Synthesis of 5-Nitrotetrazolates by the Direct Oxidation of 5-Aminotetrazole in a Single-Pot Synthesis without Isolation of Explosive Intermediates

Abstract

A readily available oxidizer, potassium superoxide can be used for the oxidation of 5-amino-1H-tetrazole (5-AT) to 5-nitrotetrazole (5-NT) in high yields in a single-pot synthesis. This strategy reduces the synthesis of this important energetic material down to a single step and eliminates highly sensitive diazonium and copper salt primary explosive intermediates. Use of dimethyl sulfoxide along with molecular sieves and 18-crown-6 as phase transfer catalyst promoted faster reaction rates and greater yield. The overall yield of this process is 48–53 % and the resultant aqueous solution of product was effectively used for the preparation of nitrotetrazole-containing primary explosive DBX-1. Unlike current methods of nitrotetrazole preparation, this entirely solution-based route results in a final solution of sodium nitrotetrazolate, without the need to handle energetic intermediates or products, making it the safest method of nitrotetrazole preparation reported to date.