Abstract: In a riding work vehicle, power of an engine is transmitted to a traveling wheel via a horizontally oriented transmission shaft and a vertically oriented transmission shaft. The traveling wheel is supported to be changeable in direction about a rotational axis of the vertically oriented transmission shaft. Each of the vertically oriented transmission shaft and a vertically oriented transmission case is provided as an inner/outer double structure expandable/contractible in association with sliding movement thereof. The vertically oriented transmission case is supported to be pivotable together with the traveling wheel. There is provided a vehicle height adjustment mechanism capable of switching, in a plurality of steps, a relative height of the traveling wheel relative to a vehicle body frame.

Abstract: A catalyst containing, as an essential component, molybdenum; bismuth; and cobalt, in which, with respect to a peak intensity at 2?=25.3°±0.2° in an X-ray diffraction pattern obtained by using CuK? rays as an X-ray source, a changing rate (Q1) per 1000 hours of reaction time represented by the following formulae (1) to (4) is 16 or less. Q1={(U1/F1?1)×100}/T×1000??(1) F1=(peak intensity of catalyst before oxidation reaction at 2?=25.3°±)0.2°/(peak intensity of catalyst before oxidation reaction at 2?=26.5°±0.2°)×100??(2) U1=(peak intensity of catalyst after oxidation reaction at 2?=25.3°±0.2°)/(peak intensity of catalyst after oxidation reaction at 2?=26.5°±0.

Abstract: 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): 1 < L ? / ? Ln ? 3 , ( 1 ) and a composition of a catalytically active component contained in the catalyst layers from the first catalyst layer to the (n-1)th layer from the gas inlet side of the reaction tube is different from a composition of a catalytically active component contained in the nth catalyst layer from the gas inlet side of the reaction tube.

Abstract: 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?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?20° C. is satisfied, when a difference between a temperature PTn of an exothermic peak in a n-th layer as counted from a gas inlet and a minimum value mTn?1 of 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 (=PTn?mTn?1), and the change rate of dT is 2.5 or less at a reaction bath temperature within a range of ±6° C. of a reaction bath temperature at which the highest yield is obtained.

Abstract: 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?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?20° C. is satisfied, when a difference between a temperature PTn of an exothermic peak in a n-th layer as counted from a gas inlet and a minimum value mTn-1 of 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 (=PTn?mTn-1), and the change rate of dT is 2.5 or less at a reaction bath temperature within a range of ±6° C. of a reaction bath temperature at which the highest yield is obtained.

Abstract: 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.

Abstract: Provided is a method for producing an unsaturated aldehyde and/or an unsaturated carboxylic acid, which enables one to achieve an operation stably over a long period of time while improving an effective yield, even in a high-load reaction, and in the method for producing an unsaturated aldehyde and/or an unsaturated carboxylic acid, multilayer filling of stacking two or more catalyst layers each containing a complex metal oxide catalyst in the axial direction of the tube under specified conditions is performed, and the catalyst layer on the most gas outlet side in the tube axis contains a catalyst containing a compound represented by a specified formulation formula.

Abstract: The present invention relates to the production of acrolein, acrylic acid or methacrylic acid by dehydration reaction of renewable raw material such as glycerin or hydroxycarboxylic acids, in the presence of a novel catalyst system supported on a carrier having a bimodal structure and a high pore volume and distribution. The dehydration reactions can be carried out for longer operation duration, so that acrolein, acrylic acid or methacrylic acid can be produced at higher productivity and for longer running time.

Abstract: 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.

Abstract: Provided is a catalyst having high activity and yield of a target product for producing an unsaturated aldehyde and/or an unsaturated carboxylic acid and further having high mechanical strength. The catalyst is a catalyst prepared by a method in which a catalyst formulation satisfies specified atomic ratios; and in the preparation thereof, a molybdenum component raw material is an ammonium molybdate, a solvent for dissolving the ammonium molybdate is water, a bismuth component raw material is bismuth nitrate, and a solvent for dissolving bismuth nitrate is a nitric acid aqueous solution, and the weight of water for dissolving the ammonium molybdate, the weight of the nitric acid aqueous solution for dissolving the bismuth nitrate, and the acid concentration of the nitric acid aqueous solution are satisfied with specified ranges, respectively.

