Sciencemadness Discussion Board

Recycling Phosphorus Pentoxide

DFliyerz - 15-3-2015 at 09:04

Phosphorus pentoxide is a very useful dehydrating agent, but also fairly hard to get. When it's used, it turns into phosphoric acid, which is sort of useless. Is there any way to recycle the phosphoric acid back into phosphorus pentoxide or a lower oxide of phosphorus?

Boffis - 15-3-2015 at 09:16

No. At least not home-chemist friendly routes.

DFliyerz - 15-3-2015 at 10:03

Quote: Originally posted by Boffis  
No. At least not home-chemist friendly routes.


Out of purely scientific interest, what are the non home-chemist friendly routes?

BromicAcid - 15-3-2015 at 12:10

If you heat the snot out of it you can work your way back to metaphosphoric acid which is a good dehydrating agent in its own right:

http://www.sciencemadness.org/talk/viewthread.php?tid=4409

Otherwise you have to reduce it back to phosphorus and then oxidize it again.

zed - 20-3-2015 at 14:19

Seems to me, you can dehydrate phosphoric acid to PPA via microwave oven and vacuum. I don't know if you can achieve Phosphorus Pentoxide status however.