Glycol, TEA and Glycerine

Discussion in 'B&W: Film, Paper, Chemistry' started by argentic, Aug 8, 2004.

  1. argentic

    argentic Member

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    Hi PAt,

    could you elaborate a bit more on glycerol (glycerine)? This is a ready available substance here in Europe, and AFAIK it's the least toxic of the glycol / TEA family. If it practically works as a non-active developer solvent, it would be an ideal candidate for a very environmentally friendly Phenidon - Vit C developer.

    Gilbert
     
  2. sanking

    sanking Member

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    I tested several developers in propylene glycol, dipropylene glycol and glycerine. The characteristics of the developers were affected very little, if any, by the solution.

    However, glycerine is very viscous and I found this to be something of an inconvenience in use as it made precise measuring more complicated than with the two glycols.

    Sandy
     
  3. Tom Hoskinson

    Tom Hoskinson Member

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    Gilbert, Polyethylene Glycol (PEG) is a good choice for those looking for a low toxicity, environmentally friendly preservative and solvent. The viscosity of PEG is much lower than glycerine. In fact, the material properties of PEG closely resemble those of water.

    "Polyethylene glycol (PEG) is a water-soluble lubricant from petroleum and/or mineral sources. PEG may be used as a binding agent, coating agent, dispersing agent, flavoring adjuvant, and plasticizer. Supplement manufacturers use it as a processing aid in compression enabling the tablets to hold together better. It also protects nutrients in the tablet from air and humidity.

    PEG is approved for use under the 21 CFR 172.820, and 173.340. It can be added to carbonated beverages, citrus fruit, non-nutritive sweeteners, tablets, and vitamin or mineral preparations.

    Synonyms and Brand Names (selected): Carbowax, Lutrol, Alkapoly Peg-200, Jeffox, and Pluracol."


    http://www.wholefoods.com/healthinfo/peg.html
     
  4. gainer

    gainer Subscriber

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    You could keep the glycerine warm. I do that with TEA in winter, as it freezes at about 70 F. I have what we call a brisker oven, used mainly for letting bread dough rise, that keeps a temperature around 100 F. I don't think glycerine is any less toxic than PEG, but it may have the advantage if you use USP glycerine in place of tech grade PEG. You can certainly try a small batch to see if the viscosity will be a problem for you. That would be the only reason for not using it.
     
  5. grommi

    grommi Member

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    Hi, I have to revive this old thread, each time I search for phenidone and diluting it I come across this thread.

    Just tried to diltue 1 gram phenidone in 20 ml glycerine = glycerol. The viscosity is not the major problem but it doesn't dilute completely. I heated it in a mantle bath of boiling water and it diluted after some minutes, but after cooling down to roomtemp some crystals again dropped out.

    Then I added another 20 ml glycerine, so 40 ml total, heated it again as described above, and that's a perfect dilution at roomtemp now. Without heating so strong it won't dilute. The melting point of phenidone is about 120 °C, so I guess it won't do any harm. I thought it might be of interest for others and I guess this "concentrate" will have a long shelf live.

    1 gram phenidone in 40 ml glycerine

    Reinhold

    PS: glycerine is quite untoxic, LD50 is 5 gram/kg, no hazardous goods classification in Germany, classified as "not dangerous for humans", used as additive in food. I got 200 ml for 2 Eur in a drugstore.
     
    Last edited by a moderator: Nov 15, 2014
  6. Gerald C Koch

    Gerald C Koch Member

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    Glycerol is very hygroscopic and therefore contains water. In fact anhydrous glycerol is actually a solid. In this respect it is a poor choice for making water free developers. The best choice is propylene glycol as it is also non-toxic and easier to handle. MEA, DEA, and TEA are all alkaline and should be avoided unless the alkalinity is desired.
     
  7. grommi

    grommi Member

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    Thanks for the additional info, Gerald. Indeed the melting point of glycerine is 18 °C, but it can be bought 99.5 % pure. pH is reported to be 5 - 7, which may be good for stability of the phenidone even if some water should be present. Mine seems to be pretty pure regarding the high viscosity. I want to use it as a stock solution for making Instol/Mytol etc. because phenidone has a poor solubility in water. Propylenglycol is also hygroscopic but has a more conveniant melting point of -68 °C. Propylenglycol would be easier to handle but glycerine is easy to buy here in local drugstores and cheap.
     
