National Institute for Researches in Inorganic Materials

Mitsubishi Chemical Corporation

Tadao Sato

Toshihiko Ishii

Tadashi Endo

Osamu Fukunaga

Tatsuo Nagano

Chika Yamazaki

Minoru Iwata

Nobuo Setaka

A monohydrate of an aminobenzenesulfonic acid derivative represented by the following formula (I), for example, 2-(1-piperazinyl)-5-methylbenzenesulfonic acid, is substantially free from weight change due to moisture absorption and can be weighed accurately in manufacturing a pharmaceutical composition for the treatment of heart diseases comprising said monohydrate.

Monohydrates of aminobenzenesulfonic acid derivatives and method for preparing thereof

A monohydrate of an aminobenzenesulfonic acid derivative represented by the following formula (I), for example, 2-(1-piperazinyl)-5-methylbenzenesulfonic acid, is substantially free from weight change due to moisture absorption and can be weighed accurately in manufacturing a pharmaceutical composition for the treatment of heart diseases comprising said monohydrate. ##STR1##

Monohydrates of aminobenzenesulfonic acid derivatives and method for

A process for producing boron nitride comprises heating a mixture consisting of borohydride of alkali metal and ammonium chloride at a temperature range of from 800.degree. to 2200.degree. C. in a non-oxidizing atmosphere.

Production of boron nitride

A process for preparing rhombohedral system boron nitride, which comprises mixing NaBH.sub.4 with at least an equimolar amount of NH.sub.4 Cl, and heating the resulting mixture in a non-oxidizing atmosphere at a temperature of at least 750.degree. C. and lower than 1000.degree. C. for at least 3 hours.

Process for preparing rhombohedral system boron nitride using NaBH.sub.4

A boron nitride complex comprising hBN in which lithium or an alkaline earth metal is diffused and supported in the form of its boron nitride. The boron nitride complex is prepared by heating hBN powder or a sintered product thereof and lithium, an alkaline earth metal, a lithium nitride or boride, or an alkaline earth metal nitride or boride in a non-oxidizing atmosphere to diffuse in and deposit on hBN powder or sintered product thereof, the lithium or alkaline earth metal in the form of its boron nitride. Also disclosed is a process for preparing a light-transmitting dense body of cubic system boron nitride, which comprises diffusing in and depositing on a sintered product of hexagonal system boron nitride, from 0.15 to 3.0 molar % of Me.sub.3 B.sub.2 N.sub.4 where Me is an alkaline earth metal, and sintering the Me.sub.3 B.sub.2 N.sub.4 -containing product thereby obtained, at a temperature of at least 1350.degree. C. under a thermodynamically stable pressure for cubic system boron nitride.

Boron nitride complex and process for its preparation, and process for

A process for producing a sintered body of cubic system boron nitride comprises steps of:

Process for producing sintered body of boron nitride

Cubic system boron nitride from rhombohedral system boron nitride is produced by a shock wave compression method. The process comprises applying a thermodynamically stable pressure to rhombohedral system boron nitride to convert it to cubic system boron nitride.

Process for producing cubic system boron nitride

Rhombohedral system boron nitride is produced by heating a boron material selected from the group consisting of boron oxide, boric acid and an oxygen-containing boron compound capable of forming boron oxide when heated, at a temperature of from 1200.degree. to 2100.degree. C. to vaporize boron oxide and reacting the vaporized boron oxide with hydrogen cyanide or cyanogen gas.

Process for producing rhombohedral system boron nitride

A process for preparing cubic boron nitride comprises heating hexagonal boron nitride and magnesium boron nitride at a temperature of at least 1350.degree. C. under a pressure at which the cubic boron nitride is thermodynamically stable, whereby the cubic boron having high strength and high purity can readily be obtainable. Also disclosed is a process for the preparation of magnesium boron useful as a starting material for the above process. This process comprises mixing hexagonal boron nitride and magnesium nitride or metal magnesium in a molar ratio of hexagonal boron nitride/magnesium being at least 0.6, and heating the mixture thus obtained, at a temperature of from 950.degree. to 1250.degree. C. under atmospheric pressure in a non-oxidizing atmosphere, e.g. a nitrogen atmosphere.

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Sakura, Japan

Tadao Sato