Benzene and Methylbenzene Flashcards
What is the hybridisation of C atoms in benzene?
sp2 hybridised
Why does benzene not undergo addition reactions easily?
The pi ring of delocalised electrons provides extra stability to the structure of benzene
Benzenes reaction with hydrogen
Reagent: H2(g)
Conditions: Pt/Ni catalyst, heat
Type of reaction: Addition/Reduction
A cyclohexane is produced
Reactions with halogens
Reagent: Cl2/Br2
Conditions: AlCl3/AlBr3 (catalysts)
Type of reaction: Electrophilic substitution
A halogenoarene is produced
Nitration
Reagent: Concentrated nitric acid + concentrated sulfuric acid
Condition: 25ºC < T < 60ºC
Type: Electrophilic substitution
Forming nitrobenzene
Friedels-Crafts Alkylation
Reagent: alkylhalide
Condition: AlCl3, heat
Type: Electrophilic substitution
Friedels-Crafts Acylation
Reagents: acylchloride
Conditions: AlCl3, heat
Type: Electrophilic substitution
Why is methylbenzene more reactive than benzene?
Because of the presence of the methyl group
Where will the second substituant enter if the first substituant is electron pushing?
On C 2,4,6
Where will the second substituant enter if the first substituant is electron pulling?
On 3 and 5
Oxidation of side chain of methylbenzene
Reagents: hot alkaline KMnO4 followed b dilute acid
Conditions: heat
Type of reaction: oxidation/redox
The alkyl group is oxidised to COOH
Explain the difference in reactivity between a halogenoalkane and a halogenoarene
Chlorobenzene does not undergo hydrolysis easily. The lone pairs present on Cl tend to get delocalised on the ring, strengthening the Cl-Cl bond, making it harder to break
