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Author: Subject: Make Potassium (from versuchschemie.de)
blogfast25
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[*] posted on 27-4-2012 at 11:53


Decane has been used by nurdrage with good results. Aromatics do not seem to be a problem either (Shellsol D contains some and is the 'solvent' of the original patent).



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alkalimetals
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[*] posted on 28-4-2012 at 23:33


Thank you very much! I'll try to synthetize potassium metal and I'll post it here :)
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nora_summers
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[*] posted on 12-5-2012 at 10:38


I finally made some potassium! It was lots of little spheres (less than 1mm) but it was clearly potassium and popped and flamed when i put them in water!

I just had to add the alcohol drop by drop and it finally started making potassium. to total amount i added was 0.5mL.

I also boiled my baby oil at 220 celsius with nothing in it (no KOH or Mg or alcohol) for a few hours and then letting it cool. I'm not sure if this did anything but i thought i should mention it here.

I also want to report my glassware seems etched now :( in reading the thread i think the glassware gets etched if you use mineral oil or baby oil for the solvent, but if you use shellsol d70 it does not get etched. can anyone confirm this? as i do not have shellsol d70 to compare to.
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blogfast25
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[*] posted on 12-5-2012 at 11:10


Nora:

If you keep refluxing the mini globules eventually coalesce into larger ones. It's this coalescencing process that takes up most of the time.

Boiling baby oil will dry it. But it's probably pretty dry to start with.

I've used Sellsol D and kerosene and didn't get any etching with either of them. Not sure about baby oil...




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nora_summers
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[*] posted on 12-5-2012 at 12:50


maybe thats why people are getting inconsistent results. some people are using baby oil, mineral oil or stuff like that. and others are using shellsol and kerosene. might explain why some are etching and that some people have to add the alcohol drop by drop instead of all at once.
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jamit
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[*] posted on 13-5-2012 at 00:39


@blogfast25

Does it matter why type of kerosene you use? Can I use the kerosene for heating? Is there anything particularly different about using Kerosene as the solvent as opposed to other solvent you have tried?:)
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blogfast25
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[*] posted on 13-5-2012 at 06:03


Quote: Originally posted by jamit  
@blogfast25

Does it matter why type of kerosene you use? Can I use the kerosene for heating? Is there anything particularly different about using Kerosene as the solvent as opposed to other solvent you have tried?:)


Not as far as I know (I used 'deodorised' lamp oil).

Yes.

No. As long as the 'solvent' is inert and has a boiling point (or range) near or above 200 C.




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watson.fawkes
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[*] posted on 13-5-2012 at 09:59


Quote: Originally posted by jamit  
Is there anything particularly different about using Kerosene as the solvent as opposed to other solvent you have tried?:)
The recommended solvents have been treated by hydrogenation, so there are quite low percentages of alkenes and aromatics. Ordinary kerosene still has significant quantities of these. For the reaction itself, I imagine this only affect yields.

It may, however, have something to do with the glass etching reported, as the combination of a double bond which can be oxidized, atomic potassium, and the mixed oxides within glass doesn't seem like a completely inert combination to me.
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blogfast25
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[*] posted on 13-5-2012 at 10:58


Nurdrage used tetralin once, without any problems. The double bonds left in there aren't really aromatic but still. Double bonds don't seem to have much effect, 'within reason' at least...



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watson.fawkes
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[*] posted on 13-5-2012 at 14:44


Quote: Originally posted by blogfast25  
Nurdrage used tetralin once, without any problems. The double bonds left in there aren't really aromatic but still. Double bonds don't seem to have much effect, 'within reason' at least...
I am admittedly reaching for a hypothesis. One solvent has reports of etching, another doesn't. I could believe that long chain olefins behave differently than cyclic compounds. It certainly might not be this, but it's the only thing so far reported that seems to have any correlation.
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[*] posted on 14-5-2012 at 05:13


How about 'quality of glass ware'? A priori I would not expect much difference between one type of glass and another in terms of alkali resistance but who knows?



