This question is about aromatic compounds and their reactions.
Propiophenone, C6H5COCH2CH3\text{C}_6\text{H}_5\text{COCH}_2\text{CH}_3C6H5COCH2CH3, can be prepared by reacting benzene with propanoyl chloride, CH3CH2COCl\text{CH}_3\text{CH}_2\text{COCl}CH3CH2COCl, in the presence of an aluminium chloride, AlCl3\text{AlCl}_3AlCl3, catalyst.
In the mechanism, propanoyl chloride reacts with the catalyst to form an acylium carbocation, which acts as the electrophile.
What is meant by the term electrophile?
Outline the mechanism for this reaction, including the generation of the electrophile, the electrophilic substitution steps (including relevant curly arrows and the structure of the intermediate), and the regeneration of the catalyst AlCl3\text{AlCl}_3AlCl3.
The table below shows directing effects for different groups in the electrophilic substitution of aromatic compounds.
| Directing effect | 2- and 4-directing | 3-directing |
|---|---|---|
| Group | −OH-\text{OH}−OH, −OCH3-\text{OCH}_3−OCH3, −CH3-\text{CH}_3−CH3 | −NO2-\text{NO}_2−NO2, −COOH-\text{COOH}−COOH, −CHO-\text{CHO}−CHO |
Predict the monosubstitution organic product(s) formed from the following reactions:
Under mild conditions, phenol, C6H5OH\text{C}_6\text{H}_5\text{OH}C6H5OH, readily undergoes tri-substitution with bromine water, Br2(aq)\text{Br}_2\text{(aq)}Br2(aq), without a catalyst. Write a balanced chemical equation for the tri-substitution of phenol with bromine.
Explain why bromine reacts much more readily with phenol than with benzene.
