Table of Contents
- 1 Why phenol is ortho and para directing?
- 2 Why activators are ortho and para directors?
- 3 Why phenol undergoes electrophilic substitution reaction at ortho and para position?
- 4 Why methyl group is ortho and para directing?
- 5 What are meta directors?
- 6 Which group is weak ring deactivators but ortho and para directors?
Why phenol is ortho and para directing?
Phenols are highly prone to electrophilic substitution reactions due to rich electron density. The hydroxyl group attached to the aromatic ring in phenol facilitates the effective delocalization of the charge in the aromatic ring. The hydroxyl group also acts as ortho para directors.
Why activators are ortho and para directors?
Why is this? Well, electron-donating groups are activators and ortho-para directors because they stabilize the intermediate cations. The intermediate cations are what is formed between the removal and addition stages.
What are ortho para directing activators?
Ortho/para director: In electrophilic aromatic substitution, a substituent that favors electrophilic attack ortho or para to the substituent. Most ortho/para directors are also activators, except for the halogens, which are deactivators.
What are ring activators?
Ring activators are groups that increase the electron density on the benzene ring and thereby make the ring more susceptible to electrophilic aromatic substitution reactions.
Why phenol undergoes electrophilic substitution reaction at ortho and para position?
1) Phenols undergo electrophilic substituition at ortho and para position because the lone pair on oxygen atom stabilises the intermediate carbocation and the stabilization is maximum at ortho and para position. Thus the presence of hydroxyl group makes the ring activating and reactive at ortho and para position.
Why methyl group is ortho and para directing?
Answer: (a) In toluene, methyl group is activating and ortho-para directing because it increases electron density at ortho and para positions.
Why are halogens ortho para directors?
Halogens are very electronegative. This means that inductively they are electron withdrawing. However, because of their ability to donate a lone pair of electrons in resonance forms, they are activators and ortho/para directing. Because they are electron withdrawing, halogens are very weak activators.
How do ortho para directors work?
If the relative yield of the ortho product and that of the para product are higher than that of the meta product, the substituent on the benzene ring in the monosubstituted benzene is called an ortho, para directing group. If the opposite is observed, the substituent is called a meta directing group.
What are meta directors?
Meta director: In electrophilic aromatic substitution, a substituent that favors electrophilic attack meta to the substituent. Most meta directors are also deactivators. Bromination of nitrobenzene gives meta-bromonitrobenzene as the major product because the nitro group is a meta director. aq.
Which group is weak ring deactivators but ortho and para directors?
Halogens: A Special Case However, because of their ability to donate a lone pair of electrons in resonance forms, they are activators and ortho/para directing. Because they are electron withdrawing, halogens are very weak activators. Electron withdrawing groups are meta directors and they are deactivators.
Why phenol is ortho para directing in nature towards electrophilic substitution reaction explain with the help of resonating structure?
Because the -OH group is a strongly activating group (see Electrophilic aromatic directing groups). The -OH group tends to be electron-donating because the extra electrons around the oxygen atom can be shared with the aromatic benzene ring. Thus, it contributes resonance structures that can be seen below.