FriendlyFinger
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Al/Hg celite HgCl2 question
Hi there, Swim said;
" Following a P2P, Al/Hg with MeOH reaction, I want to filter straight out of the flask using diatomatious earth used for pools and then distill the
MeOH under vacuum and acid/base from there.
1) Is there a chance of the freebase screwing up during distillation owing to any HgCl2 being carried in the MeOH?
2) Will HgCl2 react adversly if present during acid/base?
3) If HgCl2 is present, will acid base take it away?
Thanks,"
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IPN
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You could use the easily generated H2S (FeS + HCl for example) to precipitate basically all Hg from the solution as the insoluble HgS. I don't think
the few molecules remaining will do any harm in the end product.
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Flip
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Why go to all of that trouble?
Just filter the solution, then basify everything with a strong NaOH solution. Extract with toluene or xylene, and just wash the extracts with brine
(aq. NaCl) to remove any solvated HgCl2.
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turd
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| Quote: | | Following a P2P, Al/Hg with MeOH reaction, I want to filter straight out of the flask using diatomatious earth used for pools and then distill the
MeOH under vacuum and acid/base from there. |
Basify with NaOH before filtration. Al/Hg is infamous for producing the filter clogging sludge from hell. Don't use too much celite and wash the
filter cake thoroughly.
| Quote: | 1) Is there a chance of the freebase screwing up during distillation owing to any HgCl2 being carried in the MeOH?
2) Will HgCl2 react adversly if present during acid/base?
3) If HgCl2 is present, will acid base take it away? |
1) No. All your HgCl2 was reduced to metallic Hg by the Al.
2) No.
3) Yes.
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FriendlyFinger
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Thanks, but why basify before before filtration? tests have already done on previously saved sludge in 35% NaOH. The NaOH makes it even more
diffilcult to filter than sludge without the NaOH. Sludge with MeOH goes through much quicker.
I note that Shulgin simply filtered the IPA and sludge and Uncle Fester also filters the EtOH and sludge and washes with a little more solvent. So why
add the NaOH if not extracting with toluene etc?
thanks,
FF
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Flip
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Basification causes the aluminum hydroxide sludge to precipitate out better, so it is more 'filterable'. He is indeed correct, you'll want to filter
after basification or filter again afterwards, as you'll probably notice more 'particulate' matter swirling around after you basify it. In my post
above I wasn't giving any thought to the order, but that is in fact how things are done. Also, imho, working your extractions with toluene/xylene is
the most practical way of doing things.
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FriendlyFinger
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Yeh, actually I did notice that after the first filtration with Wattman 541, the filtrate was just a touch murky so it was filtered again through a
glass fiber filter and was crystal clear, so yes, needs to be filtered twice.
Thanks,
FF
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