MeshPL - 30-3-2016 at 03:01
So I was thinking if P4O10 can be prepared without burning phosphorus. Obviously phosphoric acid can't be simply dehydrated. But I thought that it
might be theoretically possible to decompose some sodium metaphosphates, the same way SO3 is obtained by decomposing sodium pyrosulfate:
NaS2O7 -temp.-> Na2SO4 + SO3
So here is the potential reaction (assuming sodium trimetaphosphate participates in the reaction):
2Na3P3O9 -temp.-> 2Na3PO4 + P4O10
And here assuming that sodium metaphosphates are best described as "NaPO3" (sice they can be polymeric and cyclic and so on):
6NaPO3 -temp.-> 2Na3PO4 + P4O10
I've looked at enthlapies of formation (of sodium phosphate, trimetaphosphate and phosphorus pentoxide) and found the reaction potentially exothermic
(around -2176kJ per mole of Na3P3O9). I couldn't find entropies, so I can't calculate potential free entropy or reaction constant.
Obviously, Na3P3O9 is easily obtained by heating NaH2PO4, which can be bought or made from NaOH and H3PO4.
Do you think such reaction is possible?
[Edited on 30-3-2016 by MeshPL]
[Edited on 30-3-2016 by MeshPL]