SDM
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HNO3 concentration & slight dislexia
Is vacuum distillation absolutely necessary to produce 99% NHO3? How does one check the purity of the reagent once it is produced?
[Edited on 26-9-2015 by Bert]
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battoussai114
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Nothing is absolutely necessary... but if people suggest it, then its likely the best options.
In general people check if the nitric acid is concentrated by checking if it fumes, reacts with copper without necessity for outside heat, titrate it,
convert it to a salt and run a spectrophotometric analysis... there are several options, it all depends on how much you need to be sure about purity.
In a home lab I'd say reacting with copper and fuming is more then enough.
Batoussai.
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greenlight
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If you are making RDX like in your other thread I believe it would be necessary to vacuum distill it to obtain the highest concentration possible.
You can also use the density (g/ml) to check the concentration if you have an accurate scale by weighing 1ml.
You would be looking for about 1.50-1.51g/ml if you wanted 99% HNO3.
Here is a link to a table with all Nitric acid concentrations from 1-100% and their density at all temperature ranges:
http://www.handymath.com/cgi-bin/nitrictble2.cgi?submit=Entr...
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MeshPL
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You can also distill it out of mix of anhydrous nitrate and 98% sulphuric acid.
Remember that fuming nitric acid (the one you want to produce) is very danderous, sets many things on fire including some lab gloves and easily
penetrates some of the others, so without the proper equipment, you may as well work with it bare-handed.
You also can react Cu with some HNO3, than direct NO2 fumes into 65% nitric acid, than dry Cu(NO3)2 and pyrolyse it to produce more NO2 you can add
into HNO3. NO2 will react with H2O in the acid producing more acid and removing water. Note there may be some NO2 dissolved in final product.
Also, iron and aluminium won't react with very conc. nitric acid (but will passivate) and copper will do so slowly, the addition of water will
actually speed that process up.
[Edited on 19-9-2015 by MeshPL]
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SDM
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Thanks greenlight. That is the kind of thing I was looking for. Does anyone know if a hand pump can be used for vacuum distilling HNO3, or do you have
to use an electric pump. If you can use a hand pump, is there a certain vacuum pressure that needs to be reached?
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fluorescence
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I imagine it will be quite dificult to handle it till you have it in a bottle.
In our organic chemistry practical work we had to nitrate some stuff and
fetched some 100% Nitric Acid from our Chemical Section. I filled some out
of the bottle into a small beaker but had to prepare the apparatus first.
In the time it took (about 10 min.) the clear liquid fumed quite heavily and
in went from a clear color to yellow. So I imagine from the time it takes to get
it out of the flask into the bottle it will already get yellow, although I think that
doesn't really matter for the reaction. But still be careful !
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TheChemiKid
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You should really use an electric pump, you could try to use a hand pump, but it would be really hard to do. The distillation can take hours depending
on the batch size. Having to continuously do this is difficult, as well as not keeping a constant vacuum. This can lead to other stuff coming over
when you don't want it to.
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ave369
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Using hand pumps for distillation is a huge physical exercise. I tried it several times (to concentrate H2O2) and know how physically taxing it is.
Even Buchner filtering with a hand pump may prove to be not exactly a walk in the park.
Smells like ammonia....
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SDM
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Where is the best place to get an electric rig?
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greenlight
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Ebay should have some, most are quite expensive though but definitely worth buying one if you are going to get a lot of use from it.
Fast filtering of even fine crystals when hooked up to a buchner and water white 99% nitric = Worth the money if you can afford it.
Heres one: http://www.ebay.com/itm/Laboratory-Diaphragm-Vacuum-Pump-GM-...
Be good, otherwise be good at it
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