Halogenoalkanes - Introduction (Edexcel International AS Chemistry): Revision Note

Halogenoalkanes - Introduction

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