shivam
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Chlorination of colloidal Phosphorus - PCl5??
Hey guys!
So, here's an idea that I've been pondering on..
I badly need a chlorinating agent for a reaction..
PCl3, PCl5, SOCl2 are very expensive
So i am thinking about bubbling chlorine through colloidal red phosphorus in a solvent. I guess it should form PCl5
Then filtering and crystallizing PCl5 from the solution under inert atmosphere of CO2
I broke my whole distillation setup in a mishap and still haven't purchased a new one.
So this seems like a legitimate way to go, while keeping in mind to minimize the Air exposure throughout the procedure, of course..
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woelen
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Colloidal red phosphorus? I think this is very hard to obtain. Red phosphorus does not dissolve in any solvent (at least not with destructively
reacting with it). The only thing I can imagine is that you take very finely powdered and perfectly dry red P and add this to a solvent and use a
stirring bar. Then you have to bubble Cl2 into the liquid very slowly, with small bubbles. Best would be to have a solvent in which PCl5 dissolves
well, but PCl3 also must dissolve well in that solvent. First you'll get PCl3 and as long as there is red P, PCl5 will react with it to get PCl3.
If you just want a chlorinator, then it does not matter whether you have PCl3 or PCl5. In that case you can continue your process until all red P is
gone. You then most likely have a mix of mainly PCl3 with some PCl5, dissolved in your solvent.
I am not sure about the solvent to use. CHCl3 or CH2Cl2 probably will do the job.
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mario840
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I did this reaction, just make suspension red P in chloroform with magnetic stirrer , bubling Cl2 gas into this but dry chlorine first and the end of
hose must be wide to not clogged with forming PCI5, chloroform will be very hot so make sure you have some reflux condenser and good cold water bath,
but no to cold, I realized that the reaction need some heat to much faster occurred so the 40 cm reflux condenser with cold water should work fine.
Make sure you have good "chlorine generator" it take some time to red goes into slightly yellow PCl5 , no inert atmosphere need , just at the end,
filter , wash with fresh chloroform and pack good and tight, "fuming" PCl5 work the best
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shivam
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mario840, so if I'm right, it seems from your experiment is that chloroform is a suitable solvent/medium for this as it does not dissolve PCl5
So I should expect a yellowish white suspension/slurry of PCl5 when excess chlorine is used.
Also, I'm ruling out the idea of using Dichloromethane (in spite of being easily available here) as the medium considering the big temperature rise
I think even with a good and efficient refluxing setup, much dichloromethane must be lost because of it's very low boiling point.
Just for some reference, did you calculate the yield obtained on red Phosphorous?
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mario840
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just use chloroform, cheap as water and don't dissolve PCl5 you will clearly see when red turns into white/yellow mass, yield will be very good i
don't calculate it but i "transform" 100g red P into i don't won't to lie but at least 400 g PCl5 , now i have access to everything so thionyl
chloride is more convenient for me even sulfuryl chloride, chlorinating with Pcl5 make a little "mess" byproducts, phosphoric acid and many others.
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