Electrochemical production of nitrous oxide substance pentoxide in nitric acid.

摘要

PCT No. PCT/GB89/01497 Sec. 371 Date Jul. 23, 1991 Sec. 102(e) Date Jul. 23, 1991 PCT Filed Dec. 14, 1989 PCT Pub. No. WO90/07020 PCT Pub. Date Jun. 28, 1990.A two-stage method of producing N2O5 in nitric acid from N2O4 in nitric acid consists of a first production stage in which the anodic oxidation of N2O4 in nitric acid and cathodic reduction of nitric acid are separated by a non-ionic or anionic ion exchange membrane, and a second production phase in which the product of the first stage anodic reaction is subjected to further anodic oxidation, the anodic and cathodic reactions being separated by a cationic ion exchange membrane. The use of a cationic membrane in the second stage promotes, through leakage of N2O4 to the catholyte, an increase in N2O5 concentration and decrease in N2O4 concentration within the anolyte acid while avoiding a significant loss of current efficiency. The two stages may be connected in series and operated continuously to produce a nitric acid solution containing typically 32 wt. % N2O5 and less than 2 wt. % N2O4.