Method to Prepare Methoxybenzene from Phenol

There are various methods to prepare methoxybenzene (also known as anisole) from phenol, but one of the most common and efficient methods is as follows:

1. Preparation of Sodium Phenoxide
- Sodium phenoxide is prepared by reacting phenol with sodium hydroxide (NaOH).
- Phenol and NaOH are mixed in a 1:1 molar ratio in a round-bottom flask.
- The mixture is heated and stirred until a clear solution is formed.
- The solution is then cooled to room temperature, and sodium phenoxide is obtained as a white crystalline solid.

2. Methylation of Sodium Phenoxide
- The methylation of sodium phenoxide is carried out using methyl iodide (CH3I) or dimethyl sulfate [(CH3)2SO4] as a methylating agent.
- Methyl iodide is preferred over dimethyl sulfate due to its lower toxicity and higher reactivity towards sodium phenoxide.
- The methylating agent is added dropwise to the sodium phenoxide solution while stirring and maintaining a temperature of around 70-80°C.
- The reaction mixture is then heated under reflux for several hours until the reaction is complete.
- The resulting mixture is then acidified with dilute hydrochloric acid (HCl) to obtain the crude product, which is extracted with an organic solvent such as ether or dichloromethane.
- The organic layer is then dried over anhydrous sodium sulfate (Na2SO4) and concentrated under reduced pressure to obtain pure methoxybenzene as a colorless liquid.

Overall, the method involves the following steps:

1. Preparation of sodium phenoxide by reacting phenol with NaOH.
2. Methylation of sodium phenoxide using a methylating agent such as CH3I or (CH3)2SO4.
3. Acidification of the reaction mixture to obtain the crude product.
4. Extraction of the crude product with an organic solvent.
5. Drying and concentration of the organic layer to obtain pure methoxybenzene.

This method is widely used in the laboratory and industrial settings for the preparation of methoxybenzene from phenol.