PURPOSE: To obtain the title compound useful as an intermediate of pyrethroid insecticides industrially advantageously, by catalytic oxidation of metaphenoxytoluene in a specific solvent in the presence of cobalt bromoacetate as a catalyst, and by recycling the catalyst and solvent in the reaction process.
CONSTITUTION: m-Phenoxytoluene is oxidized with oxygen or a gas comprising oxygen e.g. air, in a solution of cobalt bromoacetate in a lower fatty acid. The reaction liquid thus obtained is cooled at 60°C or below, and the deposited crystals of m-phenoxybenzoic acid are separated. The remaining mother liquor is distilled by adding an organic solvent capable of forming an azeotropic mixture with water, preferably benzene, to have 4% of water or less, and recycled in the oxidation step mentioned above. This catalyst has advantages of rapid oxidation of said raw material without a reaction initiator and a co-catalyst, and of repeated use in a simple treatment.
KANEHARA YOSHIKANE
ARIIZUMI AKIRA
