Primary Amines (CIE AS Chemistry)

Exam Questions

50 mins14 questions
1a2 marks

Propylamine can be produced from 1-bromopropane.

Complete the equation for the formation of propylamine.

CH3CH2CH2Br + .................................  →  .................................  + HBr

1b3 marks

State the necessary reagents and conditions to produce propylamine from 1-bromopropane.

1c1 mark

Name the reaction mechanism that takes place when propylamine is produced from 1-bromopropane.

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1a2 marks

Propylamine is a colourless liquid that is used to manufacture a variety of chemicals including textile resins, drugs and pesticides. It can be produced by the reaction of 1-chloropropane with ammonia.

3-7-4a-m-chloropropane-and-nh3-to-propylamine

i)
State the role of the ammonia in this reaction.
[1]
ii)
Name the type of reaction that occurs in this synthesis of propylamine.
[1]
1b3 marks

Use an appropriate chemical equation to explain why propylamine can be described as a Brønsted-Lowry base with water.

1c3 marks

The reaction between 1-chloropropane and ammonia proceeds in two steps.

 

Step 1 involves the formation of an intermediate.

Step 2 forms the final propylamine product.

 

As the reaction proceeds, the bond angles around the nitrogen atom change. Explain these changes in the bond angles around the nitrogen atom.

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2a5 marks

Fig. 2.1 shows a reaction sequence to form an amine.

3-7-2a-m-butylamine-reaction-scheme

Fig. 2.1

i)
Name compound A.
 
[1]
 
ii)
Reaction 1 heats compound A under reflux with an ethanolic solution of potassium cyanide.
 
Draw the mechanism for the reaction of compound A with the ethanolic solution of potassium cyanide to form compound B.
 
  • Identify the ion that reacts with compound A
  • Draw the product of this reaction, compound B.
  • Include all charges, partial charges, lone pairs and curly arrows.
[4]
2b1 mark

In reaction 2, vapours of compound B are converted into compound C by reacting them with hydrogen gas over a nickel catalyst.

 

Name the type of reaction that occurs in reaction 2

2c3 marks

Compound C can also be produced in a single step from compound D.

 
i)
Draw the displayed formula of compound D.
 
[1]
 
ii)
State suitable reagents and conditions for reaction 3.
 
[2]
2d2 marks

Compound C is a primary amine as there is one alkyl chain attached to the nitrogen atom.

 

Draw the skeletal formula of compound C's two isomers, which are also primary amines.

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3a3 marks

Butylamine is an organic compound used as an ingredient in the manufacture of pesticides.

One possible method of making butylamine from 1-chlorobutane is shown in Fig. 3.1.

butylamine-synthesis

Fig. 3.1

i)
Deduce the type of reaction that occurs in reaction 1.
 
[1]
 
ii)
State suitable reagents and conditions for reaction 1.
 
[2]
3b4 marks

Draw the mechanism for reaction 1 and label compound X in your answer. Include all necessary partial and full charges.

3c3 marks

Compound X undergoes another reaction in reaction 2 before butylamine is formed.

i)
Describe what occurs in reaction 2
 
[1]
 
ii)
Give the molecular formula of compound Y.
 
[1]
 
iii)
The by-products Cl- and compound Y can combine together to form compound Z. State the name of compound Z.
 
[1]

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1a3 marks

Compound X is produced from cyclohexene. An amine which is a relatively weak base containing one nitrogen atom can be produced from compound X in one step. 

Outline a mechanism for the formation of compound X from cyclohexene. You will need to give suitable reagents in your answer. 

1b2 marks

One condition that is needed to convert compound X into the amine molecule is that the reagent needs to be in excess.

ii)
State the reagent and any other required conditions for the reaction.
[2]
ii)
Suggest why the reagent needs to be in excess.

[1]

1c1 mark

Propylamine acts as a Brønsted-Lowry base when it reacts with water.

Suggest an equation to show how propylamine reacts when mixed with water.

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