Amines

Question 1

What is the suffix for an amine that is terminal?

Answer 1

-ylamine

Question 2

What is the suffix for an amine that is mid-chain?

Answer 2

-aminoalkane

Question 3

What can you react a haloalkane with to make an amine?

Answer 3

Ammonia

Question 4

What are the conditions for making an amine from a haloalkane and ammonia?

Answer 4

Excess ammonia

Question 5

What type of reaction mechanism occurs when you react a haloalkane with ammonia to make an amine?

Answer 5

Nucleophilic substitution

Question 6

If you’re reacting CH3Cl with NH3, why will you not necessarily produce CH3NH2 + NH4+Cl- only?

Answer 6

The CH3NH2 formed is also a nucleophile (spare electron pair on N)
May go on to react with other CH3Cls

Question 7

How can you roughly control the reaction so that the majority of products formed are tetramethylamine?

Answer 7

Use less ammonia/more haloalkane

Question 8

What is a use for tetramethylammonium chloride?

Answer 8

Fabric softener

Question 9

How is tetramethylammonium chloride formed?

Answer 9

CH3Cl with minimal excess ammonia
Tetramethylamine reacts with the Cl- ion to form the salt

Question 10

You can make an amine by reacting a haloalkane and ammonia. What is another method you could use?

Answer 10

Reduction of a nitrile by adding either hydrogen or LiAlH4 (a reducing agent)

Question 11

What are the conditions for the reduction of a nitrile?

Answer 11

Nickel catalyst
150*C

Question 12

During the reduction of a nitrile a nucleophile is generated. However, the reaction stops. Why?

Answer 12

It is not a nucleophilic reaction

Question 13

What is used to reduce nitrobenzene into phenylamine?

Answer 13

Sn and conc. HCl

Question 14

What is the equation for the production of phenylamine from nitrobenzene?

Answer 14

C6H5NO2 + 6[H] -> C6H5NH2 + 2H20

Question 15

What are the relative strengths of bases in the different types of amines compared to ammonia?

Answer 15

Ammonia is a weak base
Aliphatic amines are stronger bases compared to ammonia
Aromatic amines are weaker bases compared to ammonia

Question 16

What determines base strength in amines?

Answer 16

This is determined by how available the lone pair on the nitrogen is. The more likely to accept a proton, the more available the lone pair is and the stronger the base.

Question 17

Why are aliphatic amines stronger bases relative to ammonia?

Answer 17

The alkyl groups donate electron density to the nitrogen

Question 18

Why are aromatic amines weaker bases relative to ammonia?

Answer 18

The lone pair can become delocalised and participate in the pi system, reducing the availability of the lone pair on the nitrogen to accept a proton.

Question 19

What increases base strength with amines?

Answer 19

Adding more alkyl groups increases base strength, because the lone pair becomes even more available to accept a proton.

Question 20

What decreases base strength with amines?

Answer 20

Adding more benzene rings decreases base strength, because the lone pair becomes even less available to accept a proton.