TurboZfreak - 3-5-2014 at 13:21
My process has been very easy from the start and the yield was always pretty good. I have the process down to almost get 500ml per run which takes 2
hours +/-. Now here is a question that some of you might be able to shed some light on. During this process, the acid I get off the first phase, from
what i understand is considered RFNA? This is from direct vacuum distillation at 98C of pure KN03 and 98% H2SO4 at a 1.2 to 1 salt to acid ratio. The
acid I get is a bright yellow which indicates dissolved NOx in it, but the fumes that come off of it are white. I have done the calcs for temp and
weight and the purity is close to 97% +/-. Would this still be considered RFNA? One of my early runs got too hot and the acid that came off of that
run was a darker reddish-yellow and gave off definitive red fumes. The process I have figured out now uses pulsed vacuum which i found out by accident
from vacuum leaked I had. This turned out to help the reaction significantly. Now to convert the phase one acid to phase two true WFNA i mix in a
pinch of urea and use custom made PTFE bubbler and bubble pure oxygen into it at-2C. this whole process is about 2.5 hours.
[Edited on 3-5-2014 by TurboZfreak]
Metacelsus - 3-5-2014 at 13:37
If the fumes are white, it's WFNA.
TurboZfreak - 3-5-2014 at 14:09
Even though it has NOx in it? Then I would assume my end product would be considered anhydrous nitric acid? I dont mean to sound stupid, it is just
most people refer to NA that has dissolved NOx in it to be RFNA which is why this lead me to be confused.
[Edited on 3-5-2014 by TurboZfreak]
Zyklon-A - 4-5-2014 at 06:43
RFNA generally is made intentionally by dissolving N2O4 in concentrated nitric acid (~70-80%) until it's saturated. Typically it
contains ~:
83.4% HNO3, 14% NO2, 2% H2O, 0.6% HF
The purpose of the HF is to act as a corrosion inhibitor by passivation.