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US 2003/0191343 A1Published application
Catalytic gas phase oxidation process
AssigneeNippon Shokubai Co., Ltd.
InventorsHiromi Yunoki, Michio Tanimoto
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AssigneeNippon Shokubai Co., Ltd.
InventorsHiromi Yunoki, Michio Tanimoto
Estimating the term…
The object of the present invention is to provide a process in which, when the unsaturated carboxylic acid is produced, or when the unsaturated aldehyde and/or the unsaturated carboxylic acid are produced by carrying out the catalytic gas phase oxidation reaction by using the fixed-bed multitubular reactor which is packed with the molybdenum-containing catalyst, the reaction can be continued for a long time while a high yield is maintained, regardless of where the hot spot portion occurs and also even if the concentration of the raw gas is high. To solve this object, the present invention production process for an unsaturated carboxylic acid is characterized in: a particulate catalysts including, as catalytic components, an oxide and/or a complex oxide including Mo and V, or Mo, Fe and Bi as essential components, and having a hole are used; and a catalyst-packed layer of each reaction tube of the fixed-bed multitubular reactor is divided into at least two reaction zones in a tubular axial direction, wherein the packing of the catalysts is such that the diameters of the holes of the catalysts differ between at least two of the reaction zones.
A production process for an unsaturated carboxylic acid, which comprises the step of carrying out catalytic gas phase oxidation of an unsaturated aldehyde with molecular oxygen or a molecular-oxygen-containing gas by using a fixed-bed multitubular reactor which is packed with catalysts, thereby producing the unsaturated carboxylic acid;
A production process for an unsaturated aldehyde and/or an unsaturated carboxylic acid, which comprises the step of carrying out catalytic gas phase oxidation of at least one compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol, and methyl t-butyl ether as a raw material with molecular oxygen or a molecular-oxygen-containing gas by using a fixed-bed multitubular reactor which is packed with catalysts, thereby producing the unsaturated aldehyde and/or the unsaturated carboxylic acid which correspond to the raw material;
Dependencies are inferred from the claim text.
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With molecular oxygen: of >C—O—functional groups to >C=O groups
Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00: mixed oxides other than spinels, e.g. perovskite
Tungsten: containing also molybdenum
Catalysts, in general, characterised by their form or physical properties: characterised by dimensions, e.g. grain size
Term end not estimated
A. Technical Field
The present invention relates to a production process for an unsaturated carboxylic acid (e.g. acrylic acid). More particularly, the present invention relates to a process comprising the step of carrying out catalytic gas phase oxidation of an unsaturated aldehyde (e.g. acrolein) with molecular oxygen or a molecular-oxygen-containing gas by using a fixed-bed multitubular reactor which is packed with catalysts, thereby producing an unsaturated carboxylic acid (e.g. acrylic acid).
The present invention also relates to a production process for an unsaturated aldehyde and/or an unsaturated carboxylic acid. More particularly, the present invention relates to a process comprising the step of carrying out catalytic gas phase oxidation of at least one compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol, and methyl t-butyl ether as a raw material with molecular oxygen or a molecular-oxygen-containing gas by using a fixed-bed multitubular reactor which is packed with catalysts, thereby producing an unsaturated aldehyde and/or an unsaturated carboxylic acid.
(Preparation of Catalyst (1-1)):
While 10,000 parts of pure water was heat-stirred, 1,500 parts of ammonium molybdate and 96 parts of ammonium paratungstate were dissolved thereinto, and 319 parts of 20 mass % silica sol was further added thereto. To this mixed liquid, a liquid as obtained by dissolving 824 parts of cobalt nitrate, 286 parts of iron nitrate, and 4.3 parts of potassium nitrate into 1,000 parts of pure water was dropwise added under vigorously stirred conditions. Subsequently, a liquid as obtained by dissolving 343 parts of bismuth nitrate into an aqueous solution was dropwise added thereto under vigorously stirred conditions to thus prepare a suspension, wherein the aqueous solution was obtained by adding 325 parts of concentrated nitric acid to 500 parts of pure water. Next, the suspension was dried with a drum dryer, thus obtaining a dried product. This dried product was pulverized to thus obtain a powder having a particle diameter of not larger than 500 μm. To this powder, a graphite powder was added as a molding assistant in such a manner that the ratio of the graphite powder would be 3 mass %, and they were mixed for 10 minutes. Thereafter, the resultant mixture was molded by using a tablet machine into a cylindrical shape (ring shape) of 6.0 mm in outer diameter, 2.0 mm in diameter of the hole, and 4.5 mm in height. Next, the resultant molded structure was calcined under a stream of air at 450° C. for 5 hours, thus obtaining a catalyst (1-1). The composition of metal elements in this catalyst except for oxygen was as follows:
catalyst (1-1): Mo12W0.5Co4Bi1Fe1Si1.5K0.06.