Red Phosphorus

The Watcher · Dream Team

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method 1

Starting with yellow sticks, I've placed them in a high pressure hydrogenation bomb and heated to 260C for 4 hours. Probably only 30-40 percent conversion. Removing the lid in bath tub filled with water was fun- friction from metal to metal scraping lit phos inside, but the tub water instantly extinguished it. Better would be to pull water in through the valves with a Mighty Vac pump (exhausting the pump into the toilet trap) before removing lid. Separating red from yellow was a bitch. Soaking in NaOH solution and crushing phos with a pestal under NaOH solution. Phosphine caused little bursts of flame on top of solution when coming in contact with O.

method 2
Dissolve Phosphorus sticks in Carbon Disulfide and expose to Mercury vapor light or sunlight for a few hours. Red P will fall out of solution and collect on the glass. Yellow P is very soluable in CS2, red p is not.

It took me a couple of years to get up the nerve (or desperation for some rp) to attempt. Carbon Disulfide has a bp near ether, has a very high vapor pressure, and explosive (refrigerator light bulb is enough to ignite). A side effect to exposure to CS2 is insanity!!! You do not want to breath the vapor, nor do you want even a drop to touch your skin.

See, I started out with just under 1 lb of yellow sticks. Disappointed with the yield obtained from method 1, I still had over half of the sticks to convert.
I finally found the reference I was looking for on how to dissolve phoshorus in CS2 safely(Journal of Chemical Education, 1953). In a glove box, I lowered the sticks into a sep funnel 1/2 filled with water. I then pipetted a couple 100mls of CS2 in and stoppered. A couple of shakes/pressure releases and the phos was dissolved. I seperated the water and ran the CS2 solution into a flat bottom flask. Then I removed the flask from the box and placed it in sunlight. The rp conversion was 100%.

The thing is, you don't need to use CS2. Almost every other np solvent will do the same, but it takes alot more solvent . Phosphorus is at least 20X more soluable in CS2 as it is the next solvent on the list (benzene). Chloroform and Toluene were also on the listed solvents that this works with. Toluene has a higher boiling point, but its flamable. Chloroform might be safer, but its vapor pressure is very high.

The reference that gave me the idea to do this was an Inorganic Chemistry Journal from the 40's that I found at the local University library.

secret_squirrel · Thu Mar 03, 2005 3:29 am

You can get pretty cheap 7% phosphorus brazing rods. The phosphorus is a self fluxing agent for brazing . One pound of rods would have around an ounce of phosphorus in them. The balance of the rods is copper, which could be plated onto an electrode in a copper sulfate solution just like they do in copper refining. It might be nicer than scraping matchbooks, and would be very OTC!

Any thoughts?

blackone · Fri Apr 29, 2005 2:29 am

Phosphorus from brazing rods? Very interesting.
So how wold you swim it, just use the rod as anode in a cupper-sulphate solution?

Wonder if it would be possible to dissolve it in nitric acid without oxidizing the phosphorus...

Elementary · Fri Apr 29, 2005 6:11 pm

I remember reading in a chemistry book that yellow phos can be converted to red phos with UV light while in a water solution, you would probably need to liquidize the yellow in the water first to get good uv exposure.

Who needs yellow anyway, buy the red, it's out there if you google hard enough Wink

ChemLab · Fri Apr 29, 2005 7:29 pm

The Feds watch the RP in the States.

ChemLab

blackone · Sat Apr 30, 2005 6:40 am

White isn't watched?
It's not really OTC I think:)

Elementary · Sat Apr 30, 2005 11:56 pm

The feds can't check every package that comes into the country.

And if the company will send to a PO box, even better Very Happy

There is nothing better than a nice pot of RP arriving in a plain white jiffy bag Cool

iwantchronic · Fri Jun 24, 2005 11:42 am

how do i make phosphenic asid with r/phosphres so ican continue my dreams.... its to hard to perches hypo

Elementary · Fri Jun 24, 2005 2:25 pm

Maybe you mean to ask :-

How do I make hypophosphorus acid from red phosphorus ??

This is a whole different topic, but you would probably have to go through the intermediate phosphine.

Sektor · Sun Aug 28, 2005 5:51 am

There has got to be a better way for filtering this shit(rp), using coffee filters eventually the filter blocks up and dont filter no more, proper filter paper takes fuckin days and the same thing happens, it blocks up. tried gently swirling it etc, anyone got any tips? and no, buchnar no option,

Sektor · Mon Sep 05, 2005 10:14 am

and cleaning the shit, does one have to boil the RP in a HCL/H2O solution? or can swim just soak the RP overnight in HCL(30%) then dilute with water to filter? the RP has been tainted with lil paper particles,

loki · guinea pig

decanting works MUCH better altho one has to be a bit more patient.

here's how swim does it:

1 scrub off phosphorus from boxes of matches with ethanol
2 settle and decant
3 boil in ethanol, settle, decant
4 boil in shellite, settle, decant
5 boil in acetone, settle, decant
6 boil in HCl, neutralise with NaCO3, settle, decant
7 boil in water, settle, decant, repeat
8 dry and powder

loki · guinea pig

oh... i forgot to read the beginnings of this thread...

i have been thinking about the subject of phosphorus and iodine a lot the last few days and found out that one can make PI3 easily by mixing phosphorus and iodine in a suitable solvent (carbon disulphide is commonly used in industry but iodine dissolves in most nonpolars), and this PI3 formed this way, when put into contact with water the PI3 hydrolyses into phosphorous acid and hydriodic acid (and a bit of phosphines if its hot).

so if u can get white phosphorus, don't bother trying to make it into red. it dissolves in nonpolars to a sufficient degree to be able to perform the reaction... and reacts in a matter of half an hour to 100% yield of possible PI3.

i have been speculating about whether one could separate the reaction with ephedrine into two steps by making PI3 in a nonpolar and mixing it with ephedrine freebase. and then using phosphorous acid (or hypo, and possibly this may work with salts of phosphite/hypophosphite too).