Amines

Question 1

what is an amine

Answer 1

it is derived from ammonia and contains a nitrogen replaced with an organic group

Question 2

what is a primary amine

Answer 2

1 alkyl group attached to the nitrogen with lone pair and no hydrogens attached

Question 3

secondary amine

Answer 3

2 alkyl group attached to the nitrogen with lone pair and no hydrogens attached

Question 4

tertiary amine

Answer 4

3 alkyl group attached to the nitrogen with lone pair and no hydrogens attached

Question 5

quaternary

Answer 5

4 alkyl group attached to the nitrogen with lone pair and no hydrogens attached

Question 6

non aromatic amines are

Answer 6

aliphatic no beznene rings

Question 7

what are quaternary ammonium salts used for

Answer 7

to make cleaning products such as shampoo, detergents and washing up liquids

Question 8

properties of primary amines

Answer 8

pyramidal
polar
primary and secondary can form hydrogen bonds to each other and water
tertiary binds cannot form hydrogen bonds to each other
boiling points is lower than alcohols
they tend to be water soluble

Question 9

reactivity of amines

Answer 9

they contain a lone pair of electrons which is used to bond with H+ ion acting as a base and an electron deficient carbon atom where it acts as a nucleophile to donate electrons to form bonds.

Question 10

order of base strengths of amines
weakest
strongest

Answer 10

aromatic amines
ammonia
primary aliphatic amines

Question 11

why is benzene a weak base

Answer 11

benzene is an electron withdrawing group so it pulls electrons away from nitrogen into the delocalised ring structure, the electron density of nitrogen reduces the lone pair available so aromatic amines is less basic.
the Nitrogen lone pair is partially delocalised into the base strength

Question 12

why is primary aliphatic amines more stronger bases

Answer 12

alkyl groups are electron pushing so they push the electron towards the nitrogen and the electron density at nitrogen increases so lone pair availability is increases so they are more basic
‘positive inductive effect’

Question 13

what are the ways to make aliphatic amines

Answer 13

1-. reacting halogenolakanes and ammonia
2. reducing nitriles

Question 14

reacting halogenoalkane with excess ammonia is a ——- mechanisim

Answer 14

nucelophilic substitution

Question 15

how to make aromatic amines

Answer 15

reduce nitro compounds
heat under reflux the nitrobenzene and concentrated hcl and tin to form a salt which reacts with an alkali to produce the aromatic amine