Nippon Shokubai Kagaku Kogyo Co., Ltd.

Shigemi Osaka

Kazuo Hata

Tsukasa Takahashi

Norikazu Aikawa

Takahisa Sato

Hideo Suzuki

Tatsuo Kubota

Shigeru Komatsu

Teruyuki Moto

Ikuo Kurimoto

Yoshiyuki Nakanishi

Takehiko Suzuki

Masato Adachi

Toshimasa Kushihara

Youjirou Takahashi

Tsukawa Takahashi

Junichi Toyoda

Tsukasa Takashashi

A highly concentrated zirconia sol is produced by a method which comprises heating an aqueous solution of a zirconium salt in the presence of urea thereby obtaining a transparent zirconia sol, concentrating the zirconium sol with an ultrafilter membrane, and subjecting the concentrated zirconic sol to thermal concentration at a temperature of not higher than 80.degree. C. The sol thus obtained enjoys lasting stability. Optionally, this sol may incorporate therein a chelating agent and a compound of a metal other than zirconium. A slurry of the zirconia sol incorporating therein minute refractory particles is useful for the manufacture of a porous ceramic article. A ceramic product obtained by firing this slurry is advantageously used in a mold for casting.

Zirconia sol, method for production thereof, porous ceramic-producing

A zirconia sol, comprising a transparent zirconia sol obtained by hydrolysis of zirconyl ammonium carbonate and a chelating agent incorporated in said transparent zirconia sol.

Zirconia sol and method for production thereof

The present invention discloses a ceramic precursor composition, comprising (A) 100 parts by weight of at least one fine ceramic powder selected from the group consisting of zirconia and alumina and having an average particle diameter in the range of 0.01 to 2 microns and (B) 10 to 40 parts by weight of a copolymer produced by copolymerizing (a) 10 to 50% by weight of an alkyl or cycloalkyl acrylate having an alkyl group of 1 to 10 carbon atoms or a cycloalkyl group of 4 to 8 carbon atoms, (b) 30 to 80% by weight of an alkyl or cycloalkyl methacrylate having an alkyl group of 1 to 20 carbon atoms or a cycloalkyl group of 4 to 8 carbon atoms, (c) 1 to 5% by weight of a copolymerizable unsaturated carboxylic acid, and (d) 0 to 59% by weight of a hydroxyalkyl acrylate having a hydroxyalkyl group of 2 to 10 carbon atoms (providing that the total amount of the monomers is 100% by weight) and having a number average molecular weight in the range of 10,000 to 100,000 and a glass transition point in the range of -40.degree. to 0.degree. C., a ceramic green sheet made of such ceramic precursor composition, a method for the production of such ceramic green sheet, and a ceramic sheet produced by calcining such ceramic green sheet.

Ceramic green sheet

A carrier for catalyst using refractory particles as cores and having a refractory inorganic powder and optionally whiskers, inorganic oxide sols, or mixtures thereof deposited on the cores, and a method for the production thereof.

Carrier for catalyst and method for production thereof

A method for the production of inorganic minute globular particles, which comprises forming a W/O type sol emulsion by mixing at least one metal oxide-containing sol selected from the group consisting of (a) metal oxide sols and (b) mixed sols containing said metal oxide sols and an inorganic compound, an alkoxide, or a sol of at least one other element with an organic solvent insoluble or sparingly soluble in water in the presence of a surfactant; mixing said emulsion with a basic substance or an electrolyte thereby converting the sol forming the water layer in said emulsion into gel thereby obtaining globular gel particles; and subsequently heating the globular gel particles thereby expelling from the system the water in the globular gel particles in the form of a mixture thereof with the organic solvent.

Method for production of inorganic minute globular particles

An improved process for producing maleic anhydride which comprises catalytically oxidizing benzene with a molecular oxygen-containing gas in the vapor phase in a multitubular heat-exchanger-type reactor. The process is characterized in that

Process for producing maleic anhydride

A method for the production of micronized zirconia by the addition of an alkali to an aqueous solution of a zirconium salt or to a mixed aqueous solution of said zirconium salt and a stabilizer such as yttrium, calcium, and magnesium compounds, which method comprises carrying out the reaction for formation of a hydroxide by the addition of the alkali continuously in a flow type reaction system while keeping the pH of said reaction system at a fixed level, separating the hydroxide produced consequently by the reaction, and drying and calcining the separated hydroxide, and a zirconia-containing micronized particle which contains such stabilizer and has an average particle diameter of not more than 0.02 .mu.m.

Micronized zirconia and method for production thereof

A catalyst for the preparation of maleic anhydride by vapor phase catalytic oxidation of benzene with a molecular oxygen containing gas comprising a porous inert support of an alkali metal content, calculated as oxide, of at most 0.3% by weight and supported thereon a catalytic substance of a constituent composition comprising (a) 1 mole of vanadium pentoxide, (b) 0.3 to 1.2 moles of molybdenum trioxide, (c) 0.005 to 0.05 moles of phosphorus pentoxide, (d) 0.03 to 0.2 moles of sodium oxide and (d) 0 to 0.05 moles of potassium oxide.

Preparation of maleic anhydride

A catalyst for the preparation of maleic anhydride by vapor phase catalytic oxidation of benzene with a molecular oxygen containing gas comprising a porous inert support of an alkali metal content, calculated as oxide, of at most 0.3 % by weight and supported thereon a catalytic substance of a constituent composition comprising (a) 1 mole of vanadium pentoxide, (b) 0.3 to 1.2 moles of molybdenum trioxide, (c) 0.005 to 0.05 moles of phosphorus pentoxide, (d) 0.03 to 0.2 moles of sodium oxide and (d) 0 to 0.05 moles of potassium oxide.

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Himeji, Japan

Shigemi Osaka