CAIE A-Level Chemistry A2 34.1 Primary and Secondary Amines Questions

Practise amine synthesis, acylation and basicity using reagents, product structures and nitrogen lone pairs.

Exam points

select halogenoalkane substitution or nitrile/amide reduction routes to a target primary or secondary amine
draw the N-substituted amide formed when an amine attacks an acyl chloride
explain basicity by proton acceptance at the nitrogen lone pair and compare alkyl electron-donating effects

Covered syllabus points

34.1.1—Preparation of primary and secondary amines 34.1.2—Amide formation from amines 34.1.3—Basicity of aq. solutions of amines

[Maximum number: 2]

Phenylamine, $\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{NH}_{2}$ , and propylamine, $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}$ , can be produced by different reduction reactions.

Identify an organic compound that can be converted into $\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}$ by a reduction reaction. State the reagent for this reaction.
organic compound
reagent

M1: propylamide / propenamide / $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{CONH}_{2} \mathrm{OR}$ propanenitrile / $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{CN}$

M2: $\mathrm{LiAlH}_{4}$

[Maximum number: 1]

Compound Q can be synthesised from chlorobenzene in seven steps, using the route shown in Fig. 5.1.

Fig. 5.1

Identify the type of reaction that occurs in step 5.

[Maximum number: 3]

P can be used to make compound Q in a single step reaction.

Figure for Question 3 — CAIE A-Level Chemistry A2

Compare the relative basicities of compound P, compound Q and phenylamine. < <
least basic
most basic
Explain your answer.

Q< phenylamine < P [1]

any three from:

ability of N to accept a proton OR donate its lone pair to a proton

phenylamine

lone pair of N delocalised into ring

OR p-orbital on N overlaps with $\pi$ cloud of ring (and decreases electron density on N )

compound P ( $2^{\circ}$ amine)

alkyl group has a positive inductive effect (and increases electron density on N)

compound Q (amide)

lone pair of N (in amide) delocalised by C=O

OR overlap of lone pair of N with C=O (and decreases electron density on N)

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Covered syllabus points

Question 1

Question 2

Question 3