Originally posted by franklyn
... The problem then is how to dehydrate deliquescent
material into a dry powder... |
I'd try concentrating the water solution somewhat, then slowly dripping that into boiling toluene or xylene, distilling off the azeotrope. That
should leave the salt as a powder. so long as you don't add too much water at any one time.
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franklyn
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| Quote: | Originally posted by not_important
slowly dripping that into boiling toluene or xylene, distilling off the azeotrope. That should leave the salt as a powder. |
That's a cute idea, but without a proper distilation setup, retort, condensor, etc.
inadequate ventillation can pose an explosion hazard. Another way would be to
freeze dry, sublimating the ice inside a sealed bottle with a good vacuum pump.
Also air drying by paint gun spraying into a large can circulating hot dry air.
I think that boiling to a viscous syrup and then blending with Epsom salt into a
doughlike paste and precipitating the hydrated epsom salt in methanol will likely
work.
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ShadowWarrior4444
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Vacuum desiccator is likely the best option. Alternatively, if Choline Chloride doesn’t decompose at or below 100C, a wee bit of heat in a dry-air
environment should do it. (Having alot of a strong desiccant in that environment would be prudent too.
Although, a bit of water may not be that troubling for many reactions--it may even aid the solvent for some as well.
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FrankRizzo
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Edit: Never mind..dumb question 
[Edited on 7/23/2008 by FrankRizzo]
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franklyn
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Some may find this article useful
Conductivities of AlCl3 Ionic Liquid Systems & Their Application in Electrodeposition of Aluminium
http://www.jproeng.com/qikan/manage/wenzhang/208139.pdf
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franklyn
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New organic solvents based on Carbohydrates
http://deposit.d-nb.de/cgi-bin/dokserv?idn=984940677&dok...
.
Attachment: Ionic liquids of hydrated salts patent WO0226381A2.pdf (1.4MB)
This file has been downloaded 2208 times
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franklyn
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Literature on ionic liquid solvents and low melting temperature salts.
All of the patents are conveniently packaged together in 2 attached zip files.
Low Melting Nitrate salt mixtures - US7588694.pdf
These low melting temperature nitrate salt mixtures are liquid below 95 ºC
Mol % of mixture
Li ,, Na , K , Ca ,
31 , 20 , 38, 12
25 , 16 , 47, 12
27 , 11 , 50, 12
Low Melting Sugar – Urea - Salt Mixtures as Solvents for Organic Reactions
Some are liquid at less than 70 ºC
http://www.rsc.org/suppdata/CC/b4/b414515a/b414515a.pdf
Physical Properties of Alcohol Based Deep Eutectic Solvents
Doctoral Thesis containing much data and references
https://lra.le.ac.uk/bitstream/2381/4560/1/2008harrisrcphd.p...
Ionic Liquid Electrochemical processing of Reactive Metals
Doctoral Thesis containing much data and references
http://circle.ubc.ca/bitstream/handle/2429/445/ubc_2008_spri...
Basic Ionic Liquids. A Short Review
http://www.ics-ir.org/jics/archive/v6/4/review/pdf/JICS-6-4-...
Res Metallica - Ionic Liquids: Solvents of the Future
Applications of Eutectic based Ionic Liquids
http://www.mtm.kuleuven.be/resmetallica/Abbott.pdf
Ionic liquids as solvents - US7183433.pdf
Method for producing Ionic Liquids - US20080251759.pdf
Separation of Liquid Eutectic by Crystallization on Cold Surface - US5814231
Ionic Liquids for separation of Azeotropes - US7435318
.
Attachment: US7435318 _ US20080251759.zip (1.4MB)
This file has been downloaded 1765 times
Attachment: USt5814231 _ US7183433 _ US7588694.zip (1.4MB)
This file has been downloaded 1665 times
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froot
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Another interesting room temperature deep eutectic ionic liquid I found:
CaCl2-FeCl3
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MrHomeScientist
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That's interesting froot, but how exactly do you read that chart? Am I correct in interpreting that a mixture of ~67% FeCl<sub>3</sub> and
~33% CaCl<sub>2</sub> as solid salts will be liquid below 100 degrees C? I would think the hygroscopic nature of both salts would be
problematic in such a mixture.
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bquirky
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Froot Have you tryed it out ?
Im curious how hot you have to get the mixture too kick-over into a euretic mix ?
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froot
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Nope I haven't tried it yet.
If I interpret the phaser diagram correctly at about 0.68 mole FeCl3 the mixture is liquid at about 12degC. The diagram is not straight forward so I
may be overlooking something crucial to its properties.
In order to keep the mixture anhydrous I'd melt each constituent at relatively high temperatures before I mix them after which I'd decant the mix into
an airtight container where it can cool.
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