[HB]

I have trisodium phosphate dodecahydrate and I want to obtain anhydrous sod. phosphate. can I simply dry it in the oven

[Archer]

I have trisodium phosphate dodecahydrate and I want to obtain anhydrous sod. phosphate. can I simply dry it in the oven

I have no experience of this but I have had success with drying other hydrates in the oven.

You could try a 110°C oven for a few hours with a small (accurately weighed) quantity until you obtain a constant weight and then calculate the loss and see if it equals the correct weight of water as calculated from the mols of water present in the hydrate.

[Hunter2]

To get real anhydrous products, treat them with Thionyl chloride SOCl₂. The Water will be decomposed to HCl and SO₂. I t need a good hood with exhaust.

[Borek]

Just drying doesn't guarantee getting anhydrous salt, it is a matter of how strongly water molecules are kept by ions in the salt. Check if you will be able to find the thermogravimetric curve for the salt in question, it should tell you if and at what temperature phosphate becomes anhydrous.

[Hunter2]

Phosphates also have the risk to built up Polyphosphates.