6.2.1: Amines Flashcards
Describe the basicity of amines
Lone pair of electrons on nitrogen allows them to accept protons which bond by dative covalent bonds
How is the strength of a base determined ?
The availability of lone pair of electrons on nitrogen .. a higher electron density means electrons are more readily available
What forms from the reaction between methyamine and dilute acid HCl ?
Methylammonium chloride
What forms from the reaction between diethylamine and sulfuric acid ?
Diethylammonium sulfate
What forms from the reaction between trimethylamine + phosphoric acid ?
Trimethylammonium phosphate
What happens to solutions when amines react with water
OH- ions produced so pH will always be above 7
How are aliphatic amines prepared ?
Nucleophilic substitution of haloalkanes with excess ethanolic ammonia and amines
What is produced from preparation of aliphatic amines ?
Impure product of primary, secondary, tertiary and quarternary salts as primary amines have an extra lone pair of electrons to still act as a nucleophile
Haloalkane + excess ethanolic ammonia =
Primary amine + ammonium halide
Why is ethanolic ammonia used ?
As the ethanol hydrogen bonds with the ammonia to act as a solvent
Why is the preparation of aliphatic amines carried out in a thick walled vessel ?
The ammonia is gaseous so needs to not dissipate and be kept in container to react
What are 2 ways tetraalkylammonium salts produced ?
- Excess haloalkane + ammonia –> tetraalkylammonium salt + hydrogen halide
- Primary -> secondary amine … kep on reacting with excess amine + haloalkane
What conditions are required for the reduction of nitroarenes ?
Tin + conc. HCl
How is a simple nitrile group reduced ?
Give a benefit of process
- Add hydrogen in presence of Nickel catalyst
- 100% yield as no other products
Give equation for reduction of Propanenitrile
Propanenitrile + hydrogen –> Propylamine
