Meltonium
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The Best Way to Reflux a Solid
So I am preparing for an attempt at the synthesis of potassium metal through reduction with magnesium, but I am worried about my solvent. I wanted
something relatively inexpensive and easy to get that was more dense than the potassium formed. I researched prices and availability of tetralin, but
was ultimately turned off. I settled on naphthalene because I thought it would be interesting to see if it could work. To my knowledge, nobody has
done this using naphthalene (although I haven't read through that 60+ page thread)
I'm worried about the reflux. Because naphthalene is a solid at room temperature, refluxing it to get to the 200C reaction conditions could risk
clogging the condenser and lead to an explosion. Today I ran a reflux for a few minutes using an air condenser and it seemed to do okay. I insulated
the flask with two layers of aluminium foil and it seemed like the crystals would fall back down into the flask as they grew in size and weight. I
don't know how long this would hold though. Does anybody have experience with this and could give a few tips to minimize the risk?
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MrHomeScientist
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Heating the condenser to just above the melting point seems like the way to go. Not sure how best to do that, though. You could be on standby with a
heat gun to melt any clogs, though that would get tedious.
I bought some tetralin for this experiment but had a problem with my hot plate, so the reaction was never able to get going. One thing I didn't
realize when I bought it was how incredibly smelly the stuff is. So far the vapor has escaped every bottle I've put it in. I'm almost to the point of
offering it up for other members, if there's interest.
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wg48
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The recommended solvent is a none aromatic high boiling point paraffin type solvent.
Experimenters have tried partially aromatic solvents. I don’t recall if it worked or not.
Potassium reacts with naphthalene which will complicate its extraction, see the wiki entry for naphthalene.
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Meltonium
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Quote: Originally posted by wg48  |
Potassium reacts with naphthalene which will complicate its extraction, see the wiki entry for naphthalene.
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Wow. I had read the entry multiple times to see if it did react but I completely missed that.
...
Darn
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MrHomeScientist
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When I did it, I used lamp oil. Mine was initially colored blue, but that dye was destroyed by heating the oil to near-boiling. I then used the
"decolorized" oil in the actual reaction. Tetralin has the advantage that K floats in it, which should help significantly with coalescence.
Report your progress in the potassium thread! I'm eager to read about another experimenter.
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ElizabethGreene
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If you are worried about the unit failing explosively from a clog, then fit the condenser joint loosely so it can ventoff if there is an overpressure.
... or include a vacuum/gas adapter in your stack and connect it to an oil trap.
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