Mr Cole Chemistry

Reactions of Amines Questions

Reactions of Amines

Amines Worksheet

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1. Butyl-2-amine can react with ethanoyl chloride.

a) Write the equation for the reaction, using skeletal formulae rather than molecular formulae.

Equation for reaction of butyl-2-amine with ethanoyl chloride

b) State the conditions required for the reaction.

Anhydrous conditions.

This is to prevent the ethanoyl chloride from reacting with water (hydrolysis) to form ethanoic acid.

c) State the name of the product.

N-(butan-2-yl)ethanamide

(Note: this is a little beyond the A-level content)

2. 2-methyl-1-aminobenzene, also known as o-Toluidine, can undergo a series of reactions to form the molecule below. Final product structure

a) Draw the skeletal formula of o-toluidine.

b) In the first reaction of the series, o-toluidine reacts with 2-chloroethanoyl chloride. Outline the mechanism for the first reaction, including the product formed.

c) Describe and explain each step on the mechanism.

Step 1: The lone pair of electrons on the nitrogen is attracted to the partially positive carbon of the carbonyl group and forms a bond with it. This causes the pi bond electron pair between the carbon and oxygen to break and move onto the oxygen atom.

Step 2: The lone pair of electrons on the oxygen moves back to reform the double bond. The electrons in the C-Cl bond (the leaving group) move onto the Chlorine atom.

Simultaneously, the electrons move from the N-H bond onto the nitrogen, losing a H⁺ ion to neutralise the positive charge on the nitrogen.

d) State and explain the conditions required for reaction 1.

Anhydrous conditions.

This prevents 2-chloroethanoyl chloride from reacting with water to form 2-chloroethanoic acid.

e) Name the product formed in reaction 1.

2-chloro-N-(2-methylphenyl)ethanamide

f) In reaction 2, the product from reaction 1 is reacted with another molecule of o-toluidine. Outline the mechanism for the reaction.

g) Describe and explain each step on the mechanism.

Step 1: The lone pair on the nitrogen attacks the partially positive carbon bonded to the chlorine atom (nucleophilic attack). This causes the C-Cl bond to break, and the electrons from the bond move onto the chlorine atom (leaving group).

Step 2: The electrons from the N-H bond move onto the nitrogen atom, causing a H⁺ ion to be lost and neutralising the positive charge.

3. 2-phenylethanamine will react with ethanoic anhydride.

Write an equation for the reaction, using skeletal formulae rather than molecular formulae.