Sciencemadness Discussion Board

Extracting Phosphorus from P2O5.

NERV - 3-3-2003 at 10:14

I had the idea that if you react P2O5 in a pure Hydrogen enviroment you could get a solution of Phosphorus and H2O. The reaction would be as follows:

P2O5+5H2-----> P2+5H2O

I am not exatly an expert at chemistry, so I could be wrong. This could be an experament for thoes of you who can get P2O5.

a_bab - 3-3-2003 at 13:24

It won't work. You can't reduce P with H because P will react with H and you'll get phosphine.

NERV - 6-3-2003 at 10:01

Oh-well, I figured there would be a catch somewhere.

Darkfire - 16-3-2003 at 18:14

I had a way to extract P from RP but Iforgot my theory before i could post it. All i remeber is that iodine was used in the procedure, you guys are smarter than me mabey you could think of the rest.

CTR

DDTea - 16-3-2003 at 19:31

P from RP? RP = Red Phosphorus, no? Red Phosphorus is straight P.

NERV - 17-3-2003 at 10:30

Mabey Darkfire is talking about converting RP into WP.

Darkfire - 17-3-2003 at 18:02

Isnt Red Phosphorus p2o5, and isnt White Phosphorus elemental Phosphorus? If its not i just made a total ass of myself.

CTR

NERV - 18-3-2003 at 12:19

No, I am pretty sure that RP Is elemental phosphorus.

Darkfire - 18-3-2003 at 18:00

Than what the differance between wp and rp? Only reason ive broughten all this up is i remeber reading it somewhere, i gues it could have been someone giving false information.

CTR

madscientist - 19-3-2003 at 09:38

White phosphorus and red phosphorus are both forms of elemental phosphorus (called allotropes). White phosphorus is P<sub>4</sub>; red phosphorus is P<sub>10</sub> (if I remember correctly). White phosphorus is converted into red phosphorus by exposure to ultraviolet light; red phosphorus is converted into white phosphorus by heating until white phosphorus vapors are generated.

Darkfire - 19-3-2003 at 15:40

Smakes forehead, i never even conciderd that...

CTR

Blackout - 3-12-2004 at 19:30

"Isnt Red Phosphorus p2o5, and isnt White Phosphorus elemental Phosphorus?"

WP & RP are both elemental P, its like graphit and diamon, both are C.

BromicAcid - 3-12-2004 at 19:54

At moderate temperatures with a stream of hydrogen constantly flowing over the P2O5 surface this reaction would probably actually yield phosphorus. The reaction of hydrogen with phosphates similarly yields phosphorus. However I wouldn't waste P2O5 like that, it could probably be more easily reduced with aluminum powder so long as the regular requirements for working with phosphorus were meant, e.g., rigorous exclusion of oxygen. The heat of the reaction would of course volatize phosphorus as it would form so it would have to be scraped off the cold surfaces or the whole reaction vessel could afterwards be shaken with CS2 and the CS2 removed in a sealed system leaving behind your phosphorus.

budullewraagh - 3-12-2004 at 20:15

phosphorus is produced from phosphates by using silicon dioxide and carbon at high temperatures, yielding carbon dioxide and a silicate (depending on what your phosphate is)

X3PO4+C+SiO2-->P+CO2+X2SiO3

of course, this is phosphoric anhydride, so you could easily make a phosphate out of it by reacting it with a base, but at the same time, i bet you could do the above reaction without the SiO2 and yield phosphorus.
P2O5+C-->CO2+P

BromicAcid - 3-12-2004 at 21:43

That reaction is of course complicated by the fact that phosphorus pentoxide sublimes at 360C so you would probably have to resort to running 800C P2O5 vapor over carbon @ 1000C to get a noticeable reaction.

Personally I would go for aluminothermic methods or reduction with hydrogen as mentioned in at least on patent. Aluminum might react readily with it without provocation. Most any active metal, iron, magnesium, zinc, could probably be used, although magnesium would probably get violent, as might aluminum.

JohnWW - 4-12-2004 at 01:47

The sublimation of P2O5 in the reduction could be avoided or reduced by using an ionic phosphate instead, especially calcium phosphate.

I doubt that using Mg or Al or Zn powder would work well, because even if stoichiometric quantities are used there would probably be some Mg3P2 or AlP produced, with some left unreduced.

BromicAcid - 4-12-2004 at 06:51

Quote:
I doubt that using Mg or Al or Zn powder would work well, because even if stoichiometric quantities are used there would probably be some Mg3P2 or AlP produced, with some left unreduced.


I agree, just saying that it would be a simple affair mixing the two chemicals and igniting in a tube with a one way gas release and scraping out the phosphorus that collected in cooler parts of the tube.

unionised - 9-12-2004 at 04:57

Beware of the risk of phosphine being generated.
Actuall, you might do as well to deliberately add excess metal to convert the phosphate to phosphide, add acid and thermally decompose the phosphine to give the element.

cyclonite4 - 9-12-2004 at 05:30

Quote:
Originally posted by NERV
I had the idea that if you react P2O5 in a pure Hydrogen enviroment you could get a solution of Phosphorus and H2O. The reaction would be as follows:

P2O5+5H2-----> P2+5H2O

I am not exatly an expert at chemistry, so I could be wrong. This could be an experament for thoes of you who can get P2O5.


What do you mean by a solution of phosphorus? Isn't Phosphorus insoluble in almost all solvents?

guaguanco - 9-12-2004 at 12:43

Quote:
Originally posted by cyclonite4
What do you mean by a solution of phosphorus? Isn't Phosphorus insoluble in almost all solvents?


No, White phosphorus is quite soluble is some solvents.