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Author: Subject: Make Potassium (from versuchschemie.de)
blogfast25
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[*] posted on 30-4-2015 at 12:46


There's been much trouble at versuchschemie, not sure what though. If the potassium thread has been permanently lost then all the better we have this thread.



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FriedBrain
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[*] posted on 10-8-2015 at 15:27


No, the user left the forum and deleted all his threads, because of trouble with the admin.
But there is another thread about the preparation of potassium metal, I think it should be also very informative:
http://illumina-chemie.de/darstellung-von-metallischem-kaliu...

Also a user writes, that the use of n-Butanol was succesful.
And here you can find (an older?) thread from Pok. http://www.versuchschemie.de/ptopic,240058,kalium+patent+her...

[Edited on 10-8-2015 by FriedBrain]
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[*] posted on 10-8-2015 at 15:44


Quote: Originally posted by FriedBrain  
No, the user left the forum and deleted all his threads, because of trouble with the admin.
But there is another thread about the preparation of potassium metal, I think it should be also very informative:
http://illumina-chemie.de/darstellung-von-metallischem-kaliu...



Wow! That's quite a whopper of a K-nugget he's got there. Thanks for that link!




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Waffles SS
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[*] posted on 18-10-2015 at 10:09


I think this should be possible to use certain fraction of gas oil instead of ShellSol D70.

Fraction range from 200c to 240c after removing sulfur and aromatic compounds by sulfuric acid.

[Edited on 18-10-2015 by Waffles SS]
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[*] posted on 20-10-2015 at 14:28


Shellsol D70 is not necessary requiert. I used some common lamp oil with the right bp and free of armomstics. Works just as good. Sorry for my bad english. :D
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[*] posted on 20-10-2015 at 14:35


Quote: Originally posted by Feli  
Shellsol D70 is not necessary requiert. I used some common lamp oil with the right bp and free of armomstics. Works just as good. Sorry for my bad english. :D


It does. The solvent is far less critical than some believe.




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[*] posted on 20-10-2015 at 14:53


Well it just need to be a high boiling inert solvent...

[Edited on 20-10-2015 by Feli]
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[*] posted on 20-10-2015 at 15:46


I have had an attempt at this -- unsuccessfully. The medium I used was a paraffin bought from the hardware store. I have not been able to find much in the way of specific details on what it contains. The MSDS merely mentions "petroleum distillate" which is the same for a large number of different products.
I believe the temperature got up to around 200°C. I did get it refluxing nicely but it was out of the range of the thermometer I owned at that point. I should check this.
I have no idea if the paraffin contained any aromatics. What are the effects of aromatics in this context anyway? (I know this is probably somewhere in the 60 pages of this thread but I have not located it.)
I intend to add some potassium to my element collection over the summer.
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[*] posted on 20-10-2015 at 16:15


Do you know what went wrong? Common problems are tert-butanol freezing in the condenser, not enough temperature, not enough stirring, and improper choice of solvent (reacts with one or more of the other things). I used kerosene and a borrowed Sterling hotplate with magnetic stirring (set to very fast, the stir bar was a blur) and refluxed for four hours. The reaction mix was a brown slurry by the time I was done.



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[*] posted on 20-10-2015 at 16:33


I may simply have not left it for long enough. I think I gave up after an hour and a half. The oil had gone distinctly brown.
Nurdrage's video does not have significant stirring and nor did I.
Anyway, that was months ago. i am much better equipped now and will give it another shot.
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[*] posted on 21-10-2015 at 00:45


Why should the tert-butanol freeze in the condenser? You just mix it with some of your solvent and add it directly in the reaction mixture thought a syringe. Kerosene might not work for this because there is so much other waste products in it. I think you should use lamp oil which is hydrotreated if I pronounce that right. I also found out that decreasing the temperature lowers the yield quite a lot. I did it like lemmi from illumina-chemie.de (http://illumina-chemie.de/darstellung-von-metallischem-kaliu...). If you stir to vigorously its not possible for the potassium to for bigger lumps and you got lots of fine droplets of it. Separating these out is a lot of work.
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[*] posted on 21-10-2015 at 04:08


Quote: Originally posted by Feli  
Why should the tert-butanol freeze in the condenser? You just mix it with some of your solvent and add it directly in the reaction mixture thought a syringe. Kerosene might not work for this because there is so much other waste products in it. I think you should use lamp oil which is hydrotreated if I pronounce that right. I also found out that decreasing the temperature lowers the yield quite a lot. I did it like lemmi from illumina-chemie.de (http://illumina-chemie.de/darstellung-von-metallischem-kaliu...). If you stir to vigorously its not possible for the potassium to for bigger lumps and you got lots of fine droplets of it. Separating these out is a lot of work.


