Amines Flashcards
what are amines?
organic molecules that are derived from ammonia, where a carbon chain has replaced one or more of the hydrogen atoms these are called aliphatic amines
What happens if a ring replaces the hydrogen in amines?
these are called alicyclic amines.
What happens if the ring that replaces the hydrogen in amines is a benzene?
the amine is an aromatic amine.
What is the simplest aliphatic amine?
CH3NH2
What is the simplest aromatic amine?
C6H5NH2
how do we classify amines?
as primary, secondary or tertiary, depending on the number of alkyl or aryl groups attached to the nitrogen atom
What is an example of a primary amine?
CH3NH2
What is an example of a secondary amine?
(CH3)2NH
What is an example of a tertiary amine?
(CH3)3N
what suffix do primary amines where the NH2 is at the end of the molecule use?
amine
what prefix is used when the amine group is on any other carbon?
amino
in secondary and tertiary amines, what prefixes are helpful?
di,tri
what can of amines in a ring be called?
phenyl amine or aminobenzene
What are amines in terms of reactions?
weak bases; the lone pair of electrons on the nitrogen atom is a proton acceptor
What do haloalkanes react with to make primary amines?
excess ammonia- Ammonia has a lone pair on the nitrogen that acts as a nucleophile, a substitution reaction takes place
check notes
what does the first step and second step of haloalkanes reacting with excess ammonia form?
first step forms an alkyl-ammonium salt, and the second step forms the amine.
What is excess ammonia used to prevent?
further substitution of the amine group that forms- Ethylamine could further react with chloroethane to make diethylamine or even then triethylamine. The preparation of pure primary amines is difficult for this reason.
What is ethanol solvent used to do when haloalkanes react with excess ammonia?
to aid solubility and to prevent the haloalkane reacting with water to make an alcohol.
what can primary aliphatic amines means also be formed from?
reduction of nitriles
How have aromatic amines been made?
by the reduction of aromatic nitro compounds such as nitrobenzene
Why is will chlorobenzene not react with ammonia to give phenylamine?
because the benzene ring cannot be attacked by nucleophiles
What are the reagents for the preparation of aromatic amines by the reduction or nitrobenzene?
-tin and conc HCl
-Excess NaOH is then added to neutralise the acid and concert the NH3+ group into the –NH2 group
