Production of dicarboxylic acid anhydrides by the catalytic oxidation of aliphatic hydrocarbons

Claim 1

IN A PROCESS FOR THE VAPOR PHASE CATALYTIC OXIDATION OF BUTENE TO PROVIDE MALEIC ANHYDRIDE, THE IMPROVEMENT WHICH COMPRISES EFFECTING SAID CATALYTIC OXIDATION IN THE PRESENCE OF A CATALYST COMPLEX COMPRISING VANADIUM, OXYGEN, PHOSPHOROUS AND A PHOSPHORUS STABILIZER WHICH COMPRISES FROM 15 TO 85 WEIGHT PERCENT OF (1) A MEMBER SELECTED FROM THE GROUP CONSISTING OF LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CESIUM, FRANCIUM AND MIXTURES THEREOF WITH THE REMAINDER BEING (2) A MEMBER SELECTED FROM THE GROUP CONSISTING OF METALS FROM THE PERIODIC TABLE GROUP IIB AND MIXTURES THEREOF, SAID CATALYST CONTAINING FROM ABOUT 1.1 TO ABOUT 1.6 ATOMS OF PHOSPHORUS PER ATOM OF VANADIUM AND CONTAINIGN FROM ABUT 0.20 TO ABOUT 2.0 WEIGHT PERCENT OF THE SAID PHOSPHORUS STABILIZER BASED ON THE TOTAL WEIGHT OF VANADIUM, OXYGEN AND PHOSPHORUS; THE SAID CATALYST HAVING BEEN DEPOSITED ONTO CARRIER PARTICLES WHILE THE VANADIUM HAS AN AVERAGE VALENCE OF NO MORE THAN PLUS 4.6.