11O- Amines

Question 1

How to know if an amine is 1° 2° or 3°

Answer 1

1°- 1 alkyl group attached to N
2°- 2 alkyl groups attached to N
3°- 3 alkyl groups attached to N

Question 2

How to name primary amines

Answer 2

R-NH2 general formula
Alkyl group, amine
eg propyl amine CH3CH2CH2NH2

Question 3

How to name secondary amines

Answer 3

(R)(R)NH general formula R groups must be same
eg dimethylamine (CH3)2NH2

Question 4

How to name tertiary amines

Answer 4

RRRN general formula R groups must be same
(C2H5)3N triethylamine

Question 5

How to name animes with different sub groups

Answer 5

Write sub groups in alphabetical order and use priority list
CH3C2H5NH N-ethylmethylamine

NH2CH2COOH 2-aminoethanoic acid

Question 6

What are two ways of producing primary aliphatic amines

Answer 6

Nucleophilic substitution of haloalkane with ammonia

Reduction of nitriles
1. Nucleophilic substitution of haloalkanes with CN-, forms a nitrile
2. Reduction of nitrile to primary amine by [H] or Ni catalyst

Question 7

How can a primary amine to be formed from nucleophilic substitution

Answer 7

Use excess ammonia to prevent further substitution

Question 8

How can a secondary, tertiary or quaternary ammonium salt be formed from nucleophillic substitution

Answer 8

Ammonia is in limit so once primary amine is formed it reacts with haloalkane forming secondary amine etc

1. R-Cl + NH3 —> R-NH2 + Cl- + H+
2. R-NH2 + R-Cl —> (R)2NH2 + Cl-

*Easiest to know what’s happening drawn out

Question 9

Disads of preparing amines through nucleophilic substitution with NH3

Answer 9

Disad
Inefficient, mixture of 1°/2°/3°
Mixture needs to be separated by fractional distillation

Question 10

How can primary amines be produced from reduction of nitriles

Answer 10

1. Haloalkane reacts with CN- in a nucleophilic substitution reaction hot acid is needed, a nitrile is formed
2. Reduction of CN bond using H2 and Ni catalyst, forming primary amine

*this method produces a molecule with a carbon length longer by one

Question 11

Add of producing amines through reduction of nitriles

Answer 11

Only a 1° amine can be produced so purer product

Question 12

How can aromatic amines be produced (phenylamine) give overall eq

Answer 12

1.Electrophilic substitution (nitration) of a benzene with conc H2SO4 and conc HNO3, produces nitrobenzene

2. Nitrobenzene reduced to phenylamine using Sn and HCL as reducing agents
3. Reaction happens in HCL, NaOH needed to liberate amine,
   C6H5NH3+ + Cl- + NaOH—> C6H5NH2 + H2O + NaCl
   Overall equation
   C6H5NO2 + 6[H] —> C6H5NH2 + 2H2O

Question 13

What are aromatic amines (phenylamine) used for

Answer 13

Manufacture of dyes

Question 14

What type of base are amines

Answer 14

Weak bases

Question 15

What does the strength of a base depend on

Answer 15

How easily it will accept a proton (H+), the easier it accepts a proton the stronger the base

Question 16

Which of ammonia, primary aliphatic amines and primary aromatic amines is a stronger base (weakest to strongest)

Answer 16

Phenylamine (weakest)
Ammonia
Primary aliphatic amines (strongest)

Question 17

Why are secondary amines stronger bases than primary amines

Answer 17

2° has a positive inducing effect from 2 alkyl groups, increases electron density, lone pair on N is more available, 1° has a positive inducing effect from 1 alkyl group

Question 18

Why are tertiary amines LESS stronger bases than secondary amines

Answer 18

3° less soluble in water

Question 19

Why are primary aromatic amines weak bases

Answer 19

Lone pair on N atom overlap with delocalised ring of electrons on benzene, this ring withdraws electrons from N atom, lone pair on N is less available

Question 20

What are the uses of quaternary ammonium salts

Answer 20

Cationic surfactants like hair conditioner and fabric conditioner

Question 21

Equation for production of an amine (reducing nitrile)

Answer 21

R-CN + 4[H] —> R-CH2-NH2

Question 22

Equation for formation of aromatic amine (reduction of nitrile)

Answer 22

C6H5NO2 + 6[H] —> C6H5NH2 + 2H2O

Question 23

Nucleophilic addition elimination reaction of ammonia/1° amine with acyl chlorides and acid anhydrides

Answer 23

Acyl chloride
R-COCl + 2CH3NH2 —> R-CONHCH3 + CH3NH3+ + Cl-

Acid anhydride
(RCO)2O +2CH3NH2 —> R-CONHCH3 + [CH3NH3]+ + [RCO2]-

Question 24

What do amines + acyl chlorides/ acid anhydrides produce —> N-Sub Amides

Answer 24

1.Lone pair from N onto C from carbonyl bond as C is s+ and Cl is s-, arrow from carbonyl bond onto O
2. -ve charge on O, arrow from lone pair into C-O bond
Arrow from C-Cl bond onto Cl
N is +ve, arrow from H onto N