The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 05, 2000
Filed:
Aug. 16, 1999
Shunji Hyoda, Sakaide, JP;
Masaharu Kita, Sakaide, JP;
Hirotoshi Sawada, Sakaide, JP;
Shuichi Nemugaki, Sakaide, JP;
Takahiro Ueta, Sakaide, JP;
Kohki Satoh, Sakaide, JP;
Sumio Otsuka, Takamatsu, JP;
Yoshitaka Miyawaki, Takamatsu, JP;
Hiroshi Taniguchi, Takamatsu, JP;
Japan Hydrazine Co., Inc., Tokyo, JP;
Masuda Chemical Industry Co., LTD., Tokyo, JP;
Abstract
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.