freedompyro
holmes1880
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Failed to stop HNO3 from fuming.
I have been quite annoyed at my HNO3 lately. It likes to red fume during a nitration at as low as 11C...  This didn't use to happen before.
So, In an attempt to remove the fuming I first diluted 118g of my HNO3(Around 93-95%) with 25g water. Still red fuming... Then I added urea prills
slowly and they fizzed away. When prill addition caused no more fizzing I let the last tiny pieces of urea dissolve away. Then I got acid that was
white fuming. Progress!!!  But, I wanted it to totally stop fuming... So then I
diluted it with 15g more water.
Stuff is still fuming... What gives?!? I thought it stopped fuming at below 70%. Not going to dilute it any more or it's going to be a waste of H2SO4.
Also, what did the urea turn into?
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neptunium
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do you live in a very humide area? the fuming can be caused by a lot of water disolved in the air...
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Pulverulescent
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| Quote: | | Also, what did the urea turn into? |
Nitrous acid, present in nitric acid reacts with urea; 2HNO<sub>2</sub> + NH<sub>2</sub>CONH<sub>2</sub>
---> 2N<sub>2</sub> +CO<sub>2</sub> + 3H<sub>2</sub>O.
Any remaining urea forms urea nitrate!
P
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Endimion17
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It always fumes excessively during the winter because it's quite humid. Case solved. 
[Edited on 8-1-2012 by Endimion17]
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freedompyro
holmes1880
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Yea, it's very humid here.
Crap... Now I have trace amounts of urea nitrate in my nitric acid. Oh well... Not really a issue.
Red fumes coming off a nitration even at 5-10C unsettles me and filters don't handle NOX as well. Better and safer to use a around 93% WFNA than a 95%+ RFNA for most things.
Btw, what are the white fumes? Are the red ones NO2, and the white ones NO combining with water vapor?
[Edited on 8-1-2012 by freedompyro]
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Adas
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The white fumes is probably HNO3 itself.
Rest In Pieces!
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Pulverulescent
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When decolourising RFNA, only very minimal quantities of urea should be added!
P
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neptunium
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Quote: Originally posted by Endimion17  | It always fumes excessively during the winter because it's quite humid. Case solved.
[Edited on 8-1-2012 by Endimion17] |
winter is usualy the driest season (at least up here in the great lakes ) cooler air cant disolve as much water as warmer air .
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freedompyro
holmes1880
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The amount of water vapor the air can hold at a specific temperature != humidity. Humidity is the amount of water vapor in the air in relation to how
much it can hold at the current temperature.
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Pulverulescent
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Yeah, it's all about saturation . . .
P
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Endimion17
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| Quote: Originally posted by neptunium | | Quote: Originally posted by Endimion17 | It always fumes excessively during the winter because it's quite humid. Case solved.
[Edited on 8-1-2012 by Endimion17] |
winter is usualy the driest season (at least up here in the great lakes ) cooler air cant disolve as much water as warmer air .
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That matters only if he's doing this outside. Inside places without proper heating usually have high relative humidity. I myself have pretty bad
problems with it.
...
...
Dang, I forgot to close the waster water tank and now it will evaporate constantly while I'm away. %&$#?@! 
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neptunium
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ha!
yeah i put every fuming acid in the fridge (when in open container for small test ) beacause when you dont ....it wont stop fuming untill the whole
room is filled ....and then some!
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Hexavalent
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That's a good idea . . .if only I had a fridge for dedicated lab use:/
"Success is going from failure to failure without loss of enthusiasm." Winston Churchill
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