Sciencemadness Discussion Board - Nitric Acid Synthesis

Nitric Acid Synthesis

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kilowatt - 18-3-2009 at 13:50

Do they make ones that are longer than 7"?

hissingnoise - 18-3-2009 at 14:25

You could try running it without cooling, kilowatt, and check for overheating as it goes along.
It should work fine and your long electrodes should dissipate heat pretty well.
7 inch tungstens would seem to be on the short side, but they might work.
Aluminium, though, should stay inert once passified, and dissipates heat just as well as copper.
The real problem, it seems to me is getting enough absorption since the NO2 concentration will be very low.
An improvised absorption tower, though, will need a good compressor to drive it!
But you're most of the way there. . .

kilowatt - 18-3-2009 at 14:35

I have gotten the concentration up pretty high by running it without the air circulation. Perhaps an intermittent absorption would be most efficient. However for the production itself, a low concentration is more efficient. Good diffusion in the bubbler should help a lot in any case.

Maybe condensing the NO2 with a Peltier cooler would be a better option.

[Edited on 18-3-2009 by kilowatt]

hissingnoise - 18-3-2009 at 15:09

Yes, your immediate problem is the leaking oil-pump, since your set-up will produce HNO3 as it is.
Tweaking efficiency is of minor importance in home-synthesis. . .
Once you solve the leak problem, you might be able to run it continuously and get usable amounts of acid.

muze801 - 20-4-2009 at 17:45

I just attempted a Nitric Acid Synthesis last night with moderate results, using almost all makeshift apparatus.
I used a piece of Al tubing for my condenser, assuming that it would be OK due to passivation.

I added KNO3 to an excess of somewhat concentrated sulfuric acid (boiled down battery acid). After heating, my flask filled with a dark brown/red gas (NO or NO2?), and I got a nice drip of RFNA distillate in my receiving flask.

The HNO3 had some precipitate in it, that formed a crystal sheet at the bottom of the beaker, could this be AlNO3 from the tube?

hissingnoise - 21-4-2009 at 02:46

What is the wire composed of and what's it doing in the acid?
I'd be surprised if the contamination came from the aluminium tube (if it was clean), but a proper condenser would be better---if you can afford to have a variac you can afford more glass. . .

[Edited on 21-4-2009 by hissingnoise]

Picric-A - 21-4-2009 at 04:57

Conc. HNO3 has been stored in aluminium containers as they are so strongly oxidising they are not attacked by nitric acid. Especially at concentrations of 90% +...

hissingnoise - 21-4-2009 at 05:23

If a layer of Al2O3 is scratched or damaged HNO3 will reoxidise the exposed metal, dislodging the Al2O3 layer in scales, as a new layer forms.
That's what it looks like. . .

NO oxidation

Formatik - 21-4-2009 at 21:49

Quote: Originally posted by Formatik

Since then I've thought of ways to make this go more smoothly but haven't tried anything. I wonder if conc. H2O2 could be used to oxidize NO efficiently and more readily: 2 NO + 3 H2O2 = 2 HNO3 + 2 H2O

As well as combining with any NO2:

2 NO2 + H2O2 = 2 HNO3

There's some corroboration for that idea. Though still no idea on applicability under previously described conditions. NO forms HNO2 with aq. H2O2 solution, but with excess H2O2, HNO3 forms (C.F. Schönbein, J. pr. Ch. 81 [1860] 265), according to: 2 NO + H2O2 = 2 HNO2 and 2 NO + 3 H2O2 = 2 HNO3 + 2 H2O (G. Lunge, Z. anorg. Ch. 3 [1890] 568). The only way this could be useful is if the combination occurs significantly more rapidly than with air oxygen. Washing the oxides into NaOH looks simple enough, where nitrate can be eventually recovered. According to Sanfourche in C.r. 175 [1922] 469, a n-NaOH solution converts nitrogen oxides at room temperature into NaNO2 and NaNO3, with the latter dominating even in an absence of oxygen.

Note on HNO3 and Al: Aluminium is still attacked by HNO3, especially hot acid. As described in by Stillman, JACS 19 [1897], 711, for example, 1g of Al turnings, 200cc of HNO3 (d= 1.46) at 100 deg. dissolved aluminium completley within 2hrs. Even at ambient temp. the Al gets attacked and dissolved by all range of acids (d= 1.15 to 1.46) even if gradually, more rapidly in the lesser concentrated stuff.

