what is the relative bromination rates of the following aromatic compounds; clorobenzene, methoxybenzene, nitrobnzene, toluene, benzene
To determine the relative bromination rates of the aromatic compounds, we need to consider the electron-donating or electron-withdrawing nature of the substituents on the benzene ring.
1. Chlorobenzene (C6H5Cl): Chlorine is a weak electron-withdrawing group. It slightly deactivates the benzene ring towards electrophilic aromatic substitution reactions. Therefore, chlorobenzene will have a slower bromination rate compared to benzene.
2. Methoxybenzene (C6H5OCH3): Methoxy group (-OCH3) is an electron-donating group due to the presence of the lone pairs of electrons on the oxygen atom. It activates the benzene ring towards electrophilic aromatic substitution reactions. As a result, methoxybenzene will have a faster bromination rate compared to benzene.
3. Nitrobenzene (C6H5NO2): Nitro group (-NO2) is a strong electron-withdrawing group due to its strong electron-withdrawing resonance effect. It deactivates the benzene ring significantly towards electrophilic aromatic substitution reactions. Nitrobenzene will have a slower bromination rate compared to benzene.
4. Toluene (C6H5CH3): Toluene has a methyl group (-CH3) as a substituent. Methyl is a weak electron-donating group, which slightly activates the benzene ring towards electrophilic aromatic substitution reactions. Toluene will have a slightly faster bromination rate compared to benzene.
5. Benzene (C6H6): Benzene itself is considered a moderately activated aromatic compound. It undergoes bromination at a moderate rate.
Therefore, the relative bromination rates from fastest to slowest would be: methoxybenzene > toluene > benzene > chlorobenzene > nitrobenzene.