The Naked Scientists

The Naked Scientists Forum

Author Topic: carbocation stability, directing abilities, benzene acidity questions  (Read 9010 times)

Offline 113zami

  • Jr. Member
  • **
  • Posts: 11
    • View Profile
Can someone PLEASE help me with the following questions, these are not in my text book ( I have the 4th edition by L.G. Wade) and I searched online but didn't find any convincing ansewrs so I am really lost, PLEASE help, thanks alot

newbielink:http://i274.photobucket.com/albums/jj243/113zami/orgodd0002.jpg [nonactive]
1) is this group meta or ortho/para directing, and if it's ortho/para directing, is it activating or deactivating.?
I think it should be meta due to the oxygens which are electron withdrawing, am I correct?

2)Between tertiary non allylic and primary allylic carbocation which one is more stable?I know allylic makes you more stable because of resonance but this is primary allylic vs. TERTIARY non allylic carbocation, not just a primary one, so I don't know which to choose??

3)Which substituents will make the benzene more acidic, halogens or meta directing deactivators? I think the halogones should make them more acidic since they're more electron withdrawing than any meta directing group, correct?


 

Offline 113zami

  • Jr. Member
  • **
  • Posts: 11
    • View Profile
can someone PLEASE help me with these questions??, thanks
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8676
  • Thanked: 42 times
    • View Profile
The photobucket image doesn't seem to relate to the question.
 

Offline 113zami

  • Jr. Member
  • **
  • Posts: 11
    • View Profile
no, that group should be attached to the benzene ring, it's just not attached to the benzene in that image, you are getting a cyclic looking compound whith 2 oxygens in it, correct?
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8676
  • Thanked: 42 times
    • View Profile
To what part is the benzene ring attached?
 

Offline 113zami

  • Jr. Member
  • **
  • Posts: 11
    • View Profile
To what part is the benzene ring attached?

I have 2 structures, in the first structure the benzene is attached to the right hand CH2 group in the ring, in the 2nd structure the benzene is attched to the right hand CH3 group in the ring, so if you can shed some light on how this group in each of these 2 structures behaves that would be great
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8676
  • Thanked: 42 times
    • View Profile
To be honest I'm not sure. If you put a simple alkyl group like methyl on a benzener ring you activate it. A hydroxy group has the same effect. I think that structure you have looks like the activating groups here.
http://en.wikipedia.org/wiki/Activating_group

I take your point about some oxygen containing things being deactivating, but they are generally oxygen with a double bond.
Nitro, ester etc are shown here.
http://en.wikipedia.org/wiki/Deactivating_groups

Sorry I can't be more help- it's a long time since I studied that sort of thing.
 

Offline 113zami

  • Jr. Member
  • **
  • Posts: 11
    • View Profile
ok thank you very much for the help
 

The Naked Scientists Forum


 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums