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  1. #1
    Ian Grant's Avatar
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    Modern Rodinal Substitutes Part II

    Apologies for having to start a new thread but I can't read or even access the first to reply to posts.

    So with a bit of telepathy

    Quote Originally Posted by Kirk Keyes View Post
    Well, there's a problem there, as it's really hard to measure pH accurately when it gets much above 12.5 or so. You have to start getting special electrodes and the like.

    But for MSDS work, it doesn't have to be too precise.
    __________________
    Kirk

    A point that's being missed is that A&O give a figure of 2.7% Potassium Hydroxide not 3% in older Agfa MSDS.

    The pH is around 14 sure, but the actual requirement is the pH of the working dilute solution rather than the concentrate which is given elsewhere as pH 11.55, which I commented on in the first post of the thread.

    Way back Ron (PE) mentioned adjustments to Rodinal before bottling, the question we need to ask is are they adjusting on the basis of the concentrate, or also doing some tests on a dilute sample, as this will be a far more accurate indicator.

    Can someone please post a link to this continuation on the original post.

    Ian

  2. #301
    Ian Grant's Avatar
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    Quote Originally Posted by Photo Engineer View Post
    Ian;

    It is well known that Benzene sulfonates help PPDs dissolve! In fact, a close analog, pTosyl (para Toluene Sulfonic Acid) is used for all CD3 developers and CD6 developers today.

    PE
    OK, earlier post #287 you had almost no knowledge of Benzene sulphonates

    Now it's well known That's irrelevant, these are marginal chemical combinations in most uses. . . . . . . . .

    What's important is that something else happens between PPD and Benzenesulphonates, it isn't just about helping PPD to dissolve, it's preventing oxidation as well.

    The same inter-reaction is taking place with p-Aminophenol preventing or rather holding back oxidation.

    There's an equilibrium complex involved, my extremely rusty Organic chmistry is returning, my Biochemistry was my strong point

    Ian

  3. #302
    Photo Engineer's Avatar
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    Ian;

    I know nothing about benzene sulfonate itself as an antioxidant.

    As for the properties of benzene sulfonates or p-tosylates as antioxidants or as helpers in dissolving, it is known from fundamental chemistry that organic aryl amines (metol, pAP, and PPDs) all oxidize rapidly as free bases and dissolve slowly as free bases. If they are predissolved in an equmolar solution of ANY acid, then they dissolve much more rapidly in water and they are much more resistant to aerial oxidation

    The key to this is pH though and not antioxidant properties of the benzene sulfonate or p-tosylate. Sulfuric acid was used and before that Hydrochloric Acid was used. Nowdays the develoer is dissolved in the sulfonate solution and this has been saturated with SO2 gas. The SO2 gas is the true antioxidant as is the pH an assist in achieving this effect.

    This is true of all Kodak, Fuji and other color developer kits for C-41 and E6 alike.

    We were in the process of converting when I was working on the CD-6 problem and I had to convert all of my molarity tables due to the difference in molecular weight of the two salts, the H2SO4 salt and the p-Tosyl salt. I used to get the developers in powder or crystal form and had to dissolve them in water with Sulfite. Remember the "pinch of sulfite" rule in making Metol containing developers?

    And, these p-Tosyl salts are major chemical contributioins.

    BTW, benzene sulfonic acid is (C6H5)-SO3H and p-Toluene Sulfonic Acid is CH3-(C6H4)-SO3H, differing by CH2 only and it is expressed as a CH3- replacing one H-. They are virtually identical. But, benzene and napthalene sulfonates as sodium salts, especially with ballast groups are better known as detergents.

    PE

  4. #303

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    Quote Originally Posted by Photo Engineer View Post
    Grant;

    AFAIK, Benzenesulfinian is Benzene sulfinic not sulfonic which would be -sulfonian or somehing like tht. Polish speakers please verify my very rusty translating efforts of organic chemistry.

    An afterthought: We might ask pavel if he can verify that his Russian translation is benzene sulfonic..... That might also be questioned in view of my notes on Sulfinic acids.

