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    For my individual A2 coursework investigation I am looking at the rate of reaction for the reaction between iodine and propanone. To get good marks my teacher has told us that we have to go beyond our usual knowledge. I am looking at how the reaction is affected by catalysts, starting with hydrochloric acid and then sulfuric acid.

    My teacher has said that it would be good for my marks if I could find a catalyst that wasnt an acid. Does anyone have any ideas as to what substance I could use? Cheers (The reaction is catalysed by the presence of the H+ ions)
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    A base...?

    (Hint: iodoform?)
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    true, but you could get multi-iodination in the presence of a base, though this effect is smaller than if it is a alpha bromo ketone(Br more electronegative).

    edit: my bad, you are supposed to get multi-iodination in iodoform.
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    Never heard of iodoform, or multi-iodination. Can someone fill me in please?


    Would this chemical effect my results, I forgot to mention I am using colorimetry :'(
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    (Original post by dhunt18)
    Never heard of iodoform, or multi-iodination. Can someone fill me in please?


    Would this chemical effect my results, I forgot to mention I am using colorimetry :'(
    What we are talking about is the mechanism of the reaction. ie iodoform is a form of multi-iodination. This is to do with carbonyl chemistry, enolate specifically. ie in acid, you get an enol, but in base you get an enolate. enolate is an ion, enol is a tautomerised form for ketone.

    Keyword to look up in wiki: iodoform, tautomerism, enol/enolate

    But you probably won't need much of this, as you are interested in the kinetics of the reaction(ie rate), but if you understand the mechanism, it will help(in some way) to determine whether your rate eqn is proportional to the individual reactants.
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    I wont need much of the substance or much of the things you told me to look up? My bad :'(. Thanks for the info. 'n' all but I was hoping for a clear answer, my teacher wouldn't even help me out. Ohh and I need to find something before friday
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    (Original post by dhunt18)
    I wont need much of the substance or much of the things you told me to look up? My bad :'(. Thanks for the info. 'n' all but I was hoping for a clear answer, my teacher wouldn't even help me out. Ohh and I need to find something before friday
    might be faster if you just read up on this in wiki if you have time.
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    Ok, I read that up and tbh it didn't help me alot, I understand what you're trying to tell me but I just don't have an extensive knowledge of chemicals, this is why I am asking for help on a specific chemical that I should use.
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    Could you use a catalyst that would enable you to prove the requirement of H+ ions?
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    A lewis acid could catalyse the reaction like an acid. ie AlCl3 is used in friedel crafts alkylation/acylation and it is as a catalyst. If you use something similar, as the Al has vacant p orbital, then lone pair on the oxygen of carbonyl can bind to it, prompting further reaction.
 
 
 
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