To each their own, then. I found over the course of ten runs that if the water in the condenser was too cold, the tert-butanol would boil upward and freeze into acicular crystals that failed to re-enter the reaction mix (thus removing catalyst). Elsewhere in the thread, other people have had this same problem.




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[*] posted on 21-10-2015 at 04:19


If you work with such a high boiling solvent I think you dont even have to cool your condenser with water. Air cooling should be enough.
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[*] posted on 7-11-2015 at 08:35


Quote: Originally posted by Feli  
Kerosene might not work for this because there is so much other waste products in it.


Commercial kerosene is a very clean, dry distillation product from oil. Unless tampered with, it contains no ‘waste products’.

Quote: Originally posted by elementcollector1  
To each their own, then. I found over the course of ten runs that if the water in the condenser was too cold, the tert-butanol would boil upward and freeze into acicular crystals that failed to re-enter the reaction mix (thus removing catalyst). Elsewhere in the thread, other people have had this same problem.


Yes, water cooling will have the t-butanol condense and freeze up, rendering it useless.

Water cooling isn’t however necessary: an air cooled Liebig or Allihn will do just fine and will avoid freezing out the catalyst.




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[*] posted on 7-11-2015 at 11:15


Quote: Originally posted by blogfast25  
Commercial kerosene is a very clean, dry distillation product from oil. Unless tampered with, it contains no ‘waste products’.

Sorry I think I've mistaken it with petroleum.
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[*] posted on 22-12-2015 at 20:56
Avoiding the troubleshooting.


I finally have all the equipment, reactants, and time to synthesize some potassium metal. However, after reading over a good deal, if not all, of the posts in this thread, I see a recurring theme. People try 4-5 times to get the right thing, often using various methods found throughout the thread. Finally they succeed, but after many failed attempts that seem avoidable.

I want to avoid as many retries as possible (though a few times is expected), so I am here to humbly submit the exact reagents ("reagents" as in-mostly crap from walmart) I will be using for approval.

My solvent will either be this baby oil- Is it made of babies? or this lamp oil-Lamp Oil

I believe I shall first try with the baby oil.

My magnesium is form galliumsource, here-Magnesium

I bought the superfine turnings, and struggle somewhat to get them smaller. Is this necessary, and if so, what would be the best method to achieve smaller particle size? (I don't have a coffee grinder, or anything similar, just a mortar and pestle)

My KOH-Potassium Hydroxide

My Tert-Butanol-Tert-Butanol

I know the tert-butanol source seems rather shady, but it did in fact deliver!

I intend to follow the procedure outlined by woelen on this page- Very organized and nice woelen page, many thanks for it!

If anything seems wrong with any of this, I would be happy to be notified, and change my plans accordingly. I only have limited time, and would thus very much appreciate any help or corrections!
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[*] posted on 22-12-2015 at 21:41


Your reagents seem fine, but what about the apparatus? I've found that heavy stirring and good reflux is crucial.

Also, I'd give the lamp oil the first go - mineral oil just never seemed to do it for me.




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[*] posted on 22-12-2015 at 22:18


A glass 100ml Erlenmeyer flask, a sand bath, and a Liebig condenser put in the stopper on top of the Erlenmeyer for reflux. I had not thought very much about stirring, thinking that is some was needed, simply swirling the flask a little would be enough. (though I understand the difficulty in doing this, due to the sand bath and clumsy condenser on top). What would you suggest for better stirring? (considering I have no access to a magnetic stirring mechanism)

Lamp oil it is.
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[*] posted on 23-12-2015 at 06:09


Quote: Originally posted by KesterDraconis  
A glass 100ml Erlenmeyer flask, a sand bath, and a Liebig condenser put in the stopper on top of the Erlenmeyer for reflux. I had not thought very much about stirring, thinking that is some was needed, simply swirling the flask a little would be enough. (though I understand the difficulty in doing this, due to the sand bath and clumsy condenser on top). What would you suggest for better stirring? (considering I have no access to a magnetic stirring mechanism)

Lamp oil it is.


