Production of maleic acid and maleic anhydride

Claim 1

IN A PROCESS FOR THE PRODUCTION OF MALEIC ACID AND ITS ANHYDRIDE BY OXIDATION OF BENZENE WITH OXYGEN-CONTAINING GASES IN THE VAPOR PHASE AT TEMPERATURES BELOW 400*C. IN THE PRESENCE OF A CARRIER CATALYST, THE IMPROVEMENT WHICH COMPRISES USING A CATALYST WHICH HAS BEEN OBTAINED BY IMPREGNATING AND MIXING AS CARRIER SUBSTANCE TITANIUM DIOXIDE OF ANTASE STRUCTURE AND A MEAN GRAIN SIZE OF 0.05 TO 1.5 MICRONS WITH AN AQUEOUS SOLUTION OF A VANADIUM COMPLEX COMPOUND WHICH IS FORMED OF A VANADIUM COMPOUND FROM THE GROUP CONSISTING OF VANADIUM PENTOXIDE AND AMMONIUM VANADATE AND A COMPOUND FROM THE GROUP CONSISTING OF OXLIC ACID, TARTARIC ACID, PYROCATECHOL, AND SALICYLIC ACID, AND AT LEAST ONE PHOSPHOMOLYBDENUM COMPOUND FROM THE GROUP CONSISTING OF PHOSPHOMOLYBDIC ACID AND ITS AMMONIUM SALTS, THICKENING THE MIXTURE TO A DOUGH-LIKE AND KNEADABLE MASS, FORMING THE MASS WITHOUT PRESSURE INTO SHAPED BODIES HAVING A DIAMETER OF 2 TO 10 MM., DRYING THE SHAPED BODIES HAVING THEN ACTIVATING THEM BY HEATING TO A TEMPERATURE BETWEEN 170* AND 400*C. WHILE SIMULTANEOUSLY LEADING THEREOVER ABOUT 300 TO 1500 LITERS OF AIR PER LITER OF CATALYST PER HOUR, THE VANADIUM COMPOUND AND THE PHOSPHOMOLYBDENUM COMPOUND BEING USED FOR THE IMPREGNATION IN AMOUNTS SUCH THAT THE MOL RATIO OF V2O5;MOO3 LIES BETWEEN 1:1 AND 1:8 AND THE FINISHED CATALYST COMPRISES ABOUT 60 TO 80% BY WEIGHT OF TIO2, ABOUT 5 TO 30% BY WEIGHT OF V2O5, ABOUT 5 TO 30% BY WEIGHT OF MOO3 AND ABOUT 0.2 TO 1.25% BY WEIFHT OF P2O5.