Transcript Carboxylic Acids

Carboxylic Acids
Nomenclature
 Properties
 Preparation reactions
 Typical reactions
 Spectroscopy

Nomenclature

Carboxylic acids
»IUPAC
»Common
 Acid
derivatives
»IUPAC
»Common
RCOOH Preparation Reactions
Oxidation of Primary Alcohols
 Oxidation of Aldehydes
 Oxidation of Substituted Aromatics
 Carbonation of Grignard reagents
 Hydrolysis of Acid derivatives and Nitriles
 Haloform reaction
 Periodic acid Cleavage of Vicinal
Dials/Diketones
 Oxidative Cleavage of Alkenes/Alkynes

Carboxylic Acids via Oxidation
 From
Primary Alcohols
 From Aldehydes
 From Substituted Aromatics
RCH 2OH
R
C H
O
R
KMnO 4
or
K 2Cr 2O 7
²
KMnO 4
or
K 2Cr 2O 7
²
KMnO 4
or
K 2Cr 2O 7
²
RCOOH
RCOOH
COOH
Carbonation of
Grignard Reagents

O
R
C +
Mg
O
X
O
+
O
H
R C OMgX
R C OH
H 2O
Hydrolysis of Acid Derivatives
and Nitriles
+
R C G H
R
H 2O
O
OH R
R C G
H 2O
O
C OH + HG
O
C O - + GO
where G = -X,- OR, - NH2 , - NHR, -NR 2 , &- O C R
O
+
-
H or OH
RC N
R
H 2O
C NH 2
O
R
-
C OH ( R
C O )
O
O
Haloform Reaction
Cleavage of methyl carbinols
Cleavage of methyl carbonyls
H
CH 3
C R
OH
CH 3 C R
O
X2
-
OH /H2O
X2
-
OH /H2O
-
RCOO + HCX 3
-
RCOO + HCX 3
Periodic Acid Cleavage of
Vicinal Dials/Diketones
H C C H
O O
R C C H
O O
R C C R'
O O
HIO 4
HIO 4
HIO 4
2 HCOOH + HIO 3
RCOOH + HCOOH + HIO 3
RCOOH + R'COOH + HIO 3
Reactions
Alkene
Cleavage
Hot Potassium Permanganate
Alkyne
Cleavage
Hot Potassium Permanganate
Ozonolysis
R
R
KMnO 4
CH CH R'
²
C C R'
RCOOH + R'COOH
ozonolysis
RCOOH + R'COOH
or
KMnO 4
²
Typical RCOOH reactions







Conversion to carboxylate salts
Conversion to acid halides
Conversion to esters
Conversion to amides
Conversion to anhydrides
Reduction to alcohols
Decarboxylation
Carboxylates from Carboxylic Acids
 Reaction
with Active Metals
 Reaction with Strong Base
 Reaction with Weak Base
RCOOH
RCOOH
RCOOH
-
o
Na
Na OH
Na HCO 3
+
RCOO Na +
1
H2
2
RCOO - Na + + H 2O
RCOO - Na + + H 2O + CO 2
Acid Chlorides from RCOOH
 Reaction
with Thionyl Chloride
 Reaction with Phosphorus Trichloride
 Reaction with Phosphorus Pentachloride
RCOOH
3 RCOOH
RCOOH
SOCl 2
PCl3
PCl5
R
C Cl + SO 2 + HCl
O
3R
C Cl + H 3PO 3
O
R
C Cl + POCl3 + HCl
O
Ester Formation

From Carboxylic Acids
with ROH via mineral acid catalysis
via the use of diazomethane

From Acid Chlorides
From Acid Anhydrides
R
C OH

R'OH
H
O
R
C OH
O
R
C
Cl
O
CH 2 N 2
O
R
+
R'OH
C OR' + H 2O
R
R
C O CH 2 H + N 2
O
C OR' + HCl
R
O
C O
C R
O
O
R'OH
R
C OR' + R
C OH
O
O
Amide Formation




Direct Conversion of Acids to Amides
From Acid Chlorides
From Acid Anhydrides
From Esters
RCOOH
R
C
NH 3
²
-
RCOO NH 4
Cl + 2 NH 3
R
O
R
R
C NH 2
O
C NH 2 + NH 4Cl
R
+
C NH 2 + NH 4 O C R
O
O
C OR' + NH 3
O
( H 2O )
R
²
O
C O C R + 2NH 3
O
+
R
C NH 2 + R'OH
O
O
Acid Anhydride Formation
 Via
Dehydration of Carboxylic Acids
 Via Reaction of RCOCl with RCOOH
 Via Reaction of RCOCl with RCOONa
2R
C OH
O
R C
O
R C
O
( H 2O )
²
Cl + HO C R'
R
C O C R
O
R
O
Cl + O C R'
O
O
C O C R ' + HCl
O
R
O
C O C R ' + Cl
O
O
Formation of Cyclic Anhydrides
Formation of 5-m em bered cyclic anhydrides:
O
O
C
C
OH
C
OH
C
strong heat
O
+ H2 O
O
O
Formation of 6-m em bered cyclic anhydrides:
O
O
C C
OH
C
C C
O
OH
strong heat
O + H2 O
O
Reduction of Carboxylic Acids
 Lithium Aluminum
 Diborane
RCOOH
RCOOH
Hydride reduction
reduction
LiAlH4
ether
B 2H 6
diglyme
H+
H 2O
RCH 2OH
RCH 2OH
(selective reduction of
carboxyl group in
preference to carbonyl
of aldehydes/ketones)
Decarboxylation of RCOOH
 Thermolysis
of beta-diacids
 Thermolysis of beta-keto acids
C
C
COOH
COOH
²
C
COOH
C
O
²
C
H
COOH
H
C
O
+ CO 2
+ CO 2
Spectroscopy
Infrared
Pmr
Cmr