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Author: Subject: Make Potassium (from versuchschemie.de)
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[*] posted on 25-2-2011 at 10:12


Very interesting indeedy, Squirrel.

Reminder to ALL: creative ideas about potentially interesting t-alcohols should really belong in this tailor made thread:

http://www.sciencemadness.org/talk/viewthread.php?tid=15171

Specifically we’re looking for catalysts for Na synthesis. It’s believed Na alkoxides are much less soluble in hydrocarbons because of the higher lattice energy associated with the smaller Na+ ion (higher coulombic attraction – see also Madelung constant). As the free energy decrease of dissolving whatever ionic substance is part entropy (solutions always being of higher entropy) and part enthalpy (here the energy to break up the lattice) it can be expected that longer chain/specifically functional t-alcohols may strongly increase the solubility of a given Na t-alkoxide.

Of course more soluble alkoxides may also speed up K-synthesis. Currently the actual reaction time is 1 - 2 hours: the rest is dehydration of KOH and coalescence of the formed K...


[Edited on 25-2-2011 by blogfast25]
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[*] posted on 25-2-2011 at 14:41


I will try and read the the t-alcohols thread in the next few days and give it some thought.
Really instead of alkylations you want a route to a working catalyst that would start from say an OTC alkene and via hydration and rearrangement would yield a big t-alcohol in clean yield.
Simple drying and distillation and you would have your hot gear :)
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[*] posted on 26-2-2011 at 01:06


The article of interest from the J. Agric. Food Chem. is in the attachment. Hope you find it useful. :)

Attachment: jf010341b.pdf (60kB)
This file has been downloaded 1783 times

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[*] posted on 26-2-2011 at 09:36


Thanks SS and IPN: that's now saved to disc and will be scrutinised later on. Anything useful will be posted in the t-alcohol thread...
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[*] posted on 26-2-2011 at 14:17


Quote: Originally posted by Per  
@ peach: your liquid t-butanol can't be pure t-butanol because it normally solidifies very fast if it's colder than its melting point. It behaves absolutely not like gallium which takes a very long time to solidify. May it contains water or anything else.

You could try refluxing it and then you'll probably get t-butanol crystals in the condenser, if it contains any t-butanol at all.


I won’t comment on the freezing behaviour of t-butanol but Peach’s product happens to come from the same source as mine and mine works. The smell of the product is quite unmistakable. Even if it contains water that won’t impede it from working as a catalyst in this reaction.

Watch this space: Peach will get a good grade powdered Mg, use his t-butanol and you’ll get to see the photos of K-balls soon. I'd put good money on that happening real soon! That's when he stops plying with his magnesium pencil sharpeners, that is... :)

[Edited on 27-2-2011 by blogfast25]
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[*] posted on 8-3-2011 at 13:44


In case anybody is interested, here are the solubility data for a few potasium and sodium tert-alcoholates obtained from Beilstein (there was no data for the longer homologues). The most closely related to the thread topic is the solubility data for t-BuOK in hexane.

Temperature . . . . . . . . . Solvent . . . . . . . . . Solubility . . . . . . . . . Reference

Solubility of t-BuOK

25 °C . . . . . . . . . toluene . . . . . . . . . 2.3% . . . . . . . . . Organic Letters, 2004, 6, 3649-3652.
25 °C . . . . . . . . . DMF . . . . . . . . . . 6.845 g/L . . . . . . . . . Chemische Berichte, 1985, 118, 3872-3899.
88.6 °C . . . . . . . . t-BuOH . . . . . . . . . 1.9 mol/kg . . . . . . . . . Collection of Czechoslovak Chemical Communications, 1981, 46, 2166-2177.
25-26 °C . . . . . . . hexane . . . . . . . . . 0.27 g / 100 g . . . . . . . . . Journal of the American Chemical Society, 1956, 78, 4364-4367.
25-26 °C . . . . . . . toluene . . . . . . . . . 2.27 g / 100 g . . . . . . . . . . . . . . . . . . -||-
25-26 °C . . . . . . . THF . . . . . . . . . . . 25.0 g / 100 g . . . . . . . . . . . . . . . . . . -||-
25-26 °C . . . . . . . Et2O . . . . . . . . . . . 4.34 g / 100 g . . . . . . . . . . . . . . . . . . -||-

Solubility of t-AmOK
"sol. in benzene and i-PrOH" . . . . . . . . . . . . . . . . . . Journal of the Indian Chemical Society, 1981, 58, 555-557.

