Amines Flashcards
Why are primary aliphatic amines stronger bases than ammonia?
The alkyl groups are more releasing and push electrons towards the nitrogen atom and so make it a stronger base.
Why are secondary amines stronger bases than primary amines?
They have more alkyl groups pushing the electrons onto the Nitrogen atom from more angles.
Why are tertiary amines actually the weakest base?
They are less soluble in water and so makes them less strong as bases.
Why do phenylamines form less basic solutions than primary amines?
The delocalised ring in the ring structure draws the electrons from the nitrogen atom and makes the nitrogen less able to accept protons.
What is the reaction for an amine with an acid?
amine + acid = salt (positive)
How do you turn an ammonium salt back into an amine?
Add NaOH
Are the ionic salts formed from the reaction of an amine with an acid soluble or insoluble in water?
They are soluble in water
What are the uses for quaternary ammonium salts?
They can be used as cationic surfactants
Surfactants reduce the surface tension of liquids
The positive N atom is attracted to the negatively charged surfaces
Why is it better to prepare primary amines by reduction of a nitrile than the reaction of a halogenoalkane with excess ammonia?
With nitriles there will only be one product and so there will be a greater atom economy
With halogenoalkanes further substitution can occur
What happens when an amine dissolves in water?
It forms an OH- ion and the amine group forms an ammonium ion
what is a use for 4 methyl phenylamine?
Making dyes
What’s a Brønsted-Lowry base?
A proton acceptor
What could be added to aqueous methylamine to produce a basic buffer?
HCl
