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  1. #41

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    Quote Originally Posted by Tom Hoskinson
    Yes, IMO it should be possible to put everything together in a single solution.

    I was just taking it one step at a time, to see if an Amidol concentrate was feasible at all.

    The obvious next step is to try combining everything into a single solution. I got a bit side tracked in this by investigating the amidol debris residue.

    Well, I tried adding all of the chemicals to the glycoal at 250ºF at once, but the result was not satisfactory. Everything appeared to go into solution ok except the sodium sulfite, and it would not go intio solution even after raising the temperature of the solution to over 300ºF.

    If it is possible to mix all of the chemicals in one solution the order of mixing would appear to be important.

    Sandy

  2. #42
    Alex Hawley's Avatar
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    Tom, thank you for doing this research. What would be your recomendation for mixing without having a chemical hood nor a magnetic stirrer?
    Semper Fi & God Bless America
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  3. #43

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    Quote Originally Posted by sanking
    Well, I tried adding all of the chemicals to the glycoal at 250ºF at once, but the result was not satisfactory. Everything appeared to go into solution ok except the sodium sulfite, and it would not go intio solution even after raising the temperature of the solution to over 300ºF.

    If it is possible to mix all of the chemicals in one solution the order of mixing would appear to be important.

    Sandy
    Looking over my notes, I see that back in June I was exploring percentage solutions as part of looking at the MS Amidol formulation.

    "...prepared percentage solutions of KBr, sodium sulfite, sodium metabisulfite and citric acid in propylene glycol. KBr dissolves in Propylene Glycol around 230F. Sulfite (and metabisulfite) dissolve around 250F. Citric acid dissolves around 235F..."

    I apparently abandoned the effort because I was concerned that the high mixing temperatures might adversely affect the Amidol (based on anecdotal information).

    Now, I have experimental data that shows Amidol/PG can indeed survive high mixing temperatures (at least 260 F) with no apparent damage.

    I'll head over to the lab and see if any of these percentage solutions still exist (and what the percentage is).

    In any case, I can attempt to dissolve the chemicals in the following sequence:

    Propylene Glycol at 260 deg F 200 ml
    Sodium Sulfite 30 grams
    Citric Acid 3 grams
    KBr 0.2 grams
    Amidol 8 grams

    I'll post the results.
    Tom Hoskinson
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  4. #44

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    I tried dissolving 30 grams of sodium sulfite in 200ml of hot PG. Bottom line, sulfite is only slightly soluble in PG. I got maybe half of it or a little less into solution and I ended up at 340 deg. F. The solution started changing color around 320 F - it turned a dirty amber color. I dumped it and tried again.

    On the second try, I dissolved 3 grams of Citric acid and 0.2 grams of KBr in 100ml of hot PG (it dissolved around 160 F). I kept heating the solution (with continuous stirring) and when the solution temperature reached 260 F I slowly added 8 grams of sulfite - but only about half of it dissolved. I dumped that, as well.

    On my third attempt, I dissolved 3 grams of Citric acid and 0.2 grams of KBr in 100ml of hot (160F) PG, then added another 130ml of PG to the mix and when the solution temperature reached 160 F again, I slowly added 8 grams of Amidol. By the time the solution reached 190 F, most of the Amidol had dissolved. I continued heating and stirring until the solution reached 260 F. At that point a little Amidol debris remained.

    I will add the sulfite when I mix the working developer.
    Tom Hoskinson
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  5. #45

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    Quote Originally Posted by Alex Hawley
    Tom, thank you for doing this research. What would be your recomendation for mixing without having a chemical hood nor a magnetic stirrer?
    Alex, I would probably emulate Pat Gainer and heat the PG with a microwave oven (in a Pyrex beaker or measuring cup). A mixing or stirring paddle should work ok. I would choose a well ventilated, but not breezy place to do the mixing - and high humidity to keep the dust down. Then I would put on a respirator mask and my Nitrile gloves, measure and stir in the Amidol. Once the Amidol is in solution, the inhalation hazard is mostly mitigated. However, you still need to keep the solution away from exposed skin and eyes.

    For cleaning trays and utensils use diswashing detergent (that will oxidize the amidol) and plenty of water to dilute, oxidize and get rid of the amidol its oxidation products (which will stain).
    Tom Hoskinson
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  6. #46
    Alex Hawley's Avatar
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    Thanks Tom. Sounds like it should work.
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