Amines

Question 1

What compound are amines derived from

Answer 1

Ammonia

Question 2

What is the functional group of an amine

Answer 2

NH2

Question 3

What is a primary amine

Answer 3

Where 1 carbon group is bonded to the N atom

Question 4

What is a secondary amine

Answer 4

Where 2 carbon groups are bonded to the N atom

Question 5

What is a tertiary amine

Answer 5

Where 3 carbon groups are bonded to the N atom

Question 6

What is a quaternary ammonium salt

Answer 6

Where 4 carbon groups are bonded to the N atom, causing a positive charge on the molecule

Question 7

What are non aromatic amines known as

Answer 7

Aliphatic amines

Question 8

Give 3 uses of quaternary amine salts

Answer 8

Used to make shampoo, laundry detergents, washing up liquids

Question 9

What are cationic surfactants

Answer 9

Quaternary amine salts which have a long ‘tail’/1 long hydrocarbon group

Question 10

Explain how cationic surfactants act to remove oil and grease

Answer 10

The non-polar tail is attracted to the oil or grease.
The polar head will be attracted to the water.
This now allows the water and oil to mix and removes grease from clothing, skin. dishes etc

(essentially works by trapping the oil between the cationic surfactants, which allows the oil and the water to mix)

Question 11

Explain how cationic surfactants act to soften hair

Answer 11

They have a positive ammonium ion which is attracted to the negatively charged fibres and hair.
This removes static so is used in conditioners etc

Question 12

How do amines act as a base

Answer 12

They have a lone pair on the N which allows them to accept a proton (BLB)

Question 13

How do protons bond to an amine

Answer 13

They bond via a dative covalent bond (both electrons come from lone pair on N)
Only when acting as a base and accepting H+ but not in NH3, they are covalent bonds

Question 14

How many bonds does N form when its neutral

Answer 14

3 (e.g.NH3)

Question 15

What type of base is an amine

Answer 15

A weak base

Question 16

List the strength of these amines from strongest to weakest

NH3
Primary aliphatic amines
Primary aromatic amines

Answer 16

Primary aliphatic amines
NH3
Primary aromatic amines

Question 17

What determines the strength of an amine as a weak base

Answer 17

The availability of the lone pair of electrons on the nitrogen

Question 18

Explain why primary aliphatic amines are the strongest base (out of the amines)

Answer 18

Alkyl groups have a positive inductive effect
This pushes electron density towards the N atom
Therefore the lone pair on the nitrogen is more available for protonation or donation

Question 19

If a lone pair on an amine is being protonated, what is it acting as

Answer 19

A base

Question 20

If a lone pair on an amine is being donated, what is it acting as

Answer 20

A nucleophile

Question 21

Explain why primary aromatic amines are the weakest kind of base (out of the amines)

Answer 21

The lone pair on N is DELOCALISED INTO THE BENZENE RING
Therefore electron density on the N atom decreases
So the lone pair is less available for protonation or donation

Question 22

What is electron density on the N atom in an amine dependent on

Answer 22

The type of group bonded to the N atom

Question 23

What are the 2 ways to make a primary aliphatic amine

Answer 23

1: Reacting a halogenoalkane in excess NH3
2: Reducing a nitrile

Question 24

Name and outline the mechanism by which ammonia is turned into a primary amine through 1-bromopropane

Answer 24

Nucleophilic substitution

Question 25

Name and outline the mechanism by which a primary amine is turned into a secondary amine through 1-bromopropane

Answer 25

Nucleophilic substitution (arrow missing from N-H bond to N)

Question 26

Name and outline the mechanism by which a secondary amine is turned into a tertiary amine through 1-bromopropane

Answer 26

Nucleophilic substitution

Question 27

Name and outline the mechanism by which a tertiary amine is turned into a quaternary ammonium salt through 1-bromopropane

Answer 27

Nucleophilic substitution

Question 28

What are the reagent and conditions required for the amine nucleophilic substitution reactions

Answer 28

Reagent: excess Concentrated NH3 Conditions: High pressure & heat in a sealed container

Question 29

What does using an excess of NH3 in the amine nucleophilic substitution reactions lead to

Answer 29

An excess of NH3 minimises further substitution

Question 30

What does using an excess of halogenoalkanes in the amine nucleophilic substitution reactions lead to

Answer 30

Excess of halogenoalkanes favours further substitution

Question 31

Name and outline the mechanism for the formation of a primary aliphatic amine from 1-bromopropane

Answer 31

Nucleophilic substitution

Question 32

What is the downside of producing a primary aliphatic amine through reacting a halogenoalkane in excess NH3

Answer 32

Impure product

Question 33

Why does producing a primary aliphatic amine through reacting a halogenoalkane in excess NH3 lead to an impure product

Answer 33

Primary amines still have a lone pair on the N which means they can further act as nucleophiles to form secondary amines, and even further to form tertiary amines and quaternary salts

Question 34

What are the conditions and reagent for method 1(using LiAlH4) of producing a primary aliphatic amine through the reduction of a nitrile

Answer 34

Reagent: LiAlH4 Condition: In dry ether

Question 35

What are the conditions and reagent for method 2 (catalytic hydrogenation) of producing a primary aliphatic amine through the reduction of a nitrile

Answer 35

Catalytic hydrogenation Reagent: H2 Conditions: 150 degrees C Catalyst: Nickel catalyst

Question 36

Write an equation for the formation of a primary aliphatic amine using LiAlH4 from propanenitrile

Answer 36

Theres an extra alkyl group in product (just ignore it)

Question 37

Write an equation for the formation of a primary aliphatic amine using H2 and a nickel catalyst from propanenitrile

Answer 37

Question 38

What is the advantage of producing a primary aliphatic amine through the reduction of nitriles over reacting a halogenoalkane in excess NH3

Answer 38

Pure product

Question 39

What are the 2 methods to prepare an aromatic amine (NITROBENZENE TO PHENYLAMINE)

Answer 39

NITROBENZENE TO PHENYLAMINE Method 1: Using a reducing agent Method 2: Catalytic hydrogenation

Question 40

What are the 2 methods to prepare a primary aliphatic amine from the reduction of a nitrile

Answer 40

Method 1: Using Lithium aluminium hydride Method 2: Catalytic hydrogenation

Question 41

What are the reagent and conditions for method 1 (using a reducing agent) of preparing an aromatic amine in both a lab and industry

Answer 41

Lab: Reagent: Concentrated HCl Catalyst: Sn Industry: Reagent: Concentrated HCl Catalyst: Fe Both under reflux

Question 42

Write an equation for method 1 (using a reducing agent) for the preparation of phenylamine from nitrobenzene

Answer 42

Question 43

What are the reagent and conditions for method 2 (Catalytic hydrogenation ) of preparing an aromatic amine

Answer 43

Reagent: H2 Condition: 150 degrees C Catalyst: Ni

Question 44

Write an equation for method 2 (catalytic hydrogenation) for the preparation of phenylamine from nitrobenzene

Answer 44

Question 45

What are aromatic amines used in

Answer 45

The manufacture of dyes

Question 46

What are the 2 ways of reducing a nitrile to produce a primary aliphatic amine

Answer 46

1- Catalytic hydrogenation 2 - Using LiAlH4 (reducing agent)

Question 47

Question 48