Mitsubishi Chemical Corporation

Kazuyuki Iwakai

Hiroshi Kameo

Hiroki Hinoishi

Takeshi Takeuchi

Souichi Orita

Hiroshi Takeo

Hidenobu Kajitani

Tetsufumi Yamaguchi

An object of the present invention is to suppress performance deterioration of a molybdenum composite oxide-based catalyst at the time of performing gas-phase catalytic partial oxidation with molecular oxygen by using a tubular reactor. The present invention relates to a catalytic oxidation method using a tubular reactor in which a Mo compound layer containing a Mo compound and a composite oxide catalyst layer containing a Mo composite oxide catalyst are arranged in this order from a reaction raw material supply port side and under a flow of a mixed gas containing 75 vol % of air and 25 vol % of water vapor at 440&#xb0; C., a Mo sublimation amount of the Mo compound is larger than a Mo sublimation amount of the Mo composite oxide catalyst under the same conditions.

Catalytic oxidation method and method for producing conjugated diene

The invention is concerned with a method for producing a conjugated diene including a reaction step of subjecting a raw material gas containing a monoolefin having a carbon atom number of 4 or more to an oxidative dehydrogenation reaction with a gas containing molecular oxygen in the presence of a catalyst, to obtain a reaction product gas containing a conjugated diene; and a cooling step of cooling the reaction product gas, wherein in the cooling step, a cooling agent is supplied into a cooling column and brought into contact with the reaction product gas; the cooling agent discharged from the cooling column is then cooled by a heat exchanger; a precipitate dissolved in the cooling agent is precipitated within the heat exchanger and recovered; and the cooling agent from which the precipitate has been recovered is circulated into the cooling column.

Method for producing conjugated diene

Disclosed is a method for producing a conjugated diene by subjecting a monoolefin having a carbon atom number of 4 or more and an oxygen gas to an oxidative dehydrogenation reaction by using a molybdenum-containing metal oxide catalyst under heat removal with a coolant, wherein an amount of molybdenum adhered onto a cooling heat transfer surface within a reactor is kept at not more than 20 mg/m, or not only a surface roughness Ra of a cooling heat transfer surface within a reactor is not more than 3 &#x3bc;m, but a temperature difference between a reaction temperature and a coolant temperature is in the range of from 5 to 220&#xb0; C.

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Okayama, Japan

Kazuyuki Iwakai