Chapter 27 Amines, Amino acids and polymers Flashcards
What are amines?
Organic compounds, derived from ammonia, in which one or more hydrogen atoms have been replaced by a carbon chain or ring
How are amines classified?
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
How do you name an amine?
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
Why do animes act as bases in reactions?
Because of the lone pair of electrons on the nitrogen atom that can accept a proton
Describe how to form a primary amine
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
What are the two conditions for forming a primary amine?
- 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
What is an amino acid?
An organic compound containing both amine and carboxylic acid functional groups
Why can amino acids take part in both acidic and basic reactions
Amino acids contain both an acidic COOH and a basic NH2 so it will have similar reactions to both carboxylic acids and amines
Describe the esterification of amino acids with alcohols
Amino acids are easily esterified by heating with an alcohol in the presence of concentrated sulfuric acid
What is steroisomerism
Compounds with the same structural formula but a different arrangment of atoms
What conditions are required for optical isomerism in molecules?
Optical isomerism is found in all molecules that contain a chiral centre
What is a chiral centre?
A carbon atom that is attached to four different atoms or groups of atoms
What are optical isomerisms?
Non-superimposable mirror image structures
What is condensation polymerisation?
The joining of monomers with the loss of a small molecule
What are the two different cases of monomers that can be used to create polyesters?
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
How are polyesters created?
When monomers area joined together by ester linkages in a long chain to form a polymer
How is an ester linkage created?
When the carboxylic acid group in one molecule reacts with the alcohol group of another molecule
How are polyamines created?
When monomers are joined together by amide linkages in a long chain to form the polymer
how is an amide linkage created?
When the carboxylic acid (or acyl chloride) gruop in one molecule reacts with the amine group of another molecule
What are the two different cases of monomers that can be used to create polyamines?
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
How can you seperate polyesters and polyamides?
Polyesters and polyamides can be hydrolysed using hot aqueous alkali such as sodium hydroixde or by hot aqueous acid such as hydrochloric acid
What is the general formula for an a-amino acid?
RCH(NH2)COOH
Describe the preparation of aromatic amines
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
