A-Level CIE Chemistry 7.5 Amines (A Level only): (a) Carboxylic acids can be conv

Question

(a) Carboxylic acids can be converted into primary amines by the following sequence of reactions.

RCO₂H → step 1 → D → step 2 → RCONH₂ → step 3 → RCH₂NH₂

(i) Suggest the identity of intermediate D and write its structure in the box above.

(ii) Suggest the reagents for

step 1:

step 2:

step 3:

(b) Four compounds, E, F, G and H, are isomers of each other.
Each compound contains an aromatic ring and two functional groups from the following list:

• alcohol
• amide
• amine
• ester
• carboxylic acid
• phenol

(i) Which of these functional groups react readily with cold HCl(aq)?

(ii) Which of these functional groups react readily with cold NaOH(aq)?

The molecular formula of the four isomers, E, F, G and H, is C₈H₉N₂O₂. All four compounds are insoluble in water. Table 1 shows their solubilities in acid or alkali.

| compound | solubility in HCl(aq) | solubility in NaOH(aq) |
|----------|-----------------------|------------------------|
| E        | insoluble             | insoluble              |
| F        | soluble               | soluble                |
| G        | soluble               | insoluble              |
| H        | insoluble             | soluble                |

(iii) Use this information to suggest the two functional groups, taken from the list on page 10, that each compound contains.

| compound | first functional group | second functional group |
|----------|-----------------------|-------------------------|
| E        |                       |                         |
| F        |                       |                         |
| G        |                       |                         |
| H        |                       |                         |

(iv) Suggest a structure for each compound.

|   E   |   F   |
|-------|-------|
|   G   |   H   |

(a) Carboxylic acids can be converted into primary amines by the following sequence of reactions - CIE - A-Level Chemistry - Question 6 - 2015 - Paper 4

Worked Solution & Example Answer:(a) Carboxylic acids can be converted into primary amines by the following sequence of reactions - CIE - A-Level Chemistry - Question 6 - 2015 - Paper 4

Suggest the identity of intermediate D and write its structure in the box above.

Suggest the reagents for step 1.

Suggest the reagents for step 2.

Suggest the reagents for step 3.

Which of these functional groups react readily with cold HCl(aq)?

Which of these functional groups react readily with cold NaOH(aq)?

Use this information to suggest the two functional groups that each compound contains.

Suggest a structure for each compound.

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