Chapter 27 Amines, Amino acids and polymers

Question 1

What are amines?

Answer 1

Organic compounds, derived from ammonia, in which one or more hydrogen atoms have been replaced by a carbon chain or ring

Question 2

How are amines classified?

Answer 2

Amines are classified as primary, secondary or tertiary by the number of alkyl groups attached to the nitrogen atom
1 group –> Primary
2 groups –> Secondary
3 groups –> Tertiary

Question 3

How do you name an amine?

Answer 3

When the -NH2 group is on the end of the chain, add the suffix -amine to the name of the alkyl chain

When the-NH2 group is not on the end of the chain, add the prefix amino- (including a position number) to the name of the alkyl chain

Question 4

Why do animes act as bases in reactions?

Answer 4

Because of the lone pair of electrons on the nitrogen atom that can accept a proton

Question 5

Describe how to form a primary amine

Answer 5

1) Ammonia reacts with a haloalkane to create an ammonium salt
2) Aqueous alkali like NaOH is added to generate the amine from the salt

Question 6

What are the two conditions for forming a primary amine?

Answer 6

• Ethanol is used as the solvent to prevent any subsitution of the haloalkane by water to produce alcohols
• Excess ammonia is used to reduce further substitution of the amine group to form secondary and tertiary amines

Question 7

What is an amino acid?

Answer 7

An organic compound containing both amine and carboxylic acid functional groups

Question 8

Why can amino acids take part in both acidic and basic reactions

Answer 8

Amino acids contain both an acidic COOH and a basic NH2 so it will have similar reactions to both carboxylic acids and amines

Question 9

Describe the esterification of amino acids with alcohols

Answer 9

Amino acids are easily esterified by heating with an alcohol in the presence of concentrated sulfuric acid

Question 10

What is steroisomerism

Answer 10

Compounds with the same structural formula but a different arrangment of atoms

Question 11

What conditions are required for optical isomerism in molecules?

Answer 11

Optical isomerism is found in all molecules that contain a chiral centre

Question 12

What is a chiral centre?

Answer 12

A carbon atom that is attached to four different atoms or groups of atoms

Question 13

What are optical isomerisms?

Answer 13

Non-superimposable mirror image structures

Question 14

What is condensation polymerisation?

Answer 14

The joining of monomers with the loss of a small molecule

Question 15

What are the two different cases of monomers that can be used to create polyesters?

Answer 15

1) One monomer containing both a carboxylic acid and an alcohol group
2) Two monomers - one containing two carboxylic acid groups and the other containing two alcohol groups

Question 16

How are polyesters created?

Answer 16

When monomers area joined together by ester linkages in a long chain to form a polymer

Question 17

How is an ester linkage created?

Answer 17

When the carboxylic acid group in one molecule reacts with the alcohol group of another molecule

Question 18

How are polyamines created?

Answer 18

When monomers are joined together by amide linkages in a long chain to form the polymer

Question 19

how is an amide linkage created?

Answer 19

When the carboxylic acid (or acyl chloride) gruop in one molecule reacts with the amine group of another molecule

Question 20

What are the two different cases of monomers that can be used to create polyamines?

Answer 20

1) One monomer containing both a carboxylic acid (or acyl chloride) and an amine group
2) Two monomers, one containing two carboxylic acid groups (or acyl chloride groups) and the other containing two amine groups

Question 21

How can you seperate polyesters and polyamides?

Answer 21

Polyesters and polyamides can be hydrolysed using hot aqueous alkali such as sodium hydroixde or by hot aqueous acid such as hydrochloric acid

Question 22

What is the general formula for an a-amino acid?

Answer 22

RCH(NH2)COOH

Question 23

Describe the preparation of aromatic amines

Answer 23

1) Nitrobenzene is heated under reflux with a reducing agent of tin and hydrochloric acid to form the ammonium salt, phenylammonium chloride
2) The salt is reacted with excess sodium hydroxide to produce the aromatic amine