    PE
    Gentlemen,

    Really - I made with mistake with transliteration: the chemical stated in the book and the one I used is Sodium Benzenesufinate. And I assume the polish literation is the same.
    I tried to look for different sources about sulfonate and sulfinate, and it seems that both of them can be used as ani-oxidants. There is not much info unfortunately.

  5. #304

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    Quote Originally Posted by pavelt2tk0 View Post
    Gentlemen,

    Really - I made with mistake with transliteration: the chemical stated in the book and the one I used is Sodium Benzenesufinate. And I assume the polish literation is the same.
    I tried to look for different sources about sulfonate and sulfinate, and it seems that both of them can be used as ani-oxidants. There is not much info unfortunately.
    Thanks for the confirmation, Pavel.

  6. #305
    Ian Grant's Avatar
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    There's huge issues of translations here, what we, Pavel etc are reading today is based on whether translation was made correctly in the late 1940's early 50's.

    I'm not 100% on one anti-oxidant yet, and will keep looking for more contemporary (1930's information hopefully from Agfa sources.

    Ian

  7. #306
    Photo Engineer's Avatar
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    Go here to see the spelling of benzene sulfinic acid in czech.

    http://environmentalchemistry.com/yo...dihydrate.html

    There is more doubt growing in my mind about this. Sulfinic acids and Sulfonic acids are distinct in Polish, Czech and all other languages I have researched.

    One is -SO2H and the other is SO3H, and they differ in activity much as sulfite and sulfate do, thus explaining the antioxidant properties claimed for the Sulfinates in literature.

    PE

  8. #307

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    Quote Originally Posted by Photo Engineer View Post
    Go here to see the spelling of benzene sulfinic acid in czech.

    http://environmentalchemistry.com/yo...dihydrate.html

    There is more doubt growing in my mind about this. Sulfinic acids and Sulfonic acids are distinct in Polish, Czech and all other languages I have researched.

    One is -SO2H and the other is SO3H, and they differ in activity much as sulfite and sulfate do, thus explaining the antioxidant properties claimed for the Sulfinates in literature.

    PE
    Just to put things side by side,

    Benzensulfinan sodny =
    Benzenesulfinic acid, sodium salt, dihydrate
    CAS: 25932-11-0

    and

    Benzensulfonan sodnı =
    Benzenesulfonic acid sodium salt
    CAS: 515-42-4

    Notes:
    1.
    On the Czech words for sodium given here, an accent mark is found on only one of the two, but this is possibly an error IDK.

    (Sometimes non-speakers leave off such marks when they don't know how to make them.)

    2.
    Ian mentioned Polish... are Czech and Polish the same here?

    3.
    There are still a few outstanding points;

    a. Kirks q. about Benzyl Alcohol
    b. My q. about AO activity in general
    c. Ian's q. about sulphonate functioning as an AO and
    it's infrequent mention as an AO and its more common mention in
    association with photothermography.
    Last edited by Ray Rogers; 10-06-2009 at 06:53 PM. Click to view previous post history.

  9. #308
    Photo Engineer's Avatar
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    Well, I missed Kirk's comment about Benzyl Alcohol. Help me.

    As for the names, in Czech translations they seem to use Natrium derivitives for Sodium but Polish seems to use Sodowi or sodny. So, you make up your own mind. The constant seems to be Sulfinic and Sulfonic.

    PE

  10. #309

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    Quote Originally Posted by Kirk Keyes View Post
    Didn't benzyl alcohol serve this porpose as well - as a cosolvent?
    This one.

    In response to post #300:

    Originally Posted by Photo Engineer
    It is well known that Benzene sulfonates help PPDs dissolve! In fact, a close analog, pTosyl (para Toluene Sulfonic Acid) is used for all CD3 developers and CD6 developers today.

  11. #310
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    Benzyl Alcohol was only used in color developers. It assisted in transition of the oxidized color developer into the coupler solvent and it increased dye yield by this. It has not relationship to the present discussion in any way.

    PE



 

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