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    Ok guys, I've been doing a practical in chemistry, the oxidation of alcohols to aldehydes with TEMPO.

    Basically, I've done the practical but got a question:

    The product is washed to remove the TEMPO as follows:

    1. Dilute HCl containing potassium iodide is added (30cm3)
    2. 10% Sodium Thiosulphate Added (20cm3)
    3. Dilute HCl containing potassium iodide is added (30cm3)
    4. 10% Sodium Thiosulphate Added (20cm3)
    5. Brine (Saturated Sodium Chloride solution) added (20cm3)

    How do the series of washing steps remove TEMPO from the mixture?
    What is the purpose of the brine washing step?
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    Any help anyone could give would be much appreciated
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    These are in a seperating funnel? What's the solvent?
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    plus i'll give rep
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    (Original post by ChemistBoy)
    These are in a seperating funnel? What's the solvent?
    dichloromethane
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    (Original post by ChemistBoy)
    These are in a seperating funnel? What's the solvent?
    and yes, they're in a separating funnel, sorry
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    Bearing in mind that I am not an organic chemist I'd say that as KI is a well known radical scavanger it will quench the TEMPO and produce iodine. Then you need the thiosulphate to get rid of the iodine. You do it twice to be sure. The brine wash is just to remove all the polar components (salts + quenched TEMPO) whilst effectively keeping the aldehyde in the DCM. Sorry I can't be more specific but it has been almost a decade since I did this stuff.
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    (Original post by ChemistBoy)
    Bearing in mind that I am not an organic chemist I'd say that as KI is a well known radical scavanger it will quench the TEMPO and produce iodine. Then you need the thiosulphate to get rid of the iodine. You do it twice to be sure. The brine wash is just to remove all the polar components (salts + quenched TEMPO) whilst effectively keeping the aldehyde in the DCM. Sorry I can't be more specific but it has been almost a decade since I did this stuff.

    ok thats great, thank you so much
 
 
 
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