Amines as nucleophiles

Question 1

How do amines act as nucleophiles?

Answer 1

the lone pair of electrons from an amine will attack positively charged carbon aatoms

so amines, like ammonia, will act as nucleophiles

Question 2

How are primary aliphatic amines produced? draw mech

Answer 2

produced when halogenoalkanes are reacted with ammonia

there is nucleophillic substituion of the halide by NH2

Question 3

Why will a secondary amine be produced? draw mech

Answer 3

the primary amine is also a nucleophile and this will react with the halogenoalkane to produce a secondary amine

Question 4

How will the secondary amine react? draw mech

Answer 4

to give a tertiary amine

R₂NH + RX → [R₂NH₂]⁺X^-

[R₂NH₂ + X^- + NH₃ → R₂NH + [NH₄]⁺X^-

Question 5

How will the tertiary amine react

Answer 5

a quaternary ammonium salt

Question 6

Why is this not an efficient way of preparing an amine?

Answer 6

further substitution liekly

a mixture of primary, secondary and tertiary amines and a quarternary ammonium salt is produced

although products could be separated via fraction distillation

Question 7

How is the yield of a primary amine increaseD?

Answer 7

a large excess of ammonia gives a better yield of primary amine