ellafuntay
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Registered: 10-11-2014
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Viton ring
Well, the Viton ring is not the one ring to rule them all. Tonight i synthesized nitric acid for the first time, using 110g KNO3 and 60ml conc. H2SO4.
it seemed to going pretty well through the distillation, but towards the end, some black junk came down the Liebig condenser, polluting my lovely
yellow acid. the baker in me thought maybe i burnt something.
When i was cleaning up, i found that the viton ring in the thermometer holding apparatus had partially failed. it was still intact a full 360
degrees, but it appeared to have gone on a crash diet since id last seen it. luckily i had wrapped some teflon tape around the thermometer where it
exits the adapter, so i dont think any NO2 leaked out. I must admit that i allowed the temp to get too high, it topped out in the mid 90s.
i looked online and it seems that viton supposedly offers excellent resistance to nitric acid?!?! Thoughts?
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Praxichys
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I have encountered the same issue.
Hot nitric acid containing nitrogen oxides is extremely corrosive to most materials. You do not really need a thermometer for a simple nitric
acid isolation. Use a stopper instead, and judge completeness by drip rate. It is difficult to mess this up since sulfuric acid has such a high BP.
Check out those on YouTube who use a retort to do it.
If you really want to get a temperature, buy a thermometer well, which will make your apparatus entirely glass at the sacrifice of temperature response.
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ellafuntay
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Thank you for the advice. you know, i kind of figured i could have skipped the thermometer, i had watched a bunch of videos previously and saw folks
making HNO3 in coffee pots and using blow torches, etc. im just paranoid and nervous as i dont have much experience.
anyway, the stuff i made still works. it passed the copper eating test today, after i squirted a few drops of water into the beaker. gotta make
some more! and thanks for the thermometer well idea, i didnt know that they existed.
[Edited on 21-11-2014 by ellafuntay]
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