| abstract |
1. A PROCESS FOR THE OXIDATION OF AT LEAST ONE MEMBER OF THE GROUP CONSISTING OF META- AND PARA-XYLENE TO THE CORRESPONDING PHTHALIC ACID WHICH COMPRISES: (A) OXIDIZING, IN THE PRESENCE OF A POLYVALENT HEAVY METAL OXIDATION CATALYST SELECTED FROM AT LEAST ONE MEMBER OF THE GROUP CONSISTING COBALT, MANGANESE, VANADIUM AND CERIUM, THE XYLENE WITH MOLECULAR OXYGEN IN THE LIQUID PHASE WITHIN A FIRST OXIDATION ZONE UNTIL FROM ABOUT 2% TO NOT IN EXCESS OF ABOUT 70% OF THE CYLENE HAS BEEN CONVERTED TO AN XOIDATE COMPRISING UNREACTED XYLENE, TOLUIC ACID AND OXYGEN-CONTAINING C8 AROMATIC COMPOUNDS, LESS COMPLETELY OXIDIZED THAN TOLUIC ACID, SAID OXIDATE CONTAINING, ON A XYLENE- AND SOLVENT-FREE BASES, ROM ABOUT 15 MOLE PERCENT YO ABOUT 60 MOLE PERCENT OF TOLYL ALCOHOL, FROM ABOUT 15 MOLE PERCENT TO ABOUT 70 MOLE PERCENT DOF TOLUALDEHYDES, FROM ABOUT 4 MOLE PERCENT TO ABOUT 65 MOLE PERCENT OF TOLUIC ACID, FROM ABOUT 0.001 MLE PERCENT TO ABOUT 5 MOLE PERCENT OF CARBOXYLBENZYL ALCOHOLS, FROM ABOUT 0.001 MOLE PERCENT TO ABOUT 5 MOLE PERCENT OF CARBOXYBENZALDEHYDES AND FROM ABOUT 0.001 MOLE PERCENT TO ABOUT 10 MOLE PERCENT OF PHTHALIC ACIDS; (B) REMOVING AT LEAST A PREDOMINANT PROPORTION OF UNCOVERTED XYLENE FROM THE OXIDATE TO RECOVER A CONCENTRATED OXIDATE COMPRISING THE TOLUIC ACID AND THE OXYGEN-CONTAINING C8 AROMATIC COMPOUNDS LESS COMPLETELY OXIDIZED THAN TOLUIC ACID, THE EXTENT OF XYLENE REMOVAL BEING AT LEAST SUCH THAT M=5.27(E-5.355X) WHEREIN "M" IS THE NUMBER OF MOLES OF XYLENE REMAINING IN THE CONCENTRATED OXIDATE AND "X" XYLENE-FREE BASIS, OF CONCENTRATED OXIDATE AND "X" IS THE FRACTION OF THE XYLENE CONVERTED IN THE FIRST OXIDATION ZONE; (C) FURTHER OXIDIZING, IN THE LIQUID PHASE, THE CONCENTRATED OXIDATE, BY CONTINUOUSLY INTRODUCING THE CONCENTRATED OXIDATE AND MOLECULAR OXYGEN INTO A SECOND OXIDATION ZONE CONTAINING A C2-C6 ALIPHATIC CARBOXYLIC ACID SOLVENT AND AN OXIDATION CATALYST SELECTED FROM AT LEAST ONE MEMBER OF THE GROUP CONSISTING OF COBALT, MANGANESE, VANDIUM AND CERIUM DISSOLVED WITH THE SOLVENT, SAID SECOND OXIDATION ZONE BEING MAINTAINED AT A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 50*C. TO ABOUT 150*C.; (D) WITHDRAWING FROM SAID SECOND OXIDATION ZONE A SLURRY OF THE PHTHALIC ACID PRODUCT IN THE CARBOXYLIC ACID SOLVENT; AND, (E) RECOVERING THE PHTHALIC ACID PRODUCT FROM THE SLURRY. |