Amines and amides Flashcards
What are amines?
When one or more hydrogens in ammonia are replaced with an organic group such as an alkyl group or an aromatic group
What is a primary amine?
One hydrogen in ammonia is replaced
What is a secondary amine?
Two hydrogens in ammonia are replaced
What is a tertiary amine?
Three hydrogens in ammonia are replaced
What is a quaternary ammonium ion?
When a fourth organic group is added to the ammonia
What charge do quaternary ammonium ions have?
positive
What is the suffix when you name an amine?
-amine
What do you add to the prefix if its a secondary amine?
di-
What do you add to the prefix if its a tertiary amine?
tri-
How do you name an amine if there are more than one type of organic group attached?
List them in alphabetical order
What are aromatic amines?
Amines with a benzene ring attached
What are surfactants?
Compounds which are partly soluble and partly insoluble in water
What are cationic surfactants?
positively charged surfactants
What can act as cationic surfactants?
Quaternary ammonium salts
Why are cationic surfactants used in detergents?
The non-polar end will bind to grease and the polar head will dissolve in water allowing spots of grease to mix with water and be washed away
What are cationic surfactants used as?
Detergents
Fabric conditioners
Hair products
Why are cationic surfactants used in fabric conditioners and hair products?
The positively charged part of the surfactant is attracted to the negatively charged surface when hair and fabric get wet.
The coating prevents the build up of static electricity, keeping clothes and hair smooth
Why can amines act as bases?
They accept protons
How do amines accept protons?
Lone pairs of electrons on the nitrogen atom that forms a co-ordinate bond with an H+ ion
What does the strength of the base depend on?
How available the nitrogen’s lone pair of electrons is
When will a lone pair of electrons be more available?
If electron density is higher
What happens when the lone pair is more available?
The more likely the amine is to accept a proton so the stronger the base will be
What type of bases are primary aromatic amines?
Weak
Why are primary aromatic amines weak bases?
- benzene ring draws electrons towards itself
- the nitrogen’s lone pair gets partially delocalised onto the ring
- electron density on nitrogen decreases
- lone pair becomes much less available
What type of bases are primary aliphatic amines?
Strong bases
Why are primary aliphatic amines strong bases?
- alkyl group pushes electrons onto the attached groups
- electron density on the nitrogen atom increases
- lone pair is more available
What is the strengths of ammonia as a base?
In the middle of aromatic and aliphatic amines
Why is the strength of ammonia as a base in the middle of aromatic and aliphatic amines?
Doesn’t have an aromatic group to pull lone pair away or an alkyl group to lush the lone pair of electrons forward
What are amides?
derivatives of carboxylic acids
Why do amides behave different from amines?
The carbonyl group pulls electrons away from the NH2 group
From weakest to strongest, what are the strengths of amines as bases?
Weakest; Primary aromatic amines
NH3
Strongest; Primary aliphatic amines
Why are primary aliphatic amines the strongest base?
- They have an alkyl group attached which pushes electrons onto attached groups
- The electron density on the nitrogen increases, making the lone pair much more available
What functional group does amides have?
-C=O(NH2)
Why do amides behave differently to amines?
The carbonyl group pulls electrons away from the NH2 group
What is the suffix when naming amides?
-amide
What is the prefix when naming amides?
Comes form the acyl group
What are N-Substiuted amides?
Amides where one of the hydrogens attached to the nitrogen has been replaced with an alkyl group
