Production of cis-Na₂N₂O₂ and NaNO₃ by Ball Milling Na₂O and N₂O in Alkali Metal Halide Salts

Abstract

Ball milling of sodium oxides and alkali metal halide salts under a pressure of 2 atm nitrous oxide at temperatures of 38 ± 4 °C is reported. After 2.5 h of ball milling, FTIR data for both 14N2O and 15N2O additions show conclusively that cis-Na2N2O2 is formed based on excellent agreement with data reported earlier by Jansen and Feldmann who prepared pure crystalline cis-Na2N2O2 by reaction of sodium oxide and nitrous oxide for 2 h at 360 °C in a tube furnace. Continued ball milling under nitrous oxide leads to slow buildup of NaNO3 with yields on the order of 24% achieved in 20 h. Production of nitrate only occurs during active ball milling. Studies over the first 10 h reveal a trend among potassium halide salts: KBr ≅ KCl > KI ≫ KF. Ball milling of sodium oxide alone under an atmosphere of N2O gives much lower yields than ball milling in the presence of added alkali metal halide salt. Ball milling of sodium oxide and nitrous oxide in fluorocarbon oil, silicone oil, calcium fluoride, clinoptilolite, molecular sieves, and silica gel does not lead to significant yields of either cis-Na2N2O2 or NaNO3.

Mechanistic Pathways for N2O Elimination from trans-R3Sn-O-N═N-O-SnR3 and for Reversible Binding of CO2 to R3Sn-O-SnR3 (R = Ph, Cy)

“…Metal complexes of hyponitrites are much less common than the ubiquitous carbonate analogues. For example, we have recently reported generation of cis -Na 2 N 2 O 2 by the ball-milling reaction shown in reaction . The only prior report of direct reaction was that of Feldmann and Jansen at 360 °C in a tube furnace preparation. These observations indicate net favorable thermodynamics for the insertion process of N 2 O.…”

“… While nitrous oxide elimination from hyponitrites is common, examples of N 2 O addition to metal oxides to form hyponitrite complexes are rare. In this regard, Feldmann and Jansen reported formation of pure crystalline cis -Na 2 N 2 O 2 at 360 °C as shown in reaction . We have recently reported in situ preparation of cis -Na 2 N 2 O 2 by mechanochemical methods and its further oxidation to nitrate in a mixer mill under 2 atm pressure of nitrous oxide at much lower temperatures of 38 °C . While the examples of N 2 O addition to complexes forming hyponitrites are limited, the analogous reactions with isoelectronic CO 2 leading to carbonates are more common and have been much more explored .…”

“…We have recently reported in situ preparation of cis-Na 2 N 2 O 2 by mechanochemical methods and its further oxidation to nitrate in a mixer mill under 2 atm pressure of nitrous oxide at much lower temperatures of 38 °C. 5 While the examples of the analogous reactions with isoelectronic CO 2 leading to carbonates are more common and have been much more explored. 6 The fact that a much larger number of carbonate complexes exist compared to hyponitrite complexes implies greater kinetic access and also more thermodynamic stability for carbonates.…”

Redox-Active Inverse Crowns for Small Molecule Activation

“…] from Na 2 O and N 2 O that either needs heating to at least 360°C (ref. 42 ) or high-energy ball-milling 43 .…”