White phosphorus... ampoule

[bjornebarn]

Yeah, I know, the topic isn't that good, but it will do :)

I am going to synthesize some white phosphorus, by heating up a borosilicate ampoule, three centimeters high and eleven millimeters diameter, containing 250 milligrams of red phosphorus. I am thinking about simply heating the whole thing up in the oven to 250 degrees Celsius (should be enought for WP to form). However, I don't know what will happen to the ampoule if I do that. Of course there will be an increase in pressure when the P turns into gas.

What do you think will happen? If it is not a good idea, do you ahve any better?

[Anira]

Personaly that sounds like a bad idea to me. I don't like the idea of heating enclosed glass containers. But if you don't need much there is a trick to get some. I learned about this as a magic trick since if you smear some white phosphorus on to your fingers then rub them together you can make smoke with your fingers.

Originaly what you do is take a pie pan and place a match striker pad on it. Light the pad and the white phosphorus would condense on the pan. I think you might be able to place the red phosphorus on a pan with a second pan closely above it. Heat under the first pan and place ice in the second. When you are done you should get some waxy residue on the top pan.

I hope this helps you, if you want I will make a diagram.

[texaspete]

. I learned about this as a magic trick since if you smear some white phosphorus on to your fingers then rub them together you can make smoke with your fingers.

Thats crazy. White phosphorus is extremely toxic, and ignites on contact with air.

[c.Tech]

I learned about this as a magic trick since if you smear some white phosphorus on to your fingers then rub them together you can make smoke with your fingers.

Isn’t white phosphorus deadly poisonous and causes severe burns? I know I wouldn’t want something toxic on my hands. I wouldn’t even want it near me if using a glove.

[Pb1]

First, make sure the ampoule is evacuated. Then gently heat the end containing the red P and strongly cool the other end. The red P will vaporise and condense at white P at the cool end.

Any excess pressure will just result in the extra vapor condensing at the cool end. Just make sure you have good cooling and don't let the temperature get too high. As long as there's some place for the extra vapor to go (the cool part), you shouldn't have a problem.

[Anira]

Isn’t white phosphorus deadly poisonous and causes severe burns?

Well here is the original trick:

1. Take a striker from a match package.
2. Place red side down on a pie pan.
3. Light the cardboard.
4. Make sure it stays lit.
5. Rub some of the residue off pan onto finger.
6. Rub fingers together.

I would think that you end up with close to nothing since not much condenses in the first place and what you get is contaminated by the burnt cardboard. This trick probably is not something you would want to do on a bigger scale or all the time.