My experience is that stirring isn't necessary. Just try and swirl the flask a little, every half hour or so.

In his book, Leonid Lerner ('len1' on this site) mentions the procedure, without mentioning stirring:

Quote:
Thus, 100 ml Shellsol D70, 12.6 g KOH, and 6.4 g magnesium powder (up to 80% can be turnings) are heated in a 250-ml conical flask, attached to a Liebig condenser, bubbler, and dropping funnel. At 150ºC, the magnesium reacts with the molten hydrated KOH, generating hydrogen and MgO. Now 1.2 g t-BuOH in 5 ml D70 are slowly added and the temperature raised to 220ºC, generating 5.6 g potassium (82% yield) in 4 hours. During the reaction the potassium is coalesced by the regeneration of alcohol and this can be completed by swirling the solids at 65ºC in a stoppered flask with 50 ml dioxan to which 0.2 g t-BuOH have been added. The initiation stage
is very sensitive to K-reactive species in the paraffin, and equivalent reactions with sodium are much slower due to the lower solubility of sodium alkoxides.


He also prepared K successfully with this method. Yet 'len1' tried high speed stirring before that and failed to obtain metal.

[Edited on 23-12-2015 by blogfast25]




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[*] posted on 28-12-2015 at 14:20


Oddly enough, I think the lamp oil did me in on my first run. At first I thought all the bubbling and refluxing was just water and other impurities getting out, but after following woelen's instructions on how to deal with this (taking the condenser off briefly to let the water escape) it kept bubbling quite a bit. I then noticed that the temperature was staying around 185 C and going no higher.

I would attribute this to my hot plate not having a lot of power, but the plate itself was several hundred degrees celsius and the sand bath was at the required temperature (220C). Could it be that the oil was boiling at 185C , and not going any higher?

I added the tert-butanol anyway, but of course this didn't do anything. After five hours of nothing happening, and various attempts to figure out what was wrong, I simply shut it down and decided to try again tomorrow.

[Edited on 28-12-2015 by KesterDraconis]
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[*] posted on 28-12-2015 at 14:43


Quote: Originally posted by KesterDraconis  
Could it be that the oil was boiling at 185C , and not going any higher?



It's easy enough to check that.




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[*] posted on 29-12-2015 at 12:16


Quote: Originally posted by blogfast25  
Quote: Originally posted by KesterDraconis  
Could it be that the oil was boiling at 185C , and not going any higher?



It's easy enough to check that.


This was indeed the issue. I am now using the baby oil, and it has stayed at a steady 240C for a couple hours now. However, not much has happened. The magnesium has turned very grey, presumably due to oxidation, though I see no little potassium spheres yet.
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[*] posted on 10-1-2016 at 16:37


Ran across this while cleaning and thought someone might be curious with the interest in long-chain alternate catalysts: 2,6-dimethyl-2-heptanol (aka dimetol).



It's a fragrance chemical, pretty inexpensive if you buy it as such. Not OTC, but easily available from Perfumer's Apprentice in US, Hermitage Oils in EU, and last I checked Perfumer's World in Thailand still shipped everywhere else.

EDIT: I see Nicodem has mentioned this in the other thread, still worth the repost I think as these sources will sell to the "little guy."

[Edited on 1-11-2016 by Etaoin Shrdlu]
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[*] posted on 10-1-2016 at 17:09


Quote: Originally posted by Etaoin Shrdlu  
Ran across this while cleaning and thought someone might be curious with the interest in long-chain alternate catalysts: 2,6-dimethyl-2-heptanol (aka dimetol).



It's a fragrance chemical, pretty inexpensive if you buy it as such. Not OTC, but easily available from Perfumer's Apprentice in US, Hermitage Oils in EU, and last I checked Perfumer's World in Thailand still shipped everywhere else.

EDIT: I see Nicodem has mentioned this in the other thread, still worth the repost I think as these sources will sell to the "little guy."

[Edited on 1-11-2016 by Etaoin Shrdlu]


Aka tetrahydro myrcenol.

I haven't tried it yet, mainly because I don't have it. I do have dihydro myrcenol.




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[*] posted on 10-1-2016 at 17:29


That one looks nice too.
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