Alcohols in Organic Chemistry

Classification of Alcohols

• Primary (1°) alcohols: The hydroxyl group (-OH) is attached to a primary carbon atom (one alkyl group).
• Secondary (2°) alcohols: The hydroxyl group (-OH) is attached to a secondary carbon atom (two alkyl groups).
• Tertiary (3°) alcohols: The hydroxyl group (-OH) is attached to a tertiary carbon atom (three alkyl groups).

Physical Properties of Alcohols

• Boiling point: Increases with increasing molecular weight and branching.
• Solubility: Alcohols are polar, so they are soluble in water and other polar solvents.
• Viscosity: Alcohols have higher viscosity than corresponding alkanes due to hydrogen bonding.

Nomenclature of Alcohols

• IUPAC rules:
  • Parent chain: longest chain with the hydroxyl group.
  • Suffix: -ol replaces the -e ending of the parent alkane.
  • Numbering: starts from the hydroxyl group.
• Common names: derived from the alkyl group and the suffix -ol.

Reactions of Alcohols

• Combustion: Alcohols undergo complete combustion to produce CO2 and H2O.
• Dehydration: Alcohols lose water to form alkenes.
• Oxidation: Alcohols are oxidized to aldehydes or ketones.
• Esterification: Alcohols react with carboxylic acids to form esters.

Uses of Alcohols

• Solvents: Alcohols are used as solvents in various industries (pharmaceutical, cosmetic, etc.).
• Fuels: Alcohols can be used as biofuels or additives to gasoline.
• Pharmaceuticals: Alcohols are used as active ingredients or excipients in drug formulations.
• Antiseptics: Alcohols are used as disinfectants and antiseptics.