Mitsubishi Rayon Company, Limited

Toru Kuroda

Seiichi Kawato

Masahide Kondo

Motomu Oh-Kita

Masanori Nitta

Hideyasu Takezawa

Hiroyuki Naitou

Kazuhiro Ishii

Yoshiyuki Taniguchi

Yasuhiro Kabu

Masato Otani

Miezi Sugiyama

Yutaka Kinoshita

Motomu Ohkita

Tohru Shiotani

Seiichi Kawato-ku

Mieji Sugiyama

Hiroyuki Naito

Disclosed is a method for producing a catalyst, in which physical properties of a dried material or a calcined material in a production process of the catalyst are stable and a change in at least one of a catalyst activity and a selectivity to a target product is small and hence reproducibility of the catalyst is excellent. The present invention is a method for producing a catalyst containing molybdenum, bismuth, and iron, which contains the steps of washing a surface of at least one device equipped in an apparatus for the production of catalyst, to which a solid matter adheres, with a basic solution, and producing the catalyst with the apparatus for the production of catalyst thus washed.

Method for producing catalyst

Process for producing catalyst

A method for producing an unsaturated aldehyde and an unsaturated carboxylic acid through gas-phase catalytic oxidation of propylene, isobutylene or tertiary butanol, which is a raw material, with molecular oxygen in the presence of a catalyst comprising a complex oxide including molybdenum, bismuth and iron as essential components, by controlling the molar ratio of oxygen to the raw material such that a rate of reaction of the raw material is kept constant in the temperature range of from (TA-15)&#xb0; C. to TA&#xb0; C., where TA&#xb0; C. is the boundary temperature of the activation energy of the catalyst.

Method for producing unsaturated aldehyde and unsaturated carboxylic acid

Disclosed is a method of a gas-phase catalytic oxidation reaction of propylene, isobutylene, or tertiary butanol with molecular oxygen in the presence of a catalyst to produce a corresponding unsaturated aldehyde and a corresponding unsaturated carboxylic acid, in which the catalyst can be used over a long period of time. Concretely, in the presence of the catalyst containing a complex oxide including molybdenum, bismuth and iron as essential components, at least one factor of a reaction pressure and a molar ratio of molecular oxygen to a raw material is controlled to change in such a way that a rate of reaction of the raw material is kept constant in the temperature range of from (TA&#x2212;15)&#xb0; C. to TA&#xb0; C., when a boundary temperature of the activation energy of the catalyst is set to be TA&#xb0; C.

A method for producing a catalyst containing at least molybdenum, bismuth and iron including the steps of kneading particles containing catalyst components, an organic binder and a liquid, where the organic binder contains at least a high-viscosity organic binder having a viscosity of from 5,000 mPa&#xb7;s to 25,000 mPa&#xb7;s and a low-viscosity organic binder having a viscosity of from 10 mPa&#xb7;s to less than 5,000 mPa&#xb7;s, and extrusion molding the resultant kneaded mixture is provided.

Method for producing catalyst for production of unsaturated aldehyde and unsaturated carboxylic acid

The method for preserving a catalyst of the present invention is characterized in that, in a process for continuously producing an objective product by a vapor phase oxidation reaction using a phosphorus-molybdenum-vanadium catalyst containing phosphorus, molybdenum and vanadium, the phosphorus-molybdenum-vanadium catalyst retained in a reactor is maintained under a condition of a water content of 30 mg or less per 1 g of catalyst dry weight, before the start of the reaction or during the stop of the reaction. By this, deterioration of the catalyst retained in the reactor can be simply prevented.

Method for preserving catalyst

The method of producing a catalyst for synthesis of an unsaturated aldehyde and unsaturated carboxylic acid of the present invention is characterized in that the method comprises a step of adding liquid to particles containing molybdenum, bismuth and iron and kneading the mixture, and extrusion-molding this kneaded substance, a step of preserving the molded article obtained by extrusion molding, and at least one step of drying and calcining the preserved molded article, and the contact time of particles containing molybdenum, bismuth and iron with liquid is 1 to 48 hours, and the preserving time of the molded article is 50% or more of the contact time of particles containing molybdenum, bismuth and iron with liquid. According to the production method of the present invention, catalytic activity can be easily controlled, and a catalyst having high activity and high selectivity is obtained.