[Edited on 22-4-2009 by Formatik]

hissingnoise - 23-4-2009 at 11:57

N2O5 produced by oxidation of NO2 by ozone should dissolve (readily?) in water, producing (theoretically?) concentrations up to 100% white acid.
Ozonised air from a homemade NST ozoniser should be more than sufficient to oxidise the output from a Jacob's Ladder.
With H2O2 lower concentrations might be expected unless one had access to highly concentrated peroxide.

Quote: Originally posted by Formatik

Note on HNO3 and Al: Aluminium is still attacked by HNO3, especially hot acid.

Thanks for that Formatik, it's useful to know aluminium's weaknesses; presumably Al tanks for HNO3 are pretreated internally to resist corrosion.
Fluorine comes to mind. . .

[Edited on 23-4-2009 by hissingnoise]

DJF90 - 23-4-2009 at 12:44

I think a small percent of HF is added as a corrosion inhibitor for WFNA and/or RFNA. I can't remember where I read this though and have no further information on the matter.

User - 23-4-2009 at 13:55

So a parallel system with a ozone generator and a Jacobs ladder, both bubbling and/or circulating through a solution might lead to some rather interesting results.

Btw has anyone a working ozone generator.
I have 2 NTS's laying here doing nothing.

hissingnoise - 24-4-2009 at 06:43

Of course DJF90, I'd forgotten only inhibited acid, IWFNA/IRFNA is transported in Al.
My brain was in first gear. . .

User, here's an idea; in addition to ozone, air-fed ozonisers produce nitric oxides in moist air; if moisture content could be controlled within tight limits, the Jacob's Ladder could possibly be dispensed with.
A set-up like that, producing N2O5+H2O could run continuously into a cold-trap to condense a HNO3/N2O5 mixture.
Strong white HNO3 on tap would be a kind of holy grail---boiling sulphur with HNO3 producing your H2SO4. . .
You'll easily find info on building HT ozonisers. . .
I cannibalised my NSTs a long time ago. . . dammit!

User - 24-4-2009 at 13:11

The idea behind the method would be that any nitrous oxides would be oxidized to max. extend. So it just might optimize the yielding of hydrogen nitrate.
In a nutshell is producing nitrous oxides isn't much different from ozone generators.
But separation of the 2 systems working parallel just might do the trick.

Although i have seen a lot of ozone generators online I am wondering how the ones who have actually build one did it.

hissingnoise - 24-4-2009 at 14:04

I haven't tried it (yet) but a simple ozoniser could be improvised from a liebig condenser.
A close-fitting aluminium or SS tube inserted into the vapour-path would serve as one electrode and a wrapping of Al foil, taped around the outside between the water connections would be the second electrode.
The water connections would serve as air-inlet and ozonised air-outlet.
The tubing used would need to be resistant to ozone.
And just remember you're dealing with potentially lethal voltages and that caution is needed.
The output from the arc-chamber and that from the ozoniser could be led into a large jar or flask where they would mix and react before being led into water for absorption.
The amber NO2 in the arc-chamber should be oxidised to colourless N2O5 in the reaction flask.

The_Davster - 24-4-2009 at 15:31

Quote: Originally posted by hissingnoise

A close-fitting aluminium or SS tube inserted into the vapour-path would serve as one electrode

Or put a thin tube, and have the vapour path filled with an electrolyte. There is an ozone thread somewhere around here where this was done by a few, including myself.

Magpie - 24-4-2009 at 15:55

My grandparents, suffering from arthritis or rheumatism, used to have an ozone generator in their house, circa 1955. All I can remember about the generator is that it had a number of glass electrical discharge tubes about 1/2" x 1 ft long. Whenever I would visit the place reeked of ozone.

hissingnoise - 25-4-2009 at 05:34

The_Davster, the electrolytic method, AFAIK, produces less ozone than HV but low voltages are very attractive from a safety standpoint.
The beauty of NO2 oxidation though, is that it might produce acid of any concentration and above (HNO3/N2O5).
And I'm guessing that oxidation of sulphur by HNO3/N2O5 mixtures just might produce oleum.
They're potent nitrating agents that wouldn't need the dehydrating effect of H2SO4 as N2O5, itself, will act in that regard.