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[*] posted on 15-5-2012 at 09:48


How can you explain the thermodynamics involved in this reaction? If the reaction is as stated in NurdRage's video: 2Mg + 2KOH -> 2K + H2 + 2MgO

The half-reaction has to be 2K+ + Mg -> 2K + Mg2+? Which is impossible? Considering the electrode potentials.

http://www.chemguide.co.uk/physical/redoxeqia/predict.html

If this reaction is to work, there are to be a more feasible mechanism. Am I wrong here?

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[*] posted on 15-5-2012 at 11:14


A half-reaction gives no indication of the whole reaction's spontaneity. For example, should the reaction of zinc and magnesium (Zn<sup>2+</sup> + Mg -> Zn + Mg<sup>2+</sup>;) be nonspontaneous because Zn<sup>2+</sup> + 2e<sup>-</sup> -> Zn has a negative potential? You must look at the cell voltage, not the half-reaction potentials. If the cell voltage is positive, then delta G is negative and the reaction is spontaneous (but does not necessarily occur at an appreciable rate).

It is probably due to the formation of MgO being so favorable that the reaction can proceed with an appropriate catalyst.

[Edited on 15-5-2012 by barley81]
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blogfast25
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[*] posted on 15-5-2012 at 12:26


The reaction:

KOH(s) + Mg(s) == > K(l) + MgO(s) + ½ H2(g)

is thermodynamically favourable (the Standard Heat of Reaction has been calculated elsewhere in the thread). At 200 C it would normally not proceed though. That’s where the catalyst comes in: it reduces the activation energy of the reaction so that it can proceed at much lower temperatures (such as 200 C).

Half-cell potentials are a very poor guideline here: we’re not working in solution. You really need to calculate the actual ΔG in the relevant conditions, not in conditions that don’t apply.

A detailed proposes reaction mechanism, including the role of the catalyst, has been described higher up in the thread too…




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[*] posted on 7-6-2012 at 13:53


My first attempt!!

I distilled my own t-butyl alcohol from Turbo 108 octane booster, after letting the solution sit, taking the lighter fluids (leaving behind the dark, staining messy liquid), mixing with water, freezing the solution (which separated like oil and water), then distilling what WAS ice to get the required alcohol...

I mixed to NurdRage's specifications- 2.5g magnesium (Kind of old, but was refluxed and made shiny after distilling with hot mineral oil and some t-butyl alcohol) and 5g of very dry KOH into about 30mL of hot, distilled mineral oil (I previously distilled to removed lighter oils- boiled at around 230*C)

Initially, it boiled vigorously and was opaque. I figured this was the stage where it released H. I then added dropwise some t-butyl alcohol, which also greatly increased boiling, which then came to a murmur, even under increased temperature. The heated vessel would bump every minute or so, with a spray of mist, condensing and dripping into the hot oil.

8 hours later, I was left with an opaque oily solution, with some hard magnesium at the bottom. I noticed, adhered to my stir rod, was some nice shiny Mg. But no K. After letting cool overnight, and then checking it out- I dumped the contents into an open vessel, and tool some out and dropped it into water- No fizzing, popping, bubbling, nothing.

The solution came out in 2 layers- The light amber oil, opaque with KOH I would guess, was less viscous than the lower layer, which was thicker and whiter.

Any help would be appreciated... Maybe my alcohol was impure, my mineral oil had problems? I'll try cleaner Mg, and kerosene next time. But kerosene and parrafin will need perfect supervision, as opposed to "I'm in the next room, checking any 5 minutes" type.
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[*] posted on 9-6-2012 at 07:08


You're using fairly 'dodgy' ingredients, thereby possibly introducing a panoply of possible errors. Any idea of temperature during the run.

'Turbo 108 octane booster' contains t-butyl alcohol? Interesting!




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[*] posted on 11-6-2012 at 21:20


Urgh... I have access to pretty much everything but the KOH. Why is the state of Washington so lacking in scientific supplies?