Method of producing catalyst for synthesis of unsaturated aldehyde and unsaturated carboxylic acid and catalyst prepared by this method

In producing a catalyst used for synthesis of an unsaturated aldehyde and an unsaturated carboxylic acid by a gas-phase catalytic oxidation, there is used a step of packing an additive-containing catalyst precursor of the catalyst into a tubular reactor, passing a gas through the tubular reactor, and elevating, in this state, the temperature of the additive-containing catalyst precursor so that a temperature of the gas at an outlet of the catalyst precursor layer becomes higher than a temperature of the gas at an inlet of the catalyst precursor layer. The step makes possible easy and highly reproducible production of a high-performance catalyst which is small in the reduction in catalytic performance caused by, for example, the thermal decomposition of the additive contained in the catalyst precursor.

Reaction tube, process for producing catalyst and process for producing unsaturated aldehyde and unsaturated carboxylic acid

A molybdenum-based precipitate is prepared according to a process including the first step of forming a crude precipitate by pH adjustment to 6.5 or less in the presence of an alkali metal compound, and the second step of dissolving the crude precipitate in aqueous ammonia and forming a precipitate by pH adjustment to 6.5 or less. Then, the resulting molybdenum-based precipitate is washed with an acid aqueous solution having a pH of 6.5 or less and containing not less than 0.01 mole/L of ammonium root. Thus, a change in average particle diameter can be suppressed and good workability can be achieved, so that a molybdenum-based precipitate having a high purity and a desired average particle diameter can be obtained.

Method for producing precipitate and catalyst

The present invention relates to the effective utilization of a used catalyst containing at least molybdenum, an A element (at least one element selected from the group consisting of phosphorus and arsenic) and an X element (at least one element selected from the group consisting of potassium, rubidium and cesium), and provides a process for producing a catalyst, which comprises dispersing said used catalyst in water, adding thereto an alkali metal compound and/or ammonia solution, adjusting the resulting mixture to pH 6.5 or less to generate a precipitate containing at least molybdenum and the A element, and using the precipitate as a material for catalyst-constituting elements.

A method for packing of catalyst, which comprises mixing, into a shaped catalyst containing at least molybdenum and iron, used in the gas-phase catalytic oxidation of propylene, isobutylene, tert-butyl alcohol or methyl tert-butyl ether with molecular oxygen to synthesize an unsaturated aldehyde and an unsaturated carboxylic acid both corresponding to the raw material used, metal-made Raschig rings as auxiliary packing material having a bulk volume of 0.3-3.5 times that of the shaped catalyst and a packing density of 0.5-1.5 kg/l, and packing the resulting mixture into a fixed bed type reactor; and a process for producing an unsaturated aldehyde and an unsaturated carboxylic acid, which comprises subjecting propylene, isobutylene, tert-butyl alcohol or methyl tert-butyl ether to gas-phase catalytic oxidation using molecular oxygen, in a fixed bed type reactor wherein a catalyst is packed by the above method.

Method for packing with catalyst for synthesis of unsaturated aldehyde

Process for producing catalyst used for synthesis of methacrylic acid

Process for preparing a catalyst for producing methacrylic acid

A method of preparing a catalyst used for producing methacrylic acids through gas phase catalytic oxidation of methacrolein with molecular oxygen. The catalyst is represented by the formula:

Method of preparing catalyst used for producing methacrylic acids

A process for preparing a catalyst used for production of methacrolein and methacrylic acid by vapor phase oxidation of isobutylene or tertiary butanol includes adding an organic high-molecular weight compound having an average particle size of 0.01 .mu.m to 10 .mu.m, especially polymethyl methacrylate and/or polystyrene, to a MoBiFeCoNi-based catalyst, then molding the mixture and heat treating the molded product.

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Hiroshima, Japan

Toru Kuroda