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MrHomeScientist
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That does sound very exciting! I'm also eager to hear how it goes. I was trying to pursue a route to neodymium metal by electrolysis in an ionic
liquid solvent (choling chloride & urea), but that's stalled because I can't get the damn thing to stay liquid. Over time crystals start forming.
Propylene carbonate may be an alternative to try, if it works for you.
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blogfast25
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So the deep eutectic solvent didn't really work out?
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Zyklon-A
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OK, my PC was ordered last week, and should be here soon! I am going to build my power supply today. I haven't seen any references for the optimal
voltage and amperes. 10 volts seems to be used by some people, but the amperes shouldn't matter unless the metal product reacts with the solvent and
must made faster than it reacts.
How many volts/amps should I use per 100mL PC, with dissolved NaClO3?
I hope I can try this sometime week or next, as soon as it arrives.
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Marvin
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Your plan is to dissolve an oxidiser noted for explosive tendencies in an organic solvent and pass a current through it in the hope of generating
sodium metal. Is table salt really that expensive?
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Zyklon-A
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Perhaps you should read through this topic. Why would I need table salt? Are you suggesting I make a downs cell? I am trying to avoid high temps,
here.
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blogfast25
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Is NaClO<sub>3</sub> really the only available Na salt soluble in propylene carbonate? In the absence of any other anions you have to
wonder what will happen at that anode...
Marvin has a point: NaCl appears to be soluble in propylene carbonate and would be the first choice, unless you can come up with some serious reason
against it.
[Edited on 14-3-2014 by blogfast25]
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Zyklon-A
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It seems like they would have mentioned it if NaCl worked. That would have been my first try, but I assumed it wouldn't work, or else someone would
have used it. I'll give it a try, maybe it will work.
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Marvin
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If by reference you mean the 1975 electrochem paper then according to the abstract they used sodium chloride, perchlorate NaClO4,
tetrafluoroborate and hexafluorophosphate.
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blogfast25
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http://link.springer.com/article/10.1007%2FBF00608791
Abstract
The alkali metals were electrodeposited from various solutions in propylene carbonate (PC). Li, Na, K, Rb and Cs were electrodeposited from solutions
of their chlorides and AlCl3 in propylene carbonate (PC) at ambient temperature. In addition, lithium was deposited from LiCl, LiBr, LiClO4, LiPF6,
and LiBF4 solutions in PC. Sodium was reduced from NaClO4, NaPF6, and NaBF4 solutions. Potassium was obtained from KPF6 solution.
A new process is proposed for the production and electrorefining of the alkali metals at ambient temperature. Alkali metal amalgam from the commercial
mercury-chlorine cell is transferred into an AlCl3-PC electrorefining cell, where the alkali metal is dissolved anodically from the amalgam, and
deposited in a pure form at the cathode.
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MrHomeScientist
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Sorry blogfast, I just now saw your reply. I've made two batches of the deep eutectic now, the second one after drying my choline chloride in a
dessicator for a week. They both will melt into a liquid while being heated, but afterward they slowly start to solidify. My first batch is full of
little needles, and the second is mostly solid now. I need to decant the liquid portion and continue experimentation with that, but I just have been
unable to do stuff in the lab for the last 2 months. I definitely haven't given up, it's just slow going.
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Zyklon-A
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Wow, thanks for the catch, blogfast25 and Marvin . 'Sodium chlorate' wasn't just a typo, I actually got confused,
and was about to make some....
My PSU (that I am making) can put out 6.2 volts and 15.3 amps. I can also bring the voltage up to ~10, and keep the amperage the same. Which should I
do?
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BromicAcid
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From the abstract it sounds like you need the aluminum chloride complex the same as when electrolyzing solutions in nitrobenzene. Interesting, wonder
if the same potentially explosive complex coats the anode during this as well of if that is an artifact of the nitrobenzene.
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blogfast25
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Quote: Originally posted by BromicAcid  | | From the abstract it sounds like you need the aluminum chloride complex the same as when electrolyzing solutions in nitrobenzene.
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Are we talking AlCl<sub>4</sub><sup>-</sup> here?
@MrHS:
Keep calm and carry on!
@Zb:
Probably very, very gradually increase voltage and see how amps respond. At first you may still be electrolysing minute amounts of water present in
the mix, as it is much easier to reduce than Na<sub>+</sub>.
[Edited on 17-3-2014 by blogfast25]
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Zyklon-A
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Has anybody ordered from NEOBITS before? If so, how long does it usually take for the shipment to arrive?
[Edited on 31-3-2014 by Zyklonb]
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elementcollector1
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No idea on the order, but be patient - in the olden days, orders could take months.
Does anyone have any reference to the solubility of other compounds such as rare earth salts in propylene carbonate? If they are, this would be a
sweet route to neodymium, cerium and lanthanum, and also possibly samarium.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Brain&Force
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http://www.sciencedirect.com/science/article/pii/00134686828...
Not a free article, but somebody has tried reducing europium, ytterbium, and samarium in the solvent, but they were reduced to their divalent forms
rather than the free metals. Apparently the trifluoromethylsulfonates are soluble in propylene carbonate.
At the end of the day, simulating atoms doesn't beat working with the real things...
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deltaH
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I have an idea for you to try if you so wish, let's call it pulling a half-Pok  Why not use magnesium as a [sacrificial] anode, an alkali hydroxide as electrolyte (also supplying the metal to be
reduced at the cathode) and propylene carbonate as solvent?
