Ferric Ammonium EDTA, can I make it?

Discussion in 'Color: Film, Paper, and Chemistry' started by narigas2006, May 15, 2007.

  1. narigas2006

    narigas2006 Member

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    Hi all,

    I have EDTA (Ethylenediaminetetraacetic acid disodium salt), heaps;

    I have Ammonium Ferric Sulfate

    Can't I make Ammonium Ferric EDTA out of it? Many thanks!
     
  2. Photo Engineer

    Photo Engineer Subscriber

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    It is very difficult to remove the sodium.

    To make it you must start with the free acid of EDTA and add ammonia then add the iron salt, but then you end up with the negative ion associated with the iron and etc.

    It is made commercially from Ferric Oxide powder, Ammonia gas, water and EDTA in a high pressure and high temperature vessel.

    PE
     
  3. nworth

    nworth Subscriber

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    If the pH is correct and the concentration of ammonium ion, iron 3, and EDTA is correct in the final solution, why is it important to remove the sodium?
     
  4. Photo Engineer

    Photo Engineer Subscriber

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    The effectiveness of Ammonium Ferric EDTA is diminished in both bleach and blix baths by the presence of sodium Ion.

    In any event, the question was about making the ammonium salt, not the sodium salt which is what would form otherwise. You would get Disodium ammonium Ferric EDTA AAMOF, which is not very active compared to the ammonium salt sold as an ~60% solution.

    That particular method, adding disodium EDTA to Ferric Ammonium Chloride or Sulfate was how I made the first blix for Kodak. We improved it mainly through elimination of sodium.

    PE
     
  5. ahock

    ahock Member

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    PE, Is that possible to substitute Ferric Ammonium EDTA with {Ethylenediaminetetraacetic acid diammonium copper} or {Ethylenediaminetetraacetic acid diammonium salt} for use in C41 bleach action? I can get this from fluka.

    Thanks! :smile:
     
  6. Photo Engineer

    Photo Engineer Subscriber

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    The copper probably will not work. The Ammonium EDTA + Ferric Chloride in proper molar ratios + 10% excess of Ammonium EDTA will make a pretty good bleach when adjusted to pH 6.5. This is what I used initially before the startup of the EK plant making Ferric Ammonium EDTA directly.

    1 mole of Ferric Chloride + 1.1 moles of Ammonium EDTA should do the job. Adjust pH with Acetic Acit 28% and Ammonium Hydroxide solution as needed.

    PE
     
  7. bhamartist

    bhamartist Member

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    I actually have some Ferric Ammonium EDTA as part of a two part bleach-fix for a commercial dip and dunk machine, but what could it be used for by itself? How would it react to B&W films/papers?


     
  8. A_Caver

    A_Caver Member

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    I have been trying to make Ferric Ammonium EDTA by following US Patent 3767689.
    https://www.google.com/patents/US3767689
    I have tried the 1st example as follows:

    To a slurry of 512 grams (1.75 moles) of ethylenediaminetetraacetic acid in 430 ml of water at 190°F there was added 103 ml (1.5) of 28% aqueous ammonia. While continually agitating, 125.3 grams (0.54 mole) of iron oxide (Fe3O4) was added in increments over a period of 2 to 5 minutes while maintaining the temperature at or near the boiling point. After an additional 2 to 5 minutes of heating and stirring, the mixture was cooled to about 160°F and then 172 ml (2.5 moles) of 28% aqueous ammonia was added, with the result that the solution became clear and intense dark red color. The solution had a pH of 7.1 at 80°F.

    I still seem to be getting a brown stain on the film. Any help would be appreciated
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    There is a need for extra EDTA as described in other patents.

    PE