There is provided a method for producing isobutylene, in which isobutylene is produced from isobutanol with a high selectivity while suppressing a decrease in the isobutanol conversion rate under pressure. In the method for producing isobutylene according to the present invention, a raw material gas containing isobutanol is brought into contact with a catalyst to produce isobutylene from isobutanol, the method including bringing the raw material gas containing isobutanol into contact with a catalyst at a linear velocity of 1.20 cm/s or more under a pressure of 120 kPa or more in terms of absolute pressure to produce isobutylene from isobutanol.

Multi-metallic bulk catalysts and methods for synthesizing the same are provided. The multi-metallic bulk catalysts contain nickel, molybdenum tungsten, copper, and optionally, titanium and/or niobium. The catalysts are useful for hydroprocessing, particularly hydrodesulfurization and hydrodenitrogenation, of hydrocarbon feedstocks.

Multi-metallic bulk catalysts and methods for synthesizing the same are provided. The multi-metallic bulk catalysts contain nickel, molybdenum tungsten, yttrium, and optionally, copper, titanium and/or niobium. The catalysts are useful for hydroprocessing, particularly hydrodesulfurization and hydrodenitrogenation, of hydrocarbon feedstocks.

A catalyst may suppress pressure loss and coaking and produce a target substance in high yield when a gas-phase catalytic oxidation reaction of a material substance is conducted using the catalyst to produce the target substance. A ring-shaped catalyst may have a straight body part and a hollow body part, which is used when a gas-phase catalytic oxidation reaction of a material substance is conducted to produce a target substance, wherein a length of the straight body part is shorter than a length of the hollow body part and at least at one end part, a region from an end part of the straight body part to an end part of the hollow body part is concavely curved.

Multi-metallic bulk catalysts and methods for synthesizing the same are provided. The multi-metallic bulk catalysts contain nickel, molybdenum tungsten, yttrium, and optionally, copper, titanium and/or niobium. The catalysts are useful for hydroprocessing, particularly hydrodesulfurization and hydrodenitrogenation, of hydrocarbon feedstocks.

The present invention relates to carbon nanotubes having a pore volume of 0.94 cm.sup.3/g or more, and being an entangled type, a method of manufacturing the same, and a positive electrode for a primary battery which comprises the same.

A method is described for producing a catalyst having a high raw material conversion rate and a high product selectivity, as well as an excellent yield of unsaturated carboxylic acid, the catalyst being used in a vapor-phase catalytic oxidation reaction for producing an unsaturated carboxylic acid such as acrylic acid or methacrolein from an unsaturated aldehyde such as acrolein or methacrolein. The method includes a molding process of molding a powder containing a catalyst component element to produce a catalyst precursor, where a sulfur-containing inorganic compound is added to the powder, and the powder is molded in the molding process.

A method for preparing an active catalyst for high-efficiency denitration is disclosed. The method includes: a catalyst raw material is charged into a denitration reactor, NH.sub.3 and an inert gas are introduced and then heating is performed, and the temperature is held and then natural cooling is performed, thereby obtaining the catalyst. The active catalyst can greatly improve the denitration activity in low temperature range, and can not only improve the denitration efficiency under the condition without SO.sub.2 and H.sub.2O, but also can improve the denitration efficiency under the condition with both SO.sub.2 and H.sub.2O. The service life of the catalyst is prolonged under the premise of not changing the existing catalyst preparation process, and the economic benefit is significant. The denitration efficiency of a powder catalyst can be increased by 25%, and the denitration efficiency of a honeycombed catalyst or a corrugated catalyst can be increased by 20%.

An object of the present invention is to provide a catalyst ensuring that when a gas-phase catalytic oxidation reaction of a material substance is conducted using a catalyst to produce a target substance, the pressure loss and coking are suppressed and the target substance can be produced in high yield. The present invention is related to a ring-shaped catalyst having a straight body part and a hollow body part, which is used when a gas-phase catalytic oxidation reaction of a material substance is conducted to produce a target substance, wherein a length of the straight body part is shorter than a length of the hollow body part and at least at one end part, a region from an end part of the straight body part to an end part of the hollow body part is concavely curved.

Provide is a functional structural body that can suppress aggregation of metal oxide nanoparticles and prevent functional loss of metal oxide nanoparticles, and thus exhibit a stable function over a long period of time. A functional structural body (1) includes: a skeletal body (10) of a porous structure composed of a zeolite-type compound; and at least one type of metal oxide nanoparticles (20) containing a perovskite-type oxide present in the skeletal body (10), the skeletal body (10) having channels (11) that connect with each other, and the metal oxide nanoparticles (20) being present at least in the channels (11) of the skeletal body (10).