Sciencemadness Discussion Board

Reduction of sodium nitrate under CO2?

hippo - 14-2-2017 at 13:21

If sodium nitrate can be reduced under another inert gas such as N2, would it be possible to reduce it under CO2?

Aqua-regia - 15-2-2017 at 12:25

do you think NaNO3 reducing by N2 or CO2? Nope. Try to reduce with metal like Pb. Plenty description exist.

karlos³ - 16-2-2017 at 07:27

I guess the thread starter meant using these gasses for protection as inert atmosphere, while doing for example a reduction in molten lead, not using these gasses as actual reducing agent?

hippo - 16-2-2017 at 09:55

Quote: Originally posted by Aqua-regia  
do you think NaNO3 reducing by N2 or CO2? Nope. Try to reduce with metal like Pb. Plenty description exist.


I wasn't suggesting using the gasses to reduce the NaNO3, I was suggesting using them to shield the molten NaNO2 from absorbing oxygen to become NaNO3, hence why I said 'under' in the title instead of 'with'.

Amos - 16-2-2017 at 11:45

This sounds more than plausible. At the temperature at which the nitrate decomposes, it exists at an equilibrium with oxygen. If there's no oxygen present in the space above the sample, it should proceed to completion. Hopefully the reaction rate is high enough for this to be useful.

Aqua-regia - 16-2-2017 at 12:49

If your goal to producing pure NaNO2, from NaNO3 i can tell you it is impossible in home lab. There is all the time 5-10% nitrate impurity. Moreover the fractional crystallization of NaNO3/NaNO2 is a big suck. Try making KNO2, this is easier, cause the water solubility of KNO3/KNO2 are different.

PHILOU Zrealone - 16-2-2017 at 13:43

Quote: Originally posted by Aqua-regia  
If your goal to producing pure NaNO2, from NaNO3 i can tell you it is impossible in home lab. There is all the time 5-10% nitrate impurity. Moreover the fractional crystallization of NaNO3/NaNO2 is a big suck. Try making KNO2, this is easier, cause the water solubility of KNO3/KNO2 are different.

Much better AgNO3/AgNO2 and recycling of Ag via saturated NaCl to produce precipitated AgCl and dissolved NaNO2.

About the reduction of NaNO3...you may also use C and generate from it CO2 that protects the formed NaNO2 from the air...some Na2CO3 may form if the heat is too high.

[Edited on 16-2-2017 by PHILOU Zrealone]