amines, amino acids and polymers

Question 1

amines are derived from…

Answer 1

ammonia

Question 2

2 types of amines

Answer 2

aliphatic

aromatic

Question 3

aliphatic amine

Answer 3

nitrogen attached to at least one straight or branched carbon chain

Question 4

aromatic amine

Answer 4

nitrogen attached to at least one aromatic carbon ring

Question 5

why do amines behave as bases?

Answer 5

lone pair of electrons on N atom can accept a proton, forming dative covalent bond

Question 6

amine + acid ->

Answer 6

salt and water

Question 7

formation of primary aliphatic amines

Answer 7

• ammonia (nucleophile) undergoes substitution reaction with haloalkane, producing ammonium salt
• ammonium salt then reacted with excess ammonia to generate amine

Question 8

conditions required for formation of primary aliphatic amines

Answer 8

• ethanol as solvent to prevent further substitution of haloalkane with water to produce alcohols
• excess ammonia used to reduce further substitution of amine group to form secondary + tertiary amines

Question 9

2 overall stages for formation of primary aliphatic amines

Answer 9

• salt formatin

- amine formation

Question 10

formation for secondary and tertiary amines

Answer 10

• primary amine reacted with haloalkane, and undergoes substitution as it still has a lone pair of electrons on N

Question 11

2 overall stages for formation of secondary and tertiary aliphatic amines

Answer 11

• salt formation

- amine formation

Question 12

production of aromatic amines

Answer 12

• form ammonium salt by reacting nitrobenzene under reflux with tin + HCl
• react w excess NaOH to produce phenylamine

Question 13

why is methylamine a stronger base than ammonia?

Answer 13

• alkyl group (-CH3) pushes electrons away, making the charge on the N more negative, therefore meaning H-ions can be attracted more easily
• ion formed is more stable, as alkyl group spreads positive charge through molecule

Question 14

why is phenylamine a weaker base than ammonia?

Answer 14

• lone pair on N touches and partially dissociates into electron ring of phenol, and becoming delocalised with them, meaning the pair cannot fully combine with H-ions, intensity of charge is decreased
• if lone pair joins to H-ion, there must be a disruption in delocalisation (making the molecule more unstable) which requires energy + doesn’t occur easily

Question 15

amino acid

Answer 15

substance containing both amine and carboxylic acid functional groups

Question 16

how many amino acids in the body

Answer 16

20

Question 17

what is an α-amino acid

Answer 17

an amino acid where amine group is attached to α-carbon (2nd carbon atom, next to carbonyl group)

Question 18

general amino acid formula

Answer 18

RCH(NH2)COOH

Question 19

why do amino acids have reactions similar to both acids and amines?

Answer 19

because they contain both carb. acid and amine functional groups

Question 20

3 main reactions of amino acids

Answer 20

• w. HCl
• w. aqueous alkalis
• w. alcohols

Question 21

product of reaction between amino acid and HCl

Answer 21

ammonium salt

Question 22

product of reaction between amino acid and aqueous alkali

Answer 22

salt and water

Question 23

product of reaction between amino acid and alcohol

Answer 23

ester and water

Question 24

amide

Answer 24

product of reaction between acyl chloride w. ammonia and amines

Question 25

chiral center

Answer 25

a carbon atom attached to 4 different atoms/groups of atoms

Question 26

optical isomers

Answer 26

2 non-superimposable mirror image structures

Question 27

how many optical isomers for a chiral carbon

Answer 27

1 pair

Question 28

only α-amino acid which doesn’t contain a chiral carbon

Answer 28

glycine - H2NCH2COOH

Question 29

condensation polymerisation

Answer 29

joining of monomers with loss of a small molecule, usually water or hydrogen chloride

Question 30

how many functional groups needed for condensation polymerisation

Answer 30

2

Question 31

polyesters

Answer 31

2 monomers joined by ester linkages

Question 32

2 ways of making a polyester

Answer 32

• 1 monomers, containing both carb acid and alcohol functional group
• 2 monomers, one containing carb acid group and the other containing alcohol group

Question 33

why is lactic acid a good monomer to use in making polyesters?

Answer 33

it is derived from maize, making it more sustainable then polymers from fossil fuels

Question 34

2 monomers needed for polmerisations of polyesters

Answer 34

• 1 diol - 2 hydroxyl groups

- 1 dicarboxylic acid - 2 carboxylic acid groups

Question 35

uses of polyesters (3)

Answer 35

• clothing
• electrical insulation
• plastic bottles

Question 36

polyamides

Answer 36

monomers joined together by amide linkages

Question 37

2 ways of making a polyamide

Answer 37

• 1 monomers, containing both carb acid/acyl chloride and amine functional group
• 2 monomers, one containing carb acid/acyl chloride group and the other containing amine group

Question 38

how to hydrolyse condensation polymers

Answer 38

using hot aqueous alkali or acid

Question 39

ligand

Answer 39

molecule/ion which can donate a pair of electrons to the transition metal ion

Question 40

coordination number

Answer 40

total number of coordinate bonds formed between central metal ion and ligands

Question 41

stereoisomer

Answer 41

same molecular formula, different arrangement in space

Question 42

enantiomer

Answer 42

2 non-superimposable mirror image structures (same as optical isomer)

Question 43

type of reaction making aromatic amine from benzene

Answer 43

reduction