Types of amines:

• they are derived from ammonia molecules and they all contain a nitrogen atom.

• primary amines

  • Only one of the hydrogens in an ammonia molecule has been replaced with an alkyl group

• secondary amines

  • two of the hydrogens in an ammonia molecule have been replaced with an alkyl group

• tertiary

  • all 3 of the hydrogens in an ammonia molecule have been replaced with an alkyl group

• quaternary

  • there are 4 alkyl groups around the nitrogen atom and the nitrogen has a positive charge

• aromatic amines

  • they are primary amines

  • they contain a benzene ring

• non aromatic amines are known as aliphatic amines

cationic surfactants

• quaternary ammonia salts are used in cleaning products

  • when they have a long hydrocarbon tail they are referred to as cationic surfactants

  • they are made from a positive end group and are attracted to negative ions

    • eg. tetramethylammonium chloride

• they work using their polarities

  • the non-polar head is attracted to the oil/grease

  • the polar head is attracted to the water

  • they allow the oil and water to mix to remove it from clothes, skin ect.

• they make an emulsion

  • this is because they let water and oil mix

• they also remove static

  • the positive ammonium ion is attracted to negatively charged hair and fibres

  • that allows it to remove static

  • it is used in conditioner and fabric conditioner

amines as bases:

• they accept H+ ions

  • this is because they have a lone pair of electrons that allows them to do so

  • the proton bonds through a coordinate bond where both electrons come from the lone pair

• the strength of the base depends on how available the lone pair is on the nitrogen

  • the higher the electron density the more available the electrons are

  • the type of group that is bonded to the nitrogen decides the electron density

    • aromatic amines —> ammonia —> primary aliphatic amines (weakest to strongest)

• aromatic amines

  • they pull electrons away from the nitrogen into the ring

  • the electron density at the nitrogen is reduced so they are less basic

  • they attract the proton the least

• aliphatic amines

  • alkyl groups push electrons towards the nitrogen.

  • the electron density at the nitrogen increases so they are more basic

  • they attract the proton the most

• THEY ARE ALSO NUCLEOPHILES

  • this is because of the lone pair of electrons

preparation of aliphatic amines

• they are made in two ways

  • reacting a halogenoalkane with excess ammonia

  • reducing a nitrile

• reaction of a halogenoalkane with excess ammonia

  

  • ammonia attacks the partially positive carbon

  • then an intermediate is formed with a positive nitrogen and a Br- ion

  • second ammonia then reacts with the hydrogen to remove it.

• a reaction of a halogenoalkane with excess ammonia may produce impure products

  • it can produce secondary, tertiary, and quaternary salts as well

  • this is because primary amines still have a lone pair and can still act as a nucleophile

  • the amine can then react with any other halogenoalkanes to make salts

  • the mechanism is the same for the continued reaction but instead of two ammonia molecules its 2 amines

  • eg. (CH₃CH₂)₂NH + CH₃CH₂Br ➔ (CH₃CH₂)₃N + HBr

• reducing nitriles

  • this is the cheapest way to make primary amines

  • it uses hydrogen gas and a nickel or platinum catalyst

  • the reaction is called catalytic hydrogenation

  • it only produces primary amines

    • a pure prodyct

  • eg.R-C≡N + 4[H] ➔ R-CH₂-NH₂

• using a strong reducing agent

  • the method is more expensive as LiAlH4 is expensive

  • the reducing agent is dissolved in a non-aqeous solvent

production of aromatic amines:

• they are made with the reduction of a nitro compound

  • nitrobenzene is reduced to make an aromatic amine

• step 1:

  • heat nitrobenzene under reflux with concentrated HCl and tin to form a salt

  • 6 reducing agents are used

• Step 2:

  • the salt reacts with an alkali to produce an aromatic amine such as phenylamine

• 

amides:

• they are derivatives of carboxylic acids

  • their functional group is -CONH2

  • has an NH2 instead of the OH group of carboxylic acids

• N-substituted amides

  • one of the hydrogens is replaced with an alkyl group

• production:

  • made from an acyl chloride and ammonia

  •