Haloalkanes

• Haloalkanes aka as organohalides or alkyl halides
• halogen is always considered as a substituent to a parent organic molecule
• two reactions haloalkanes undergoes:

  • nucleophilic substitutions (Sn)
  • elimination reactions (E)
• General Properties of Haloalkanes:

  • higher boiling points
  • increase in boiling and melting points is proportional to the size of the alkyl group
  • increase in boiling and melting points is proportional to the size of the halogen atom
  • do not exhibit H-bonding, therefore not miscible with water
• Synthesis of Haloalkanes:

  • radical substitution with Cl2/ Br2 of alkanes
  • Electrophilic Addition of HX and X2 to alkanes
• Synthesis of Haloalkanes:

  • radical substitution with Cl2/ Br2 of alkanes
  • Electrophilic Addition of HX and X2 to alkanes
  • bromination of allylic carbon with NBS
• Radical Substitution (SR)

  • X-X /hv
• Electrophilic addition (AE) of HX and X2

  • HX/ether or peroxide if NM
  • X2/DCM or CCl4
• Bromination of allylic carbon

  • Br2, NBS/ hv or CCl4
• Allylic carbon - carbons adjacent to a vinylic carbon
• Tertiary -OH = most reactive via nucleophilic substitution 1
• Secondary -OH and Primary -OH less reactive and requires higher temperature via nucleophilic substitution 2