Edexcel A Level Chemistry:复习笔记3.4.1 Classifying Halogenoalkanes

Naming halogenoalkanes

• We use the prefixes
  • Fluoro for fluorine
  • Chloro for chlroine
  • Bromo for bromine
  • Iodo for iodine
• The name of the halogenoalkane is based on the orignal alkane
  • So CH3CH2CH2Br would be 1-bromopropane
• The position of the halogen atom must be taken into account
  • So CH3CH(Br)CH3 would be 2-bromopropane
• Finally the substituents are listed alphabetically
  • So  CH3CH(Cl)CH2Br would be 1-bromo-2-chloropropane

Classifying halogenoalkanes

• Halogenoalkanes can be classified as primary, secondary or tertiary depending on the number of carbon atoms attached to the C-X functional group
  • A primary halogenoalkane is when a halogen is attached to a carbon that itself is attached to one other alkyl group
  • A secondary halogenoalkane is when a halogen is attached to a carbon that itself is attached to two other alkyl groups
  • A tertiary halogenoalkane is when a halogen is attached to a carbon that itself is attached to three other alkyl groups

Primary, secondary and tertiary halogenoalkanes