Solubility of t-BuONa
25 °C . . . . . . . . . toluene. . . . . . . . . 6% . . . . . . . . . Organic Letters, 2004, 6, 3649-3652.
83.4 °C . . . . . . . . t-BuOH. . . . . . . . . 0.89 mol/kg . . . . . . . . . Collection of Czechoslovak Chemical Communications, 1981, 46, 2166-2177.
30 and 60 °C . . . . t-BuOH . . . . . . . . . ? . . . . . . . . . Journal of the American Chemical Society, 1956, 78, 3614.




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[*] posted on 8-3-2011 at 14:03


Very interesting indeed Nicodem, thanks…

I’ve been looking for solubility data on alkali alkoxides high and low and pickings aren’t rich at all…
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[*] posted on 14-3-2011 at 09:20


More balls of K!

This experiment was carried out using ‘outdoor lamp oil with citronella’ (why do they have to scent everything nowadays, huh?) It’s essentially a medium-heavy kerosene with a small (but unknown) amount of citronella essential oil added to it. It’s a cheerful transparent yellow.

I chose it because at 10 - 15 C its density measured 0.865 g/cm3, so it’s reasonable to expect molten K will float in it. The lamp oil was also given a solvent extraction treatment to eliminate the citronella (and dye?) See end.

40 ml of the oil, 6.1 g KOH flakes, 3.1 g good purity coarse Mg powder and 1 g of 2-methyl-2-butanol were combined (the so-called one pot method) in a 200 ml conical flask in the usual set up (kitchen towel glass tube cooled with iced water as refluxer):



I started off with a pre-heated sand bath at 13:35. I added iced water to the refluxer about every 10 minutes. Temperature developed as follows: 13:47 = 130 C; 13:55 = 155 C (clouding starts); 14:00 = 165 C; 14:08 = 180 C; 14:15 = 185 C; 14:19 = 190 C (first sighting of micro globules of floating K); 14:24 = 195 C; 14:28 = 200 C and my thermocouple can read no higher. H2 evolution was swift from about 75 C and decreased sharply after about 1 h.

At 14:30 I took this photo: an ‘archipelago’ of small balls of K (below and right to the letter K):



At 14:45 it looked like this: larger archipelago and clear coalescence of the micro globules into slightly larger ones. But yield looked decidedly small…




Around that time I had a major disruption: I ran out of gas! Temperature plummeted fast to below 190 C and the K-globules basically… disappeared. I attributed this to the vapours contracting and air getting into the flask and to the K. The solvent had turned greenish/brown.

I quickly changed gas bottles but must have been below 200 C for about 30 minutes.

I noticed small K balls at the bottom of the flask and soldiered on. These coalesced very quickly: below is a photo at 15:45:



Noticing no further coalescence after that, I stopped the experiment at 16:00. That’s pretty good time: take away the 30 minutes at lower temperature the test was basically only 1 hour and 40 minutes long!

Funnily enough, it appears that the very small globules floated in the solvent but the larger ones didn’t!

*****

Pre-treatment of the oil:

Three subsequent solvent extractions were carried out with a glass separating funnel: 50 ml of oil with 30 ml of acetone, then with 30 ml of alcohol (denaturated with methanol), then with 30 ml of water. The final product was slightly cloudy and boiled slightly bumpily. I added about 10 g of anhydrous MgSO4, stirred it for a few hours and left it to stand overnight. A clear liquid was obtained after decanting off. But it still smelled slightly of citronella…

Whether or not citronella oil interferes with the K synth. I don’t know. It may even be beneficial to it, who knows?


[Edited on 14-3-2011 by blogfast25]
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[*] posted on 14-3-2011 at 10:56


Congrats on the lemon-flavored Potassium!!! :D :D

Oh I'm itching to do that experiment, I have all the gear and most of the chems (still waiting for reagent-grade KOH from my supplier). That last picture is quite impressive! Are the globules of K easy to separate from the bottom crud after cooling?

