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The Boring Stuff
I'm well acquainted with various fields of science & engineering, but my foray into the world of chemistry is relatively recent.

I'm in a location (probably most of us are to some degree) where many chemical reagents are highly scrutinized and difficult to legally obtain from legitimate supply houses in any appreciable quantity. To do so is considered highly suspicious, requires a business account, legal documents, and so on. In short, it's a headache and it's very uncomfortable for amateur chemists/experimentalists.

And possibly rightfully so. While googling chemical (i.e. red phosphorus) purification methods, it quickly becomes apparent why. Most of the information available is in the form of poorly written (often dubious) discussions between amateur illicit drugs manufacturers.

But I digress. Despite all this, I'm determined to continue my exploration and extraction of phosphorus in it's various allotropes.


The Interesting Stuff
The only readibly available consumer class product (that im aware of) which contains red phosphorus is the humble safety-match striker pad. Here they're only something like $2 for twenty, so it seemed like a good place to start.

The sample can be collected in a bowl with the use of a solvent and/or sufficient agitation. Pretty easy. Although naturally it contains some undesired impurities, particularly including fine particles of glass frit, an unknown adhesive, the odd stray paper/cardboard fibres, and probably traces of a few various other things.

Washing with solvents and decanting seems to work to a degree, however on drying it cakes and adheres to its container almost like a paint. It's not the pulverulent powder described in the literature. In suspension with various solvents, fine particles can be seen while agitating, yet a somewhat viscous milky yellow substance rapidly adheres to the sediment upon settling.

Some sources recommend alkaline and acidic solutions (e.g. HCl, H2SO4, H2O2, NaOH, etc.) for removing various impurities. While other sources claim acids and bases like these will react with the desired red phosphorus, creating undesired molecules such as phosphorus pentoxide and ortho-phosphoric acid.

Furthermore if the desired effect is to reduce the organic compounds to a fine black elemental carbon powder, the challenge of separation still remains.

However, in my experience, when mixing with H2SO4, it seems no phosphorus is left in the beaker at the end.

It will apparently crystalize when heated under pressure, so that seemed like a possible solution, but supposedly the black allotrope posseses different properties, is highly unreactive, and can't be converted back to the red allotrope, so might not be viable.

Does anyone have a solution or suggestion for how to purify the red phosphorus? Thanks in advance.


References

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  • $\begingroup$ So in short, you want to extract the red P on match striking pads, using easy-to-obtain chemicals and apparatus. $\endgroup$ – Aniruddha Deb Sep 21 at 12:33
  • $\begingroup$ If it comes down to extracting phosphorus from matchsticks, you can watch this wonderful video by NileRed: youtube.com/watch?v=5ZrfNAHDjWU&t=1s $\endgroup$ – Nilay Ghosh Sep 21 at 12:34
  • $\begingroup$ @AniruddhaDeb I want to purify it; separate it from the organic components, particularly the adhesive. it seems to have a real affinity for the red phosphorous resulting in a cloudy colloid or suspension. it's proving quite difficult to separate the two. $\endgroup$ – voices Sep 21 at 12:50
  • $\begingroup$ @NilayGhosh thank you. i've seen it before. and several others. my results were similar, but i can't seem to separate it from this adhesive goop. $\endgroup$ – voices Sep 21 at 13:00

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