coppercone
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How useful is a laboratory glsssware powder auger?
So i had it in my mind for a whileto think about getting some concrete design work done on making a 24/40 scale powder auger which can be sealed up
and carefully add powder to a reaction much like a addition funnel can. The mechanism can be sealed up and high temp materials used so you can even
add the powder and bake it to aid in airless chemistry maybe.
Using magnetic coupling of course.
But how usefuk is this? Can anyone think of reactions that can benefit from solids addition rather then liquids onto solids?
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XeonTheMGPony
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they all ready have those, pricey things how ever.
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coppercone
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How well do they typically worj? I am looking at existing designs and i kinda get the feeling that moisture getting into them or solvent might cause
stuff to start sticking to the walls, it kind of looks like precise addition (i.e. addition of precalculated quantities) might be difficult, but it
seems well suited for things like gas generation
I imagined something somewhat more mechanically advanced to ensure more powder gets into the reaction..
An option might be to meave an addition funnel over the powder auger wash the thing out when most of the reaction is completed.. But this solution
seems very situational.
I also thought that warming the whole assembly with wire might prevent inadvertant condensation.
I actually don't know how temperature effects vapor phase reaction.
Is it impeded by elevating temperature or do you jeed to heat it to the decomposition point to achieve anything? Like with CaCl2 for instance or some
thing else which is highly hydroscopic
I assume formation of the hydrate is less favorable because of greater knetic energies.. But how measurable is it typically in terms of clump
reduction?
Granted precautions should be taken but i can imagine some henious bullshit like a slug of alcl3h2o forming in your auger
Or p2o5 going bad 
[Edited on 21-5-2018 by coppercone]
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Magpie
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you may find this useful:
https://www.sciencemadness.org/whisper/viewthread.php?tid=18...
The single most important condition for a successful synthesis is good mixing - Nicodem
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coppercone
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can't say im thrilled about sticking my hands into the fume hood. I thought I was past that stage in my life. the balloon thing is pretty methlabesque
and makes me feel primitive
we must fix the powder auger instead of resorting to such things 
Another idea I have is to just introduce a flow path through the auger, so there is a stream of nitrogen or argon that is moving fast enough to
prevent the ingress of vapors in that junction?
[Edited on 22-5-2018 by coppercone]
[Edited on 22-5-2018 by coppercone]
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Panache
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Quote: Originally posted by coppercone  | can't say im thrilled about sticking my hands into the fume hood. I thought I was past that stage in my life. the balloon thing is pretty methlabesque
and makes me feel primitive
we must fix the powder auger instead of resorting to such things
Another idea I have is to just introduce a flow path through the auger, so there is a stream of nitrogen or argon that is moving fast enough to
prevent the ingress of vapors in that junction?
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Theres nothing primitive about a balloon, god i remember hydrogenation labs that looked like a circus.
If the combined 200years of know how from schott, ace and co cannot come up with a way of adding powders conveniently i dare say neither will we.
That is not to discourage innate human ingueninity.
powders are a fucker for one simple reason, unlike liquids, almost all of which obey normal newtonian fluid dynamics, powder properties vary greatly
so designing a piece of kit that allows for it all is not possible, actually it is, its called a hand and a balloon!!
And magpie nicely dug post there!
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coppercone
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I need some kind of tracer particle to use so i can see gas flows when i am experimenting with this stuff to see whats feasible
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SWIM
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Some old lab manuals suggest using a test tube attached to the flask with a length of Gooch crucible tubing.
Panache's plastic bag procedure is a big improvement on this for practicality.
And control too, I bet.
If stuff clumps up in the test tube, you gotta shake it out, but with Panache's bag you'd have more control for portion-wise addition.
The tendency of the solids in a conventional powder funnel to clump and dissolve from refluxing solvent can be reduced in many cases by mounting the
funnel atop a short condenser with a wide enough inner diameter.
At least this helps in 24/40 and up. Haven't tried it with smaller glass. Might tend to jam up too much with smaller diameters.
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coppercone
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I figure you can also form stuff into pellets with sintering in some cases for easy flow control that's moisture resistant.
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Panache
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| Quote: Originally posted by coppercone | | I need some kind of tracer particle to use so i can see gas flows when i am experimenting with this stuff to see whats feasible
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that is funny!!
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BromicAcid
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I've used the auger's that already exist, basically an addition funnel with an auger at the bottom the feeds the material downward. For any reaction
you would need one for they work poorly. I.e., the vapors creep up into the solids and react there usually making a gummy mess or you're trying to
dose in a reactant at reflux and the vapors again enter the auger and start to gum it up anyway.
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Magpie
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Here's some more experience with powder addition:
http://www.sciencemadness.org/talk/viewthread.php?tid=9623#p...
The single most important condition for a successful synthesis is good mixing - Nicodem
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