Electrosynthesis of  N 2 O 5 by Controlled‐Potential Oxidation of  N 2 O 4 in Anhydrous  HNO 3

Abstract

The anodic oxidation of N2O4 in aqueous and anhydrous HNO3 has been investigated by controlled‐potential techniques and found to be an excellent method for the preparation of solutions of N2O5 in anhydrous HNO3 . The product solutions can be used directly for the nitrolysis of organic compounds. The oxidation is carried out at approximately +1.85V vs. SCE (aq) at platinum or titanium‐supported iridium oxide anodes. Up to 40g quantities of N2O5 have been prepared with good energy efficiency in a laboratory‐scale, divided cell with a porous Vycor or Nafion separator. Complete oxidation of the N2O4 occurs in a region of low solvent background current; however, the overall current efficiency is reduced to ∼65%, apparently because of transport losses of N2O4 and N2O5 to the catholyte. Several of the species resulting from the dissociation of N2O4 and N2O5 in the solutions have been identified by Raman spectroscopy.

Comparison of anionic membranes used to concentrate nitric acid to beyond the azeotropic mixture

“…Harrar et al did not observe hydrogen evolution at 99% nitric acid; however, they did produce N 2 O 4 at the cathode [20,21].…”

“…Harrar et al carried out one of the few studies using high nitrate concentrations; they used a divided cell to produce N 2 O 5 , with anolyte solutions of N 2 O 4 in approximately 99% nitric acid, and with catholyte solutions of the acid alone. The cathodic reaction was the production of N 2 O 4 , which in theory, after separation from water, could be recirculated and used as the anolyte feedstock [20,21].…”

The filter-press FM01-LC laboratory flow reactor and its applications

“…In extreme cases, such as electrosynthesis of dinitrogen pentoxide in anhydrous nitric acid [17][18][19][20][21] in section 5.2, expensive fluorocarbon polymers might be used for the cell body and the electrolyte flow reservoir and tubing is normally fluorocarbon polymer based.…”

“…7). Both laboratories described rectangular channel flow cells in later publications [17,18]. The California studies in collaboration with US state departments resulted in a 1987 patent [21] as did the Southampton activity in collaboration with the UK MOD [20].…”

Electrochemical Methods for Synthesis of Energetic Materials and Remediation of Waste Water

“…Thus, nitration by N 2 O 5 /HNO 3 can be used to prepare substrates such as nitramines, which are sensitive to decomposition by sulfuric acid. N 2 O 5 can be generated via oxidation of N 2 O 4 in nitric acid [29] and the reactions at the anode and cathode are shown below (Eqs. (10.9)-(10.11)):…”