Abstract: The present invention provides an aluminum hydroxide powder having a predetermined cumulative pore volume which falls within a range suited for the production of a high purity alumina, and a method for producing the same. It is possible to produce an aluminum hydroxide powder having high bulk density and high firing efficiency, and an aluminum hydroxide having high shape retention.

Abstract: The present invention provides an aluminum hydroxide powder having a predetermined cumulative pore volume which falls within a range suited for the production of a high purity alumina, and a method for producing the same. It is possible to produce an aluminum hydroxide powder having high bulk density and high firing efficiency, and an aluminum hydroxide having high shape retention.

Abstract: The present invention provides a photocatalyst dispersion liquid comprising at least a titanium oxide particle which is obtained by a sulfate process and in which the content of sulfuric acid in terms of elemental sulfur is 1000 ppm or less, a tungsten oxide particle, and a dispersion medium for dispersing these particles, wherein a content ratio of the titanium oxide particle to the tungsten oxide particle is 1:8 to 8:1 by mass ratio, and further provides a photocatalyst functional product comprising a photocatalyst layer formed using the photocatalyst dispersion liquid.

Abstract: A photocatalyst dispersion liquid contains titanium oxide particles, tungsten oxide particles, a phosphoric acid (salt) and a dispersion medium, and a containing amount of the phosphoric acid (salt) is from 0.001 mol times to 0.2 mol times with respect to the titanium oxide particles. In this photocatalyst dispersion liquid, the aggregation of the particles is suppressed and thus solid-liquid separation is not easily generated. According to this process for producing a photocatalyst dispersion liquid, titanium oxide particles are dispersed in a dispersion medium containing a phosphoric acid (salt) dissolved therein to obtain a titanium oxide particle dispersion liquid, and then tungsten oxide particles are mixed in the titanium oxide particle dispersion liquid.

Abstract: To provide a photocatalyst dispersion liquid obtained by dispersing titanium oxide photocatalyst particles and tungsten oxide photocatalyst particles in a dispersion medium, where the surfaces of both titanium oxide photocatalyst particles and tungsten oxide photocatalyst particles are charged positively or negatively. In the photocatalyst dispersion liquid, the titanium oxide photocatalyst particles and the tungsten oxide photocatalyst particles, which are dispersed in the dispersion medium, are not aggregated easily, and a solid-liquid separation is not generated.

Abstract: The present invention provides a method for producing a titanium oxide. The method can be applied to produce a titanium oxide having a large specific surface area. The method typically entails calcinating at least one titanium oxide precursor selected from a titanium hydroxide and titanium peroxide, wherein the calcination occurs in the presence of nitrogen and at a steam pressure of at most about 8,000 Pa.

Abstract: A titanium oxide dispersion composition is provides, the composition comprising a solvent and a titanium oxide with an average secondary particle diameter of 100 nm or smaller, the dispersion composition having a maximum intensity within the range of from 435 nm to 700 nm of a primary differential spectrum of a transmittance spectrum, wherein the transmittance spectrum is measured using an ultraviolet-visible spectrophotometer after adjusting a solid content of the dispersion composition to be about 2% by weight. The composition provides a film having a high hydrophilicity under the irradiation of a visible light.

Abstract: The present invention provides a method for producing a ceramic dispersion composition, the method comprising the step of heating a mixture of a ceramic powder having a photocatalytic activity, a dispersant and a solvent at a temperature of about 70° C. or higher without substantially letting the solvent out of the reaction system. The ceramic dispersion composition can be used for providing a film showing a high hydrophilicity by light irradiation.

Abstract: The present invention provides a method for producing a titanium oxide. The method can be applied to produce a titanium oxide having a large specific surface area. The method typically entails calcinating at least one titanium oxide precursor selected from a titanium hydroxide and titanium peroxide, wherein the calcination occurs in the presence of nitrogen and at a steam pressure of at most about 8,000 Pa.

Abstract: A process for producing a titanium oxide is provided which comprises the steps of (i) mixing an acidic solution of a titanium compound with a nitrogen-containing basic organic compound to obtain a reaction product and (ii) calcining the obtained product. The titanium oxide exhibits a high photocatalytic activity by visible light radiation.

Abstract: A photocatalyst is provided, which comprises a titanium oxide and a metal-containing compound other than titanium oxide on the surface of the titanium oxide, wherein the metal-containing compound is a metal oxide having an acid site and the photocatalyst has a BET specific surface area of about 55 m2/g or larger, or wherein the metal-containing compound is a basic metal-containing compound and the photocatalyst has an anatase-crystalline structure and an anatase-crystalline size of about 10 nm or larger. The photocatalyst shows sufficiently high photocatalytic activities by irradiation of visible light.

Abstract: A titanium oxide particle showing high photocatalytic activity with a small particle size can be efficiently produced in a method which comprises the steps of (1) mixing together or sequentially a titanium compound, a base and a foaming agent, wherein the hydroxyl group provided by the base is in a molar amount of about 2.1 times to about 3 times of the titanium atom in the titanium compound; and (2) calcining a solid resulting from said mixing together or sequentially of said titanium compound, said base and said foaming agent.

