Sciencemadness Discussion Board

Purification of Sodium/Potassium Nitrite

ZeLaboratorium - 29-10-2017 at 13:00

I am currently planing on preparing some nitrites in my home lab by leading NO2 in a cooled sodium/potassium hydroxide solution.

2xNO2 + H2O ------> HNO3 + HNO2

Since i am planning to make this on a a rather small scale, recrystallisation from water does not seem like an viable way to seperate the nitrite from the nitrate.
At the moment, I am looking for a solvent which would make the seperation easier, but i cannot find the solubilities in other sovents online or any of my litrature.

Can anyone give me any advice on what solvent to use, or where to find the information I am looking for ?

Melgar - 30-10-2017 at 05:16

Quote:
Since i am planning to make this on a a rather small scale, recrystallisation from water does not seem like an viable way to seperate the nitrite from the nitrate.
At the moment, I am looking for a solvent which would make the seperation easier, but i cannot find the solubilities in other sovents online or any of my litrature.


That's because all the other solvents are organic, and mixing NO2 with an organic solvent is something you only do if you have a death wish. It's a very, very strong oxidizer.

Aqua-regia - 30-10-2017 at 05:21

This is a boring job, but workable. Separation of the desired products from water solution maks a big different: If the target ones sodium nitrate /sodium nitrite, this is hopeless, but KNO3/KNO2 seperating is easy. Look the solubility table of KNO2 /KNO3 in water.

Better route if you can generating NO + NO2 equimolar, it this case the product almost NaNO2 (or KNO2) This is the industrial pathway for it.

Na2CO3 + NO +NO2 ——> 2 KNO2 + + CO2↑

For home lab would prefering reduction of nitrate with lead. You can find a lot of description.



[Edited on 30-10-2017 by Aqua-regia]