Magpie, I know various medicinal claims have been made for ozone-therapy but I didn't know it could treat arthritic conditions.
Still, it's great to walk into a place to be met by the clean smell of ozone---I love it!

Magpie - 25-4-2009 at 07:53

Quote:

Magpie, I know various medicinal claims have been made for ozone-therapy but I didn't know it could treat arthritic conditions.

Actually, I think it was just quackery. They seemed to think it helped but I've never seen any official agreement on this.

Listening to the snapping from the electrical discharge and the strong smell of ozone was a bit intmidating to me as a child. I didn't hang around that machine for very long.

crazyboy - 25-4-2009 at 08:05

Yeah that sounds scary, but I love the smell of ozone...even if it's toxic.

hissingnoise - 25-4-2009 at 09:02

Quote: Originally posted by Magpie

Actually, I think it was just quackery. They seemed to think it helped but I've never seen any official agreement on this.

Negative ions produced by the machine would have a positive effect on mood so there were some definite benefits.
Makes me want to go out and buy an ioniser for just that reason. . .

Formatik - 25-4-2009 at 12:42

Don't smell it too much. O3 is extremely aggressive to the lungs. I was doing an ozonation latley outside and didn't really inhale it but could smell it, and afterwards there was blood in my spit for over a day. Next time I'll always wear the gas mask.

hissingnoise - 26-4-2009 at 08:07

Realistically Formatik, blood in the sputum could just as easily be caused by a minor chest infection but linking it to your ozone exposure is understandable. . .
Had it persisted, a visit to your doctor would have been advised.

Would a mask give full protection against ozone?

Formatik - 26-4-2009 at 14:41

I suspect the appearance of blood was due to lung trauma caused by the ozone. Regardless, I did get treatment. I've done other ozonations and when wearing the gas mask, and not a trace of ozone could be smelled, so from my experience a gas mask alone offers excellent protection.

hissingnoise - 27-4-2009 at 06:22

Your ozone generator must be an effective piece of kit, Formatik---is it commercial or home-built, and have you ever considered oxidising NO2 or SO2 with it?

Formatik - 27-4-2009 at 14:09

It's commercial. I haven't oxidized SO2 or NO2. Oxidizing SO2 with H2O2 is less hassle and simpler and that I have done, but had some problems with the SO2 generator, so quit the experiment (H2SO4 thread). With SO2 at least I expect the reaction to be quite exothermic. Dry O3 will not react with SO2, but in the presence of H2O immediate oxidation to H2SO4 occurs according to Schönbein (J. pr. Ch. 95 [1865] 469/79, 472; etc). Liquid O3 doesn't react with liquid SO2, which might be hard to believe but that was established by Briner, Lachmann (Helv. chim. Acta 26 [1943] 346/57).

The reaction of O3 with nitrogen oxides can be more complex. Some reactions with NO, NO2, N2O5: Leading NO into liquid air cooled liq. O3-O2 mixture will form a green compound (same one from leading NO into liquid air), which explodes as the solution evaporates. Blowing N2O4 into O3-containing O2 forms N2O5, gives also a blue coloring. Rapid leading in of O2-O3 mixture at 0 deg. over the surface of liq. N2O4 gives a blue flame at the end of the inlet tube which sometimes travels through the weakly blue gas leaving behind brown NO2 - Lemon, Lowry (J. chem. soc. 1936 1409/12). N2O5 and O3 give NO3 containing bluish gas at cool temps (0 deg.) which can be ignited.

It might just be my view on it, but frankly, I think ozone is worthless for synthesis. The operations take too long or are low efficiency, or plagued by other complications. Example: bubbling ozonated air into 75 mL 10% NH4OH in a slightly covered (to allow some recirculation) 1L RB flask for 2.7 hours. Although clearly some white NH4NO3 fog was visible after the operation, the solid recoverable was: 0.05 to 0.1g. Not counting loss of NH3 by evaporation. Maybe the water interfered a lot here, since ozone is barely soluble it probably required the O3-air current to push NH3 out of the solution in order to react with it (in the gas phase).

