Abstract: The invention provides a novel inorganic fiber composed of the elements of silicon, carbon, boron and nitrogen of which the Si/B molar ratio is 2:1 to 200:1. The inorganic fiber is obtained by a method comprising the steps of: (a) preparing an organoborosilicon polymer by heating a mixture of an organopolysilane and an organoborazine compound, e.g. B-trimethyl-N-triphenyl borazine, to effect thermal decomposition and polycondensation reaction; (b) spinning the polymer into a fibrous form; (c) infusibilizing the fiber of the polymer by thermally oxidizing in an oxidizing atmosphere or by irradiating with ionizing radiations; and (d) calcining the infusibilized fiber at 900.degree. to 1800.degree. C. The inventive inorganic fiber is more stable at high temperatures than conventional silicon carbide fibers.

Abstract: The invention provides a method for the preparation of an ultrafine powder of silicon carbide having an extremely fine and uniform particle size distribution of spherical agglomerate particles each formed of crystallites of 5 nm or smaller in size. The silicon carbide powder is prepared by the vapor phase pyrolysis of a specified methyl hydrogen(poly)silane as diluted with a carrier gas, e.g. hydrogen, to give a concentration of 40% by volume or lower at a temperature of 750.degree. to 1600.degree. C. The silicon carbide powder can readily be sintered at a temperature of 1750.degree. to 2500.degree. C. even without addition of a sintering aid to give a sintered body of extremely high density reaching 80% or larger of the theoretical value which can never be obtained of the conventional silicon carbide powders.

Abstract: The invention provides a novel organoborosilicon polymer comprising two types of the recurring monomeric units represented by the general formulas of, one, --SiR.sup.1.sub.2 --CH.sub.2 -- and, the other, --BR.sup.2 --NR.sup.3 --, in which R.sup.1, R.sup.2 and R.sup.3 are each a hydrogen atom or a monovalent hydrocarbon group. Such an organoborosilicon polymer is readily prepared by the thermal decomposition polymerization reaction of an organopolysilane compound and a borazine compound at 250.degree. to 500.degree. C. and useful as a precursor of an inorganic ceramic material or inorganic fibers or as a binder of ceramics.

Abstract: A novel class of tetrahydropyran-5-one compounds are provided which are 2-alkoxy- or 2-acyloxy-3,4-dihalogeno-6-alkyl tetrahydropyran-5-ones expressed by the general formula ##STR1## where R.sup.1 is an alkyl group, R.sup.2 is an alkyl or an acyloxy group and X is a halogen atom. The compounds are synthesized by the reaction of a 2-furyl carbinol compound with a halogen in the presence of an alcohol or a carboxylic acid. The compounds are useful as an intermediate for the synthetic preparation of various useful compounds including maltol as a flavor.