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Contrabasso
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A process for Nitric acid would be most helpful and fit alongside the Lead Chamber process described for the manufacture of Sulphuric acid.
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franklyn
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I've thought about this some and I believe 68% nitric acid can be dried prior
to distillation using Chile saltpeter and Epsom salt in the following way.
One needs first to dry the MgSO4•7H2O by cooking in an oven at high heat
for a couple of hours. The proceedure is to mix into the acid both salts which
metathetically reform in solution as hydrated salts.
* Note that more water is indicated below at the right than on the left
so that the hydrated forms shown will not be realized in practice.
Na2SO4•7H2O and Mg(NO3)2•2H2O are the lesser hydrated variants.
. . . . . . . . . . . 17 HNO3 + 28 H2O | + | 4 NaNO3 + 2
MgSO4 => 2 Na2SO4•10H2O + 2 Mg(NO3)2•6H2O
. . . . . . . . . . . . . . . . | . . . . . . . . .| . . . . . . . . . . .| . . . . . . . . . . | . . . . . . . . . . . .
| . . . . . . . . . . . . . . . . . . |
molar mass . . 1071 . . . . . 504 . . . . . . .
340 . . . . . . . .240 . . . . . . . . . .644 . . . . . . . . . . . . . . . 512
1575 grams of 68 % acid are represented above which may be proportioned for
any lesser amount. So for 500 grams of acid at 30 ºC the proceedure would be
to divide it into two beakers , one holding 300 grams of acid and the other 200.
Add and mix in 108 grams of NaNO3 to the beaker with 200 grams acid, then add
and mix in 76 grams of MgSO4 into the other beaker with 300 grams acid.
One then pours and stirs both amounts togther , promptly placing into the freezer
for about half an hour to chill. Solubility of Sodium sulfate drops from a maximum
of 49.7 grams per 100 g water at 32.4 °C to almost nothing at 0 °C .
In the presence of other more soluble salts the solubility of Sodium sulfate is
markedly diminished. Hence when the mixture is retrieved from the freezer,
a precipitate of just about 204 grams of hydated Sodium sulfate should be plainly
seen. After filtering the now much more concentrated acid Mg(NO3)2 mixture is
ready for distillation according the patent given above US2463453.
Solubilities at 30 ºC
- Source - Solubilities of Inorganic and Organic Substances
MgSO4 - 29 % of solution or approximately 409 grams per liter H2O - page 184
NaNO3 - ~49 % of solution or about 960 grams per liter H2O - page 307
*note: what is indicated for NaNO3 in the reference is more than what is
calculated by using the 8.o6 mols per liter given.
Related posts by garage chemist
http://www.sciencemadness.org/talk/viewthread.php?tid=9450#p...
http://www.sciencemadness.org/talk/viewthread.php?tid=1851#p...
http://www.sciencemadness.org/talk/viewthread.php?tid=2823#p...
and one from Bromic Acid
http://www.sciencemadness.org/talk/viewthread.php?tid=946&am...
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chief
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I never did it -- but: Ba(NO3)2 + 2 H2SO4 ==> BaSO4 + 2 HNO3
BaSO4 should ppt., ready ! Has anyone tried this ??
The Ba(NO3)2 might stem from fireworks (those brillant-candles, on the iron-wire):
==> ppt out BaCO3
==> react with some dilute HNO3
==> dry the Ba(NO3)2
==> do the conc. HNO3-reaction, yielding BaSO4
--> recycle the BaSO4, using soda (there was a thread on this, by me)
Raw BaSO4 may be found as filler-material in heavy-weight high-polish-paper !!
Those -heavy- books contain BaSO4 as filler !
Besides: The alchemists, as I believe, distilled saltpeter with Iron- or Copper-vitriole; the forming H2SO4 reacted with the saltpeter, etc .
(Copper-vitriole + "Alaun" + Saltpeter: http://www.retrobibliothek.de/retrobib/seite.html?id=114115)
[Edited on 21-9-2008 by chief]
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chloric1
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Nice franklyn but we are not dissolving your salts in pure water we are dissolving them in concentrated HNO3. I am not so sure you will get mcuh of
the salts to dissolve. Sodium nitrate might be only slightly soluble in concentrated HNO3 because of common ion effect. Secondly, dried epson salts
might not dissolve at all.
Fellow molecular manipulator
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Xenoid
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| Quote: | | Besides: The alchemists, as I believe, distilled saltpeter with Iron- or Copper-vitriole; the forming H2SO4 reacted with the saltpeter, etc .
(Copper-vitriole + "Alaun" + Saltpeter |
Yes, I have often wondered why the old method attributed to "Geber" has not been mentioned in this thread; distillation of copperas (ferrous sulphate)
with saltpetre and alum. All the ingredients are available from a garden centre.
Does anyone know the exact function of alum in this procedure?
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Formatik
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Yeah it works. Heating on low flame CuSO4.5 H2O with KNO3, the mixture turns green and gives off red-brown NO2 gases. I never tried to condense it
though. Heating Cu(NO3)2 itself at low heat will already form NO2 gases. Maybe it could form and decompose in situ by heating KNO3 with some neutral
or acidic inorganic copper salts.
[Edited on 21-9-2008 by Formatik]
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chief
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Instead of Ba(NO3)2 + H2SO4 ==> 2 HNO3 + BaSO4
possibly also : Pb(NO3)2 + H2SO4 ...
might work, and Pb is more available.
PbSO4 is as insoluble as BaSO4, and (I _believe_) also insoluble in conc. HNO3
But no guarantee, think yourselves ... !
