nitration of benzene Flashcards
1
Q
briefly summarise the reactivity of bezene
A
- delocalised pi electron cloud makes it stable
- stable molecules undergo substitution
- attacked by positive electrophiles
- making it electrophilic substitution
2
Q
what is nitration of benzene?
A
the substitution of a nitro group into the benzene ring
3
Q
state the 3 steps of electrophilic substitution
A
- formation of electrophile
- electrophilic attack
- reformation of catalyst
4
Q
what conditions are involved in nitration?
A
- concentrated H2SO4 catalyst
- 50 degrees
5
Q
how is the nitronium ion electrophile produced?
A
- reaction of nitric acid with H2SO4
- forms NO2+, HSO4- and H2O
6
Q
describe the electrophilic attack for nitration
A
- nitronium ion accepts an electron from the pi cloud shown by an arrow from the cloud out to ion
- benzene ring becomes positive, cloud only covers 4 sides of ring
- H loses electron into the cloud to reform it so H is positive
- end product = benzene ring with nitrate attached and H+
7
Q
describe how the catalyst is reformed in nitration
A
HSO4- + H+ –> H2SO4
8
Q
why can temperature not exceed 50 degrees?
A
denitration occurs
