amines Flashcards
How are amines formed from haloalkanes?
Haloalkanes are added to ammonia dissolved in ethanol
How is an amine formed from a nitrile?
A haloalkane is converted to a nitrile via nucleophilic addition and then is reduced to an amine
What reducing agent is used for a nitrile to an amine?
LiAlH4
How are amines formed from nitrobenzene?
Nitrobenzene is formed from electrophilic substitution and is reduced with tin and conc. HCl. NaOH is then added to release the phenylamine.
This is then extracted by steam distillation and ethoxythane
Finally there is final distillation
Why are amines basic?
The nitrogen has a lone pair which can accept protons
How is benzenedizonium produced?
Nitrous acid is reacted with phenylamine below 10C
Why isn’t benzenedizonium isolated?
It is explosively unstable
How is phenol formed from benzenedizonium?
Water is added to it
How is iodobenzene formed from benzenedizonium?
Aqueous KI is added
What are azo-dyes?
Azo dyes are formed from benzenedizonium reacting with phenols or amines
Which part of the azo dye produces colour?
The N triple bond N acts as the chromophore
How is the chromophore formed in azo dyes?
There is an overlap of pi electrons from both of the benzene rings since both nitrogens are partially incorporated, forming a conjugated system
What does a chromophore do?
Absorbs and reflects specific wavelengths of radiation
If a blue light were shone onto a yellow azo dye what colour would it appear?
Black since no radiation is reflected/ all is absorbed
Describe the process of recrystallisation
- Dissolve in minimal solvent (ethanol)
- Filter to remove insoluble impurities
- Cool in a water bath
- Filter again
- Dry in a drying oven
- Take MP and compare to book value
