What Are Carboxylic Acids?
Functional group of a carboxylic acid is a carboxyl group (carbonyl +
hydroxyl = COOH)
Aliphatic carboxylic acid – RCOOH
Aromatic carboxylic acid – ArCOOH
What Are The Physical Properties Of Carboxylic Acids?
Significantly higher boiling points than other types of organic compounds
Result from their polarity and from the fact that they form very strong
intermolecular H bonds
Also interact with water molecules by H bonding through both their C=O
and OH groups more soluble in water
Hydrophilic carboxyl group increases water solubility while hydrophobic
hydrocarbon chain decreases water solubility
What Are The Acid-Base Properties Of Carboxylic Acids?
Carboxylic acids are weak acids
Stronger acids than alcohols because resonance stabilizes carboxylate
anion by delocalizing its negative charge
React with NaOH, KOH, and other strong bases to form water-soluble
How Are Carboxyl Groups Reduced?
Most resistant to reduction, not affected by catalytic reduction 2H /M)
Lithium aluminum hydride (LiAlH )4reduces carboxylic acid to a primary
o Initial product is an aluminum alkoxide, which is then treated with
water to give the 1° alcohol and LiOH + Al(OH) 3
Catalytic hydrogenation does not reduce carboxyl groups but does reduce
alkenes to alkanes
o Therefore, we can use H /M 2o reduce the functional group
selectively in the presence of a carboxyl group
It is possible to reduce an aldehyde / ketone carbonyl group selectively in
the presence of carboxylic group via NaBH 4
What Is Fischer Esterification?
Treatment of a carboxylic acid with an alcohol in the presence of an acid
catalyst gives an ester
Acid-catalyzed esterification is reversible
In the Fischer esterification, the –OR portion of an alcohol replaces the –
OH portion of a carboxylic acid After addition of a nucleophile to a carbonyl, one possible mechanism is
for the tet