Did you do this outside or inside? I won't have much of a choice but to do this inside and conduct the evolving hydrogen through a vinyl tube outside. So you added the alcohol prior to heating?

Robert




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[*] posted on 14-3-2011 at 13:29


Quote: Originally posted by Arthur Dent  
Congrats on the lemon-flavored Potassium!!! :D :D

Oh I'm itching to do that experiment, I have all the gear and most of the chems (still waiting for reagent-grade KOH from my supplier). That last picture is quite impressive! Are the globules of K easy to separate from the bottom crud after cooling?

Did you do this outside or inside? I won't have much of a choice but to do this inside and conduct the evolving hydrogen through a vinyl tube outside. So you added the alcohol prior to heating?

Robert


No reagent grade KOH needed: technical grade (e.g. Biodiesel) is fine.

The globules are loose from the crud (slag), bar a few small ones. In this case some of the crud was BLACK. Unreactive with water, so must be carbon. Who ordered that??? Carbonised citronella? Diels-Alder on high boilers?

Inside is fine. Calulate the amounts of hydrogen, Robert: it's negligible.

Yes, I add all the ingredients all at once and then start heating. Fourth time now, no problems... Done away with that silly ritual ('programmed addition')...

Edit:

Yield for this test was somewhat below par: only 27 %. This is mainly due to:

1. some small (1 - 3 mm) globules still found in slag not accounted for. Slag highly active (fine K)
2. interruption: the floating metal oxidised away
3. the carbonised material was highly unusual. No one’s ever reported this.

All in all not a run-of-the-mill run…

Density of the solvent, post reaction, was measured as 0.858 g/cm3, somewhat lower than initial. And the liquid appears slightly less viscous. Some thermal cracking may have occurred there by lowering the molecular weight of the average hydrocarbon chains..

[Edited on 15-3-2011 by blogfast25]
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[*] posted on 9-4-2011 at 07:32


@BlogFast: Holy frijolee! Awesome experiment! I admit that I skipped over the entire thread but I'll get to reading it as time permits. I get similar results with my experiments with molten salts with the black 'carbony' crud and all. I call it sodium ore but can't say for sure what it really is. It appears that carbonate is being reduced to carbon in my case (no solvents or oils in my setup). I'm able to pretty easily coalesce the Na from this stuff and eventually refine the Na to a mirror finish.

Heres a video of a little bit of the 'ore' I collected....

http://www.youtube.com/watch?v=SZVrbsPMOrg


And a video of some Na after an initial refinement (coalesced)...

http://www.youtube.com/watch?v=VSJxKTFsDHo&NR=1

I look forward to reading the thread (all thirty-some pages so far)!

Tom

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[*] posted on 9-4-2011 at 12:15


Nice balls of sodium, tanker78!

Have you seen this guy melting down blocks of Na as if they were made of lard? In a frying pan too! Talks like you would to a cookery class...

http://youtu.be/-6jVyDFqy0Q


[Edited on 9-4-2011 by blogfast25]
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[*] posted on 9-4-2011 at 19:21


Quote: Originally posted by blogfast25  
Nice balls of sodium, tanker78!

Have you seen this guy melting down blocks of Na as if they were made of lard? In a frying pan too! Talks like you would to a cookery class...

http://youtu.be/-6jVyDFqy0Q


Yeah, I'd seen that one before. Cooking up some sodium as if it was corned beef hash. The description says they had purchased 3,000 pounds of Na ..... :o

What have you been doing with the K that you extract? I mean do you leave the globules in their original state or do you make bigger globules?

Tom
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[*] posted on 10-4-2011 at 10:05


3000 lb, eh? 'Life's not fair', is all I can say!

For now not very much. I want to scale up and speed up before I do ‘interesting things’ with it. Filling a clean glass pipette with the stuff is one of them (because it brings out the metallic nature of the substance so much more).

But the real goal here is also sodium, using the same principle and process. But it needs a catalyst that’s more suitable for Na redox synthesis…
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[*] posted on 14-4-2011 at 06:43


Well yesterday I got my Merck magnesium. I will give it a try when i have more time to spare.
I got this product: , the 250 g one
http://www.merck-chemicals.com/romania/magnesium/MDA_CHEM-80...
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[*] posted on 15-4-2011 at 13:59


BlogFast: I don't mean to be a pest but can you describe the black stuff in a little more detai? You mentioned above that it contains fine K. How fine and in what form? I assume you mean it contains spherelets. One more thing, does the black crust 'ting' when you tap it lightly on a hard surface?

