3.3.3.1 nucleophilic substitution

• what do halogenoalkanes contain?

  polar bonds
• why do they contain polar bonds?

  halogens are more electronegative than carbon atoms
• what is formed from the electron density?

  d+ and d- regions
• nucleophiles 


  electron donator - contain a lone electron pair that is attracted to d+ regions of molecules
• common nucleophiles


  CN- ; NH3 ; OH-
• how must the nucleophiles be shown?

  with a lone electron pair and (often) a negative sign
• nucleophilic substitution


  reaction mechanism that shows how nucleophiles attack halogenoalkanes - produces alcohols or amines from halogenoalkanes
• nucleophilic substitution mechanism - alcohol

  
• nucleophilic substitution mechanism - amines

  
• the greater the Mr of the halogen in the polar bond, the lower the bond enthalpy - can be broken more easily
• the rate of reaction for these halogenoalkanes is faster
• nucleophilic substitution reactions can only occur for primary and secondary halogenoalkanes