Recovery of phthalic acid products

Claim 1

A PROCESS FOR THE RECOVERY OF BENZENE CARBOXYLIC ACIDS FROM A MIXTURE CONTAINING THE THREE ISOMERIC PHTHALIC ACIDS, BENZOIC ACID AND ACETIC ACID OBTAINED AT A TEMPERATURE ABOVE 140*F. UP TO 525*F. BY THE LIQUID PHASE OXIDATION WITH MOLECULAR OXYGEN OF MIXED XYLENES CONTAINING MONOALKYLBENZENE IN THE PRESENCE OF ACETIC ACID AND A CATALYST CONSISTING ESSENTIALLY OF BROMINE AND A METAL OXIDATION CATALYST WHEREIN ACETIC ACID IS PRESENT IN SAID MIXTURE IN AN AMOUNT OF FROM 30 TO 50 PARTS PER 100 PARTS TOTAL MIXTURE BY WEIGHT AND WHEREIN SUBSTANTIALLY ALL OF THE ISOPHTHALIC ACID IS IN SOLUTION, COMPRISING CRYSTALLIZING FROM SAID REACTION MIXTURE A SOLID GROSS PHTHALIC ACID PRODUCT CONTAINING SUBSTANTIALLY ALL THE TEREPHTHALIC AND ISOPHTHALIC ACIDS AND FROM 70 TO 80% OF THE ORTHOPHTHALIC ACID AT A TEMPERATURE OF FROM 130 TO 150*F., SEPARATELY RECOVERING SOLID GROSS PHTHALIC ACID PRODUCT AND AS A FIRST MOTHER LIQUOR THE ACETIC ACID SOLUTION, SELECTIVELY DISSOLVING ORTHOPHTHALIC ACID FROM SAID GROSS PHTHALIC ACID PRODUCT WITH FROM 1.5 TO 5 PARTS WATER PER PART OF GROSS PHTHALIC ACID PRODUCT BY WEIGHT AT A TEMPERATURE OF FROM 200* TO 210*F LEAVING A SECOND SOLID PHTHALIC ACID PRODUCT CONTAINING TEREPHTHALIC ACID AND ISOPHTHALIC ACID, SELECTIVELY DISSOLVING ISOPHTHALIC ACID FROM SAID SECOND PHTHALIC ACID PRODUCT WITH WATER AT A TEMPERATURE ABOVE 210*F. AND AT A PRESSURE TO MAINTAIN WATER IN THE LIQUID PHASE LEAVING UNDISSOLVED TEREPHTHALIC ACID, SEPARATING SAID UNDISSOLVED TEREPHTHALIC ACID FROM THE AQUEOUS SOLUTION OF ISOPHTHALIC ACID, RECOVERING AN ISOPHTHALIC ACID PRODUCT FROM THE AQUEOUS SOLUTION THEREOF, RECOVERING ORTHOPHTHALIC ACID BY CRYSTALLIZATION FROM THE AQUEOUS SOLUTION THEREOF, SEPARATELY RECOVERING FROM THE FIRST MOTHER LIQUOR ACETIC ACID AND A BENZOIC ACID PRODUCT.