| 摘要 |
PURPOSE:To obtain the titled comopound, by melting phthalic acid replaced with a halogen or sulfonic group at the 4-position with an caustic alkali, replacing the halogen or sulfonic group with OH, acidifying the reaction mixture to give a crude reaction product, extracting the reaction product with an organic solvent, removing the solvent, and distilling the reaction product. CONSTITUTION:Easily obtainable phthalic acid replaced with a halogen or sulfonic group at the 4-positions is melted with an caustic allkali such as caustic soda, caustic potash, etc., the halogen group or sulfonic group is replaced with hydroxyl group, acidified, to crystallize crude 4-hydroxyphthalic acid, which is extracted with an inert organic solvent (especially acetone has good selectivity, is stable and preferable), the solvent is removed, and it is distilled under reduced pressure to give 4-hydroxyphthalic anhydride.
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