Phenolates (also called phenoxides) are anions, salts, and esters of phenols, containing the phenolate ion. They may be formed by reaction of phenols with strong base.[1]
Properties
Alkali metal phenolates, such as sodium phenolate hydrolyze in aqueous solution to form basic solutions.[2] At pH = 10, phenol and phenolate are in approximately 1:1 proportions.
The phenoxide anion (aka phenolate) is a strong nucleophile with a comparable to the one of carbanions or tertiary amines.[3] Generally, oxygen attack of phenoxide anions is kinetically favored, while carbon-attack is thermodynamically preferred (see Thermodynamic versus kinetic reaction control). Mixed oxygen/carbon attack and by this a loss of selectivity is usually observed if the reaction rate reaches diffusion control.[4]
Uses
Alkyl aryl ethers can be synthesized through the Williamson ether synthesis by treating sodium phenolate with an alkyl halide:[5]
- C6H5ONa + CH3I → C6H5OCH3 + NaI
- C6H5ONa + (CH3O)2SO2 → C6H5OCH3 + (CH3O)SO3Na
Production of salicylic acid
Salicylic acid is produced in the Kolbe–Schmitt reaction between carbon dioxide and sodium phenolate.
