tsathoggua1
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Magnesium boride, diborane safety
Alrighty, so I've been working away at creating some boron, in the amorphous state. Method is electrolytic using sodium borate as the substrate in
aqueous soln., a saturated solution is being electrolyzed with a 5V 35A input via a pair of nickel wire (around 2mm dia, guitar fretwire, may contain
other metals but nickel based)
Tried Fe and it stopped conducting when moved.
The nickel electrodes have been going for nearly 13-14 hours, possibly more and there is now a deposit of dark material at the bottom of the solution.
Electrolysis of molten borax is also apparently successful.
To produce B2H6, both for reductions as THF or Pyr complexes and for pyrolytic degradation and purification of the boron, is simply taking fine
magnesium powder and boron powder (amorphous, probably) and fusing them together with a torch successful, or is an arc or plasma jet level of heating
necessary?
How about packing the boron/Mg mixture as a fine powder (I have both very fine Mg dust and 20-30uM Al dust if Al boride would serve better) into a
metal tube and heating it with a brazing torch or moving an induction heater slowly back and forth along the metal pipe, whilst sending a stream of
argon down the bore through the Mg-B mixture.
Now, I've never encountered diborane before. For those who have, and who recognize the smell..could you describe it? slightly sweetish, softly
metallic, not harsh, but sicklyish sound about right? Because something like that is coming off the electrolytic cell. No pyrophoricity noted but the
solution is aqueous, I do not expect it could live as more than a transient intermediate if generated at all. Solution is hot, and highly alkaline,
around PH 11.
Just how toxic is diborane, and how toxic are the hiigher boranes in comparison to diborane?
[Edited on 19-3-2017 by tsathoggua1]
[Edited on 19-3-2017 by tsathoggua1]
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Elemental Phosphorus
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Diborane is extremely toxic, or OSHA and NIOSH overestimate its toxicity, but probably the former, as they recommend a supplied-air, full face
respirator for just a concentration of 15ppm. CDC says that pentaborane caused death in half of monkeys, in 2 minutes, at a concentration of 244 ppm,
but just 3 ppm was the LC50 for mice over 4 hours
40 ppm of diborane was lethal in half of rats after 4 hours.
https://www.cdc.gov/niosh/idlh/19624227.html
https://www.cdc.gov/niosh/idlh/19287457.html
Sorry I couldn't help you with the other things, but exercise EXTREME caution with boranes.
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tsathoggua1
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Thank you. I knew they were toxic as shit, or at least, that diborane was.
This is nuke-suit stuff then. What is the toxicity trend as the borane series gets higher/larger? E.g diborane, pentaborane, decaborane,
Are its adducts as dangerous? and do they offgas diborane/other boranes?
[Edited on 19-3-2017 by tsathoggua1]
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Elemental Phosphorus
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I am having a hard time finding data on adducts but looking at the LC50 values for pentaborane, it is even more toxic than diborane, its IDLH being
just 1 ppm, where diborane's IDLH is 15 ppm.
Decaborane is less toxic than pentaborane though:
https://www.cdc.gov/niosh/idlh/17702419.html
There is a lot of good information on adducts starting on page 929 here, though I could not find specific information on off gassing of boranes:
https://books.google.pl/books?id=Mtth5g59dEIC&pg=PA946&a...
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tsathoggua1
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Looks like I'm going to have to invest in some new gear to handle this stuff. I've been contemplating getting a fully self-contained NBC suit for a
while now.
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Elemental Phosphorus
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I would never handle boranes personally. The Navy had an explosion at a plant a while ago, killing a number of people. While they are interesting
chemically, I would be too afraid of gassing my neighborhood to do it.
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PirateDocBrown
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The joke for us was that you can always tell the boron chemists by the fingers they lack.
But that said, I've handled B2H6 before. In a good strong fume hood, through syringes/cannulae, and under dry N2 or Ar. But wearing only gloves,
goggles, and lab coat as protection.
I still hate HF more.
[Edited on 3/20/17 by PirateDocBrown]
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tsathoggua1
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Well I have the advantage of working at night. My circadian rhythyms are inverted from the normal. When I am awake, everybody else locally is asleep,
and vice versa, I sleep during the day. And this is something that if done, will be done outside, with every possible exit covered with dow-corning
high-vac grease for ground glass joints, NBC suit for personal protection with mask bearing dual ABEK1 canisters worn just for the fuck of it
underneath, so to speak. (overkill, in other words) and positive pressure O2 supply. And I'd not be making 'military' quantities of boranes, but
using the adducts as reducing agents primarily.
'Tis one of the advantages if being autie, your circadian rhythms are completely fubar, I can go for weeks without sleeping at night for more than an
hour or two, although granted, as my old man said, don't want a bunch of dead cats on the lawn either. (I'm very much a cat-person although that would
be easy enough to guess anyhow)
Although in my case, its eyes. I'm more or less a fucking cyclops. Got all my fingers though. Still, some of the feminine gender seem to like the
eyepatch, in a rakish sort of way. Anhydrous ammonia. Police raiding and removing label of bottle of alkali metal amide.Pretty much nuff said.
[Edited on 20-3-2017 by tsathoggua1]
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