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Reduction of benzophenone

  1. Mar 3, 2010 #1
    Why do you have to add sodium borohydride slowly to reduce benzophenone to benzhydrol? And why do we have to place the reaction in iced water?
     
  2. jcsd
  3. Mar 4, 2010 #2

    Char. Limit

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    Because you need to control the amount of heat released in the reaction. You don't want the whole thing to explode... or maybe you do. That might be a fun thing to try.
     
  4. Mar 4, 2010 #3
    After we got the solid from the reaction of benzophenone with sodium borohydride, then we dissolved the solid in a minimum amount of hot methanol. Why do we add the same amount of water to get the resulting solution to a cloudy point?
     
  5. Mar 4, 2010 #4

    Char. Limit

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    The methanol, I assume, would isolate the (former) benzophenone, and water is needed to complete the reaction. (any acidic substance with a pKa than can protonate a diphenylmethoxide ion, really) Since diphenylmethanol has a solubility of just 0.5 g/L at room temperature, the cloudy stuff is probably that.
     
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