Nippon Kayaku Kabushiki Kaisha

Tomoyuki Kawamura

Ryota Hiraoka

Tatsuhiko Kurakami

Motohiko Sugiyama

Shogo Yasuda

Tomoaki Kobayashi

Yuuta Nakazawa

Toru Kawaguchi

Hideo Yoshida

Takanori Nakano

Hiraoka Ryota

Sugiyama Motohiko

Yasuda Shogo

Provided is a method for producing an unsaturated aldehyde including subjecting an alkene to partial oxidation using a fixed bed multi-tube reactor to produce the corresponding unsaturated aldehyde, in which n catalyst layers (n is 2 or more) in a gas flow direction in a reaction tube are provided, when a filling length of the catalyst layers from a first catalyst layer to an (n−1)th catalyst layer from a gas inlet side of the reaction tube is L, and a filling length of an nth catalyst layer from the gas inlet side of the reaction tube is Ln, a relationship between L and Ln satisfies the following equation (1): and

Method for producing unsaturated aldehyde

Provided is a method for producing at least one of an unsaturated aldehyde and an unsaturated carboxylic acid from an alkene by an oxidation reaction, in which a n-layered catalyst layer (n&#x2265;2) is provided in a gas flow direction in a reaction tube, two or more kinds of catalysts having different activities are used; and the catalysts are packed in such a manner that dT&#x2264;20&#xb0; C. is satisfied, when a difference between a temperature PTof an exothermic peak in a n-th layer as counted from a gas inlet and a minimum value mTof a temperature of a catalyst layer which appears between an exothermic peak in a (n-1)th layer and an exothermic peak in a n-th layer from the gas inlet is represented as dT (=PT&#x2212;mT), and the change rate of dT is 2.5 or less at a reaction bath temperature within a range of &#xb1;6&#xb0; C. of a reaction bath temperature at which the highest yield is obtained.

Method for producing at least one of unsaturated aldehyde and unsaturated carboxylic acid and catalyst for producing at least one of unsaturated aldehyde and unsaturated carboxylic acid

A method for producing at least one oxidation product selected from the group consisting of acrolein and acrylic acid is provided. This method can alleviate concerns about deterioration of a gas-phase oxidation catalyst and reaction runaway in a restart period after a shutdown, and can allow the reaction to proceed in a stable state. Using a fixed-bed reactor filled with a gas-phase oxidation catalyst, at least one source gas selected from the group consisting of propylene and acrolein is subjected to a gas-phase contact oxidation reaction while a heating medium is caused to contact with or circulate through the fixed-bed reactor and thereby to heat the fixed-bed reactor. The temperature of the heating medium when the load is maximum in the restart period after the shutdown is controlled to be lower than the temperature of the heating medium when the load is maximum in an initial start-up period.

Restarting method

Provided is a catalyst for manufacturing an unsaturated aldehyde and/or an unsaturated carboxylic acid, which is prepared by a method in which a molybdenum component raw material is composed of only an ammonium molybdate, the weight of water for dissolution is 8.5 times or less relative to the weight of molybdenum contained in the ammonium molybdate; and a bismuth component raw material is composed of only bismuth nitrate, the weight of a nitric acid aqueous solution for dissolution is 2.3 times or more relative to the weight of bismuth contained in the bismuth nitrate, and a nitric acid concentration in the nitric acid aqueous solution for dissolving the bismuth nitrate is 10% by weight or more.

Catalyst for manufacturing unsaturated aldehyde and/or unsaturated carboxylic acid and manufacturing method of same, and manufacturing method of unsaturated aldehyde and/or unsaturated carboxylic acid

Provided is a method of subjecting an alkene to partial oxidation by using a fixed bed multitubular reactor, thereby producing an unsaturated aldehyde and/or an unsaturated carboxylic acid each corresponding to the alkene, wherein a plurality of catalyst layers formed by N division (N is N&#x2267;2) with respect to a gas flow direction of a reaction tube are provided, and when a change (&#xb0; C.) of hot spot temperature per 1&#xb0; C. change of reaction bath temperature in the catalyst layer is designated as Sn, at least one of the plurality of catalyst layers is regulated to Sn&#x2266;6.

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Yamaguchi, Japan

Tomoyuki Kawamura