Abstract: A titanium oxide dispersion composition is provides, the composition comprising a solvent and a titanium oxide with an average secondary particle diameter of 100 nm or smaller, the dispersion composition having a maximum intensity within the range of from 435 nm to 700 nm of a primary differential spectrum of a transmittance spectrum, wherein the transmittance spectrum is measured using an ultraviolet-visible spectrophotometer after adjusting a solid content of the dispersion composition to be about 2% by weight. The composition provides a film having a high hydrophilicity under the irradiation of a visible light.

Abstract: The present invention provides a method for producing a ceramic dispersion composition, the method comprising the step of heating a mixture of a ceramic powder having a photocatalytic activity, a dispersant and a solvent at a temperature of about 70° C. or higher without substantially letting the solvent out of the reaction system. The ceramic dispersion composition can be used for providing a film showing a high hydrophilicity by light irradiation.

Abstract: A titanium oxide precursor which is used for producing a fine-particle titanium oxide showing a high photocatalytic activity is provided. The titanium oxide precursor is an oxygen-atom-containing titanium compound other than anatase-form titanium oxide, and has a maximum exothermic peak at a temperature in the range of from about 30° C. to about 500° C. in a differential thermal analysis curve and shows decrease in weight in a thermogravimetry curve at about the same temperature at which the maximum exothermic peak is shown in the differential thermal analysis curve when subjected to a thermogravimetry and differential thermal analysis under the condition of a temperature rising rate of 20° C./min.

Abstract: A photocatalyst is provided, which comprises a titanium oxide and a metal-containing compound other than titanium oxide on the surface of the titanium oxide, wherein the metal-containing compound is a metal oxide having an acid site and the photocatalyst has a BET specific surface area of about 55 m2/g or larger, or wherein the metal-containing compound is a basic metal-containing compound and the photocatalyst has an anatase-crystalline structure and an anatase-crystalline size of about 10 nm or larger. The photocatalyst shows sufficiently high photocatalytic activities by irradiation of visible light.

Abstract: A process for producing a titanium oxide is provided which comprises the steps of (i) mixing an acidic solution of a titanium compound with a nitrogen-containing basic organic compound to obtain a reaction product and (ii) calcining the obtained product. The titanium oxide exhibits a high photocatalytic activity by visible light radiation.

Abstract: A process for producing coumarin and a derivative thereof represented by formula (2): ##STR1## wherein R.sub.1 to R.sub.4 each represents a hydrogen atom, a methyl group, or an ethyl group, provided that at least two of R.sub.1 to R.sub.4 each represents a hydrogen atom,the process comprising the step of heating a 3-(2-cyclohexanoyl)propionic acid ester represented by formula (1): ##STR2## wherein R.sub.1 to R.sub.4 are as defined above and R.sub.5 represents an alkyl group having from 1 to 4 carbon atoms,in the presence of a palladium catalyst, thereby to allow the ester of formula (1) to undergo cyclization and dehydrogenation reactions, the latter stage of the reactions, in which the conversion of the 3-(2-cyclohexanoyl) propionic acid ester used as a starting material has reached about 80% or more, being conducted at a higher temperature than that for the former stage of the reactions.

Abstract: A process for producing a 3,4-dihydrocoumarin compound represented by formula (II): ##STR1## wherein R.sub.1 to R.sub.4 are as defined in the specification, comprising the steps of:(1) heating a 3-(2-cyclohexanoyl)propionic acid ester compound represented by formula (I): ##STR2## wherein R.sub.1 R.sub.5 are as defined in the specification, in the presence of at least one solid metal catalyst, thereby to allow said compound of formula (I) to undergo ring formation and dehydrogenation to yield said 3,4-dihydrocoumarin compound of formula (II) and, as a by-product, a coumarin compound represented by formula (III): ##STR3## wherein R.sub.1 to R.sub.

Abstract: A process for producing a coumarin derivative represented by formula (II): ##STR1## wherein R.sub.1 to R.sub.4 are as defined in the specification, comprising the step of: subjecting to a ring formation and dehydrogenation reaction a 3-(2-cyclohexanoyl)-propionic acid ester derivative represented by formula (I): ##STR2## wherein R.sub.1 to R.sub.4 are as defined in the specification, the ring formation and dehydrogenation reaction being (1) conducted by use of a catalyst comprising a carrier having supported thereon palladium and either of chromium oxide and chromium hydroxide, or (2) conducted by use of a catalyst comprising a carrier having supported thereon palladium or a catalyst comprising a carrier having supported thereon palladium and either of chromium oxide and chromium hydroxide, in the presence of a promoter which is at least one member selected from the group consisting of magnesium trisilicate, zirconia, metallic chromium, and metallic tungsten.