Amines as nucleophiles and their synthesis

1
Amines as nucleophiles and their synthesis

• L.O.
• Understand the reaction of amines and ammonia
  with haloalkanes.
• Know one application of quaternary ammonium
  salts.
• Know how amines can be prepared from nitriles.
• Know how aromatic amines can be prepared from
  nitro compounds.

2

• Consider the reaction between ethylamine and an
  excess of bromoethane
• Write the mechanism for the nucleophilic
  reaction.
• Consider what type of product you got. Would it
  react with an excess of bromoethane?
• Write down all the possible products you may get
  in the reaction.

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NUCLEOPHILIC SUBSTITUTION

• Lone pair on N can attack ? C of haloalkane.

-
NH4X
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NUCLEOPHILIC SUBSTITUTION

• H on N is swapped by R from haloalkane.
• Product also has lone pair on N so product reacts
  further.

• To get mainly 1y amine use XS NH3.

• To get mainly 4y ammonium salt use XS RX.

5
TASK

• Give all the organic products formed when
  methylamine reacts with chloroethane.
•  
• 2) Draw the mechanism for the formation of the
  tertiary amine in this reaction.
• 3) Draw all the organic products formed when
  diethylamine reacts with 2-bromopropane

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NUCLEOPHILIC SUBSTITUTION
methylamine chloroethane (products 1st
mechanism)
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NUCLEOPHILIC SUBSTITUTION
diethylamine 2-bromopropane (products)
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NUCLEOPHILIC SUBSTITUTION
4y ammonium salts

• Ones with some long chain alkyl groups can be
  used as cationic surfactants.
• Often used in fabric softener as many fabrics
  have ve charge on surface.

e.g. (CH3)2N(CH2)16CH32 Cl-
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MAKING ALIPHATIC 1y AMINES
1 Reaction of NH3 with haloalkanes

• Need to separate mixture of products.

2 Reduction of nitrile compounds
10

• Give two synthetic paths to making butylamine.
  Give equations for all reactions.

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Butylamine
a) CH3CH2CH2CH2Cl 2 NH3 ? CH3CH2CH2CH2NH2
NH4Cl

• CH3CH2CH2Cl KCN ? CH3CH2CH2CN KCl
• CH3CH2CH2CN 4 H ? CH3CH2CH2CH2NH2

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MAKING AROMATIC AMINES