1. PF Contest - Win "Conquering the Physics GRE" book! Click Here to Enter
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Certain elimination reaction

  1. Apr 18, 2006 #1
    hey i wanted help on understanding a particular reaction
    we have a compound
    1(4-Nitrophenyl)-1-phenylpropan-2-ol and its reaction with concentrated sulphuric acid at the suitable temperature.
    Actually our teacher said that it would form 1(4-Nitrophenyl)-1-phenylprop-1-ene after the elimination reaction but i was wondering that since NO2 is a strong deactivating -R group so it will not let the carbocation get stabilised at that position.
    Am i thinking right that one of the resonating structures of the product so formed would lead to great destabilisation and increase in total energy content?
    this is contradictory as this would give the compound with formula 3(4-Nitrophenyl)-3-phenylprop-1-ene
    Could anybody give me the explaination for the product?

    Thanks anyway
  2. jcsd
  3. Apr 19, 2006 #2


    User Avatar
    Homework Helper
    Gold Member

    • The resonance stability increases with the increased number of contributing structures
    • Whether a single hypothetical contributing structure will contribute significantly to resonance will depend on it's relative stability.
    So, I think that while the N02 group will not stabilise the carbocation at that position, the other resonance structures (due to the phenyl group) will indeed stabilise the carbocation and thus form 1(4-Nitrophenyl)-1-phenylpropan-2-ol.
  4. Apr 19, 2006 #3
    yes i know that the phenyl does contribute to the stability with its resonating structures but isnt there a great rise in the energy of the compound and instability if there is any resonating structure which is destabilising and in this case it is a Strong -R group ( NO2)
    anybody has any references to any sites which tells how resonance energy varies with such factors? i ll be grateful if somebody could provide me such a link:smile:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook