Sciencemadness Discussion Board

interesting experiments with red phosphorus?

LD5050 - 29-4-2017 at 08:21

I just acquired a good amount of red phosphorus and I was wondering if any of you had some ideas on interesting experiments I could do with it. I recently tried converting it into white phosphorus by heating and bending a test tube into a 90 degree angle filling the closed end with a couple grams of r phos. and plugged the other end with glass wool and heated. I recovered very little amounts of white phos. which was cool to mess around with.

Anyone know of higher yielding method of red phos to white phos.?

I was thinking of making some phosphorus tribromide for shits and giggles...

Any ideas would be appreciated!

subskune - 30-4-2017 at 11:25

Hi,
I think you could try to set up a destillation to recover the white phosphorus with higher yield. I've no idea what temp you do need but it will be a lot. Don't forget to cool the condensor with warm water (approx. 50C) to avoid freezing phosphorus in it. I think you know its dangerous... pbr3 is great like pcl3 you can use it for (poly)ester synthesis and halogination in general. Additionally simply burning is a great experiment. You'll recive anhydrous p4o10 which can not only be used to make phosphoric acid but is also an ecellent drying agent. You can for example dry an amide to nitrile.

Magpie - 30-4-2017 at 12:10

Look in prepublication at Pyro's procedure.

JJay - 30-4-2017 at 13:21

I read a post recently saying that it can be used with hydriodic acid to reduce ketones. I'm actually pretty skeptical about that if only because I don't know what the mechanism would be. I also doubt that combination will reduce secondary alcohols in general as is commonly claimed on message boards... I'm pretty sure it will only reduce benzylic and allylic alcohols. So I'd probably try making toluene out of benzyl alcohol, toluene out of benzaldehyde, n-octane out of 2-octanol, and 1-octene out of 1-octen-3-ol.

If it works for all four (unlikely), the rumors on messages boards are true and the mechanism behind HI reduction is not fully understood by the scientific community. I suspect the reduction works for benzyl alcohol and 1-octen-3-ol but not the other compounds.

Do note that some of the reagents required for these experiments are hard to acquire or even illegal to own in many jurisdictions. I think it is legal for an amateur to own them in the U.S. (though probably frowned upon by the authorities) as long as they are not used in the commission of a crime. They are hard to obtain. But if you have phosphorus, maybe you have access to the other reagents?

Melgar - 1-5-2017 at 22:53

Quote: Originally posted by JJay  
Do note that some of the reagents required for these experiments are hard to acquire or even illegal to own in many jurisdictions. I think it is legal for an amateur to own them in the U.S. (though probably frowned upon by the authorities) as long as they are not used in the commission of a crime. They are hard to obtain. But if you have phosphorus, maybe you have access to the other reagents?

Yeah, the laws in the US tend to apply to the seller rather than the buyer, and they usually just require keeping records of transactions, which is typically enough to scare away would-be criminals and keep businesses from engaging in suspicious sales. I work in the precious metals business, and believe me, NO precious metal broker wants the feds scrutinizing their records! I imagine that's true of other businesses as well.

The HI chemistry you were talking about sounds a bit... well, boring. Benzyl alcohol to toluene? At least it'd be easy to find standards! Personally, I think the best thing about phosphorus is the range of chemistry that it gives you easier access to. Feel like trying some organolithium chemistry, or a Grignard reagent? PBr3 + alcohol, then react with lithium/magnesium. Need some TBAB? Bromobutane and ammonia will do the job. Need an acid chloride for a Friedel-Crafts acylation? PCl5 (or PBr3) can do it! Ooh, best one yet: react SO2 and Cl2 in the presence of phosphorus. It's probably the easiest route to thionyl chloride, and also gives phosphoryl chloride in equal molar quantities. They can be separated by distillation. Phosphoryl chloride is plenty useful too.