Japan Hydrazine Co., Ltd.

Masuda Chemical Industry Co., Ltd.

Other

Masuda Chemical Industries Co., Ltd.

Shuichi Nemugaki

Shunji Hyoda

Masaharu Kita

Hirotoshi Sawada

Takahiro Ueta

Sumio Otsuka

Yoshitaka Miyawaki

Kohki Satoh

Hiroshi Taniguchi

Takashi Ogawa

Koki Sato

Yuhki Kubo

Atsushi Sugino

A process for preparing 5,5'-bi-1H-tetrazolediammonium salts (BHT.2NH) maintaining a high yield through oxaldiimidic acid dihydrazide (OAH) from the starting materials which are cheaply available and are easy to handle. The 5,5&#x2032;-bi-1H-tetrazolediammonium salts (BHT.2NH) are prepared by dissolving the oxaldiimidic acid dihydrazide (OAH) obtained by the reaction of hydrated hydrazide with dicyan in an aqueous solution of a weakly acidic compound such as acetic acid, dropwisely adding an aqueous solution of sodium nitrite thereto to form an azide thereof and to effect the cyclization reaction by heating, adding an aqueous solution of sodium hydroxide to the reaction product to convert it into a 5,5&#x2032;-bi-1H-tetrazoledisodium salt (BHT.2Na), reacting it with an aqueous solution of ammonium chloride, and recovering the formed ammonium salt as sparingly soluble crystals.

Process for the preparation of 5,5'-bi-1H-tetrazolediammonium salts using hydrazine hydrate and dicyan as starting materials

A process for the preparation of a highly pure 5,5&prime;-bi-1H-tetrazolediammonium salt comprising adding a small amount of ammonia water to a reaction solution containing a 5,5&prime;-bi-1H-tetrazolediammonium salt synthesized in the presence of a copper catalyst, removing by filtration the blue insoluble components of formed copper.ammonia.5,5&prime;-bi-1H-tetrazole complex to obtain a filtrate of the 5,5&prime;-bi-1H-tetrazoledisodium salt and reacting the filtrate with an aqueous solution of ammonium chloride, and recovering the formed, highly pure ammonium salt as sparingly soluble crystals.

Process for the preparation of highly pure 5,5&prime;-bi-1H-tetrazolediammonium salts

A process for the preparation of a 5,5'-bi-1H-tetrazole diammonium salt by dropwisely adding the aqueous hydrogen peroxide to which a small amount of weakly acidic substance has been added, to a starting aqueous solution containing hydrogen cyanide or sodium cyanide or potassium cyanide, sodium azide and a catalytic amount of copper sulfate preferably at a low temperature to maintain the pH of the reaction solution over a range of from 5 to 6, heating the reaction solution to effect the oxidation and cyclization reaction, reacting the reaction product with ammonium chloride or an aqueous solution thereof, and recovering the formed ammonium salt in the form of sparingly soluble crystals. The desired product is obtained in a high yield and in a high purity from the starting materials which are cheaply available and are easy to handle through a decreased number of steps, i.e., through a one-pot reaction without requiring cumbersome after-treatment.

Process for the preparation of 5,5'-bi-1H-tetrazole salt

A process for the preparation of a 5,5'-bi-1H-tetrazole diammonium salt by using dicyan, sodium azide, ammonium chloride and water as a reaction medium. This process is industrially advantageous since the 5,5'-bi-1H-tetrazole diammonium salt is synthesized and, then, the precipitated crystals thereof are simply isolated by filtration to obtain the 5,5'-bi-1H-tetrazole diammonium salt maintaining an yield which is not lower than 90%. The 5,5'-bi-1H-tetrazole diammonium salt is a gas-generating agent for air bags, which is lowly toxic and is easy to handle.

Method for preparing 5,5'-bi-1H-tetrazole salt

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Shuichi Nemugaki