RECOVERY METHOD OF OXIDATION-CATALYST MATERIAL IN PRODUCTION-PROCESS OF TEREPHTHALIC ACID

摘要

PURPOSE: Provided is a process for recovery oxidation-catalyst material from a mother liquid prepared from a production-process terephthalic acid in an active state, high purity and high rate of recovery. Thereby it is possible to minimize used amount of sodium carbonate to reduce equipment scale of after-process, to improve effect of impurity removal and to save operation-cost. CONSTITUTION: An oxidation-catalyst material from a mother liquid having water-solubleoxidation-catalyst material and acetic acid is recovered by a process comprising the steps of: evaporating the mother liquid; removing insoluble particle by filtration concentration mother liquid; evaporating a filtration-solution for removing acetic acid in the filtration-solution to make sludge; melting the sludge into mixed extraction-solvent containing water and methylacetate, followed by extracting catalyst material in water-soluble layer and organic impurity in oil layer; adding alkali-metal base in the extraction-solution of water-soluble layer to precipitate catalyst material; making a solid cake by filtration the precipitated solution; melting the solid cake in acetic acid, followed by recycling in oxidation process of terephthalic acid.