I may have misunderstood your post; is the 'slag' you speak of the same as the 'carbonized material'?

Tom
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[*] posted on 22-4-2011 at 07:59


Testing alfa-terpineol as a catalyst

Today I tested commercial terpineol obtained from Kremer.de (the Shellsol guys). Commercial terpineol is a mixture of tertiary terpene alcohols, alfa-terpineol being the main component and a tertiary “2-methyl-2-ol” type alcohol.

No potassium globules of any significant size were obtained. I used 2 ml of terpineol with the usual recipe, added right from the start. A medium heavy commercial kerosene was used as solvent.

For this occasion I’d connected the conical flask/refluxer with a cold trap and a simple gaszometer in order to measure the hydrogen evolution over time:



Left: sand bath, conical flask reactor with paper towel refluxer.
Middle: cold trap: the gas is led through a test tube immersed in iced water.
Right: gazometer: an inverted 100 ml measuring cylinder allows to approximately determine gas evolution over time.

Gas evolution started as usual in my experiments from about 70 C onwards, very vigorously. So much so that initial volume measurements failed because the cylinder just filled up too fast, so I lost quite some hydrogen there. From about 30 minutes into the test regular hydrogen evolution measurements were made without fail, obtaining values (in chronological order) like 400 mmol/s; 156 mmol/s; 4.5 mmol/s; 3.27 mmol/s; down to about 0.71 mmol/s after about 3 hours of refluxing at T > 200 C. In total (but from the measurements only) 420 ml of gas were obtained. But because of the fact that entire batches of 100 ml of gas were initially lost, I believe the actual evolved hydrogen gas to be closer to 800 - 1000 ml!

While I saw the usual break up (dehydration) of the KOH flakes early on, I didn’t see any MgO precipitate or K-globules appear.

The test was stopped after 3 h. After cooling a sample of the mixture of solids was tested with water. A small amount of gas was released (several times) but I didn’t see any K catching fire with the usual telltale flame colour.

What’s puzzling is the hydrogen generation (no condensate was found in the cold trap during or post-test, indicating the refuxer works well and the kero contains no light fractions), which initially made me think the usual redox reaction was taking place. Even 800 ml isn’t far removed from the theoretical value (for 100 % conversion) of 1.4 l (including dehydration hydrogen) and also well exceeds what could be generated by the alcohol merely reacting with the Mg powder.

******************

Tanker78:

Don’t worry about the black, it’s almost certainly carbon from Diels-Alder. But that never occurs with good solvents: mine (on that particular occasion) contained citronella and possibly other crap (a dye, for instance)

‘Slag’ is a general term for the by-product of a metallurgical reduction, in this case the slag is MgO.



[Edited on 22-4-2011 by blogfast25]
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[*] posted on 23-4-2011 at 08:56


Quote: Originally posted by blogfast25  
From about 30 minutes into the test regular hydrogen evolution measurements were made without fail, obtaining values (in chronological order) like 400 mmol/s; 156 mmol/s; 4.5 mmol/s; 3.27 mmol/s; down to about 0.71 mmol/s after about 3 hours of refluxing at T > 200 C.


Oooops! Erratum: above, 400 mmol/s should have been 40 mmol, likewise 156 mmol/s should have been 15.6 mmol/s. My bad.

**************

I tried to breathe some new life in the remains of the terpineol test by decanting off the solvent (by then a jelly-like mass) and replacing it with fresh kerosene and 2M2M. Only 20 ml could be decanted off (the rest being ‘stuck’ in the solids) and I added 30 ml of fresh kero and 1 ml of 2M2B.

As expected no hydrogen surge from dehydrating the KOH was observed at the start of heating. But from about 130 C hydrogen started to come over at about 7.5 mmol/s. Alas it quickly tailed off and it was clear not much potassium was being formed (no MgO slag seemed to be formed either) and the test was abandoned after about 45 min..

