Catalysis

Claim 1

A PROCESS FOR THE PREPARATION OF MALEIC ANHYDRIDE WHICH COMPRISES THE PARTIAL OXIDATION OF BENZENE WITH MOLECULAR OXYGEN IN THE PRESENCE OF A CATALYST CONSISTING ESSENTIALLY OF A REFRACTORY SUPPORT IN PARTICULATE FORM OF ABOUT 0.2 TO ABOUT 0.5 INCH AVERAGE DIAMETER, AND HAVING A SURFACE AREA IN THE RANGE OF 0.002 TO 10 SQUARE METERS PER GRAM AND A MIXTURE OF ABOUT 1 PART MOO3, 1.5 TO 8 PARTS V2O5, 0.1 TO 0.01 PART P2O5, 0.1 TO 0.01 PART NA, AND 0.1 TO 0.01 PART NI, CONTAINING ABOUT 3 TO 15 PARTS PER WEIGHT OF SUPPORT PER PART OF SAID MIXTURE, SAID CATALYST BEING OBTAINED BY PROVIDING THE CATALYST SUPPORT WITH A MIXTURE OF THE PRECUSOR OF THE ABOVE MATERIALS, DRYING AT A TEMPERATURE UP TO ABOUT 175*C., HEATING AT A TEMPERATURE IN THE RANGE OF ABOUT 175 TO 320*C. WITH A LINEAR AIR FLOW THROUGH THE CATALYST IN THE RANGE OF 0 TO 7.7 CM./MIN. AND THEN HEATING AT A TEMPERATURE IN THE RANGE OF 320 TO 400*C. WITH A LINEAR AIR FLOW IN THE RANGE OF 0.58 TO 21.1 CM./MIN. AT A TEMPERATURE IN THE RANGE OF ABOUT 400*C. TO 550*C., AND RECOVERING MALEIC ANHYDRIDE FROM THE REACTION MIXTURE.