Electrochemical investigation of 2,2-dinitroethene-1,1-diamine (FOX-7) in aqueous media

Abstract

Redox properties of 2,2-dinitroethene-1,1-diamine (FOX-7) were electrochemically investigated by DC polarography, cyclic voltammetry and preparative electrolyses, and electroreduction products were analysed. The polarographic reduction of FOX-7 in aqueous buffered solutions exhibited a total sum of limiting currents corresponding to the expected 18 electrons. This result fits well with the chemical reduction of this energetic material resulting in ethan-1,2-diamine. Exhaustive electrolysis, however, did not yield this product and the passed charge for total degradation of this compound corresponds only to 4–7 F. As the main products, gaseous N₂, N₂O, NO and NH₃ were proved by combination EC–GC–MS and, besides that, nitrite anions and ammonia ions were identified by other methods. All these observations suggest that instead of electrochemical reduction, an electrochemically initiated degradation process accompanying the exhaustive electrolysis occurs. This seems to be analogous to the chain of reactions during explosion, which are slowed down by a very low concentration and cooled by the solvent.