White phosphorus is poisonous and can spontaneously ignite when it comes in contact with air. For this reason, white phosphorus must be stored under water and is usually used to produce phosphorus compounds. Red phosphorus is formed by heating white phosphorus to 250°C (482°F) or by exposing white phosphorus to sunlight. Red phosphorus is not poisonous and is not as dangerous as white phosphorus, although frictional heating is enough to change it back to white phosphorus.
From
http://education.jlab.org/itselemental/ele015.html (http://education.jlab.org/itselemental/ele015.html)
That is a VERY nice idea with the vacuum pump though, I have to get building a furnace
Please, not in your parents' basement.
Seriously, this is one of the more dangerous ways to get precursors I've read about. Unless you really know what you're doing, don't do this.
Honestly, if bees are willing to try something like this, why don't we see more posts about biosynthing E or converting urea to H3PO3?
[Edit]
Hmm, did some UTFSEing and converting urea to H3PO3 is completely imaginary, don't know what I was thinking.
[/Edit]
about 1200 degrees C off the top of my head
Look a few posts up, scottydog says - temperatures exceeding 1500 degrees Celsius
The resulting chemical reaction produces gaseous phosphorus, which is condensed to liquid form and subsequently processed after cooling.
Ahhh really who wants to do this? esp getting gaseous phase of something described as easily ignitable in air and must be stored under water..... ::)