Convert PDTA ferric sodium salt to ammonium salt, is it possible?

[lamerko]

regarding this i did the following: i bought a bag of sodium ferric EDTA and also a bag of PDTA, parentheses here the bag of DTPA is Sodium hydrogen ferric DTPA but lets start with the EDTA. i prepared a saturated solution of sodium ferric EDTA (100-110gr/L) to this i added 15gr of ammonium chloride and ammonia little by little until a pH of 5.8, it seems that by stoichiometry this makes EDTA ferric ammonium salt, but i am a newbie at this so any help is accepted. ah this solution i only added 80gr of ammonium bromide. i developed an E6 film using the formulas i am familiar with and used this bleach that i prepared. I am attaching a photo of the result:

This looks pretty interesting. Are you using any accelerators?

 

[Rudeofus]

@Josaw98 if you mix Sodium Ferric EDTA and Ammonium Chloride in water, then you get Sodium, Ammonium, Ferric, EDTA and Chloride ions all in solution. There is no exchange taking place, just a mix. Since you add Ammonium Bromide anyway, the addition of Ammonium Chloride is mostly pointless.

Regarding the red color: my typical Ammonium Ferric PDTA bleach is pale green, and as soon as I use it, it turns red. Once I mixed such a bleach with Potassium Bromide instead of Ammonium Bromide, and the soup started red colored from the onset - and worked well. I have no explanation for the different color between pure ammonium cation and mix of ammonium and potassium cation, but somehow the color changes.

Regarding Copper Sulfate: once you mix these into water, the hydration state of that salt should be completely irrelevant. I have no explanation for this demand of "white anhydrous Copper Sulfate". While I am not a chemical engineer, many of the older authors weren't either, so their texts sometimes contain strange claims. If you want to make sure, that no copper residue stays on your film, make sure, that your bleach stays acidic. Warning: most bleaches raise their pH when they are put to work, so do check pH when you reuse this soup.