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plante1999
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Yes, you simply got to boil it down to re-use it.
I never asked for this.
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blogfast25
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NaCl + H2SO4 ('Draino; is good enough)
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Zyklon-A
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Ah, that's what I figured, I will do a small experiment with making AlCl3 today, maybe a few grams. I also will make a chlorine generator
to make a lot of it, but that will be much later.
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elementcollector1
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So, if the cell only consumes K+ and Cl-, while leaving AlCl3 alone, what exactly is the point of preparing anhydrous
KAlCl4? Seems like it would amount to the same result in terms of ions in solution. It would certainly be something to try...
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Zyklon-A
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I'm not entirely sure to be honest. But I doubt they would have gone through the trouble to make it if it wasn't needed. Whatever the case, I'm going
to make it, as I want to stick to what I know works. I could skip the AlCl3 and just buy it, but making it is much cheaper.
Buying potassium tetrachloroaluminate is out of the question, I could only find it at SIGMA, and even there, it appears to be
discontinued.. Whatever that means. Quote: Originally posted by deltaH  | I was thinking of 'simply' co dissolving anhydrous AlCl3 and KCl in reasonably dry propylene carbonate and not so much preparing incredibly
anhydrous KAlCl4 by fusing salts under anhydrous conditions as the authors have done.
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I have no idea if this will work, although blogfast25 seems to think it won't, so I'll trust him until further experiments explain
the "ifs" and "whys".
| Quote: Originally posted by blogfast25 |
I think your proposed procedure wouldn't work but I'm not sure why. For starters, if it can be done that easily, why bother preparing the
KAlCl<sub>4</sub> separately as they did in that paper?
Water is of course a great enemy of AlCl<sub>3</sub>, which causes it to hydrolyse. Minute amounts of water can never be entirely
avoided, of course. I would certainly go to every bit of reasonable trouble to eliminate water as much as possible. |
[EDIT] It seems to me that fusing the salts wouldn't be that hard. Probably $15 worth of equipment and an inert/anhydrous atmosphere. It
will require a couple days of planning, a hot torch, and several hours of free-time. Nothing I and many others haven't done, and don't do time and
time again.
[Edited on 16-4-2014 by Zyklonb]
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deltaH
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I look forward to reading about your efforts in preparing KAlCl4.
In regards to making anhydrous AlCl3, I recall my supervisor once upon a time lamenting having to sublime it for purification. Wiki quotes
a sublimation temperature of a mere 180C, so... perhaps you may want to look into methods that prepare it chlorothermally (if they even exist/are
feasible) killing two birds with one flaming ball of phosphorus?
...and no... I don't mean igniting ferric chloride and aluminium powder... that would probably be rather suicidal!
[Edited on 16-4-2014 by deltaH]
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Zyklon-A
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What is chlorothermally?
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deltaH
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lol, your link was funny  , what I meant is a thermite-like reaction where you
exchange chlorine instead of oxygen, the idea would be to pick candidates such that the reaction is not too exothermic as a gaseous product will be
produced (and so could be potentially explosive if very exothermic), namely, sublimed aluminium chloride.
For example igniting zinc chloride and aluminium? Shooting totally from the hip, but you get the idea... (the latter being probably no good anyhow)
Or maybe lead (II) chloride and aluminium... but then who has lead (II) chloride just lying around and probably too exothermic, though does have the
nicety that the chloride salt is anhydrous to start with and lead has a very low melting point and high boiling point.
Out of interest, using the NIST Webbook, I determined the standard enthalpy of vaporisation for aluminium chloride to be 121 kJ/mol, so as you can
see, that 'sinks' some energy.
Anyhow, if there's no precedence for chlorothermal reactions like these, then it's probably too dangerous or unlikely to succeed to be worth it... was
just a side thought.
[Edited on 16-4-2014 by deltaH]
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blogfast25
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delta H:
Reductions of chlorides instead of oxides are fairly rare for several reasons:
1. the resulting chloride usually has much lower heat of formation than the corresponding oxide, making these reactions less thermodynamically
favourable. AlCl3 is a case in point because it's only a semi-ionic compound, with much lower enthalpy of formation than alumina. For chlorides, Al is
therefore a fairly poor reducing agent.
2. the resulting chloride is usually much more volatile than the corresponding oxide. This creates problems of containment.
One important chloride reduction does spring to mind: the Kroll process for Ti and Zr. MCl<sub>4</sub> + 2 Mg === > M + 2
MgCl<sub>2</sub>. It is not an 'easy' process.
The reductions of FeCl3 and ZnCl2 with Al I predict (off the top of my head, without calculation) not to be thermodynamically favourable (Delta G >
0).
