27.1 Amines

Question 1

What is an amine?

Answer 1

organic compounds

derived from ammonia

when H atoms are replaced.

Question 2

What is the formula of ammonia?

Answer 2

:NH₃

Question 3

Why is there a lone pair on the Nitrogen of Ammonia?

Answer 3

nitrogen is in group 5, so has 5 outer electrons.

uses 3 outer electrons in covalent bonding,

leaves 2 unpaired electrons on N.

Question 4

What is an aliphatic amine?

Answer 4

amine where

N is attached to (straight chain/branched) alkyl group(s)

Question 5

What do you call an amine attached to one or more alkyl groups?

Answer 5

aliphatic amine

Question 6

What is an aromatic amine?

Answer 6

amine where

N atom is attached to aromatic ring

Question 7

What do you call an amine attached to an aromatic ring?

Answer 7

aromatic amine

Question 8

What is a primary amine?

Answer 8

Amine formed by substituting 1 H atom in NH₃

with R groups

Question 9

What is a secondary amine?

Answer 9

Amine formed by substituting 2 H atoms in NH₃

with R groups

Question 10

What is a tertiary amine?

Answer 10

Amine formed by substituting 3 H in NH₃

with R groups

Question 11

What degree is this amine?

Answer 11

primary

(because only 1 H is replaced)

Question 12

What degree is this amine?

Answer 12

secondary

(because only 2 H atoms are replaced)

Question 13

What degree is this amine?

Answer 13

tertiary

(because 3 H have been replaced)

Question 14

What is the IUPAC name for this molecule?

Answer 14

ethylamine

Question 15

What is the IUPAC name for this molecule?

Answer 15

propylamine

Question 16

What is the IUPAC name for this molecule?

Answer 16

2-aminobutane

Question 17

What is the IUPAC name for this molecule?

Answer 17

2-methylpropylamine

Question 18

What is the IUPAC name for this molecule?

Answer 18

2-aminoheptane

Question 19

What is the IUPAC name for this molecule?

Answer 19

N-methylpropylamine

Question 20

What is the IUPAC name for this molecule?

Answer 20

N-ethyl-N-methylpropylamine

Question 21

Are amines acidic or basic? Explain why.

Answer 21

basic

can act as proton acceptor

since H⁺ can form dative covalent bond with N

Question 22

Amine + Proton ⟶

Answer 22

ammonium ion

Question 23

NH₃ + H⁺ ⟶

Answer 23

NH₄⁺

Question 24

What is the formula of ammonium?

Answer 24

NH₄⁺

Question 25

Write the chemical equation for the protonation of ethylamine:

Answer 25

C₂H₅NH₂ + H⁺ ⟶ C₂H₅NH₃⁺

Question 26

Amine + Acid ⟶

Answer 26

ammonium salt

Question 27

Ammonium salt + Alkali ⟶

Answer 27

Amine + Salt + Water

Question 28

Haloalkane + Ammonia ⟶

Answer 28

Ammonium Salt

Question 29

Write the chemical equation for the reaction between chloroethane + ammonia:

Answer 29

CH₃CH₂Cl + NH₃ ⟶ CH₃CH₂NH₃⁺Cl^-

^{(haloalkane + ammonia ⟶ ammonium salt)}

Question 30

What are the steps of forming a primary amine from a haloalkane?

Answer 30

Salt formation:

Haloalkane + Ammonia ⟶ Ammonium salt

Amine formation:

Ammonium salt + Sodium Hydroxide ⟶ Amine + Salt + Water

requires excess NH₃, ethanol solvent

Question 31

What are the conditions for preparing primary amines?

Answer 31

• EXCESS NH3
  
  • reduces further substitution by ensuring as many haloalkane molecules react
• ETHANOL SOLVENT
  
  • no substitution of haloalkane using water ⟶ alcohol

Question 32

What are the steps of forming a 2° amine from a haloalkane?

Answer 32

Salt formation:

Haloalkane + 1° amine ⟶ 2° ammonium salt

Amine formation:

Ammonium salt + Alkali ⟶ 2° amine + Salt + Water

Question 33

How do you form an aromatic amine?

Answer 33

1. Nitration of benzene ⟶ Nitrobenzene
   
   1. HNO3, concentrated HCl catalyst
2. Reduction of nitrobenzene ⟶ phenylamine
   
   1. Sn, HCl catalyst
   2. • NaOH

Question 34

Write a chemical equation for the reduction of nitrobenzene:

Answer 34

C₆H₅NO₂ + 6[H] ⟶ C₆H₅NH₂ + 2H₂O

Sn / concentrated HCl

NaOH