killswitch - 24-9-2013 at 14:26
The distillation of a mixture of KNO3 and 98% sulfuric acid under vacuum is the most common route to WFNA.
Without the vacuum the nitric acid is a bright reddish-orange from dissolved oxides of nitrogen, and contains considerable amounts of nitrous acid.
This is typically dealt with by passing a stream of dry air through the nitric acid until the color is mostly gone, then adding tiny quantities of
urea.
My question is whether there is a better way, one that makes use of the dissolved oxides rather than get rid of them.
Would distillation of a mixture of KNO3 and KMnO4 reduce the amount of NOx present by oxidizing it to N2O5 via O3 produced by the decomposing
permanganate anion?
bfesser - 24-9-2013 at 15:19
First off, you're posting this in the wrong sub-forum. Second, you've shown no sign of effort to find the answers on your own. Finally, nitric acid
has been discussed ad nauseam. Try searching before posting.
AndersHoveland - 24-9-2013 at 18:09
Basically, the answer is no. Anhydrous nitric acid is not stable when heated, and those nitric oxides cannot recombine with O2 to make anhydrous
nitric acid. At some concentration point, the concentrated red fuming nitric acid can just no longer absorb any more oxygen, and it has reached its
limit.
Slow evaporation might be a possibility, if one has the proper glassware, but it would have to be kept away from any light. I do not know what it is
called, but here is a certain type of glassware meant meant for evaporation with two horizontally connected bulbs. Liquid from one bulb gradually
evaporates, goes through the connecting tube, and condenses at the bottom of the other bulb.
bfesser - 24-9-2013 at 19:23
<a href="https://en.wikipedia.org/wiki/Kugelrohr" target="_blank">Kugelrohr</a> <img src="../scipics/_wiki.png" />?