Chem 4:7 - Amines Flashcards
How are amines derivatives of ammonia?
One or more of the H replaced by alkyl or aryl group.
Amines reactivity?
Very
What do the primary secondary and tertiary names indciate
How many substituents on the N group.
What are the shape of primary amines?
Amines keep the pyramidal shape but have a lone pair repelling the substituents
Can H bond to eachother but H bonds not as strongas oxygen.
What is the solubility of amines like?
V soluble in alcohols and water bc can form H bonds
Most amines more soluble in less polar substances
Boiling points of primary amines?
Amines BP lower than alcohol
What state are shorter chain amines
?
gases at room temp
what state are longer chain amines
volatile liquids.
Amines has a lone pair, therefore what can it do
?
- Act as base , aceepting a proton
- Bond with electron deficient carbon , acting as a nucleophile
When amine acts as a nucleophilem what happens to the nitrogen
it gains a positive charge
When amines act as bases, reacting with acids , what do they form ?
Salts
What will phenyl amine dissolve in
Excess HCL
look at flashcard
What does the strength of a base depend on ?
how readily it accepts an H+ ion
What is the inductive affect
Alkyl and aryl groups release e’s away from them therefore torwards the Nitrogen
This makes them better electron par donor
- amines are better than ammonia
why are 2ndary bases better than primary
because they have 2 inductive effects
but why are tertiary not as good bases as 2ndary
because they are not as soluble in water
When are primary aliphatic amines produced?
when ammonia reacts with a haloalkane
What can happen when the primary amine is produced
it has a lone pair therefore can act as a nuclephile to prod secondary amine
What then happens after the 2ndary amine is formed?
it reacts again with a haloalkane to form a tertiary amine
what happens when the tertiary amine is formed?
Reacts with another haloalkane again to form quarternery amine but this doesn’t have a lone pair.
What 2 steps does the preparation of amines involve from a haloalkane?
HA’s react with a CN ion in aq ethanol and CN- replaces halide ion by nucl subs to form nitrile.
- RBr + CN-»_space;» R-CN + Br-
Nitriles contain FG CtriplebondN therefore can be reduced to a primary amine by HYDROGENATION using Ni/H2
- R-CN + H2»_space;» R-CH2NH2
How to make phenylamine?
Step 1)
Benzene can either be reacted with nitric acid or sulphuric acid
This produces nitrobenzene
Step 2)
Nitrobenzene reduced to phenylamine using tin and HCl as red agent
H reduces nitrobenzene by replacing O with H