[Edited on 28-4-2009 by Formatik]

Copper based nitric acid prep

Alexein - 3-6-2009 at 23:47

3 part video on "home" nitric acid synthesis.... home if you happen to have sophisticated glassware... ah well.

http://www.youtube.com/watch?v=2yE7v4wkuZU

The first 2 methods are variations on a copper based approach. Horribly expensive (in terms of cost/yield ratio) but a simple approach nonetheless. The last method is the classic sulfuric acid & nitrate salt distillation prep.

User - 4-6-2009 at 02:21

Ah well so expensive does it not have to be.
I mean there is so much scratch copper laying around.
And if you have your sources HCl is almost for free.
I like the idea.
If it is so very practical , thats a second thing.

497 - 4-6-2009 at 03:32

It seems to me that the reaction between a persulfate salt and N2O4 could yield fairly pure and concentrated HNO3 via:

N2O4 + H2O --> HNO3 + HNO2
then
Na2S2O8 + H2O + HNO2 --> 2NaHSO4 + HNO3

overall:
Na2S2O8 + 2H2O + N2O4 --> 2NaHSO4 + 2HNO3

Why wouldn't this work? Persulfate should be a more than strong enough oxidizer to oxidize NO2- to NO3-.

It seems to me it would be possible to add just a near stoiciometric amount of water to yield very concentrated HNO3. Unless it wouldn't run to completion without excess H2O for some reason? I don't know.

EDIT;
Another related possibility is potassium peroxymonosulfate (aka Oxone) which is available quite cheaply as a pool chemical. Maybe like so:

KHSO5 + H2O + N2O4 --> KHSO4 + 2HNO3

[Edited on 4-6-2009 by 497]

DJF90 - 4-6-2009 at 03:55

Persulfate is a kinetically hindered oxidant; it is very strong but also quite slow. A catalytic amount of silver (I) can be used to greatly improve its oxidative speed by froming AgO as the oxidising species. This should also not affect the production of nitric acid in the way that you suggest.

[Edited on 4-6-2009 by DJF90]

lopos123 - 4-6-2009 at 04:29

I don't know if this sounds interesting, but i've found this in a chemistrybook.
Picture

[Edited on 4-6-2009 by mikkello]

User - 4-6-2009 at 05:16

Sure does, if the amounts produced are of any use at all.
And if there are no heavy contaminations.
Bisulfates and NO3 salts are cheap ass.

I've just tried it and indeed it releases densy brown fumes.
The big issue would be that when it is heated decomposition directly effects the output.

[Edited on 4-6-2009 by User]

cobrasniper555 - 13-6-2009 at 01:07

@Formatik: Very cool! I have been doing research on laboratory run at the Ostwald process for a while now and have thought about performing this experiment sometime soon. I am very glad to see that both you and kilowatt have pictures and/or video on the subject. However, I do have a question. Would it be possible to bubble the NO2 through a basic solution of potassium bicarbonate or something similar? I don't want to worry about the concentration of the HNO3 dissolved, but rather have some KNO3 form within the reaction vessel. If the concentration of the base is low enough within the water, and the water is cool, then wouldn't the KNO3 be precipitated out, instead of dissolving as well? This would surely make collecting easier.

hissingnoise - 13-6-2009 at 03:43

Bubbling NO2 into a basic solution will give a mixture of nitrite and nitrate. . .

User - 13-6-2009 at 05:14

I am not sure about this but might adding a strong oxidizer prevent this?
Besides i can imagine making your own KNO3 from almost thin air is cool, but in what way would this be useful ?

Why are there so little people experimenting with the ostwald process, I mean even if it would produce low yields it would be great.

[Edited on 13-6-2009 by User]

hissingnoise - 13-6-2009 at 06:15

Well, because the catalysts are ridiculously expensive for one thing. . .
And because getting purified NH3 to the catalyst at the correct temperature together with a stoichiometric volume of O2 is just too difficult.
The absorption towers represent the final straw. . .

User - 13-6-2009 at 06:50

I just like to be open minded, maybe iam a dreamer.

A pt screen or wire is an investment that if used with a little care lasts a lifetime.
Well even if both reagents are way of stoichiometric amounts I can imagine the process still runs, or is it so fragile ?