  8. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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    I don't know much, but HC-100 has glycerol, thick as syrup and an opened bottle lasts for years. On a pyrocat thread, one person, Terry Christiansen mixes it in glycerin and his developer lasts a while. I wonder how you dissolve chems in such a thick medium?
     
  9. grommi

    grommi Member

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    You need to heat the glycerol, then 1 g phenidone in 40 ml is not a big deal. But I have no clue how HC-110 is made and what it contains.
     
  10. Alan Johnson

    Alan Johnson Subscriber

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    Here the solubility of ascorbic acid in propylene glycol is quoted as 50g/L but in glycerol it is only 10g/L:
    http://en.wikipedia.org/wiki/Ascorbic_acid
    Can you dissolve enough ascorbic acid in glycerol to make a useful concentrate?
     
  11. grommi

    grommi Member

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    No, neither in glycol nor in glycerol. But that's not the question.
     
  12. Alan Johnson

    Alan Johnson Subscriber

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  13. Rudeofus

    Rudeofus Subscriber

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    Mark Overton dissolves 4.2 g Ascorbic Acid in 11.8 ml Glycol ...

    Personally I wouldn't worry too much about the toxicity of your Phenidone solvent. If you work in a dark room, you should be able to handle Diethylene Glycol or Propylene Glycol without hurting yourself or others ...
     
  14. grommi

    grommi Member

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    Propylene glycol is useful, no doubt, and as untoxic as glycerol, but again, this is not the question. I made a double strength Mytol-clone last year and the rest of the stock solution is yellow now after 12 months stored at room temp and still works. So a water based solution is not a major problem, but...... But mixing was not so easy, even now after 12 months I have some phenidone needles in the solution. So I was in search of an easily available solvent for the phenidone. Making a pre-dilution of the phenidone in a proper solvent other than water sounded good for me. Also weighing 0,2 grams is is not easy even with an affordable microscale. Weighing 1 gramm is easier and more precise with that scale and using a syringe for the final measuring is very precise. Maybe prediluting the phenidone in alcohol would be a useful alternative, but I guess the solution will not keep as good as a solution in PG or glycerol. I was in a drugstore some days ago, saw the glycerol and took it. Cheap, no ordering, no shipping coast, immediately availavble. Anyway, now I can make small batches of double strength Mytol stock in a couple of minutes without having to fiddle with with weighing and the proper dilution of the phenidone. That's why I did what I did and thought it could be interesting for someone else.
     
    Last edited by a moderator: Nov 15, 2014
  15. Gerald C Koch

    Gerald C Koch Member

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    HC-110 contains ethylene glycol and diethylene glycol but no glycerol (glycerine) and no water.
     
  16. Rudeofus

    Rudeofus Subscriber

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    Doesn't HC-110 use a mixture of TEA and DEA (or their respective SO2 adducts) as solvent?
     
  17. albada

    albada Member

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    Yes, I discovered that dissolving sodium metaborate in PG (propylene glycol) increases the solubility of ascorbic acid. The mocon concentrate described in that link creates the same image-quality as XTOL, but you need to add the sodium sulfite separately from the concentrate.

    Mark Overton
     
  18. Gerald C Koch

    Gerald C Koch Member

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    The adducts perform the roles of sodium sulfite and potassium bromide present in a conventional developer. Since there is no water present it is difficult to get ionic compounds into solution. The old chemical axiom is "Like dissolves like." in other words organic solvents dissolve organic compounds and water dissolves ionic compounds like potassium bromide. The DEA HBr adduct is a source of bromide ions when the concentrate is diluted with water. The same goes for the DEA sulfite adduct in that it supplies sulfite ions. The MEA and DEA used in the formula adjust the pH of the working strength developer. But they may also provide some solvent action too. As I mentioned in an older post you can get bromide into your glycol & TEA based concentrates by using ammonium bromide. This chemical dissociates into ammonia and hydrogen bromide in contact with any of the ethanolamines. When the solution is warmed the ammonia is driven off leaving the TEA Hbr adduct. So you don't have to forsake bromide in homemade concentrates.
     
  19. Gerald C Koch

    Gerald C Koch Member

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    Borates would seem to violate the like dissolves like but this is due to the borate ion forming a complex with two adjacent OH groups present in some glycols, glycerin and sugars. This explains why catechol loses most of its developing ability when borates are present.