tom haggen
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sulphuric acid and nitric acid aren't miscible?
well I finally got around to distilling nitric acid for the first time. popped my nitric acid cherry. Anyway, I got a poor yield do to my shitty
equipment. However, my final product apparently weighed out to a very concentrated weight. The acid was bright yellow and totally fuming. I added it
to some sulfuric acid for a simple nitration and the 2 acids did not mix together? I was like what the fuck? I'm not an expert but I was under
the impression that these 2 acids were miscible with one and other. I guess I will try my nitration anyway and see how it goes. Does anyone know what
could be causing this?
Is it because mabey there is NO2 disolved in my nitric acid? Sorry for my lack of knowledge, any advice would be greatly appreciated. oh ya I used one
of those tubes from the fish store and it totally got fucked up. So anyone who reads this that might have been thinking of using one it sucks. Thats
not even considering the fact that once the tube gets really hot it starts sliping off the flask. It almost seems like I synthesized hydrochloric
acid.
[Edited on 24-3-2004 by tom haggen]
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Esplosivo
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I cannot understand how they did not mix. Did the acids form two seperate layers, as when oil is mixed with water? What's the concentration of
the sulphuric acid you have used? I know sulphuric acid is denser than water, but I have never known and neither seen that sulphuric and nitric acid
are immiscible!
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tom haggen
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The sulphuric acid was like 92%, and yes the acids formed 2 seperate layers. The only thing I can thing of is that some how when I distilled my nitric
acid it might have picked up some oil when it came over through the plastic tubing. But then again, I know my nitric acid must have contained some
water content so It wouldn't have mixed with the oil? I think it was a fucking anomaly.
[Edited on 24-3-2004 by tom haggen]
[Edited on 24-3-2004 by tom haggen]
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tom haggen
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Well my nitration worked. So that means that my nitric acid was good. The question still remains why these 2 acids formed 2 separate layers? Heres
some proof my nitration worked. Try to guess what I nitrated.
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Esplosivo
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Was that nitroglycerine?
Probalbly, as you said, there was some oil layer that formed and floated above the acid mixture (oil floats on water, and therefore it will surely
float on conc. sulphuric acid which has a higher density than water). The nitric acid must still have dissolved in the sulphuric acid for the
nitration to occur, therefore your HNO3 is good. Just pay attention what you're nitrating though, I wouldn't like thinking of nasty
catalytic impurities and what they could do.
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tom haggen
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I almost want to rule out that it was oil causing the separation. Heres why, Had there been oil in my nitric acid I would have had 2 layers before I
added my nitric acid to my sulfuric acid. When I first distilled my nitric acid it was one layer of yellow fuming liquid. I wasn't untill I added
it to the sulphuric acid that I got 2 layers. However, once I started nitrating my glycerin, the 2 acids started mixing together. As you can tell from
above my nitration was sucessful.
[Edited on 24-3-2004 by tom haggen]
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Mumbles
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You said you used plastic tubing. This is a no-no for high conc. nitric. My best guess would be that it dissolved some of the oil or plastic, and
brought it over with it. If you've ever used rubber stoppers you can see it dripping after a while. When you added it to the sulfuric, the
nitric mixed with the Sulfuric, making the nitration mix, and the oil came out. As for why it would be soluble in Nitric, but not in Sulfuric I
don't have a clue.
If you have any left, I'd try adding some to water. If the same thing happens, I bet it's the oil from the plastic.
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tom haggen
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Well that can be the only explanation. unfortunatley I only synthesized a very small amount so theres none left. I don't think i'm going to
be messing around with synthesizing nitric acid anymore untill I get a proper distillation setup. Oh ya I was using the same tube to distill
nitromethane a couple of weeks ago from model fuel. Thats probably where the oil could have come from. Even though I cleaned the tube very well, its
possible that the tube could have absorbed some of the oil.
[Edited on 24-3-2004 by tom haggen]
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smile
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what is the purpose to mix sulphuric acid and nitric acid?
sorry, I can't give any help, I am just curious. 
[Edited on 9-4-2004 by smile]
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Mumbles
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Its for nitration. The Sulfuric Acid acts as a dehydrator for the water formed keeping the reaction going. It also ionises the Nitric to
NO2<sup>+</sup>.
This could easily be found with a simple google search, or in one of the fine books Polverone shares with us.
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smile
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| Quote: | Originally posted by Mumbles
Its for nitration. The Sulfuric Acid acts as a dehydrator for the water formed keeping the reaction going. It also ionises the Nitric to
NO2<sup>+</sup>.
This could easily be found with a simple google search, or in one of the fine books Polverone shares with us. |
oh, thanks~ 
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The_Davster
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Well I did a little test on this matter. A small piece of ruber stopper was placed in 70% clear nitric in a brown glass bottle(also with a rubber
seal on lid so I ended up wrecking that nice brown glass dropping bottle:mad
after a week the nitric acid had turned yellow, the piece of stopper had mostly dissolved, and the rubber seal on the bottle had melted. I would have
tested for miscibility with H2SO4 but, I have none .
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