Amines

• Explain why butan-1-amine is a stronger base than ethanamine

  Alkyl induction

  therefore increase electron density on the nitrogen

  lone pair of electrons on Nitrogen more available to accept proton
• Write an equation for the reaction between ammonia and bromopropane

  NH3 + CH3CH2CH2Br -> CH3CH2CH2NH2 + HBR
• What is the mechanism of the reaction between ammonia and bromopropane?

  nucleophilic substitution
• Explain the two different roles of ammonia in the reaction between ammonia and bromopropane

  Nucleophile when attacking partially positive carbon

  Base as accepts a proton
• Explain why excess ammonia must be used in the reaction between ammonia and bromopropane

  Increases likelyhood of primary amine

  Greater chance bromoethane molecule reacts with NH3 rather than an amine product
• What is the mechanism for the reaction of ethanamine and ethanoyl chloride

  nucleophilic addition-elimination
• Name two methods of preparing amines

  Haloalkane + HCN/ KCN/H+ -> nitrile

  nitrile + reducing agent -> amine

  
  

  Haloalkane + NH3 -> amine
• Write an equation for the reduction of propanenitrile using [H]

  C2H5CN + 4[H] -> C3H7NH2
• Give two examples of [H]

  LiAlH4 / ether

  NaBH4 / ethanol

  
  

  H2 + Ni catalyst
• Write an equation for the reduction of nitrobenzeneand give the reducing agent

  C6H5NO2 + 6[H] -> C6H5NH2 + 2H2O

  
  

  tin (Sn) and conc HCl
• Write a [H] equation for the reduction of 2,4,6 trinitobenzene

  C6H3(NO2)3 + 12[H] -> C6H3(NH2)3 -> 6H2O
• Put ammonia, phenylamine and propanamine in order of base strength. Explain your answer.

  CH3CH2CH2NH2 > NH3 > C6H6NH2

  
  

  CH3CH2CH2NH2 - alkyl induction pushes electron density onto Nitrogen lone pair, more available to accept proton

  NH3 - N lone pair available to accept proton but no increase in electron density

  C6H6NH2 - N lone pair delocalised into benzene ring therefore less available to accept proton
• Explain why phenylamine cannot be made by reacting bromobenzene with ammonia (3 reasons)

  NH3 is a nucleophile but benzene only attracts electrophiles

  Benzene has high electron density so not attracted to NH3

  C is not partially positive so wont attract NH3