Aromaticity Flashcards
How is the structure of benzene achieved
Every carbon is bonded to two other carbons and one hydrogen, and the remaining electron dissociates to form an electron dense ring
How does benzene react
Substitution reactions
How is benzene nitrated
Using nitric acid and sulfuric acid catalyst on ice
How is benzene alkylated
Using an aluminium chloride catalyst and CH3Cl, giving a by-product of HCl
How is benzene halogenated
Using aluminium chloride/iodide/bromide and creating a by-product of HCl/HBr/HI
What happens when you oxidise methylbenzene in acidified potassium manganate
You create benzoic acid
What happens when you react methylbenzene with KOH. What happens when you then add HCl
You get the salt of the benzoic acid, Potassium benzoate. Adding HCl creates benzoic acid again, and the potassium forms KCl
Describe how benzoic acid is acidic
The electrons from the O atoms dissociate into the ring and the H atom is more easily lost
How do you decarboxylate benzoic acid
Adding soda lime under a high heat causes benzene, sodium carbonate and water to form
How do you test for benzoic acid
Add sodium carbonate and observe effervescence
How do you reduce benzoic acid
Using lithium tetrahydroaluminate in ether
How does a methyl substitution affect further substitutions on the benzene ring
Little effect
How does an OH substitution affect further substitutions on the benzene ring
Activates the benzene ring, higher force of attraction easier to react
How does an NH2 substitution affect further substitutions on the benzene ring
Makes it harder to react, draws electrons away from ring
How does a Cl substitution affect further substitutions on the benzene ring
Little effect on the reactivity, but all three lone pairs delocalise to the ring, making the C-Cl bond very strong.
