Abstract: An inorganic fiber-reinforced ceramic composite material comprising a matrix of a ceramic and inorganic fibers as a reinforcing material, characterized in that(a) the inorganic fibers are specified inorganic fibers containing silicon, either titanium or zirconium, nitrogen and oxygen, and(b) the ceramic is at least one material selected from the group consisting of carbides, nitrides, oxides, glass ceramics, graphite and specified inorganic materials containing silicon, either titanium or zirconium, nitrogen and oxygen.

Abstract: A process for producing a sintered ceramic body, which comprises heating a semi-inorganic block copolymer at a temperature of from 500.degree. to 2300.degree. C. in an environment of vacuum or inert gases, reducing gases or hydrocarbon gases, said copolymer comprising polycarbosilane blocks having a main-chain skeleton composed mainly of carbosilane units of the formula (Si--CH.sub.2) and zirconoxane units of the formula (Zr--O); and shaping the heated product, and simultaneously with, or after, the shaping of the heated product, sintering the shaped product at a temperature of from 800.degree. C. to 2300.degree. C. in an environment of vacuum or inert gases, reducing gases or hydrocarbon gases; and a sintered ceramic body consisting substantially of Si, Zr and C and optionally of O, said sintered body being composed substantially of(1) an amorphous material consisting substantially of Si, Zr and C and optionally of O, or(2) an aggregate consisting subtantially of ultrafine crystalline particles of .beta.

Abstract: A process for producing an organometallic copolymer composed of a polycarbosilane portion and a polymetallosiloxane portion crosslinked with each other, which comprises reacting (1) a polycarbosilane having a main chain skeleton composed mainly of carbosilane units of the formula --Si--CH.sub.2 --, with (2) a polymetallosiloxane having a main chain skeleton composed of metalloxane units of the formula --M--O-- wherein M represents Ti or Zr and siloxane units of the formula --Si--O--, in an organic solvent in an inert atmosphere thereby to bond at least some of the silicon atoms of said polycarbosilane to at least some of the metal atoms M and/or silicon atoms of said polymetallosiloxane through an oxygen atom; and the organometallic copolymer obtained by the aforesaid process.

Abstract: Continuous inorganic fibers consisting substantially of Si, Ti and C and optionally of O, said fibers being composed of (1) an amorphous material consisting substantially of Si, Ti and C and optionally of O, or (2) an aggregate consisting substantially of ultrafine crystalline particles of .beta.-SiC, TiC, a solid solution of .beta.-SiC and TiC and TiC.sub.1-x wherein 0<x<1 and having a particle diameter of not more than 500 A, in which amorphous SiO.sub.2 and TiO.sub.2 sometimes exist in the neighborhood of these ultrafine crystalline particles, or (3) a mixture of said amorphous material (1) and said aggregate (2) of ultrafine crystalline particles. The aforesaid continuous inorganic fibers can be produced by the following steps: a first step of preparing a semi-inorganic block copolymer comprising polycarbosilane blocks having a main chain skeleton composed mainly of carbosilane units of the formula --Si-CH.sub.

Abstract: A polymetallocarbosilane having a number average molecular weight of 700 to 100,000 derived from a polycarbosilane having a number average molecular weight of 200 to 10,000 and containing a main-chain skeleton represented mainly by the general formula ##STR1## wherein R represents a hydrogen atom, a lower alkyl group or a phenyl group,and an organometallic compound represented by the general formulaMX.sub.4Wherein M represents Ti or Zr, and X represents an alkoxy group having 1 to 20 carbon atoms, a phenoxy group or an acetylacetoxy group,at least one of the silicon atoms of the polymetallocarbosilane being bonded to the metal atom (M) through an oxygen atom, the ratio of the total number of the structural units --Si--CH.sub.2 -- to the total number of the structural units --M--O-- in the polymetallocarbosilane being in the range of from 2:1 to 200:1; and a process for production thereof.

Abstract: A process for producing an organometallic copolymer composed of a polycarbosilane portion and a polymetallosiloxane portion crosslinked with each other, which comprises reacting (1) a polycarbosilane having a main chain skeleton composed mainly of carbosilane units of the formula --Si-CH.sub.2 --, with (2) a polymetallosiloxane having a main chain skeleton composed of metalloxane units of the formula --M-O-- wherein M represents Ti or Zr and siloxane units of the formula --Si-O--, in an organic solvent in an inert atmosphere thereby to bond at least some of the silicon atoms of said polycarbosilane to at least some of the metal atoms M and/or silicon atoms of said polymetallosiloxane through an oxygen atom; and the organometallic copolymer obtained by the aforesaid process.

Abstract: Continuous inorganic fibers consisting substantially of Si, Ti and C and optionally of O, said fibers being composed of (1) an amorphous material consisting substantially of Si, Ti and C and optionally of O, or (2) an aggregate consisting substantially of ultrafine crystalline particles of .beta.-SiC, TiC, a solid solution of .beta.-SiC and TiC and TiC.sub.1-x wherein 0<x<1 and having a particle diameter of not more than 500 A, in which amorphous SiO.sub.2 and TiO.sub.2 sometimes exist in the neighborhood of these ultrafine crystalline particles, or (3) a mixture of said amorphous material (1) and said aggregate (2) of ultrafine crystalline particles. The aforesaid continuous inorganic fibers can be produced by the following steps: a first step of preparing a semi-inorganic block copolymer comprising polycarbosilane blocks having a main chain skeleton composed mainly of carbosilane units of the formula --Si--CH.sub.

Abstract: A process for producing a sintered ceramic body, which comprises heating a semi-inorganic block copolymer at a temperature of from 500.degree. to 2300.degree. C. in an environment of vacuum or inert gases, reducing gases or hydrocarbon gases, said copolymer comprising polycarbosilane blocks, having a main-chain skeleton composed mainly of carbosilane units of the formula --Si--CH.sub.2 -- and titanoxane units of the formula --Ti--O--; and shaping the heated product, and simultaneously with, or after, the shaping of the heated product, sintering the shaped product at a temperature of from 800.degree. C. to 2300.degree. C. in an environment of vacuum or inert gases, reducing gases or hydrocarbon gases; and a sintered ceramic body consisting substantially of Si, Ti and C and optionally of O, said sintered by being composed substantially of(1) an amorphous material consisting substantially of Si, Ti and C and optionally of O, or(2) an aggregate consisting substantially of ultrafine crystalline particles of .beta.

Abstract: Isopentene is produced in a high yield by a method wherein disproportionation of a hydrocarbon mixture containing n-butene and isobutene is carried out by bringing, at 200.degree. to 350.degree.C, the hydrocarbon mixture into contact with a composite catalyst which has been prepared by depositing a barium or strontium compound and a silver compound onto a carrier material consisting of an activated high purity alumina carrier to produce a precursory composite catalyst, calcining the precursory composite catalyst at 300.degree. to 900.degree.C, and isolating the resulted isopentene from the reaction mixture.