amines
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what do primary aliphatic amines act as ?
bronsted lowry bases (a proton acceptor)
why are primary aliphatic amines stronger bases than ammonia ?
as alkyl groups are electron releasing
why are secondary amines stronger bases than primary?
they have more alkyl groups that are substituted onto the N atom in place of H atoms so more electron density is pushed onto the N atom (as the inductive effect of alkyl groups is greater than that of H atoms), so making the lone pair of electrons on the nitrogen more readily available
base strength order of amines?
Aromatic amines < ammonia< primary amines< tertiary amines< secondary amines
base strength of aromatic amines?
lone pair of electrons on the nitrogen delocalise with the ring of electrons in the benzene ring. This means the lone pair on the N is less able to accept protons
what is formed when amines react with acids?
ammonium salts
what can you add to an ammonium salt to reform the amine?
NaOH
how do you maximise the amount of primary amines formed ?
use an excess of ammonia (NH3)
how do you promote the formation of quaternary salt?
excess halogenoalkane
what can quaternary salts be used for?
cationic surfactants (fabric softeners and hair conditioners)
why are primary aliphatic amines weak bases
as they only produce a low concentration of hydroxide ions
what will the ionic salts be if the water is evaporated
solid crystals because of the strong ionic interactions
disadvantages of Preparing amines from nitriles in a 2 step reaction
• it is 2 steps so may have a lower yield • KCN is toxic