8.2 Reactions of Carboxylic Acids

LEARNING GOALS

After   Chapter 8.2,    you will    be  able    to:

Recall  the reactant    types   used    in  acyl    substitution    reactions   to  form    the major   carboxylic

acid    derivatives,    such    as  amides  and esters

Describe    the mechanism   of  nucleophilic    acyl    substitution    reactions

Identify    the conditions  that    would   lead    to  spontaneous decarboxylation of  a   carboxylic

acid

Predict the products    of  an  acyl    substitution    reaction:

The properties of carboxylic acids make them highly reactive in a number of different categories.
Several of the most important reactions are described here.

SYNTHESIS OF CARBOXYLIC ACIDS

As described in earlier chapters, carboxylic acids can be prepared via oxidation of aldehydes and
primary alcohols. The oxidant is often a dichromate salt (Na 2 Cr 2 O 7 or K 2 Cr 2 O 7 ), chromium trioxide
(CrO 3 ), or potassium permanganate (KMnO 4 ), as shown in Figure 8.8, but several other oxidizing
agents can also work. Remember that secondary and tertiary alcohols cannot be oxidized to
carboxylic acids because they already have at least two bonds to other carbons.