Sciencemadness Discussion Board

Diazonium salts from NO2 instead of NaNO2+HCl ?

rockyit98 - 7-4-2020 at 11:27

i need Diazonium analog of p-Phenylenediamine but i don't have NaNO2 and my HCl is have Iron impurity.cant get hold of either but have Con.HNO3 so i can make NO2 by reacting with Cu. i know Nitrogen dioxide disproportionates into nitric acid and nitrous acid in cold aqueous solution. 2NO2 + H2O → HNO3 + HNO2
since i'm gonna need cold condition anyway, whould this work?
ArNH2 +2NO2----->{ArN2+](NO3)- +H2O
thinking of making NO2 and store it in a balloon and slowly reacting with cold OC p-Phenylenediamine while stir the solution.
the end product is explosion hazard if brought to room temperature

DrIronic101 - 7-4-2020 at 12:22

I think it might work, but I think this is just way too complicated and dangerous. If you have concentrated nitric acid, react it with sodium hydroxide or bicarbonate/carbonate to obtain sodium nitrate. Then heat the sodium nitrate in activated carbon with calcium hydroxide to yield sodium nitrite.

As for the HCl, I don't think it really makes a big difference for this reaction. But if you're still worried you could try the two-container technique to purify it.

clearly_not_atara - 7-4-2020 at 14:10

The fact that you are even considering this suggests that you do not have nearly enough respect for the incredibly unstable and explosive salt benzene-1,4-bis-diazonium.

The nitrate does not appear to have been reported, probably because nobody is that stupid. The salt is typically obtained as the hexafluorophosphate or the tetrafluoroborate. In any case, nitrous acid is not sufficient to prepare this monster of a salt; nitrosonium salts are preferred. See:

[Edited on 7-4-2020 by clearly_not_atara]

rockyit98 - 8-4-2020 at 04:10

as long as Diazonium ion stays in the solution it doesn't care about what anion it gonna have when it crystallize. so stable enough to do some chemistry with it.