http://www.ck12.org Chapter 25. Organic Chemistry
FIGURE 25.26
Oxidation of a primary alcohol.A secondary alcohol forms a ketone when oxidized. The secondary alcohol cannot be further oxidized to produce a
carboxylic acid. Tertiary alcohols cannot be oxidized in this way, because the carbon atom bonded to the OH group
is not also bonded to any hydrogens.
FIGURE 25.27
Oxidation of a secondary alcohol.Formation and Hydrolysis of Carboxylic Acid Derivatives
Esters
In the presence of a strong acid catalyst, such as sulfuric acid, an alcohol and a carboxylic acid can combine to form
an ester and water.
FIGURE 25.28
Ester formation from a carboxylic acid and
an alcohol.This reaction is reversible. The reverse reaction, in which water adds to an ester in order to form an acid and
an alcohol, is referred to ashydrolysisof the ester. Because the reverse reaction happens so readily, we need to
manipulate this equilibrium in order to achieve a high yield of the ester product. For example, if we increase the
amount of one of the starting materials, the reaction will be shifted in the direction of ester formation according to
Le Chatelier’s Principle. Usually, the less expensive starting material would be used in excess.
Conversely, we can also remove one of the products (generally water) in order to drive the reaction forward. If
the reaction is run above the boiling point of water, the H 2 O product will leave the system as a gas, shifting the
equilibrium to the right. Chemical drying agents also provide ways to remove water from active participation in the
equilibrium.
Amides
A similar reaction can occur between a carboxylic acid and an amine (Figure25.29).