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    When PCl5 is added to an alcohol will the reaction be more vigorous with
    a) Methanol
    b) ethanol
    why?

    Secondly, would the PCl5 test work on carboxyllic acids. Also would the sodium test work on acids?

    thanks
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    (Original post by jsmith6131)
    When PCl5 is added to an alcohol will the reaction be more vigorous with
    a) Methanol
    b) ethanol
    why?

    Secondly, would the PCl5 test work on carboxyllic acids. Also would the sodium test work on acids?

    thanks
    PCl5 with alcohol is a chlorination process. So, essentially you are introducing Cl anion to a delta positive C. The more delta positive the C is(primary>secondary>tertiary), the more favourable it is for Cl- to attack at that position(at the intermediate stage).

    yes Na would even react with alcohol to fizz off H2 just like water + metal rxn.
    So, here, it'd simply be acid(organic) + metal rxn.

    PCl5 would also react with RCO2H to form acyl chloride, ROCl. Again driving force here is the formation of strong P=O bond at some stage.
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    which would react faster though, methanol or ethanol, with PCl5
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    (Original post by jsmith6131)
    which would react faster though, methanol or ethanol, with PCl5
    i do know that was your original question, but hey i have told you the arguments, so you have to decide based on this knowledge. come on!
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    oh so its methanol
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    (Original post by jsmith6131)
    oh so its methanol
    this is a sn2 like reaction, so i was wrong in my arguments just now, my aplogies.

    yes, methanol should react faster than ethanol simply because of the less sterically crowded 5-coordinate transition state.
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    is this a simpler way of putting it: smaller carbon chain, greater proportion of molecule is OH group so greater proportion of molecule reacts with PCl5
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    (Original post by RCB)
    is this a simpler way of putting it: smaller carbon chain, greater proportion of molecule is OH group so greater proportion of molecule reacts with PCl5
    i disagree. how small would you say small then? 1,2 carbons? 4,5 carbons? greater proportion? how great?

    an ambiguous case of neo-pentyl halide doesn't undergo either sn1 or sn2 under normal conditions despite it having a primary centre.
 
 
 
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