Alcohols

• General Formula: R-OH

• Name of the functional group: Hydroxyl

Naming Alcohols

• Add “ol” to the end of the alkane name.

Alcohol Types

• Primary (1°) alcohols – hydroxyl is bonded to a terminal carbon

• Secondary (2°) alcohols – hydroxyl is bonded to a carbon attached to 2 alkyl groups (Cs)

• Tertiary (3°) alcohols – hydroxyl is bonded to a carbon attached to 3 alkyl groups (Cs)

• Polyalcohols: alcohols with more than one hydroxyl group

• Cyclic alcohols: cyclohexanol

• Aromatic alcohols:

Properties of Alcohols

• Alcohols have a much higher boiling point than alkanes because of the hydroxyl group

• This makes the alcohol molecule polar and allows them to form hydrogen bonds, increasing the intermolecular forces

• Small alcohols have a high solubility in polar solvents (water)

• In long-chain alcohols, the hydrocarbon portion is nonpolar making larger alcohols good solvents for non-polar compounds.

Reactions

• Hydration of alkenes

  • Requires a catalyst such as H2SO4

  • Addition reaction

  • Makes 2 & 3 alcohols (Markovnikov’s rule)

• Hydration of alkyl halides

  • Substitution reaction

  • Makes 1 alcohols

• Elimination/Dehydration

  • Prepares alkenes from alcohols

  • Requires catalyst (H2SO4)

Combustion of Alcohols