Mitsubishi Chemical Corporation

Mitsubishi Chemical Industries Limited

Mitsubishi Kasei Corporation

Masayoshi Murayama

Masumi Ito

Masakatsu Hatano

Kenji Shima

Masayuki Otake

Yuji Kawaragi

Kazunori Oshima

Yasushi Tsurita

Toru Koyama

A process for producing a vanadium-phosphorus oxide-containing catalyst precursor, which comprises (a) introducing into an organic solvent a vanadium alkoxide as a pentavalent vanadium compound and a phosphorus compound in the presence of a reducing agent capable of reducing the pentavalent vanadium compound to a tetravalent state, (b) hydrolyzing at least a part of the vanadium alkoxide before or after the introduction of the phosphorus compound, and (c) heating the vanadium-containing liquid medium obtained in step (b), in the presence of the phosphorus compound to reduce at least a part of vanadium to a tetravalent state.

Process for producing a vanadium-phosphorus oxide catalyst precursor

A process for producing a precursor of a phosphorus-vanadium oxide catalyst for production of maleic anhydride by vapor phase oxidation of a hydrocarbon having 4 carbon atoms, which comprises reacting phosphoric acid and a pentavalent vanadium compound in an organic solvent capable of reducing at least a portion of the pentavalent vanadium to a valence state of +4, the phosphoric acid being substantially composed of orthophosphoric acid, and a phosphoric acid solution whose concentration is 88 to 96% being used as a source of the phosphoric acid; and a process for producing the catalyst comprising dry-pulverizing the catalyst precursor.

Process for producing a phosphorus-vanadium oxide catalyst precursor,

A process for producing a crystalline oxide of vanadium-phosphorus system, which comprises hydrothermally treating an aqueous medium containing (1) a tetravalent vanadium compound, (2) a pentavalent phosphorus compound, (3) a coordinate compound having at least two ligand atoms selected from the group consisting of oxygen atoms and nitrogen atoms and (4) a compound of at least one metal element selected from the group consisting of iron, nickel, cobalt and chromium, to form a crystalline oxide of vanadium-phosphorus system having an X-ray diffraction pattern shown in Table A:

Process for producing crystalline oxide of vanadium-phosphorus system

An oxidation catalyst composition produced by comprising mixing at least one crystalline composite oxide, as the first component, selected from the group consisting of (i) a crystalline composite oxide containing vanadium and phosphorus and showing the characteristic X-ray diffraction peaks as identified in the following Table A and (ii) a crystalline composite oxide containing vanadium and phosphorus and showing the characteristic X-ray diffraction peaks as identified in the following Table B, an aqueous solution, as the second component, containing vanadium and phosphorus, and silica sol, as the third component, to form an aqueous slurry, spray-drying the slurry, and calcining the solid particles thereby obtained:

Oxidation catalyst composition

A process for preparing an oxidation catalyst composition comprises mixing at least one crystalline composite oxide, as the first component, selected from the group consisting of (i) a crystalline composite oxide containing vanadium and phosphorus and showing the characteristic X-ray diffraction peaks as identified in the following Table A and (ii) a crystalline composite oxide containing vanadium and phosphorus and showing the characteristic X-ray diffraction peaks as identified in the following Table B, an aqueous solution, as the second component, containing vanadium and phosphorus, and silica sol, as the third component, to form an aqueous slurry, spray-drying the slurry, and calcining the solid particles thereby obtained:

Process for preparing an oxidation catalyst composition

There is disclosed a catalytic composition represented by the formula:

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Yokohama, Japan

Masayoshi Murayama