| abstract |
THE COBALT RECOVERY PROCESS OF PRESENT INVENTION CAN PROVIDE SUBSTANTIALLY COMPLETE RECOVERY OF COBALT ACETATE CATALYST FROM THE OXIDATION OF META- OR PARA-XYLENE TO PHTHALIC ACIDS, THE COBALT ACETATE BEING IN CATALYTICALLYACTIVE FORM AND RELATIVELY FREE FROM SIDE REACTION AND METAL CORROSION PRODUCTS. THE REACTION MEDIUM WHICH CONTAINS ACETIC ACID SOLVENT, AFTER TREATMENT TO RECOVER THE ISOPHTHALIC OR TERPHTHALIC ACID PRODUCT, IS THEN DEHYDRATED, BY PHYSICAL OR CHEMICAL MEANS, COOLED IF DESIRED, AND FILTERED TO RECOVER INSOLUBLE, ANHYDROUS COBALT ACETATE, WHILE THE BY-PRODUCT ACIODS AND METAL CORROSION PRODUCTS REMAIN IN THE ACETIC ACID SOLVENT. THE CATALYST IS REFORMED BY DISSOLVING THE COBALT ACETATE IN FRESH ACETIC ACID CONTAINING ENOUGH WATER TO FORM THE SOLUBLE TETRAHYDRATE FROM THE ANYDROUS SALT. |