6.2.1 - Amines Flashcards
(25 cards)
How do you name amines?
-amine or amino
Why are amines so
reactive?
The lone pair of electrons on the Nitrogen - due
to polar N-H bond
Why are amines so
reactive?
The lone pair of electrons on the Nitrogen - due
to polar N-H bond
What shape are amines
around the N? Bond angle?
Trigonal pyramidal, 107 degrees
due to lone pair on N
What kind of intermolecular
forces do amines have? Why?
Hydrogen bonding due to polar N-H bond and
lone pair of electrons on N atom.
Do amines have
intermolecular forces which
are stronger than or weaker
than alcohols? Why?
Weaker, as N has a lower electronegativity than
O → weaker hydrogen bonding
How can amines
act as bases?
The lone pair on the nitrogen atom accepts a
proton
How can/when do amines
act as nucleophiles?
When they bond with an electron-deficient C
atom (donate lone pair from N)
What is the product from the
basic action of an amine
with water?
RNH3
+
- ammonium ion, which forms a salt with
an anion
Write an equation for
methylamine reacting with
HCl.
methylamine + HCl -> methylammonium chloride
In order to be the strongest
base, what must a particular
amine have (out of a set of
amines)?
Greatest electron density around the N atom,
making it a better electron pair donor (attracts
protons more)
What effect do alkyl groups
have (on electron density
and base strength)?
Positive inductive effect - increase electron
density around N → stronger base
Place the following in order
of base strength (in
general): NH3
, 1o
amine, 2o
amine, phenylamine.
2
o
amine > 1o
amine > NH3
> phenylamine
How can primary amines
then form 2o
, 3o
amines and
4
o
ammonium ions?
Multiple substitutions; primary amine is a
nucleophile that attacks the original haloalkane
etc
What are the problems with
this method?
Not efficient as low yield of 1o
amine due to
multiple substitutions
What are the problems with
this method?
Not efficient as low yield of 1o
amine due to
multiple substitutions
How would you maximise
the yield of the primary
amine?
Use excess ammonia
What type of mechanism is
the reaction of a haloalkane
with a cyanide ion?
Nucleophilic substitution
What conditions does this
reaction require? What is
the product formed?
Ethanol as a solvent
A nitrile is formed
How do you get from a
nitrile to a primary amine?
(name of reaction type and
reagents/catalysts).
Reduction using Nickel / Hydrogen catalyst
Why is this a purer method
of synthesising amines?
Only the primary amine can be formed
What conditions are needed
to form nitrobenzene from
benzene?
Concentrated H2SO4
and HNO3
to form the NO2
+
ion for electrophilic attack
How do you form an
ammonium chloride salt
from nitrobenzene? What
conditions are needed?
Reduce the nitrile using Tin / HCl → forms an
ammonium salt with Cl-
ions
Room temperature
Equation for the reaction of
nitrobenzene → phenylamine.
C6H5NO2
+ 6[H] → C6H5NH2
+ 2H2O
