Phenols Flashcards
1
Q
what is phenol?
A
a weak acid that partially dissociates in water to form a phenoxide ion
2
Q
what is phenol more acidic than?
A
alcohols
3
Q
what is phenol less acidic than?
A
carboxylic acids
4
Q
how is phenol’s weak acidity shown?
A
undergoes a neutralisation reaction with NaOH but does not with carbonates
5
Q
why is phenol more reactive than benzene?
A
- phenol has a better relative ease of electrophilic substitution compared with benzene
- in phenol. there is a lone pair of electrons from the oxygen p-orbital of the -OH group which is delocalised and being donated to the pi system of the phenol
- the electron density increases, so is higher than benzene
- so phenol attracts the electrophile more strongly than benzene
6
Q
what are the 2- and 4- directing effect of electron donating groups?
A
- OH
- NH2`
7
Q
what are the 3- directing effect of electron withdrawing groups?
A
- NO2
8
Q
what type of reactions does phenol take place in?
A
- electrophilic substitution reactions
9
Q
what are the electrophilic substitution reactions of phenol?
A
- with bromine to form 2,4,6-tribromophenol
- with dilute nitric acid to form a mixture of 2-nitrophenol and 4-nitrophenol
