The reduction of nitrate and nitrite ions in basic solution with sodium borohydride in the presence of copper(II) ions

The reaction of NaNO3 and NaBH4 with added Cu(OH)2 in 1 M NaOH at 65°C under Ar rapidly produced NH3, Cu metal, and H2 with NO2 − formed as an intermediate. The overall equation describing the reaction is: A direct reaction of NaNO2 with NaBH4 under the same conditions as those used with NaNO3 follows the equation: The reductions of nitrate and nitrite with NaBH4 did not take place in basic solution unless Cu(OH)2 was present.