Sciencemadness Discussion Board

Sodium nitrite conversion to sodium nitrate

bluamine - 17-1-2023 at 18:37

Hi everyone!!
What are oxidizer agents that can be used to convert sodium nitrite to sodium nitrate?
Can sodium hypochlorite or dichromate work?

Bedlasky - 17-1-2023 at 19:45

Yes, they work. In the case of dichromate you need acidic environment (nitrite is decomposed by acids), so you must add slowly nitrite in to acidified dichromate. Problem is that your product will be contaminated with chromium. And in the case of hypochlorite your product will be contaminated with NaCl. So cleanest oxidazing agent is acidified H2O2.

Why do you want to convert precious nitrite in to cheap nitrate? Usually people want to convert nitrate to nitrite. In my opinion it is waste of good reagent.

bluamine - 18-1-2023 at 01:35

Quote: Originally posted by Bedlasky  


Why do you want to convert precious nitrite in to cheap nitrate? Usually people want to convert nitrate to nitrite. In my opinion it is waste of good reagent.


I already have a good amount of nitrite and it won't be probably useful for any project I am planning to do..
I'm wondering if hydrogen peroxide method will need heat or something
I wouldn't use dichromate if I have any alternatives

woelen - 19-1-2023 at 01:54

The reaction between H2O2 and nitrite is sluggish. It helps if you add some acid, but try to keep the amount as low as possible. It adds impurities and leads to decomposition of nitrite. Maybe you could even try without acid, but with gentle heating to avoid decomposition of H2O2.

Keras - 19-1-2023 at 02:36

Why do you want to convert from nitrite to nitrate? Nitrite is much more convenient in a lot of reactions, especially for nitration of aromatic compounds, especially if your goal is to make amines.

bluamine - 15-2-2023 at 03:25

Quote: Originally posted by woelen  
The reaction between H2O2 and nitrite is sluggish. It helps if you add some acid, but try to keep the amount as low as possible. It adds impurities and leads to decomposition of nitrite. Maybe you could even try without acid, but with gentle heating to avoid decomposition of H2O2.

Should I use a weak or strong acid?
And well I only have access to 3% hydrogen peroxide solution, so it would be hard to concentrate it
Quote: Originally posted by Keras  
Why do you want to convert from nitrite to nitrate? Nitrite is much more convenient in a lot of reactions, especially for nitration of aromatic compounds, especially if your goal is to make amines.


Well my goal isn't amines in this case, but I actually would like to know how nitrite can be used for nitration

woelen - 16-2-2023 at 00:29

You can concentrate H2O2 by freezing out part of the water. Let it freeze for half of its volume. The ice on top of it mostly is water, the liquid at the bottom is appr. 5% H2O2.
If you use this batch for freezing again, you might get close to 10% H2O2. You'll lose some H2O2 in the process though. The ice will contain some water.