LifeisElemental
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Use of Scrubber in Atmospheric Distillation
Hello all!
I apologize if this is a violation of UTFSE but I had looked and was unable to find any discussion on this. (Likely my own error)
I plan to distill nitric acid at atmospheric pressure without a vacuum. I am worried of the possibility of NO2 gas being released so I am
considering adding tubing connecting the vacuum adapter to an alkaline solution.
I have created an image depicting the apparatus I plan to construct. Would this be functional?
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numos
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If you do this reaction outside or in a fume hood, nitrogen oxides are not a problem. If you want to do this inside without a fume hood you may want
to use a scrubber, but I suggest simply doing this reaction outdoors.
But yes that system would work well as a scrubber.
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hissingnoise
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A scrubber is neither necessary nor desirable in this instance.
A large proportion of evolved NO2 will dissolve in the distillate with very minor quantities escaping . . .
Good ventilation is advisable, though!
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gdflp
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That would be functional, the nitrogen dioxide will react as follows 2NO2 + 2NaOH --> NaNO3 + NaNO2 + H2O. As long as the reactants are cooled
before hand and the distillation is not allowed to surpass 83°C, only very small amounts of NO2 are formed. Even with the alkaline scrubber, I would
not do the distillation indoors unless you have a fume hood.
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Metacelsus
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Watch out for suckback; if you use a scrubber you should add a trap.
Even without vacuum this is still an issue, due to gas pressure changes with temperature.
[Edited on 23-7-2014 by Cheddite Cheese]
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LifeisElemental
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Thank you all very much for the advice! I had actually planned to perform the reaction indoors and no longer will.
Quote: Originally posted by Cheddite Cheese  | Watch out for suckback; if you use a scrubber you should add a trap.
Even without vacuum this is still an issue, due to gas pressure changes with temperature.
[Edited on 23-7-2014 by Cheddite Cheese] |
If possible, could I get an idea of what a trap is? It's a concept I have a very difficult time of grasping. I've searched "what is a trap" and
similar questions and have not found anything that clicked with me.
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arkoma
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A=reaction vessel (in your case the vacuum takeoff would be this)
B=empty flask
C=Neutralizing solution.
Part "B" catches any backflow from a pressuredrop and prevents it from entering into the receiving flask. NaOH and HNO3 suddenly mixing
would not be good. Flask "B" would catch and prevent that from occuring.
edit--fixed bb tag
[Edited on 7-24-2014 by arkoma]
"We believe the knowledge and cultural heritage of mankind should be accessible to all people around the world, regardless of their wealth, social
status, nationality, citizenship, etc" z-lib
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LifeisElemental
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That is a great explanation Arkoma! Thank you all again, I will likely not plan to carry out this reaction for a short while until I acquire some
adequate ventilation. However, I greatly appreciate the kind advice on the topic.
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Praxichys
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For NO2, just get a length of clear plastic tubing and shove it down a drain until it's past the trap. You could also run the tube outside. No sense
in wasting chemicals scrubbing something that you're not releasing a whole lot of to begin with.
Vapors from nitric acid usually aren't a problem during a distillation. It's the disassembly of the apparatus afterward that is going to release the
most. Keep that into consideration. A fume hood or outside is best.
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The Volatile Chemist
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Have fun! Post some pictures!
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plante1999
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The picture reminds me, Anyone here tried the lab scale coal pyrolisis? If so, got pictures? I wanted to do the experiment and even ad bought a lot
of small pieces of bituminous coal for it but time was faster then I.
[Edited on 24-7-2014 by plante1999]
[Edited on 24-7-2014 by plante1999]
I never asked for this.
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Magpie
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| Quote: Originally posted by arkoma |
A=reaction vessel (in your case the vacuum takeoff would be this)
B=empty flask
C=Neutralizing solution.
Part "B" catches any backflow from a pressuredrop and prevents it from entering into the receiving flask. NaOH and HNO3 suddenly mixing
would not be good. Flask "B" would catch and prevent that from occuring....
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Very nice sketch. But for clarity: to prevent suckback the trap B functions by keeping the solution in C from sucking back into A.
Of course it also works the opposite way too, as you state.
The single most important condition for a successful synthesis is good mixing - Nicodem
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arkoma
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can't take credit for sketch, kiped it from this article. First clear image I found that could apply to LifeisElemental's question 
"We believe the knowledge and cultural heritage of mankind should be accessible to all people around the world, regardless of their wealth, social
status, nationality, citizenship, etc" z-lib
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chemrox
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Can't you run a long hose out a window somewhere? I used to do this before I had a hood. Also a fan in a window could serve for NOx
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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The Volatile Chemist
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The hose down the drain or out the window is my fav. idea. In the confined space I have, it's kinda necessary at times. As for buffer flasks, has
anyone actually seen a situation where they saved the solutions from mixing? I've rarely used them, so I don't know if they're necessary all the time
or not...
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aga
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Funny you should say that.
Today i used a buffer flask in the nitric nurdrage with copper thing, as the last time i got a bottle of Green and a bottle of Blue.
So i used a buffer flask today, and ended up with three bottles.
Green, Blue and Empty.
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