FIELD: chemistry.
SUBSTANCE: invention relates to a method of producing maleic anhydride in a fluidised bed by oxidising material which contains C4 hydrocarbons with molecular oxygen or oxygen-containing gas in a reactor with a fluidised bed at reactor temperature 325-500°C in the presence of a catalyst capable of working in the fluidised bed, containing mixed oxides of vanadium and phosphorus, wherein the catalyst is prepared as follows: (a) preparation of a catalyst precursor containing mixed vanadium and phosphorus oxide; (b) packing the catalyst precursor; (c) crushing the catalyst precursor to particles whose average size is less than one micrometre in diametre; (d) moulding particles which are capable of working in the fluidised bed, with bulk density greater than or equal to 0.75 g/cm3 from the packed crushed catalyst precursor; and (e) annealing said particles in boiling conditions, where output of the maleic anhydride is increased by adding a compensating catalyst into the reactor with the fluidised bed, wherein said compensating catalyst contains alkyl ether of orthophosphoric acid of formula (RO)3P=O, where R is hydrogen or C1-C4 alkyl and at least one R is C1-C4 alkyl, where the compensating catalyst is prepared by saturating the catalyst obtained according to steps (a) to (e) with alkyl ether of orthophosphoric aid. The invention also discloses a method of improving operation of the mixed vanadium-phosphorus oxide catalyst for producing maleic anhydride from butane in a fluidised bed. The invention also relates to a catalyst capable of working in the fluidised bed, for producing maleic acid by oxidising material which contains C4 hydrocarbons.
EFFECT: invention ensures high output of the end product at low working temperatures.
31 cl, 2 tbl, 2 ex
