M6S2: Nitrogen Compounds and Polymers

Amines

• Suffix: -amine/-amine ion

• Nitrogen lone pair can form dative covalent bond with H⁺ = NH₄⁺

• Donates lone pair and accepts lone proton = base

Amines and acids

Amine neutralised = ammonium salts

Producing aliphatic amines from haloalkanes

Heat haloalkanes with excess of ethanolic ammonia (ammonia dissolved in ethanol)

Producing aromatic amines by reducing nitro compounds

• Heat mixture of nitro compound with tin metal & conc HCl under reflux = aromatic ammonium salt

• Add alkali e.g. sodium hydroxide solution = aromatic amine

Amides

• Carboxylic acid derivative

• -CONH₂

• Acts differently to amines, carboxyl group pulls electrons from rest

Naming amides

• If primary, name of stem group, followed by -amide

• Secondary have a prefix to describe alkyl chain directly attached to nitrogen group

• Suffix in the general form of N-alkyl-

• Eg: N-ethylpropanamide

Amino acids

• Two functional groups:

  • Amine(NH₂)

  • Carboxyl(COOH)

• General formula: RCH(NH₂₎COOH

Amino acid and alkali

• Carboxylic group in amino acid reach = conjugate base

• Can combine with positive ion = salt

Amino acid and acid

Amine group can reach with acid to form salt of the conjugate acid

Formation of esters from amino acids

Carboxylic acid in amino acid can react with alcohol in presence of strong acid catalyst to form ester

Chiral carbon

Has four different groups attached to it

Enantiomers/Optical isomers

Mirror images that cannot superimpose

Addition polymer

Double bonds in alkene break and join to make long chains

Polyamides

• Dicarboxylic acids & Diamines

• Carboxyl & amine group form amide link

• Water molecule lost every link

Polyesters

• Dicarboxylic acid & Diol

• Carboxyl + hydroxyl = ester link

Hydrolysis of polyamides

Hydrolyse easier with acid

Hydrolysis of polyesters

• Hydrolyse easier with base

• Metal salt of dicarboxylic acid formed