Abstract: A catalyst for producing butadiene using n-butene as a raw material, a process for producing the same and a process for producing butadiene using the catalyst are provided, and specifically, a catalyst for producing butadiene by gas-phase contact oxidative dehydrogenation of n-butene, which is capable of stably producing butadiene in a high yield from the beginning of the reaction, a process for producing the same and a process for producing butadiene, in which the catalyst is a shaped catalyst containing a complex metal oxide having molybdenum as an essential ingredient, wherein the pore volume of macropores is 80% or more, more preferably 90% or more, based on the total pore volume, are provided.

Abstract: There is provided a process for producing a shaped catalyst for a fixed bed oxidation reaction or a fixed bed oxidative dehydrogenation reaction, the catalyst having both of sufficient mechanical strength and catalyst performance, and the catalyst is produced by supporting a catalyst powder containing a complex metal oxide having molybdenum as an essential ingredient on an inert support by a tumbling granulation method at a relative centrifugal force of 1 to 35 G.

Abstract: There is provided a process for producing a shaped catalyst for a fixed bed oxidation reaction or a fixed bed oxidative dehydrogenation reaction, the catalyst having both of sufficient mechanical strength and catalyst performance, and the catalyst is produced by supporting a catalyst powder containing a complex metal oxide having molybdenum as an essential ingredient on an inert support by a tumbling granulation method at a relative centrifugal force of 1 to 35 G.

Abstract: Provided is a catalyst having high activity and yield of a target product for producing an unsaturated aldehyde and/or an unsaturated carboxylic acid and further having high mechanical strength. The catalyst is a catalyst prepared by a method in which a catalyst formulation satisfies specified atomic ratios; and in the preparation thereof, a molybdenum component raw material is an ammonium molybdate, a solvent for dissolving the ammonium molybdate is water, a bismuth component raw material is bismuth nitrate, and a solvent for dissolving bismuth nitrate is a nitric acid aqueous solution, and the weight of water for dissolving the ammonium molybdate, the weight of the nitric acid aqueous solution for dissolving the bismuth nitrate, and the acid concentration of the nitric acid aqueous solution are satisfied with specified ranges, respectively.

Abstract: A catalyst for producing butadiene using n-butene as a raw material, a process for producing the same and a process for producing butadiene using the catalyst are provided, and specifically, a catalyst for producing butadiene by gas-phase contact oxidative dehydrogenation of n-butene, which is capable of stably producing butadiene in a high yield from the beginning of the reaction, a process for producing the same and a process for producing butadiene, in which the catalyst is a shaped catalyst containing a complex metal oxide having molybdenum as an essential ingredient, wherein the pore volume of macropores is 80% or more, more preferably 90% or more, based on the total pore volume, are provided.

Abstract: There is provided a process for producing a shaped catalyst for a fixed bed oxidation reaction or a fixed bed oxidative dehydrogenation reaction, the catalyst having both of sufficient mechanical strength and catalyst performance, and the catalyst is produced by supporting a catalyst powder containing a complex metal oxide having molybdenum as an essential ingredient on an inert support by a tumbling granulation method at a relative centrifugal force of 1 to 35G.

Abstract: The present invention relates to the production of acrolein, acrylic acid or methacrylic acid by dehydration reaction of renewable raw material such as glycerin or hydroxycarboxylic acids, in the presence of a novel catalyst system supported on a carrier having a bimodal structure and a high pore volume and distribution. The dehydration reactions can be carried out for longer operation duration, so that acrolein, acrylic acid or methacrylic acid can be produced at higher productivity and for longer running time.

Abstract: An object of the present invention is to provide a catalyst for glycerin dehydration reaction for producing unsaturated aldehyde and unsaturated carboxylic acid at higher yield by a dehydration reaction of glycerin, and that can reduce a decrease in time of the conversion ratio of glycerin and the yields of unsaturated aldehyde and of unsaturated carboxylic acid. Another object of the present invention is to provide a catalyst for glycerin dehydration reaction that can produce acrolein and acrylic acid at higher yield by the dehydration reaction of glycerin, and the catalyst has a longer life. Still another object of the present invention is to provide a method for preparing the catalysts above.