PC2M6

• Ethers

  Formed when an oxygen atom bonds to two alkyl or aryl groups
• Classification of Ethers

  • Classified according to the symmetry of substituents
  • Classified according to structure - the position of the oxygen atom
• Symmetrical ethers


  Ethers with identical substituents
• Unsymmetrical ethers


  Ethers with different substituents
• Aliphatic ethers


  Ethers with alkyl substituents
• Aromatic ethers


  Ethers with aryl substituents
• Physical properties of ethers

  • Solubility
  • Boiling point
  • Miscibility
• Solubility of ethers

  • Ethers containing up to 3 carbon atoms are soluble in water due to hydrogen bond formation
  • Solubility decreases with increase in number of carbon atoms
  • Ethers are appreciably soluble in organic solvents alcohol, benzene, acetone etc.
• Boiling point of ethers

  • Comparable to alkanes
  • Lower than alcohols of comparable molecular mass
• Miscibility of ethers with water

  Resembles that of alcohols
• Dehydration of Alcohols

  Alcohols undergo dehydration in the presence of protic acids (H2SO4, H3PO4) to form ethers
• Ethers

  Relatively low chemical reactivity, but more reactive than alkanes
• Ethers

  • The two lone pairs of electrons on the oxygen atom afford the ether molecule some reactivity
  • Ether molecule is subject to reacting with strong acids and serves as a Lewis base
• Ether hydrolysis

  Ethers resist undergoing hydrolysis, but are often cleaved by acids, which results in the formation of an alkyl halide and an alcohol
• Pharmaceutical applications of ethers

  • Anesthetic
  • Antiseptic
• Williamson Synthesis

  • It can be used in the laboratory to produce either symmetrical or unsymmetrical ethers.
• Synthesis Reactions of Ethers

  • Williamson’s Reaction
  • Dehydration of Alcohols
• MEDICINAL/PHARMACEUTICAL USE OF ETHERS

  Sevoflurane - Anesthetic

  Ethylene Dioxide - Antiseptic/Disinfectant

  Diethyl Ether - Solvent for extraction

  Methoxyflurane - Anesthetic
• Detecting Ether Substituent of Drugs

  Metoprolol - Beta blocker for antihypertension

  Phenacetin - Analgesic and antipyretic
• Ethers can also be classified according to:

  • aliphatic
  • cyclic
  • Aromatic
• Boiling Point

  n-Pentane - 309.1 K

  Ethoxyethane - 307.6 K

  Butan-1-ol - 390 K