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crazyboy
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Do you think this vacuum can pull sufficient pressure to distill nitric acid with no/minimum decomp? http://www.surpluscenter.com/item.asp?UID=2008111217250165&a...
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watson.fawkes
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Oh no. Not even close. That pump is
specified as 25" Hg max. That's 635 mm Hg. Subtracting that from 1 atm = 760 mm Hg, you get 125 mm Hg. I'm not sure that's even classified as vacuum,
just low pressure.
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S.C. Wack
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Well, that's enough vacuum to lower the bp of water to 43C...I sometimes use an oilless Gast that pulls that (not for this), because you don't always
need a turbovac. I think a relevant question here is what, exactly, is a reasonable maximum pot temperature for doing this.
Though a Nalgene aspirator should really be the way to go. I would not trust any train of base to clean it up completely before hitting metal, though
this may be colored by my intense dislike of the fuming acid.
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crazyboy
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Thanks... any suggestions? I don't want an aspirator (I have one) because I cant run a hose and I don't have a sink were I work. I tried a 1/2 HP pump
but it got hot and water went back into the vacuum outlet.
By the way will this http://www.grainger.com/Grainger/items/5Z667?cm_mmc=Google%2... or this http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnu... work?
I'm a bit confused with its vacuum capabilities maybe someone has some idea?
Also and more importantly I made the poor choice of buying a threaded thermometer adapter and my o-ring and cap got melted by nitric acid even though
I wrapped them in Teflon tape. I know I need a side arm adapter with three ground glass joints but I cant seem to find a 24/40 thermometer adapter
that will hold a vacuum and not get corroded by hot nitric acid.
Please help.
[Edited on 13-11-2008 by crazyboy]
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ppoowweerr
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I was playing around the net and found a "Nitric acid substitute". I couldn't find an MSDS or anything that was informative. It said that the ONLY
time this salt was a suitable replacement for nitric acid is when added to HCl ie. to make aqua regia. Does anyone know what this "salt" is? The only
thing that comes to mind is ammonium nitrate, but since I have never combined the two materials I am not sure if it is viable.
I dont really need the pure nitric acid since I don't want to nitrate any energetics, aqua regia is my intended product so any information is
appreciated.
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not_important
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Likely sodium or potassium nitrate, or possibly a persalt that oxidises the HCl to free chlorine.
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Contrabasso
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Vacuum!
I have seen a scheme whereby an aspirator is fed by a waterpump recirculating a reasonable volume of water. Now I really fancy this with a plastic
aspirator and a plastic pump all the corrosive waste should be in the water for sensible disposal, AND the pump should live reasonably long (unlike an
oil filled rotor pump).
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hissingnoise
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Adding small amounts of NaHCO3 to the pump-water might protect the pump from acids carried over by the vacuum.
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hissingnoise
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Then again, IMO, the increase in HNO3 concentration afforded by vacuum-distillation really isn't worth the extra hassle.
Atmospheric distillation from anhydrous (predried) KNO3 and 98% H2SO4 gives RFNA which can be decolourised by bubbling ozonised air or oxygen through.
~98% HNO3 can be prepared this way without resorting to (awkward) vacuum set-ups.
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3287
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It's been mentioned that platinum and copper can be used to oxidize ammonia.
Transition metals in general are often used for purposes of oxidation. Could another transition metal catalyst be used instead, making the process
more suitable for the labless mad scientist?
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hissingnoise
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The oxidation of ammonia on copper does not produce NO---NH3 is decomposed by the reaction.
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Bohrium
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Nitrates do not react as 2XNO3 + H2SO4 --> X2SO4 + 2HNO3.
Because H2SO4 is diprotic, it will react like this: XNO3 + H2SO4 --> XHSO4 + HNO3.
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hissingnoise
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| Quote: | Originally posted by Bohrium
Because H2SO4 is diprotic, it will react like this: XNO3 + H2SO4 --> XHSO4 + HNO3. |
Actually both protons can be used as in this scheme; 2KNO3 +H2SO4---> K2SO4 + 2HNO3.
A smaller quantity of H2SO4 is used but the bisulphate is the preferred byproduct in practice. . .
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vulture
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| Quote: |
Actually both protons can be used as in this scheme |
No they can't, HNO3 is a stronger acid than HSO4-.
One shouldn't accept or resort to the mutilation of science to appease the mentally impaired.
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Jor
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Are you sure vulture?
At room temperature yes, then only the first proton can protonate KNO3 or similar, as the HNO3 is not yet a gas at those temperatures.
But at higher temperatures, above the boiling point, the equilibrium is pushed more and more to the right, because HNO3 escapes from the system as a
gas.
It is also possible to produce HCl from NaHSO4....
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hissingnoise
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With respect, vulture, it's to do with the volatility of the acids, the pot-temperature and the stoichiometry of the reactants, not acid-strength. . .
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Bohrium
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| Quote: | Originally posted by hissingnoise
With respect, vulture, it's to do with the volatility of the acids, the pot-temperature and the stoichiometry of the reactants, not acid-strength. . .
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HSO4- will not disassociate in any considerable yield, so it will be unable to bond to free NO3- and boil off. So, you will be left with a bunch of
HSO4- and X+ in solution, which will eventually crystallize.
[Edited on 16-1-2009 by Bohrium]
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hissingnoise
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Bohrium, it's quite simple, the proton in a hydrogen-sulphate is acidic and being acidic it is replaceable/reactive---this is elementary text-book
stuff!
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