Chapter 27 Amines

Question 1

what is an aliphatic amine ?

Answer 1

nitrogen atom attached to at least one straight or branched carbon chain (methyl amine)

Question 2

What is an aromatic amine ?

Answer 2

Nitrogen atom attached to an aromatic ring (benzene) phenylamine is simplest aromatic

Question 3

How are amines classified ?

Answer 3

Question 4

How to name amines ?

Answer 4

• alkyl or Aryl prefix followed by amine e.g methylamine, phenylamine
• amino prefix followed by alkane or aromatic stem

Question 5

How do amines act as weak bases ?

Answer 5

• Amines act as weak bases since the lone pair on the N is able to form a dative bond with a proton (proton acceptors)
• the salt is called ammonium salt

Question 6

How to prepare primary aliphatic amines ?

Answer 6

• haloalkanes are gently warmed with excess ammonia with an ethanol solvent

Question 7

How to produce amines (from nitriles) ?

Answer 7

• react the nitrile with H2 and Nickel catalyst

Question 8

How to produce amines (from nitriles) ?

Answer 8

• react the nitrile with H2 and Nickel catalyst

Question 9

How to produce secondary and tertiary amines from haloalkane ?

Answer 9

• nucleophilic substitution reaction
• a primary amine + haloalkane + (ethanol + heat) -> secondary amine
• tertiary amine can be formed by further substitution of secondary amine

Question 10

How to form an aromatic amine ?

Answer 10

• a nitrobenzene compound is made first
• nitrobenzene + Tin + HCl + reflux -> phenyl amine
• phenyl amine reacts with HCl so the ammonium salt formed is removed by adding NaOH, forming the amine, NaCl, H2O

Question 11

What are the physical properties of primary Amines ?

Answer 11

• boiling points higher than similar hydrocarbons due to hydrogen bonds
• if the carbon chain isn’t too long soluble in water due to H-bonds

Question 12

Why are aliphatic amines more basic than aromatic amines ?

Answer 12

• if the electron density on the N is increased it is a stronger base
• alkyl groups repel electrons leading to greater electron density on N
• aryl groups attract electrons leading to less electron density on N

Question 13

What is an alpha-amino acid ?

Answer 13

• alpha amino acid contain both an amine and CA group that is separated by the alpha carbon atom

Question 14

what is the general formular for amino acids ?

Answer 14

• RCH(NH2)COOH

Question 15

how to name amino acids ?

Answer 15

• CA group always takes priority so amine will be at position 2
• 2-aminobutanoic acid

Question 16

what is the reaction of AA with acids ?

Answer 16

Question 17

what is the reaction of AA with alkalis ?

Answer 17

Question 18

what is the reaction of AA with alcohols ?

Answer 18

Question 19

what are amides ?

Answer 19

• amine group bonded with a carbonyl group
• produced when acyl chloride + ammonia/amine
• can be primary, secondary, tertiary

Question 20

how are amides hydrolysed under acidic conditions ?

Answer 20

• Amide -> CA + ammonium salt
• since amine formed will react with acid

Question 21

how are amides hydrolysed under alkali conditions ?

Answer 21

• carboxylate salt and amine
• CA formed will react with alkali

Question 22

what is a chiral centre ?

Answer 22

• a chiral centre is a carbon with 4 different atoms/groups bonded to it
• AKA enantiomers

Question 23

how to draw an opical isomer ?

Answer 23

Question 24

what are condensation polymers ?

Answer 24

• condensation polymers are the joining of 2 monomers with 2 different functional groups with the elemination of a small molecule e.g H20
• polyesters have an ester link (COOH + OH)
• polyamides has an amide link (COOH + NH2)

Question 25

example of **polyester**

Answer 25

Question 26

example of **polyamide**

Answer 26

Question 27

how to **hydrolyse polyesters** ? | reactants + products

Answer 27

Question 28

how to **hydrolyse polyamides** ? | reactants + products

Answer 28

Question 29

what is the **difference between addition and condensation polymerisation** ?

Answer 29