Topic 28: Amines

Question 1

Amine functional group

Answer 1

R-NH2

Question 2

Naming amines

Answer 2

Methylamine CH3NH2
Ethylmethylamine (C2H5)(CH3)NH

Question 3

Making an amine using haloalkane

Answer 3

Nucleophilic substitution of haloalkane with :NH3 creates primary amine

Question 4

Only make primary amine

Answer 4

Excess ammonia otherwise the amine can act as the nucleophile with the haloalkane to make a secondary alkane.

Question 5

Quaternary amine use

Answer 5

Cationic surfactant, used in hair conditioner

Question 6

Making an amine from nitrile

Answer 6

Reduction of nitriles
Reducing agent [H]
CH3CH2CN + 4[H] —> CH3CH2CH2NH2

Question 7

Reducing agent for making amine from nitrile

Answer 7

LiAlH4 in ether
or
2H2 with Ni catalyst

Question 8

Amines as bases

Answer 8

Increases in “goodness” of base as lone pair becomes more available.
Most available in primary amine then ammonia then phenylamine

Question 9

Inductive effect

Answer 9

Electron pushing effect

Question 10

Making phenylamine

Answer 10

Nitrobenzene is reduced to phenylamine

Question 11

Conditions for making phenylamine

Answer 11

Tin catalyst, conc. HCl, under reflux makes H2, hydrogen then reduces nitrobenzene by removing the O2

Question 12

Intermediate of making phenylamine

Answer 12

Phenylammonium salt then reacts with NaOH this makes phenylamine and water

Question 13

Boiling point of amines

Answer 13

Increases with Mr Higher than alkanes as H bonding

Question 14

Quaternary amines

Answer 14

Ammonium salts (+ve charge)
Ionic

Question 15

Aromatic amines

Answer 15

NH2 on benzene ring - phenylamine

Question 16

Solubility of amines

Answer 16

Decreases as get heavier,
Lower mass soluble in water as H bonding
Soluble in organic solvents

Question 17

Amines acids/bases

Answer 17

Bases, lewis as lone pair (on N) donor and Bronsted Lowry as proton acceptors

Question 18

Amines as nucleophiles

Answer 18

Lone pair on N can attack e- deficient centre

Question 19

Strength of amines as bases

Answer 19

Increased electron density on N means able to pick up protons eaiser

Question 20

Electron withdrawing substituents on amines

Answer 20

Benzene rings, decrease e- density on N so lone pair is less effective, so decreased basicity

Question 21

Electron releasing substituents on amines

Answer 21

CH3 groups, electron density is increased on N so lone pair more effective, so increased basicity

Question 22

Amines and water

Answer 22

CH3NH2(g) + H2O(l) <===> CH3NH3+(aq) + OH-(aq)

weak alkaline solution

Question 23

Amines in acids

Answer 23

C6H5NH2(l) + HCl(aq) —> C6H5NH3+Cl- (aq)

Produce salts (phenylammonium chloride)

Question 24

Ammonium salts with sodium hydroxide

Answer 24

C6H5NH3+Cl-(aq) + NaOH(aq) —> C6H5NH2(l) + NaCl(aq) + H2O(l)

Question 25

N substituted amines

Answer 25

Prefix letter N, to show that the other group is attached to the nitrogen

Question 26

Conditions for prep of amines with haloalkanes

Answer 26

Reflux in aqueous, alcoholic solution under pressure

Question 27

Conditions for prep of amines with nitriles

Answer 27

Reflux in aqueous, ethanolic solution

Question 28

https://www.youtube.com/watch?v=KW8IPSYTq08