http://bcis.pacificu.edu/~polverone/muspratt1/c-834.html (http://bcis.pacificu.edu/~polverone/muspratt1/c-834.html)
http://www.geocities.com/dritte123/NaNO2.html (http://www.geocities.com/dritte123/NaNO2.html)
sorry to be a pain but a few years ago endless bees triied converting NaNO3 -> NaNO2 (Ab2 included) we all wasted alot of time (and NaNO3) some destroyed their hotplates and glass with Xtreme temps, but no one was successful at anything other than a series of failed reactions.
Really? Hmmm, SWIM accomplished it no problem using KNO3, it was very easy. Used the procedures outlined on Rhodium's with no problem whatsoever. The Pb turns orange as it is oxidized and bubbles of O2 are noted. SWIM used a stove at high heat (maybe you didn't heat it enough?). This was allowed to react for over an hour (it started smoking). The residue was then cooled, taken up in hot water, filtered, evaporated, and the unreacted KNO3 allowed to crystallize (KNO2 will never crystallize from solution). This was repeated until everything was boiled down to a light yellow flaky and very hygroscopic solid.
The filterate from the reaction was basic (pH ~9), and the KNO2 worked fine for a diazotization (although there was some lead impurities still in it). SWIM can't imagine what problems a bee might have with this synthesis, it's quite straight forward.