1.4 Alcohols

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

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