amines [O2] PAPER 2 Flashcards
primary amine?
secondary amine?
tertiary amine?
amide functional group?
quaternary ammonium salt?
base strength of amines, in increasing base strength order
aromatic amine < ammonia < primary amine < secondary amine < tertiary amine
product when an amine reacts with a large excess of haloalkane, R–X?
undergoes nucleophilic substitution until all the Hs on the N of the amine are replaced by the R group of R–X to form a quaternary ammonium salt
Explain why 3-aminopentane is a stronger base than ammonia.
in 3-aminopentane, lone pair on N is more available due to positive inductive effect
Primary amines can be prepared by the reaction of halogenoalkanes with ammonia or by the reduction of nitriles.
Justify the statement that it is better to prepare primary amines from nitriles rather than from halogenoalkanes.
• with halogenoalkanes, further reactions of primary amines occur, so lower atom economy
• with nitriles, no further reaction occurs, so higher atom economy
(green) turns blue
2-step process in preparing an amine by reduction of nitriles?
STEP 1:
• nucleophilic substitution reaction between KCN and a halogenoalkane
• conditions – aqueous alcoholic
STEP 2:
• reduction of nitrile using H2
• conditions – Ni catalyst
preparation of aromatic amines using nitro compounds?
• nitro compound is reduced
• tin and concentrated HCl
• products = aromatic amine + water
• reagents = nitro compound + [H]
• E < G < F
• strength depends on availability of lone pair on N
• in E, the lone pair on N is delocalised into the ring, so the lone pair is less available
• in F and G, N is next to alkyl groups, so positive inductive effect, so lone pair is more available
give a use of quaternary ammonium salts?
cationic surfactant
