CARBOXYLIC ACIDS

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CARBOXYLIC ACIDS
Properties and Synthesis
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NOMENCLATURE
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IUPAC NOMENCLATURE

• -oic acid IUPAC ending
• -carboxylic acid IUPAC ending for ring compounds

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Naming
3-Methylbutanoic acid b-Methylbutyric
acid Isovaleric acid
2-Chloropentanoic acid a-Chlorovaleric acid
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Naming
2-Methylpropanoic acid a-Methylpropionic
acid Isobutyric acid
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More Naming
Benzoic acid Benzenecarboxylic acid
Cyclohexanecarboxylic acid
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Common Names
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SYNTHESIS OF CARBOXYLIC ACIDS
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Oxidation of Primary Alcohols with
KMnO4
two a-hydrogens
MnO2
precipitate
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Oxidation of Primary Alcohols
with K2Cr2O7
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Oxidation of Side Chains
Example
D
KMnO4
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Carbonation of Grignard Reagents
( or Alkyllithium Compounds )
( R-Li )
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Formation of Nitriles and Hydrolysis
DMSO
H2SO4
H2O
SN2
heat
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SYNTHESIS OF CARBOXYLIC ACIDS
( DUE TO LACK OF SPACE REACTION CONDITIONS ARE
ABBREVIATED)
( benzene R sidechain R )
KMnO4
KMnO4
KMnO4
CrO3
or KMnO4
H2SO4
CrO3
H2O
H2SO4
H2SO4
DIBAL or
NaCN acetone
CO2
Rosenmund
KMnO4
H2O
H2SO4
SOCl2
Li or Mg
H2O
or
Chap 19
This is all stuff you know!
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ACIDITY
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Carboxylate Ion Formation
They are acids, ya know !
carboxylate ion
carboxylic acid
pKa 5
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Protonation and Deprotonation of a Carboxylic
Acid
..

..
..
..


..
-
..
..
H2SO4
NaOH

..
..
..

H2SO4

..
..

..
equivalent structures
due to resonance

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• Electron-withdrawing Groups
• strengthen acids
• weaken bases
• Electron-releasing Groups
• weaken acids
• strengthen bases

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Substituents with Electron-Withdrawing Resonance
( - R ) Effects
X
Y
-R substituents strengthen acids and weaken
bases
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Substituents with Electron-Releasing Resonance (
R ) Effects
hydroxy
alkoxy
mercapto
acyloxy
methyl
alkyl
dialkylamino
amino
fluoro
chloro
bromo
iodo
R substituents weaken acids and strengthen
bases
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Substituents with Electron-Withdrawing
( - I ) Inductive Effects
X
carboxyl
cyano
alkoxycarbonyl
sulfonic acid
alkoxy
acyl
dialkylamino
hydroxyl
fluoro
mercapto
bromo
amino
iodo
chloro
trimethylammonium
nitro
-I substituents strengthen acids and weaken
bases
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Substituents with Electron-Releasing Inductive (
I ) Effects
R
methyl
alkyl
carboxylate
oxide
I substituents weaken acids and strengthen
bases
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increasing acidity
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(No Transcript)
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ortho
ortho
meta
meta
para
para
Benzoic Acid pKa 4.19
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4.06
4.08
4.48
4.46
2.97
Benzoic Acid pKa 4.19
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Benzoic Acid pKa 4.19