Naming Alkyl Halides

Introduction

• Alkyl halide or haloalkane:
  • Alkyl: Carbon chain
  • Halide: Halogen (Group 7 on the periodic table, represented as X)
  • Halogens: Fluorine, Chlorine, Bromine, Iodine

Naming Rules

• Similar to naming organic compounds
  • Halogen acts as a substituent and comes under the prefix category
  • For halogen names in compounds:
    • Drop "ine" and add "o"
    • Fluorine becomes Fluoro
    • Chlorine becomes Chloro
    • Bromine becomes Bromo
    • Iodine becomes Iodo

Examples

Single Halogen

1. Identify and highlight the parent chain
2. Number the chain from the side giving the lowest number to the halogen
3. For example: 2-bromo butane
   • 4 carbon chain = Butane
   • Single bonds = "ane"
   • Halogen substituent on carbon 2 = 2-bromo

Multiple Halogens

• Identify parent chain
• Number for lowest combination
• Example: 2,2-Dichloropropane
  • 3 carbon chain = Propane
  • Single bonds = "ane"
  • Two chlorine atoms on carbon 2 = 2,2-dichloro

Halogen and Carbon Substituents

• Equal priority
• Number to get the lowest set of numbers
• Example 1: 2-bromo-3-methylpentane
  • 5 carbon chain = Pentane
  • Bromine on carbon 2 = 2-bromo
  • Methyl on carbon 3 = 3-methyl
• Example 2: 3-bromo-2-methylpentane
  • Bromine on carbon 3 = 3-bromo
  • Methyl on carbon 2 = 2-methyl

Same Position

• Use alphabetical order for numbering
• Example: 2-iodo-5-methylhexane
  • 6 carbon chain = Hexane
  • Iodo on carbon 2 = 2-iodo
  • Methyl on carbon 5 = 5-methyl

Substituted Cyclohexane

• Start numbering from halogen
• Example: Fluorocyclohexane
  • 6 carbon ring = Cyclohexane
  • Fluorine is only substituent = Fluoro

Multi-Substituted Cyclohexane

• Start numbering from carbon with more substituents
• Consider direction for lowest numbers
• Example: 1,1-dichloro-3-iodocyclohexane
  • Two chlorines on carbon 1 = 1,1-dichloro
  • Iodo on carbon 3 = 3-iodo

Pi Bond and Halogen

• Pi bond has priority
• Example: 4-chloro-1-butene
  • 4 carbon chain = Butene
  • Double bond starts from carbon 1 = 1-butene
  • Chlorine on carbon 4 = 4-chloro

Additional Resources

• Ebook: "10 Secrets to Acing Organic Chemistry" available at leerside.com/orgosecrets
• Online tutoring available at leerside.com/orgotutor

Conclusion

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