amines, amino acids and proteins

Question 1

aliphatic amine

Answer 1

nitrogen atom is attached to at least one straight or branched carbon chain

Question 2

aromatic amine

Answer 2

nitrogen atom is attached to an aromatic ring

Question 3

primary amine

Answer 3

nitrogen atom attached to 1 alkyl or aryl group

Question 4

secondary amine

Answer 4

nitrogen atom attached to 2 alkyl or aryl group

Question 5

tertiary amine

Answer 5

nitrogen atom attached to 3 alkyl or aryl group

Question 6

amines as bases

Answer 6

• lone pair of electrons on the nitrogen atom
• can accept a proton
• dative covalent bond is formed

Question 7

formation of primary amines

Answer 7

• haloalkane + NH₃ →ammonium salt

- ammonium salt + NaOH (aq) → primary amine

Question 8

formation of secondary amines

Answer 8

• haloalkane + primary amine → ammonium salt

- ammonium salt + NaOH (aq) → secondary amine

Question 9

formation of tertiary amines

Answer 9

• haloalkane + secondary amine → ammonium salt

- ammonium salt + NaOH (aq) → tertiary amine

Question 10

condensation polymerisation

Answer 10

joining of monomers with loss of a small molecule

Question 11

how can polyesters be made?

Answer 11

• one monomer containing a carboxylic acid and an alcohol group
• 2 monomers, one containing 2 carboxylic acid groups and other containing 2 alcohol group

Question 12

how can polyamides be made?

Answer 12

• one monomer containing a carboxylic acid (or acyl chloride) and an amine group
• 2 monomers, one containing 2 carboxylic acids groups (or acyl chlorides) and other containing 2 amine groups

Question 13

polyamides

Answer 13

condensation polymers formed when monomers are joined together by amide linkages on a long chain to form the polymer

Question 14

polyesters

Answer 14

condensation polymers formed when monomers are joined together by ester linkages to form the polymer

Question 15

how can polyesters and polyamides be hydrolysed?

Answer 15

• using hot aqueous alkali (e.g. hot NaOH)

- using hot aqueous acid (e.g. hot HCl)

Question 16

what are the characteristics of addition polymerisation?

Answer 16

• monomers contains a C=C double bond

- backbone of polymer is a continuous chain of carbon atoms

Question 17

what are the characteristics of condensation polymerisation?

Answer 17

• 2 monomers, each with 2 functional groups
• 1 monomer with 2 different functional groups
• polymer contains ester or amide linkages

Question 18

conditions to make primary amines

Answer 18

• ethanol as a solvent- prevent any substitution of the haloalkane by water to produce alcohols
• excess ammonia is used- reduces further substitution of amine group to form secondary and tertiary amines

Question 19

why is the reaction for making primary amines unsuitable for making a pure primary amine?

Answer 19

• product still contains a lone pair of electrons on the nitrogen atom that can react further with a haloalkane to form a secondary amine