Anyway, the route I think I'll go is thus:

-Vaseline as main liquid, because of density (compared to molten K), 20mL.
-T-butanol distilled from the Turbo Octane Booster 108, 1mL.
-KOH from... wherever I'll get KOH. Electrolysis?
-Magnesium from shaved magnesium firestarter block.

Questions:

I will have a Graham coiled condenser shortly, so how do I set this up to condense the fumes from the reaction (while still letting H2 escape)? Pretty sure it involves hooking the condenser to the top of the flask, placing Al foil loosely on top, and running water (or air?) through. Or a wet paper towel, I saw that a few pages back.

How fine, in your opinion, should the magnesium be for best results? I have a ball mill and/or hacksaw if entirely necessary.

Is there a good way to 'clean' any K formed without using toluene?

Are there any easier substitutes for the reagents I'm using? I have what is stated to be 99.9% mineral oil, but K doesn't float in this.




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[*] posted on 12-6-2012 at 05:10


Sure does, according to multiple Google sources :)

http://www.hotrodders.com/forum/octane-booster-info-124750.h...
Quote:

Turbo Octane Boost 108
(No percentages given)
Methanol
t-Butyl alcohol


I distilled the t-butyl alcohol out with some heat, about 90*C, then froze it- It froze, the oil that came over with it did not. Also, letting the Turbo 108 sit for an extended period (after purchasing and transporting it) settled out all the garbage.

As for the K, I refluxed at around 210*C, just enough for the mixture to boil and occasionally bump.


[Edited on 6-12-2012 by Wizzard]
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[*] posted on 15-6-2012 at 04:12


Quote: Originally posted by Wizzard  
Sure does, according to multiple Google sources :)

http://www.hotrodders.com/forum/octane-booster-info-124750.h...
Quote:

Turbo Octane Boost 108
(No percentages given)
Methanol
t-Butyl alcohol


I distilled the t-butyl alcohol out with some heat, about 90*C, then froze it- It froze, the oil that came over with it did not. Also, letting the Turbo 108 sit for an extended period (after purchasing and transporting it) settled out all the garbage.



How much t-butanol did you manage to distill from it?
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[*] posted on 15-6-2012 at 04:58


Quote: Originally posted by MyNameIsUnnecessarilyLong  


How much t-butanol did you manage to distill from it?


Also, was any identifying test (density, MP or BP) carried out on the product?




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Wizzard
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[*] posted on 15-6-2012 at 05:56


Only about 2ML, I cut the operation short when I realized I had enough, it was coming over very slow. I tested it's approximate boiling point and melting point, it froze around 10*C (it was a fairly thick liquid, almost gel-like, in relation to the lighter alcohols which also came across but were removed, they did not freeze and I simply extracted the frozen substance from the rest after putting the bottle in the fridge). Boiling was right very brisk when moderate heat was added (I did this with a cold finger to re-distill the small amount, just to double purify it, neglecting efficiency and waste).

I have more distilling now, I had a 'batch error' where the plastic vessel I had the gasoline additive in apparently did not agree with the product- It promply leaked like a sieve, and my work area smelled of gas for some number of hot days. That was the reason for cancellation of the previous distillation process :)
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[*] posted on 15-6-2012 at 07:02


Sounds like the catalyst wasn't the source of your problems...



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[*] posted on 15-6-2012 at 13:15


Anything you'd recommend? I'm going to re-run the process with the same ingredients, once I distill more t-butyl alcohol. See if the same problems arise... I have new ingredients on the way.
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[*] posted on 16-6-2012 at 22:54


Looks good, any one have translated or something ?
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blogfast25
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[*] posted on 17-6-2012 at 07:54


Quote: Originally posted by Wizzard  
Anything you'd recommend? I'm going to re-run the process with the same ingredients, once I distill more t-butyl alcohol. See if the same problems arise... I have new ingredients on the way.


Try 'one pot'? Just start with all ingredients mixed in your reactor, then start heating. It's what I do.




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