3.11 Amines Flashcards
what is an aliphatic amine?
- R group attached is an alkyl group
what is an aromatic amine?
- contains an aryl group ( benzene or phenyl )
how do you name amines
- use longest chain name + amine suffix
how would you name CH3NH2
methyl amine
how would you name CH3CH2NH2
ethyl amine
how would you name CH3NHCH3
dimethylamine
give the conditions, type of reaction for reaction of halogenoalkanes with ammonia
- nucleophilic substitution
- excess, hot ethanolic ammonia under pressure
how can you prepare an amine from reduction of nitriles?
using LiAlH4 or Ni catalyst
4 [H] per C=N bond
2H2 per C=N bond
give the first reaction and conditions for preparation of phenyl amine
- benzene undergoes nitration
- conc nitric acid and conc h2so4
- 25-60 degrees
give the reaction and conditions for second step of preparation of phenylbenzene
- reduction of nitrobenzene with hot tin and conc HCl under reflux to form acidic mixture
what are the basic properties of amines
- NH3 can accept a proton, acting as an acid
- they can act as bases by donating a lone pair of electrons
what is the last step for preparation of phenyl amine
- sodium hydroxide added to acidic reaction to form phenylamine
- seperated via steam distillation
how is strength determined of ammonia and amines as bases
- strength depends on ability of lone pairs on electrons on nitrogen atom to accept a proton
- stronger the base, more readily a proton is attracted.
what factors affect strength of ammonia and bases
positive inductive effect
• alkyl groups donate electron density to nitrogen atom causing lone pair of electrons to become more available
delocalisation
• presence of aromatic rings such as benzene cause lone pair of electrons on nitrogen atom to be delocalised into benzene ring
• lone pair becomes less available, hence weaker
how do cationic surfactants work
- they are quarternary ammonium salts with a positively charged head and a non-polar tail
- hydrophobic tail dissolves in grease, while hydrophilic head interacts with water
- allows them to act as emulsifiers