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![[Post New]](/templates/default/images/icon_minipost_new.gif) 21 Nov 2007 20:34:33 IST
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EXPLAIN ORTHO EFFECT ON ACIDITY OF CARBOXYLIC ACIDX
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"Nenenthedhavano naake teleedu"
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21 Nov 2007 20:37:39 IST
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to make aromatic carboxylic acids more acidic u got to reduce the amount of resonance.
so say i introduce a big group in the ortho position ,due to steric repulsions the planarity of the ring is lost and hence resonance is reduced,making the acid more acidic.
rate if useful
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science-
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the most eternal
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21 Nov 2007 23:03:43 IST
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go to the link give below
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22 Nov 2007 10:25:06 IST
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Perfet answer madman (oops i am sorry to call you be this name.)
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Krishna Gopal Singh
B.Tech Chemical Engg
IIT Delhi 2002
Currently doing PhD from IIT Delhi |
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22 Nov 2007 13:19:28 IST
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nobody is perfect yaar ....anyway i got the answer.... thanks for ur reply...
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"Nenenthedhavano naake teleedu"
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There are several reactions that have ortho selectivity.
Electrophilic aromatic substitution:
Here the ortho effect could be explained three different ways:
1. Electron donating substituents increase electron density on the ring, specifically at the ortho and para positions, which makes the reaction faster.
2. Electron donating substituents have lone pairs which stabilize the carbocation intermediate.
3. Electron donating substituents stabilize the positive charge on the ring through an inductive dipole effect.
The Kolbe-Schmidt, aromatic Claisen, and Fries rearrangement reactions essentially operate the same way, but usually are not covered (if at all) until the second semester of organic chemistry.
The newest type of reaction is called "directed ortho metalation". Unless you are in an advanced organic synthesis, probably at the graduate level, you won't encounter this. The concept is easy to understand, but a little difficult to get to work in an undergraduate lab.
Is this what you were looking for?
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