Selective hydroxylation of phenol or phenolic ethers
AssigneeSolvay Interox Limited
InventorRobert Alexander Walker Johnstone
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Abstract
Phenols, and related aromatic compounds, phenolic ethers, can be hydroxylated selectively using hydrogen peroxide in the presence of an amorphous or crystalline tin or cerium phosphate catalyst in a solvent containing an aliphatic carboxylic acid. The process is particularly suitable for phenol itself, and advantageously employs a catalyst obtained by heating an hydrated amorphous or crystalline tin or cerium phosphate for example at about 100.degree. C. A convenient hydroxylation temperature is in the range of 50.degree. to 90.degree. C., and a convenient solvent is acetic acid.
Claims18
A process for the hydroxylation of a substrate comprising a phenol or related aromatic compound by reaction with hydrogen peroxide in the presence of a catalyst, wherein the substrate comprises a phenol or phenolic ether, the reaction is carried out in a solvent containing an effective amount of an aliphatic carboxylic acid and the catalyst comprises one or both of tin (IV) or cerium (IV) phosphate.
A process according to any preceding claim wherein the catalyst employed therein is obtained by reacting tin or cerium chloride or sulphate with phosphoric acid.
Dependencies are inferred from the claim text.