FireFly - 19-2-2003 at 21:14
Does anyone know of a synthesis for White Phosphorus?
Thanks,
N.P.
Polverone - 19-2-2003 at 23:42
There is already a long thread "preparation of elemental phosphorus" that you could have found with the search function.
http://www.sciencemadness.org/talk/viewthread.php?tid=65
Here's the executive summary: preparing white phosphorus is straightforward, at least in theory, if you can achieve and sustain high temperatures
(> 1000 C) for several hours. There are other methods that promise to work at somewhat lower temperatures. The most promising of these methods use
aluminum to reduce various phosphorus compounds. Nobody who visits this forum has yet procured useful (greater than a few centigrams) quantities of
phosphorus by any of these methods, though there have been some promising preliminary experiments with aluminum. I have never seen anyone on Usenet or
other web forums claim to produce usable quantities of phosphorus by any of these methods either.
As I said, the chemistry is straightforward, but most people who have attempted have been using carbon as the reducing agent, a la historical methods
(ordinary furnace) or modern industrial methods (arc furnace). These methods require too much engineering and/or Open Space Without Neighbors to be
practical for most amateurs. I think the aluminum route will eventually be made practical. The Great White Phosphorus Bear is in our sights. He's
so close I can hear him breathing sometimes. If I had more spare time I might be taking more shots at him, and eventually bag him like I did the
Cyanide Panther. Certainly great prestige within the hobby chemist community (whatever that's worth) awaits the first person who can show
they've made phosphorus and give a writeup for others to follow. In certain circles accompanying instructions for conversion of the white
allotrope to red would also be joyfully received, but that is a fairly minor challenge compared to getting the elemental P to begin with.
PoDuck - 20-2-2003 at 03:15
So, it looks to me that the biggest inhibitor of getting phosphorus using the old method is the heat. I don't understand why it wouldn't be
possible to get temperatures high enough to produce the right effect. In actuality, I don't understand why the furnace itself has to be air
tight at all.
Would it not be possible to use the design of the home built foundry and then create a ceramic crucible that has the ability to direct the gas put out
by it through the chimney of the furnace. Then you could get extremely high tempuratures without worrying about the furnace being air tight, and you
could build it for less than $50.
Something like this:
The crucible and it's upside down funnel top need to be made of some sort of ceramic. Steel may also work if you could be sure you don't
get the temperature too high, the ceramic would be easier to get a decent seal on though. There would be some thermal resistant cord placed around
the circumference of both the top and bottom sections of the crucible section. It won't be air tight, but it should create enough pressure to
force the air to go through the copper tubing instead. You would put some copper tubing in the end of the funnel and run it to a container filled
with water.
I have built a foundry before, and I know that with the right design for the burner, you can get propane to tempuratures near this. If you were to
use a different type of gas, or be able to insert oxygen into the process, you should have no problems melting a steel crucible, much less heating
phosphorus to the right tempurature.