But after cooling the solids did test unequivocally positive for potassium with clear mini ‘explosions’ and the right flame colour. Dowsing the lot in much cold water I later found back loads of unreacted Mg, confirming (if confirmation was still needed) that alfa-terpineol didn’t work as a catalyst.

Intent on finally doing something useful today, I then ran a standard synth. with 2M2B (‘one pot’ method) and the gazometer. Again the size and speed of the initial dehydration hydrogen prevented me from measuring the initial gas rate accurately and about 200 ml of H2 were not quantified as rate. But only about 5 min into the test hydrogen evolution started to subside a bit and regular measurements of hydrogen evolution rate were then made. The results are summarised in the graph below:



Despite the scatter early on, this looks very much like the result of a reaction with depleting reagents. Note also that temperature was still strongly changing too: the first data point was taken at T = 114 C, the last four at T > 200 C. In total about 1 l of hydrogen was evolved during those measurements.

It also confirms what I suspected much earlier on: at 200 C or higher the reaction, bar a bit of slow fizzing out, is basically over in about 1 hour, the rest is coalescing time.

After 4 hours refluxing and cooling the potassium was found in the shape of mostly 0.5 cm balls, many stuck in the solid slag, I think I may have gone a bit too high in temperature. They will re-coalesced tomorrow.

I decanted off the solvent/catalyst mixture at about 70 C into a cold glass beaker and immediately it set to a jelly-like, ‘cheesy’, semi-solid substance, some 30 ml of it. This somewhat puzzling: there's not supposed to be any significant amounts of KOH left (and it’s not soluble in kerosene anyway) and according to the proposed reaction mechanism there should be about 0.1 mol of potassium 2-methyl-2-butanoate in the solvent. But the quantity seem to high for it to be just potassium 2-methyl-2-butoxide. Of course if it is the alkoxide then it should be recyclable: fresh magnesium would reduce it, liberating the alcohol which then would enter the cycle again…



[Edited on 24-4-2011 by blogfast25]
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[*] posted on 23-4-2011 at 17:07


I discovered this topic yesterday and have pretty much read every page. Amazing discovery and work by Pok and the others who replicated it and tested different solutions.

A few questions:

- Why was a technique like this never discovered before? Was it because it was SO unusual that nobody though of it?

- Can this technique be used to make Rb and Cs (obviously with a lot more care needed with the final product.
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[*] posted on 24-4-2011 at 04:01


Hi and welcome!

As you know pok’s experiments were based on an existing patent. Why and how it was developed we don’t know. It certainly seems a bit of an ‘alchemist’s dream’ to make potassium at low temperature and without using an electrolysing current…

The patent (which is referenced and linked to near the top of this thread) is well worth reading (and quite readable) and mentions also production of sodium and caesium (but not Li or Rb). So far only one experimenter here (Nurdrage) has applied the method to sodium but w/o success. Personally I believe we need a more ‘powerful’ catalyst for the reduction of sodium with this method, hence the attempts at trying to create other t-alcohols, see e.g. here:

http://www.sciencemadness.org/talk/viewthread.php?tid=15171
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[*] posted on 24-4-2011 at 10:11


Latest crop of K globules under recycled Shellsol in a 100 ml conical flask:



Mostly 0.5 - 1 cm balls, nicely clean-skinned, some smaller ones too. Will be further coalesced tomorrow for yield determination.

*******

I investigated the jelly-cheesy material that solidified from the 70 C solvent yesterday. After standing overnight, a lot of the stuff had actually ‘disappeared’ and there was clear solvent to be seen. So I filtered off the off-white ‘cheese’ with a paper filter, obtaining about 15 ml of perfectly clear and colourless solvent. It unmistakably smelled of 2M2B.

The solid matter was washed with several aliquots of isooctane (I was assuming that if there was potassium 2-methyl 2-butoxide that it wouldn’t be soluble in isooctane) and then a final rinse with acetone. After dripping dry the filter plus solid was dried at 70 C on a hot plate (in open air). The dry residue was dutifully scraped off the filter and weighed: there was only 0.22 g there; that was the small amount of stuff that yesterday, swollen by the kerosene, made up almost 30 ml of gelatinous matter!

It was transferred to a dry test tube and about 1 ml of water was added to it but nothing happened: no dissolution, no heat of dissolution, no reaction. This kind of excludes it being KOH or MgO.

