Aldehydes and Ketones Chapter 4

Study Notes

Aldehydes have at least one hydrogen attached to the carbonyl group, while ketones have two carbons attached to the carbonyl group.

Find the longest carbon chain that contains the aldehyde group.
Change the ending of the root hydrocarbon name by dropping –e and adding –al.
Number the longest carbon chain so the C=O group has the lowest number.
All other branches and groups are named and located using standard IUPAC system.

Formaldehyde: a gas at room temperature, used as a sterilizer, embalming fluid, and starting material for plastics such as Formica and Bakelite.
Acetone (propanone): an important organic solvent, used in nail polish remover, and miscible with water.
Progesterone and Testosterone: female and male sex hormones, respectively, which are ketones.
Some aldehydes and ketones are used in flavorings, such as Vanillin (vanilla), Cinnamaldehyde (cinnamon), Citral (citrus flavoring), and Camphor (medicinal odor).

The carbonyl group is moderately polar, but it cannot hydrogen bond between molecules.
The polarity of the C=O group allows for interactions, but the attraction is not as strong as hydrogen bonding.
The boiling point of aldehydes and ketones is higher than alkanes, but lower than alcohols.
Low molecular weight aldehydes and ketones are water-soluble due to hydrogen bonding with water molecules.

Oxidation: aldehydes and ketones can be oxidized to produce other compounds.
The difference in reactivity toward oxidation is the chief reason why aldehydes and ketones are classified in separate families.
Hydrogenation: aldehydes and ketones can be reduced to alcohols by the addition of H2 in the presence of catalysts.