symboom
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Oxidation of phosphine to phosphorus
Reading over the wiki phosphine can oxidize in air to form phosphorus pentoxide is their a mild oxidizer that can oxidize phosphine to phosphorus in
solution while making phosphorus
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unionised
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Working with phosphine has a reasonable chance of killing you .
However, if you insist...
Heating it will get it to decompose into phosphorus and hydrogen.
If I had a death-wish I might try reducing calcium phosphate with excess aluminium- in the hope of getting aluminium phosphide- then acidifying the
product and heating the gases evolved in order to make phosphorus.
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karlos³
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Heating the gasses in an inert atmosphere without having them ignite themselves is surely a very, very difficult task.
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woelen
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Working with phosphine can kill you. The same is true for working with Cl2 (the latter is even more toxic) or with HCl.
I think that when done carefully, outside, or in a fumje hood, you can work with that kind of gases. With Cl2 people work more comfortably, because it
is much more accessible for the home chemist. This kind of remarks may make people afraid. It is better to warn about the risks, tell people that if
they are inexperienced, that there is a bigger risk of severe accidents. Educating people about risks is better than raising fear for being killed.
There are only very few chemicals which I really avoid working with, these are the systemic poisons, which can have long-lasting effects or long-term
effects (e.g. H2Se, AsH3, many Hg-compounds, certain organics). The immediate toxicity of e.g. PH3, AsH3 and SbH3 is comparable, but the systemic
effect of AsH3 is much worse than the effect of PH3 and even SbH3 is much less toxic in the long term than AsH3. The same is true for nearly any
As-compound. That's why I am very reluctant to work with arsenic, simply because even exposure to small amounts can have long-lasting effects.
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unionised
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Quote: Originally posted by karlos³  | | Heating the gasses in an inert atmosphere without having them ignite themselves is surely a very, very difficult task. |
If it was easy, it wouldn't be fun.
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symboom
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I was referring to the process of making white phosphorus using aluminum and phosphate salt it is known that white phosphorous is made this way along
with phosphine it seems like trying to reduce the phosphine to white phosphorus to increase yield is more trouble than it's worth. Would leading the
phosphorus vapors into bleach help or will the hypochlorite destroy the white phosphorous? Many don't use an inert environment for this process and
just let the phosphine burn off.
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draculic acid69
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| Quote: Originally posted by symboom | | I was referring to the process of making white phosphorus using aluminum and phosphate salt it is known that white phosphorous is made this way along
with phosphine it seems like trying to reduce the phosphine to white phosphorus to increase yield is more trouble than it's worth. Would leading the
phosphorus vapors into bleach help or will the hypochlorite destroy the white phosphorous? Many don't use an inert environment for this process and
just let the phosphine burn off. |
Why create a deadly gas only to let it burn off?
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draculic acid69
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If one could turn a graphite crucible into a rxn vessel( sealing electrodes thru a lid with a exit tube leading to water) one could probably use a
electric arc furnace to quickly make p4 on a larger scale.maybe.sounds better than phosphine
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WGTR
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It seems like the topic of phosphorus is rather popular lately, and it's also been a while since I've documented a project here. I have been throwing
an idea around in the back of my mind for some time about making small quantities of this interesting element.
Basically I would produce it from a phosphate salt directly inside of a large, inverted, test tube. Kanthal wire (16 gauge) would be wound into a
tight coil inside of which would be placed a small metal basket (maybe a thimble?). Of course, the heating coil and basket would be small enough that
the test tube would fit easily over them without them directly touching the glass.
Then, the heater wires would connect to cooled brass feedthroughs that fit through a thick sheet of hard silicon rubber. A small tube would also fit
through the rubber, such that it could be used to exhaust the air from the test tube when the tube sits inverted on top of the rubber.
Then (and this picture may not be clearly obvious without a photo) a couple of stacked foam cups can be installed over the test tube, such that the
inverted dome of the glass tube pokes through the bottom, inside the cup. Then, this can be filled with cold water/liquid nitrogen/whatever to keep
the glass cool, while the heater, basket, and phosphate salt mix, is red hot.
Ideally, with heat under a moderate vacuum, the phosphorus would boil out of the reaction cup and deposit on the cold end of the test tube. After the
reaction is finished, your reagent(s) of choice could be added to the test tube, and the tube could be used as a reaction vessel for whatever
small-scale experiment you have planned for the day.
If anyone is interested I might do it, but would probably post it to the phosphorus thread instead of doing it here.
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clearly_not_atara
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Woelen: I would think the greater risk involved with phosphine is not its toxicity, but its pyrophoricity. If it can be made free of diphosphine it
will be a little safer. But then heating it will not be easy.
I wonder if you could arylate phosphine, though. If you can get the first aryl group on there, the next two are much easier.
EDIT:
Diaryliodonium salts and photoactivation seems promising:
https://onlinelibrary.wiley.com/doi/abs/10.1002/chem.2019029...
[Edited on 6-2-2020 by clearly_not_atara]
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woelen
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Indeed, phosphine produced by an amateur will almost certainly contain a little diphosphine (P2H4, similar to hydrazine) and this makes the gas
self-inflaming in contact with air. I have done some experiments with phosphine and I bubbled the gas into an inverted test tube under water. The
other day, the water-surface in the inverted test tube was covered by some yellowish 'frost'. The phosphine in the test tube was not self-igniting
anymore, but still it was very flammable.
So, working with phosphine has its risks. It is toxic (acutely) and it is extremely flammable. A nice combination 
Always think before you begin. Think about what happens if everything goes into flames. Think about what happens if a cloud of PH3 is released into
the air. Simply choosing the right location for your experiment (e.g. outside, on a concrete floor or tiled floor, a few meters away from anything
flammable) can make the risks acceptable (a fire then only leads to loss of your experimental setup and equipment). Also, always work small scale. I
made phosphine a few times and did some experiments with it (you can find one of them on my website), but I never made more than a few test tubes full
of gas.
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XeonTheMGPony
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| Quote: Originally posted by karlos³ | | Heating the gasses in an inert atmosphere without having them ignite themselves is surely a very, very difficult task. |
bottle of Oxygen Free Nitrogen in the M size 79 dollars cad!
5% hydrogen OFN is harder to find but reducing used for oven brazing.
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symboom
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What about a shieldng gas of CO2 if sodium carbonate is mixed with the reaction mixture?
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