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  1. #1
    Athiril's Avatar
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    p-aminophenol (paracetamol questions)

    Okay,

    So once I've filtered my paracetamol, if I want to store the powder/solid form, am I better off storing the paracetamol before adding sodium hydroxide to convert to 4-aminophenol?

    Or am I better off boiling off the liquid after adding sodium-hydroxide?


    Also since I use methylated spirits and coffee filters to filter my tablets, will it reduce the amount of (or add anything harmful concerning developing) paracetamol (pre-sodium hydroxide) or 4-aminophenol (post-sodium hydroxide) if I burn the methylated spirits off?

  2. #2
    Murray Kelly's Avatar
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    Since paracetamol is 7 times more soluble in alcohol you could just filter and let it evaporate in the open air.
    The binder/filler of the tablets appears to be water soluble, mostly, and those making their own PaRodinal find in practice it doesn't hurt.
    I must add, the manufacturers vary the stuff binding the tablets so your mileage may vary on that point. Try it and see. It's cheap enough.
    Murray

  3. #3

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    I have some paracetamol and sodium hydroxide mixture in solution in a full sealed bottle which is now 11 months old.I never got round to using it.I just tried it and it developed a film leader.Unless the dry powder is particularly wanted it appears to keep in solution in a full sealed bottle.

  4. #4
    sun of sand's Avatar
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    Been 8 months and a week since I made paracetamol last. No filtering. Ground to a fine powder is all. Made the same and stored the same but turned dark very quickly and crystallzied quite a bit first attempt.
    Currently this 2nd batch is nowhere near as dark -more of a light maple syrup- and no crystals.
    Stored in tiny screw cap medicine bottles and this time a couple tiny glass bottles as well.
    Glass bottles you can see some cloudiness at the bottom but that's it.

    Did a little undiluted test on film leader and unopened plastic parodinal was nearly as good as the glass parodinal -doubt it matters
    but the glass parodinal IS noticably less oxidized
    plastic contained parodinal turned the stronger inky jet black into a bit warmer charcoal black

    Parodinal in half full plastic bottle only managed a dark brown


    After trying parodinal bought myself real rodinal and use this homemade for lith film

  5. #5
    Des
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    I made some Parodinal (100 ml) using the formula pro-rata. After 4 days I have a 100ml brown glass bottle at least 1/3 full of crystals! Is this too much. Should I reduce the Sodium Hydroxide?
    Thanks

  6. #6

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    The Parodinal formula calls for 200g/L sodium sulfite anhydrous but the solubility of sodium sulfite heptahydrate (.7H2O) is only 266 g/L which by my calculation corresponds to 143 g/L sodium sulfite anhydrous.So the crystals are probably just sodium sulfite heptahydrate,ie,harmless.
    Even so, IDK how they came to be 1/3 bottle full,there is usually just some at the bottom of the bottle.

  7. #7
    Des
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    Thanks for the reply Alan.
    There is definately at least 1/3rd of a bottle of crystals. I was wondering if, as I read in another post, the original formula uses too-much sodium hydroxide. I seem to recall the comment that 4.0g would have been sufficient and not the 20.0g in the formula.

  8. #8

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    100ml should only use 20g sodium sulfite, 8g sodium hydroxide.The hydroxide is very soluble, at this concentration it would not form crystals.
    Are you sure these amounts were used to start? Manufacture of vintage Parodinal is a fine art.

  9. #9

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    Hello.
    Some months ago i cook 250ml parodinal. I use a digitaltruth recept. There were a lot of crystals.
    3 weeks ago i added 250 ml water. Now there are no crystals and it work fine. in the begining i reduce it 1:40, now i use 1:20.
    The only thing i am afraid of is the durability of the solution.
    I'm not filtering it.



 

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