The idea is to oxidise magnesium at the anode and form magnesium hydroxide sludge (as it's very insoluble) and reduce whatever metal from the
hydroxide you employed at the cathode. This may well give you an ambient electrolytic route to the alkali metals.
I am unsure whether alkali hydroxides would react with propylene carbonate at ambient conditions. However, according to the reference I've attached,
it seems common practice to employ sodium hydroxide as a catalyst in carbonate exchange reactions, so for example refluxing ethylene/propylene
carbonate with methanol and sodium hydroxide yields ethylene/propylene glycol and dimethyl carbonate. So I think it might be ok provided you don't run
your cell too hot.
The nice thing about this is that you shouldn't need to run the cell with too much power (relatively speaking) because you make use of the large
reduction potential of magnesium metal. This should also help you to not generate excessive heat when running the cell, though some heating is
unavoidable. Excercise caution especially as propylene carbonate is high boiling; a heat sink on your cell may be a good idea if you're planning to
put through substantial current!
This way you also don't need to worry about making the anode out of anything special and I assume magnesium is easy enough for the amateur chemist to
obtain.
Attachment: Organic carbonates.pdf (379kB)
This file has been downloaded 581 times
[Edited on 1-4-2014 by deltaH]
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MrHomeScientist
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| Quote: Originally posted by deltaH | | The idea is to oxidise magnesium at the anode and form magnesium hydroxide sludge (as it's very insoluble) and reduce whatever metal from the
hydroxide you employed at the cathode. |
Insoluble in water perhaps, but do you have any data on its solubility on the solvent in question?
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deltaH
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| Quote: Originally posted by MrHomeScientist | | Quote: Originally posted by deltaH | | The idea is to oxidise magnesium at the anode and form magnesium hydroxide sludge (as it's very insoluble) and reduce whatever metal from the
hydroxide you employed at the cathode. |
Insoluble in water perhaps, but do you have any data on its solubility on the solvent in question? |
I'm afraid not and indeed solubilities is at the core here. I don't expect it to work for lithium though as lithium hydroxide behaves similarly to
magnesium hydroxide as solutes go, both of which tend to be rather insoluble.
But large cations are usually more soluble in organic solvents than smaller ones, so potassium hydroxide is probably ones best bet and if it were me,
I'd start there and then perhaps try sodium hydroxide if I can get it to work with potassium.
On a similar note, Ba2+ and K+ have similar ionic radii, so if one could get it to work with potassium hydroxide and if you can
get it, one might be inclined to try barium hydroxide.
Sadly, I beleive the goal of lithium or sodium via this route will remain ellusive, but hey, even 'just' obtaining potassium or barium metal would be
rewarding, no?
[Edited on 1-4-2014 by deltaH]
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Zyklon-A
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Sounds great! I shall try potassium first.
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deltaH
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Aside from poor solubility, I also think dissolution may be very slow! In fact, if one is going to do this in appreciable amounts, having some prills
of hydroxide stirring round in your electrolyte may be a good idea so as to replenish it in solution as it is consumed, just in case the solubility is
very low, which is most likely! Hmm... this is starting to sound like a challenging build, GOOD LUCK!
[Edited on 1-4-2014 by deltaH]
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Zyklon-A
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Yeah, well I probably have plenty of time, while I wait for my PC (propylene carbonate), I don't have KOH at the moment, but I can make some perhaps.
Got some NaOH though.
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deltaH
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I found this datasheet (see attached) for DMSO that lists solubilities of a wide range of inorganic salts. I figured, failing good data for propylene
carbonate, DMSO is start for a comparison as it is also a highly polar aprotic solvent. But take note, with a lower dipole moment of 4 D, compared to
propylene carbonate's 4.9 D!
From this data it appears that my suggestion to start with potassium hydroxide was a poor one as it is less soluble than sodium hydroxide in DMSO,
with solubilities of 13mg KOH /100g DMSO and 35mg NaOH / 100g DMSO, respectively, both of which are very low.
But lithium halides have no issue, lithium chloride happily dissolving at 10.2g / 100g DMSO! Calcium chloride, on the otherhand, is listed as
insoluble. Magnesium chloride hexahydrate is listed as 1g /100g DMSO, presumably the water present helps somewhat in the case of the hexahydrate salt.
Unfortunately, no data for magnesium hydroxide solubility even in DMSO 
So, while experimentation will yield the answers, we have some basis to speculate that lithium as lithium chloride may indeed work with magnesium as
an anode, particularly if one has excess lithium chloride so that it can replenish and maintain saturation as it's reduced as well as helping to
surpress the solubility of the magnesium chloride forming on the anode.
Also, be warned, if your concentration of electrolyte is very high, do start with a low voltage and work up as I think you may find your cell highly
conductive which may result in too much current flowing!
Attachment: Solubilities of substances in DMSO.pdf (1.2MB)
This file has been downloaded 1796 times
[Edited on 4-4-2014 by deltaH]
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Zyklon-A
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Unfortunately, I can't download it at the moment because I'm on a public computer, but I will as soon as I get home.
I think alkali halides will be easiest, mostly because they are easy to get, and cheap.
I've got lots of magnesium so an anode will be easy to make....
Should I use SS as a cathode?
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deltaH
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I've been meaning to ask what you plan to use as the cathode Yeah SS should be
fine, except it's not a great conductor and may get warm if you operate at high current density. Consider using nickel or plated nickel if you have
something like that.
By all means, do also experiment with alkaline cells as well (especially if you already have sodium hydroxide), the data I found is for DMSO
and while it is suggestive, we still don't know for a fact what the propylene carbonate will do.
When is your propylene carbonate supposed to arrive anyhow?
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