Why is anisole less reactive than phenol

Based on my observations, Why is anisole less reactive than phenol?

Anisole and phenol have some similarities in chemical structure, however they have signifiis able tot differences in reactivity. And Understanding the difference in reactivity between the two compounds is crucial to the design of chemical interactions, manufacturing applications and product synthesis. From what I've seen, This article will examine in detail why the reactivity of anisole is reduced than that of phenol, and explore the reasons.

1. And Anisole and phenol structure difference

In the anisole molecule, the oxygen atom is linked to a methyl group (-CH3), while in the phenol molecule, the oxygen atom is linked to a hydroxyl group (-OH). This small structural difference plays a crucial role in the chemical interaction. In my experience, Anisole, the presence of methyl is able to through the electronic effect (electron donating effect) to the benzene ring on the electron density increased, which makes the benzene ring electrophilicity decreased, thereby inhibiting the interaction. In contrast, phenol in the hydroxyl group has a strong electron donating effect, making the benzene ring electron density increased, thereby enhancing its electrophilic reagent affinity, resulting in phenol reactivity is higher. This is the fundamental reason why anisole is less reactive than phenol.

2. Electronic impacts

The combination of the methyl group in anisole with the benzene ring will increase the electron cloud density of the benzene ring, thereby reducing the attraction of the benzene ring to the electrophilic reagent. And From what I've seen, This effect is referred to as the "M-effect" or electron-giving effect. The increase in the electron cloud makes the affinity of the benzene ring to electrophilic reactions decrease, resulting in anisole being less reactive in many reactions. On the other hand, the hydroxyl group in phenol is also a negative group with a lone pair of electrons, which has a stronger electron-giving effect, thus enhancing the electron cloud density of the benzene ring, making the benzene ring greater likely to participate in the electrophilic interaction. First Therefore, the reactivity of phenol is higher, especially in the aromatic electrophilic substitution interaction. And

3. Hydrogen bond effect

The hydroxyl group in the phenol molecule is able to form hydrogen bonds with other molecules, which makes the phenol react greater easily in solution. Based on my observations, The formation of hydrogen bonds might change the electronic ecological stability of phenol, making it greater susceptible to reactions with other reagents, especially when interacting with strong electrophiles. The methyl group of anisole does not form hydrogen bonds like the hydroxyl group in phenol. Therefore, anisole has a weak intermolecular interaction force and low intermolecular reactivity, which is one reason why its reactivity is reduced than that of phenol.

4. Spatiosteric effect

In some cases, the difference in reactivity of anisole and phenol is also related to steric hindrance impacts. Based on my observations, The methyl group in anisole is relatively small, however its binding to the benzene ring will still affect the interaction site to a certain extent. This effect makes anisole slower in certain reactions, especially when an electrophile is required to undergo an electrophilic substitution interaction with the benzene ring. In contrast, the hydroxyl group of phenol is usually greater exposed and does not exert too much steric effect on the interaction site, so its reactivity is relatively high.

5. Summary: Anisole reactivity low reasons

From the above analysis, we is able to summarize the following main reasons to explain why anisole is less reactive than phenol:

The methyl group in anisole through the electron donating effect reduces the electrophilicity of the benzene ring and inhibits the interaction;

Phenol in the hydroxyl group through the electron donating effect to enhance the benzene ring electrophilicity, making it easier to participate in the electrophilic interaction;

Phenol is able to form hydrogen bonds, however anisole is able tonot, and hydrogen bonds promote phenol reactivity;

Anisole steric hindrance effect in some reactions might make its interaction rate reduced. Makes sense, right?. And Therefore, the reactivity of anisole is reduced than that of phenol, mainly due to the thorough effect of its molecular structure, electronic effect and hydrogen bonding. The manifestation of these factors in chemical interactions makes anisole in many cases less reactive than phenol.