Amines

Question 1

Describe bonding in amines and shape

Answer 1

3 bonding pairs
One lone pair
Trigonal pyramidal

Question 2

Number of alkyl groups in primary, secondary and tertiary amines

Answer 2

Primary = 1 alkyl group
Secondary = 2 alkyl groups
Tertiary = 3 alkyl groups

Question 3

Nomenclature
Ending and prefix

Answer 3

Ending -amine
Prefix methyl- , ethyl- , propyl and so on

Question 4

Properties - solubility

Answer 4

As the hydrocarbon part increases the solubility decreases
They dissolve due to hydrogen bonds
The lone pair can form a dative Bon’s with the hydrogen of a water molecule

Question 5

Properties - boiling points

Answer 5

Increase with molecular mass or chain length
Higher boiling points than corresponding alkanes due to hydrogen bonding

Question 6

Properties - basicity

Answer 6

Longer hydrocarbon chain causes an increase in basicity
Alkyl groups are electron-releasing causing an increased electron density

Question 7

List the ways to prepare aliphatic amines

Answer 7

From halogenoalkanes and ammonia gas
From the reduction of nitriles

Question 8

Equation for halogenoalkanes to produce amines
What visible product is formed

Answer 8

RCl + NH3 —> RNH2 + HCl
HCl is white misty fumes

Question 9

Conditions for the formation of amines from halogenoalkanes

Answer 9

Heating the halogenoalkane with ammonia gas Nader pressure in a sealed container.

Question 10

Describe the movement of electrons and atoms within the reaction of halogenoalkanes with ammonia gas to produce nitriles

Answer 10

A nucleophilic attach by the lone pair of electrons of ammonia on the electron-deficient carbon atom in the halogenoalkane producing a primary amine.

Question 11

What can happen to the amine formed from the reaction of halogenoalkanes with ammonia
And why

Answer 11

The amine also has a lone pair of electrons meaning it cold also act as a nucleophile attacking the halogenoalkane

Question 12

Equation for the reaction between amines and halogenoalkanes
What is the organic product
What is visibly produced

Answer 12

RCl + RNH2 —> R2NH + HCl
Secondary amine produced
And white Misty fumes

Question 13

How is the reaction with amines and halogenoalkanes prevented when trying to only produce primary amines.

Answer 13

Ammonia is shed in excess so it outnumbers the molecules of primary amine formed

Question 14

What does some access ammonia react with when trying to prevent the formation of secondary amines
What is the equation

Answer 14

RCl

RCl + 2NH3 —> RNH2 + NH4Cl

Question 15

Equation for the production of amines from nitriles

Answer 15

RCN + 4[H] —> RNH2

Question 16

Conditions for the production of amines from nitriles

Answer 16

Agent LiAlH and dry ether

Question 17

Give the equation for the formation of aromatic amines

Answer 17

C6H5NO2 + 6[H] —> C6H5NH2 + 2H2O

Question 18

Give the reagent and conditions for the formation of aromatic amines

Answer 18

Tin is mixed with concentrated hydrochloric acid and heated under reflux

Question 19

How is the oxidation achieved to produce an aromatic amine with the tin, hydrochloric acid reagent

Answer 19

Reduction is achieved through the oxidation of tin to tin(II) an tin (IV) ions, and through the hydrogen produced in the reaction between tin and the acid.

Question 20

What can the product aromatic amine react with
Give the equation
How can it be reversed

Answer 20

Can react with the acid present to form ions
C6H5NH3+ + OH- <—> C6H5VH2 + H2O
It is a reversible reaction and can be reversed by adding an alkali

Question 21

List the reactions amines can do

Answer 21

React with water
React with acids
React with acyl chlorides
React with halogenoalkanes
React with copper (II) ions

Question 22

Equation for the reaction of amines and Acids
2x equations
What’s the main difference between the first and second.
What is the main product

Answer 22

RNH2 + HNO3 —> RNH3+ + NO3-
RNH2 + HCl <—> RNH3+ + Cl-
First is irreversible and second reversible
For ionic salts

Question 23

Equation for the reaction of amines and water
2x equations
What type of solution is formed

Answer 23

RNH2 + H2O <—> RNH3+ + OH-
NH3 + H2O <—> NH4+ + OH-

Form alkaline solutions

Question 24

What type of reaction and explain the reaction between acyl chlorides and amines

Answer 24

Addition - elimination reactions.
Two molecules joins and a small molecule is eliminated e.g. HCl or H2O

Question 25

Equation for the reaction of acyl chlorides and amines Main products

Answer 25

R1COCl + R2NH2 —> R1CONR2 + HCl Amides are produced

Question 26

Equation for the reaction between halogenoalkanes and amines What type of reaction What is the organic product

Answer 26

R1NH2 + R2X —> R1NHR2 + HX Substitution, secondary amine

Question 27

What is the equation for the reaction involving the R1NHR2 product from halogenoalkanes reacting with amines What is produced

Answer 27

R1NHR2 + RX —> R1NR2 + HX A tertiary amine

Question 28

What is the equation for the reaction involving the R1NR2 product from halogenoalkanes reacting with amines

Answer 28

R1NR2 + RX —> R1N + R2 + Cl-

Question 29

Why can ammonia react with copper (II) ions

Answer 29

Ammonia can act as a lone pair donors with transition metals

Question 30

Give the equation for the reaction between ammonia and copper (II) ions What forms

Answer 30

[Cu(H2O)5]2+ + 4NH3 —> [Cu(NH3)4(H2O)2]2+ + 4H2O A pale blue precipitate which then dissolved to give a deep blue solution in butylamine

Question 31

Give the equation for the formation of the pale blue precipitate

Answer 31

[Cu(H2O)6]2+ + RNH2 —> [Cu(H2O)4(OH)2] + RNH3+

Question 32

Give the equation for the formation of the deep blue solution

Answer 32

[Cu(H2O)4(OH)2] + RNH2 —> [Cu(RNH2)4(H2O)2]+ + 2H2O + 2OH-