Phenolates

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]

Structural formula of the phenolate ion

Properties

Main article: sodium phenoxide

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.

See also

• Sodium phenolate