Aldehydes, Ketones, and Carboxylic Acids

Introduction to Carbonyl Compounds

Organic compounds containing a carbon-oxygen double bond (carbonyl group) are fundamental in organic chemistry. The nature of the groups attached to the carbonyl carbon determines whether the compound is an aldehyde, ketone, or carboxylic acid.

• Aldehydes: The carbonyl group is bonded to at least one hydrogen atom.

• Ketones: The carbonyl group is bonded to two carbon atoms.

• Carboxylic Acids: The carbonyl group is bonded to a hydroxyl group (-OH).

The general structures are:

• Aldehyde:

• Ketone:

• Carboxylic Acid:

Nomenclature and Structure of Carbonyl Groups

The naming of aldehydes and ketones follows IUPAC rules, with specific suffixes and prefixes to indicate the functional group present.

• Aldehydes:

  • Functional group:

  • Suffix used: -al (e.g., methanal, ethanal)

  • Prefix used: formyl- (when the group is a substituent)

• Ketones:

  • Functional group: (carbonyl between two carbons)

  • Suffix used: -one (e.g., propanone, butanone)

  • Prefix used: keto- or oxo- (when the group is a substituent)

Example: The compound is named ethanal (IUPAC) or acetaldehyde (common name).

Common Names of Aldehydes and Ketones

Many simple aldehydes and ketones have traditional common names based on the number of carbon atoms in the molecule. The prefixes are derived from Latin or Greek numerals:

These prefixes are combined with the suffix -aldehyde for aldehydes and -one for ketones.

Examples of Common and IUPAC Names

Key Points:

• The common name often indicates the structure and the number of carbons.

• IUPAC names are systematic and based on the longest carbon chain containing the carbonyl group.

Summary Table: Suffixes and Prefixes for Carbonyl Compounds

Example: The compound is called acetone (common name) or propanone (IUPAC name).

Additional info: Carboxylic acids, though mentioned, are not detailed in the provided notes. Their functional group is , with the suffix -oic acid and prefix carboxy- when used as a substituent.