But because of its volatility, removing AlCl3 from the reagent mix may make these reactions practically possible nonetheless. If the target chloride
is itself somewhat volatile this may impose limitations on temperature.
All in all direct synthesis of AlCl3 seems the 'easiest' route by far.
Where oxidic reductions aren't an option for whatever reason, fluoridic ones can be contemplated.
[Edited on 16-4-2014 by blogfast25]
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Zyklon-A
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Ah, yes that makes sense. I will distill it anyway, because the reaction of chlorine and aluminum is very exothermic, and will easily vaporize the
aluminum chloride.
BTW, is it possible to do a chloral-thermal reaction with something like sodium chloride and aluminum oxide? Of course it won't really be like a
thermite, because it will be highly Endothermic , but if heated very hot, will the low boiling point of aluminum chloride drive the
equilibrium to the right?:
Al2O3 + 6 NaCl <--> 2 AlCl3 + 3Na2O.
I didn't have much luck with regards to making AlCl3 today, but I will try again. I didn't really have a good apparatus to control the
reaction, but I just got a nice SS pipe that should work great!
I will report my progress when it's done.
[EDIT] I didn't see blogfast25's post until now, question partially answered.
[Edited on 16-4-2014 by Zyklonb]
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blogfast25
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Because of the insanely high heat of formation of alumina, that process would require temperatures at which NaCl also becomes volatile. So, no: it's
unlikely to yield anything but 'salty alumina'.
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deltaH
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I'll leave it at that in this thread because I don't want to derail this topic, but it's an interesting hypothetical idea and so too are your
points... I think we should start up a new thread from this dedicated to it's consideration.
I suggest we start by considering the thermodynamics of the lead (II) chloride version, because out of the quick ones I could think, that seems like
the most feasible.
By the by, the fact that it's not too exothermic is desirable in this case, so long as it's exothermic enough to proceed and maintain a reactive melt.
The fact that AlCl3 is produced as a vapour is also desired! So yeah, bad thermite, but maybe a good way of making pure AlCl3...
well at least a madscience way 
Zyklon, pay no attention to my "dangerous unreferenced speculation"!
[Edited on 16-4-2014 by deltaH]
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12AX7
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| Quote: Originally posted by blogfast25 |
2. the resulting chloride is usually much more volatile than the corresponding oxide. This creates problems of containment. |
Or opportunities...
| Quote: | | The reductions of FeCl3 and ZnCl2 with Al I predict (off the top of my head, without calculation) not to be thermodynamically favourable (Delta G >
0). |
FeCl3 is interesting I think, because it's a strong Lewis acid like AlCl3. If nothing else, the boiling point of AlCl3 is lower (IIRC?), so it could
be evaporated out of a mixture.
It all has to be anhydrous of course...
| Quote: | Where oxidic reductions aren't an option for whatever reason, fluoridic ones can be contemplated.
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There's also the carbochloric approach, Al2O3 +3C + 3 Cl2 --> 2 AlCl3 + 3 CO, which is used with titanium (speaking of!), but has the obvious
downside of involving (essentially) hot powdered sapphire, which is probably even less reactive than the titanium approach!
Tim
[Edited on 4-17-2014 by 12AX7]
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deltaH
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I've created a thread in beginnings for this subtopic on chlorothermal routes to AlCl3 and KAlCl4 directly as well (by including KCl in the mix!)
[Edited on 17-4-2014 by deltaH]
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blogfast25
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Tim:
FeCl3 anh. is hard to get and hard to prepare. And it has a relatively low BP too.
The carbochlorination of alumina works but is hard for home scientists.
[Edited on 17-4-2014 by blogfast25]
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Zyklon-A
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Does anyone know anything about these ionic liquids?
| Quote: |
Ionic liquids are salts which are fluid at ambient temperatures. They have several advantages over conventional molecular solvents, which make them
environmentally compatible:
•Dissolves many different inorganic and organic materials
•Highly polar
•Consist of loosely co-ordinating bulky ions
•Very low vapour pressure
•Liquid window of up to 300 ºC enabling wide kinetic control
•Most liquids thermally stable >200 ºC
•Immiscible with many organic solvents
•Non-aqueous polar alternatives for phase transfer processes
•Relatively inexpensive
•Easy to handle and store
We have identified a large number of opportunities that take advantage of the features listed above:
•Metal Plating
•Electropolishing
•Metal Reprocessing
•Phase transfer media
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They don't say if they would react with highly electro-positive metals.
[EDIT] Here is a description:http://www.scionix.co.uk/index.php?view=article&catid=39...
[Edited on 2-5-2014 by Zyklonb]
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