SHADYCHASE54
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how to deal with posphine fumes?
Okay I have a quick problem that I would really appreciate some advice on. I am running a purification step that may or may not result in the
evolution of phosphine gas. Is there anything I might load my wash bottles with that would clear this volatile before venting it outdoors? Thanks in
advance for any advice.
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SHADYCHASE54
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Okay I will clarify what I am doing, I intend on purifying some red P. "alarm bells ringing!" well chill out I want to purify the P as I am going to
chlorinate P in glacial acetic acid in hopes of producing acetyl chloride. Its worth a shot.
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UnintentionalChaos
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Potentially talking out my ass...
[Edited on 1-26-11 by UnintentionalChaos]
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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SHADYCHASE54
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geat advice thanks a bunch
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ScienceSquirrel
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The best idea in my opinion is to do the experiment in a vented apparatus connected to a tube leading out to the open air.
Phosphine will quickly react in the atmosphere to form phosphoric acids that will then fall in the rain. Further reactions will result in the
formation of phosphate salts and the phosphorous will then join the phoshorous cycle that has gone on for billions of years.
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not_important
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ou're talking the standard boiling with alkali purification? Before that stir the red P with warm benzene, toluene, tech xylene, dichloromethane,
dichloroethane, or similar solvent; most of these dissolve 1 g or more of P4 per 100 cc when warm.
Boiling with concentrate HNO3 is also supposed to remove yellow from crude red phosphorus, and without PH3 production as the P4 is oxidised to H3PO4.
I've not tried this or seen a detail description.
Or for your purposes just leave it unpurified, and be careful about the addition rate of the Cl2.
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ThatchemistKid
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I am not to familiar with this method of making acetyl chloride. I know that PCL3 reacts with glacial acetic to make acetyl chloride, but I am
thinking that with the excess of glacial acetic that will be present in your set up that all of your acetyl chloride will react to form acetic
anhydride and you will not really isolate acetyl chloride...just a thought.
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SHADYCHASE54
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Thank you for the responces I appreciate it more than you know. So am I then right to assume that thereis not a viable to way wash out the phosphine
how about bubbling it through an oxidant? maybe
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Sedit
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What method do you plan to use to purify it that will generate PH3?
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
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SHADYCHASE54
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It's my intent to follow the procedure listed in, "Handbook of preparative inorganic chemistry," boil gently in dilute aqeous hydroxide for 24hr rinse
excess hyroxide and boil in H2O for 24hr but i think i'll cut it to 12hr on both steps? then dry under vacuum.
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not_important
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Don't shorten the NaOH boiling. You may be able to half the rinse time if you give several stir-and-drain steps before the rinse boil.
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SHADYCHASE54
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It really takes that long of a NaOH boil to do away with the adhearing impurities? have any of you done this? one last Q. why is it that in the book,
"Purification of lab. chemicals," they merely suggest a H2O boil followed by hot filtration?
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not_important
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The alkali boil removes unconverted yellow phosphorus by converting it to PH3, NaH2PO2, and Na2HPO. You are doing a reaction between a solid - red
phosphorous - and an liquid, diffusion in the solid takes time; there's yellow phosphorus in solid solution in the red.
If the purification reference starts with commercial red, then it's already undergone the alkaline boil; contaminates are likely oxyacids of
phosphorus and their salts so a simple water boiling removes them.
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SHADYCHASE54
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Thank you for the explanation, mine is supposed to be lab grade however it has one hell of a bad rotten egg stink to it? It may be old but aside from
that I trust the supplier as trust worthy.
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The WiZard is In
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Eidted by The WiZard is In to correct errors noted by DJF90
Quote: Originally posted by SHADYCHASE54  | | Okay I have a quick problem that I would really appreciate some advice on. I am running a purification step that may or may not result in the
evolution of phosphine gas. Is there anything I might load my wash bottles with that would clear this volatile before venting it outdoors? Thanks in
advance for any advice. |
Granted — you can never be too good looking; rich; safe,
and phosphine is the chemical of choice by a large number
of people to end all suffering
My J.T.Baker chemical catalogue for technical grade red
phosphorus lists it yellow phosphorus content at Max. 0.015%
[0.075gms per 500]
Presumable you could burn it off.
The Curious method of production of phosphorous (III)
chloride in Inorganic Syntheses II:145-147 does not make mention
of any requirement to purify ones red P. Would think I, yes,
any yellow P would simply be chlorinated along with its red cousin.
As was previously mentioned years back the US Army spent a lot
of time/money on ways to purify red P for use in small arms primers.
If you run it through Google.com/patents you will find
a 'hole bunch of their patents. I believe they best method they
found was boiling in HNO3. That said they were interested in
removing more than white P and phosphoric acid.
djh
---
Carthago Deleta
An embassy hastened to Rome with authority to meet all demands.
The Senate promised that if Carthgage would turn over to the
Roman consuls in Sicily 300 children of the noblest families as
hostages, and would obey whatever orders the consuls would
give, the territorial integrity of Carthage would be preserved. The
Carthaginians gave up their children with forebodings and
laments; the relatives crowded the shores in a despondent
farewell; at the last moment the mothers tried by force to prevent
the ships from sailing; and some swam out to sea to
catch last glimpse of their children.
[D&D III:106]
[Edited on 27-1-2011 by The WiZard is In]
[Edited on 27-1-2011 by The WiZard is In]
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DJF90
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Wizard you've made an error or two. Firstly, 0.015% of 500g is a measely 0.075g, not 7.5g as you say. Secondly, P4 is white phosphorus, which is not
being purified, but being removed in the purification of the red allotrope (which, being an amorphous solid with no "molecular structure", is
best described just as P).
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The WiZard is In
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| Quote: Originally posted by DJF90 | | Wizard you've made an error or two. Firstly, 0.015% of 500g is a measely 0.075g, not 7.5g as you say. Secondly, P4 is white phosphorus, which is not
being purified, but being removed in the purification of the red allotrope (which, being an amorphous solid with no "molecular structure", is
best described just as P). |
Yes. I blame my errors on Global Warming.
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mr.crow
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You could use Bromine instead, reacts violently with red P and white P to make PBr3. One mol of PBr3 can make 3 mols of acetyl bromide. It also stinks
and reacts with oxygen.
BUT you can't do it in situ, PBr3 catalyzes alpha-bromination with Br2 so you will get bromoacetic acid instead. Use a slight excess of P to get rid
of all the free bromine then add your acetic acid.
Double, double toil and trouble; Fire burn, and caldron bubble
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ScienceSquirrel
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The suggested method is by reaction with sodium hypochlorite or similar materials;
http://www.praxair.com/praxair.nsf/0/98a2939cec509dc785256a8...
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SHADYCHASE54
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Thank you everyone for your posts some have been helpful. In particular I send a happy thanks to ScienceSquirrel for finally answering my original
question, you rock!
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