Chapter 27 - Amines, Amino Acids, Amides and Chirality

Question 1

What is an amine

Answer 1

• derived from ammonia (NH3)
• contains a nitrogen atom where all of the hydrogen atoms are replaced with an organic group

Question 2

primary amine

Answer 2

• nitrogen with one organic group attatched to it

Question 3

secondary amine

Answer 3

• nitrogen with two organic groups attached to it

Question 4

tertiary amine

Answer 4

• nitrogen with three organic groups attached to it

Question 5

quaternary amine

Answer 5

• this is a positive ion and contains one dative covalent bond
• nitrogen cation with four organic groups attached to it

Question 6

how do amines act as a base

Answer 6

• amines have a lone pair of electrons on the nitrogen
• proton acceptors
• proton bonds to the amine in a dative covalent bond, both electrons from the bond come from the lone pair on the nitrogen

Question 7

what affects how strongly the amine acts as a base?

Answer 7

• strength of base depends on the availability of the lone pair of electrons on the nitrogen
• the higher the electron density of the groups on the nitrogen, then the electrons are more readily available

Question 8

what are the two ways of producing an aliphatic amine?

Answer 8

• reacting a haloalkane with excess ammonia (one molecule of haloalkane reacts with two molecules of ammonia)
• or reducing a nitrile

Question 9

haloalkane reacts with excess ammonia to produce

Answer 9

• primary aliphatic amine and ammonium halide salt

Question 10

downsides of reacting haloalkane with excess ammonia to produce aliphatic amine

Answer 10

• this reaction process produces secondary, tertiary and quaternary salts so the product is impure
• this occurs because primary amines have lone pair of electrons on the nitrogen so can act as a nucleophile and attack unreacted haloalkane

Question 11

How are aromatic amines made

Answer 11

• made by reducing nitro compounds (such as nitrobenzene)

Question 11

what are aromatic amines used for

Answer 11

used to make dyes and used in pharmaceuticals

Question 12

what are steps when making aromatic amines?

Answer 12

• heat under reflux (for volatile compounds) nitrobenzene with concentrated HCl and tin to form a salt like C6H5NH3+ Cl-
• the salt is reacted with an alkali like NaOH to produce an aromatic amine

Question 12

What is an amide

Answer 12

derivative of carboxylic acids and have functional group CONH2

Question 12

What are alpha amino acids and what are their general formula

Answer 12

• the NH2 group and the COOH group are attached to the same carbon atom in the chain
• RCH(NH2)COOH

Question 12

what is an amino acid?

Answer 12

contain an amino group (NH2) and a carboxyl group (COOH)

Question 13

how do amino acids react with alkalis

Answer 13

• they react with the carboxylic acid group in amino acids to form a conjugate base RCH(NH2)COO- which combines with a positive ion to form a salt

Question 13

why are amino acids amphoteric and what does amphoteric mean

Answer 13

amino acids are amphoteric, meaning they have acidic and basic properties

Question 13

how do amino acids react with acids

Answer 13

• acids react with the amino group to form a conjugate acid

Question 13

What is optical isomerism

Answer 13

• a form of stereoisomerism (same structural formula but different arrangement of atoms in space)
• mirror images of each other and have a chiral carbon atom

Question 13

how do amino acids react with alcohols

Answer 13

• alcohols react with the carboxylic acid group in amino acids to produce esters
• requires a strong acid catalyst (like sulphuric acid catalyst)

Question 13

what is a chiral carbon atom

Answer 13

carbon atom with four different groups attached to it

Question 13

what are enantiomers

Answer 13

• when optical isomers are arranged in two different ways, forming two different molecules
• mirror images of each other which are non super impossible

Question 13

what is addition polymerisation

Answer 13

• alkenes are the monomers which make up addition polymers
• double bond opens up to form the polymer

Question 13

properties of poly(alkenes) : produced by addition polymerisation

Answer 13

• saturated molecules
• non polar, hence unreactive and don’t degrade well in landfill

Question 14

what are the two main types of condensation polymers

Answer 14

polyamides and polyesters

Question 15

what is required for condensation polymerisation

Answer 15

• 2 different monomers with at least 2 functional groups react together
• when they react a link is made, and a smaller water molecule is eliminated

Question 16

how are polyamides produced

Answer 16

by reacting a diamine and a dicarboxylic acid together

Question 17

how are polyesters produced

Answer 17

by reacting a diol and a dicarboxylic acid together

Question 18

what is the hydrolysis of condensation polymers

Answer 18

• condensation polymers can be hydrolysed (split using water) to produce the original monomer