PURPOSE: m-Phenoxybenzoic acid containing the para-isomer is recrystallized with an aromatic hydrocarbon solvent in high recrystallization yield to give the highly pure m-phenoxybenzoic acid useful as a raw material for antiinflammatory analgesics or synthetic pyrethroid insecticides.
CONSTITUTION: Highly pure m-phenoxybenzoic acid is prepared by recrystallizing m-phenoxybenzoic acid containing the para-isomer with an aromatic hydrocarbon solvent (e.g. benzene, toluene, xylene, etc.) in a recrystallization yield of as high as ≥95%, wherein the para-isomer content is reduced e.g. from 1W3% to ≤0.005%. The preferable amount of the solvent is 50W500 parts by weight on the basis of 100 parts by weight of m-phenoxybenzoic acid in the mixture, and a high recrystallization yield can be attained even with comparably small amount of the solvent. The solvent forms the azeotrope with water and therefore can be easily dehydrated. The solvent is also the most suitable medium for the successive chlorination-reduction process, and the efficiency of solvent utilization in the whole process can be increased.
| JPS56113719 | ALKOXYLATION OF CRESYLIC ACID |
| JP2018027900 | METHOD FOR PRODUCTION OF AROMATIC TETRACARBOXYLIC ACID |
| JPH09278774 | PRODUCTION OF OXEPIN DERIVATIVE |
KANEHARA YOSHIKANE
KATOU ISHIO
OOZEKI TAKASHI
WATANABE YUKIO