Then 2 ml of 1 M HCl was added, again nothing happened.

Then 2 ml of 36 % HCl was added and slowly, over several minutes the residue dissolved almost completely, leaving behind some oily drops near the top of the liquid meniscus. Unfortunately the oil doesn’t smell of 2M2B, so I can’t really prove the reaction K 2-methyl-2-butoxide + HCl --- > KCl + 2M2B took place. The oil may be residual kerosene, for instance…



[Edited on 24-4-2011 by blogfast25]
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[*] posted on 24-4-2011 at 15:26


Quote: Originally posted by blogfast25  
Hi and welcome!

As you know pok’s experiments were based on an existing patent. Why and how it was developed we don’t know. It certainly seems a bit of an ‘alchemist’s dream’ to make potassium at low temperature and without using an electrolysing current…

The patent (which is referenced and linked to near the top of this thread) is well worth reading (and quite readable) and mentions also production of sodium and caesium (but not Li or Rb). So far only one experimenter here (Nurdrage) has applied the method to sodium but w/o success. Personally I believe we need a more ‘powerful’ catalyst for the reduction of sodium with this method, hence the attempts at trying to create other t-alcohols, see e.g. here:

http://www.sciencemadness.org/talk/viewthread.php?tid=15171


Ah..i see. Sorry, i thought it was Pok's patent. I guess i should read things better. Ill give the patent it a once over, but i must confess, my chemistry is limited to enthusiast as i studied Physics at Uni, so understand next to nothing about the chemical reactions happening or what makes the t-alcohols so special in this case.

Im just flabbergasted at the "ease" of this procedure. It certainly would be very exciting to see it also work on Cs.

Thanks for the reply by the way.

[Edited on 24-4-2011 by thethule]
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[*] posted on 25-4-2011 at 08:16


Yes to Cs but it’ll have to wait until Na has been tackled: CsOH isn’t easy to come by for hobbyists.

Meanwhile, another potassium floating experiment failed. I’ve been trying to get potassium to float in various hydrocarbon liquids but to no avail. Density is the key point here (stating the blindingly obvious). At RT the density of potassium is about 0.862, at MP (63.4 C) about 0.828. So I took the heaviest hydrocarbon liquid I had lying about : 10W40 engine oil (for petrol engines, from TESCO) and dunked a few very small globules of K and one about 0.5 cm in it. The density of the oil had previously been determined as 0.884 at RT.

Well, bizarrely the small ones did float but the larger one didn’t… Heating to about 160 C didn’t change anything… except that the small ones dived too! At 160 C the density was again estimated to be about 0.834.

Interestingly, the engine oil, undoubtedly compounded with antioxidants and other adjuvants, did not react noticeably with the molten K.

I seem to recall nurdrage got floating potassium with Nujol (IR paraffinic oil) and that’s got a density of only 0.838. I just don’t get it…
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AndersHoveland
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[*] posted on 25-4-2011 at 10:30


The density of potassium metal is 0.862 g/cm3, whereas magnesium has a much higher density, 1.738 g/cm3.
It is quite possible that the large globules of potassium contain some unreacted magnesium metal particles inside, or perhaps the globule consists of an alloy of potassium with a lesser portion of magnesium dissolved inside.

It is suggested that you measure the density of the "potassium" you have obtained and do some calculations. The yields from this reaction may be significantly lower than first thought.

[Edited on 25-4-2011 by AndersHoveland]
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[*] posted on 25-4-2011 at 10:49


Blogfast, you're bringing a [cheerful] tear to my eye. First, you broke from convention and did the 'one pot' method. Now, you're using engine oil. What next?!? :D

I can't speak for everyone but I think the work you're doing and the work that pok, woelen, nurd and others have done here is universally appreciated! Even the failed attempts by peach (for one) are insightful. I wish I had the equipment and reagents for this. I'm pretty much lost when it comes to organics but this would make a hell of an introduction, no?

I'm working on finding a stable hydrocarbon that is only slightly more dense than Na. Such a HC should float K but so far I haven't had any luck with clear HC's around the garage. Mineral oil turns dark after a while so maybe a clear HC isn't really an option anyway. I'll post up any such OTC HC if I find one.

Tom
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