Aromatic compounds + amines Flashcards
1
Q
Benzene formula
A
C6H6
2
Q
Outline the structure of the benzene ring
A
- Planar cyclic
- Each C bonds covelantly to C next to it + 1 H
- Unpaired e- is located in p-orbital to form ring of delocalised e-
- All C-C bonds are the same length - 140pm
3
Q
Why is benzene more stable than cyclohexene
A
Delocalised ring of e-
4
Q
Why do arenes undergo electrophilic substitution?
A
Benzene ring is region of high electron density so attracts electrophiles
5
Q
What are arenes used for?
A
Dyes + pharmaceuticals
6
Q
What are the uses for nitro compounds?
A
- Can be reduced to form aromatic amines - dyes + pharmaceuticals
- Explosives - 2,4,6-trinitromethylbenzene
7
Q
How are quaternary ammonium salts formed?
What are their uses?
A
- Quaternary ammonium ions are +ve, they hang round any -ve ions
- QAS w/ 1 long hydrocarbon chain are used for cationic surfaces - hydrocarbon chain binds to nonpolar substances like grease, cationic head dissolves in water - fabric cleaners + hair product
- +ve charged ammonium ion binds to -ve surfaces such as hair/fibre - gets rid of static so used in fabric conditioners
8
Q
Why is a primary amine a strong base?
A
- Alkyl group push e- onto N
- e- density on N inc
- Lp more available
- More likely to accept a proton
9
Q
Why are aromatic amines weak bases?
A
- Benzene ring draws e- towards itself
- N lp partially delocalised onto ring
- Electron density on N dec
- Lp less available
- Less likely to accept proton
10
Q
What is an alternative to using LiAlH4 when reducing nitriles to amines?
A
- Catalytic hydrogenation
- Hydrogen gas
- Nickel catalyst
- High temp + pressure
11
Q
Amide functional group
Outline why they act differently to amines
A
-CONH2
Carbonyl group pulls e- away from NH2 group
