Prepration of arenes from phenol by reduction with zink dust
Phenol is reduced to benzene by passing it's vapour over heated zinc dust.
Kolbe's reaction of phenols
Phenoxide ion generated by treating phenol with sodium hydroxide is even more reactive than phenol towards electrophilic aromatic substitution. Hence, it undergoes electrophilic substitution with carbon dioxide, a weak electrophile. Ortho hydroxybenzoic acid is formed as the main reaction product.
When phenol is treated with chloroform in the presence of aqueous sodium hydroxide at 340 K followed by hydrolysis, an aldehyde group is introduced into the ring mainly at o-position.