[sachabinky]

Could a substitution Reaction with Potassium Chloride and Sodium Pyrophosphate work to Produce Potassium pyrophosphate?
- or is it best made up from Potassium Phosphate, then heating?

I see there is a process described for the fomation of Tin Pyrophosphate from the aforementioned Sodium Compound, using Stannous Chloride in solution, as a substitution reaction.

[chenbeier]

If you do so you will not get a clean product. It will be a mixture of potassium and sodium pyrophosphates and chlorides.
Better is the heating process, but I think you have to use potassium dihydrogen phosphate.

[sachabinky]

Thank you very much.

[Babcock_Hall]

You should be able to put an ion-exchange column such as Dowex-50 into the potassium form and put sodium pyrophosphate onto this column.  Sodium ions will displace potassium ions.  The exchanger would have to be present in large excess.

[Babcock_Hall]

To follow up on my previous comment, one needs a large excess, typically at least 20-fold in terms of equivalents, of exchange capacity in the ion-exchanger, in order for this to work.