DJF90 - 13-6-2009 at 10:00

With excess oxygen I can see no reason why nitric would not be produced. With excess ammonia, ammonium nitrate would form which may produce problems (clogging of orifices etc), beside meaning nitric acid would not be the product.

Formatik - 13-6-2009 at 12:10

Quote: Originally posted by cobrasniper555

@Formatik: Very cool! I have been doing research on laboratory run at the Ostwald process for a while now and have thought about performing this experiment sometime soon. I am very glad to see that both you and kilowatt have pictures and/or video on the subject. However, I do have a question. Would it be possible to bubble the NO2 through a basic solution of potassium bicarbonate or something similar? I don't want to worry about the concentration of the HNO3 dissolved, but rather have some KNO3 form within the reaction vessel. If the concentration of the base is low enough within the water, and the water is cool, then wouldn't the KNO3 be precipitated out, instead of dissolving as well? This would surely make collecting easier.

Well, you will also have some NO in there. This doesn't react with either aq. NH3 or bicarbonate in solution. Definetly not fast enough if it does. It should react with a stronger base like aq. NaOH. Bubbling NO2/NO into the aq. hydroxide will give you NaNO3 and NaNO2, with NaNO3 predominating.

Quote: Originally posted by User

Why are there so little people experimenting with the ostwald process, I mean even if it would produce low yields it would be great.

The Ostwald process uses high pressure, that's tricky to pull off in a laboratory setting. This is also just one reason why lab preparations you read about in the books use a nitrate salt and sulfuric acid. You're supposed to also cool the NO/air or oxygen mixture so that NO2 conversion is favored. Though the Ostwald process actually even today is the prime industrial method of nitric acid production.

cobrasniper555 - 14-6-2009 at 00:48

I thought about that right after I posted, I was just thinking of materials and chemicals I already have. After a lengthy search on the Ostwald process, I've found this video link: http://www.youtube.com/watch?v=OcPchpqer04&feature=relat... . It is very interesting because the instructor seems to pump oxygen in there as well. I'm thinking the same setup with an oxygen generator (2H2O2 -MnO2-> O2 + 2H2O) pumping in oxygen.
The picture below builds off of the video link I provided. As for the solution that the NO2 (considering that the reaction vessel works properly)bubbles through, I am thinking some distilled water or a 3% H2O2 solution. I’m sure there’s many flaws in this design, because I’m looking for a cheap way to do it. I have a very expensive and well-equipped set but this is just how I prefer things. So please, provide any criticism that you have.

User - 14-6-2009 at 02:54

I like the simplicity, it proofs that even a very primitive setup does work (neglecting the extend).
Well the receiver has to be a hell of a lot more efficient then this.
Are you planning on making a continues process?

cobrasniper555 - 14-6-2009 at 04:53

Not as this setup. I want to make a continuous process later on, but this is more of a temporary stage. Think of it as fundamentals towards a new project. I'll develop new plans eventually, if this attempt at a "proof of concept" succeeds. The receiver is very simply drawn but I'll fortify it to keep pressure and maybe recycle the gases. Then again, these would just be additions and improvements upon completion and success of this simple setup. I'll try it later today to see how well it works. I suppose I'll post results if any are interested.

Formatik - 14-6-2009 at 15:25

Quote: Originally posted by cobrasniper555

I’m sure there’s many flaws in this design, because I’m looking for a cheap way to do it. I have a very expensive and well-equipped set but this is just how I prefer things. So please, provide any criticism that you have.

Alright. The process isn't very efficient, because some of the moist unreacted NH3 will mix with react with the formed NO2. Converting NO to NO2 is also frustrating under regular working conditions (the reaction is also slow). The catalyst contact time of the reaction gases in the actual process is also very short to reduce undesirable side reactions (USP3927182 explains the basics, that's a good reference to look at).

[Edited on 14-6-2009 by Formatik]

grndpndr - 15-6-2009 at 11:19

Speaking of PRIMITIVE setups I just lost an e-bay NOS corning brand pyrex retort marked with model # capacity 250ml and maker Inside original packaging at less cost than modern chinese junk.Bid 25 lost it at $29had high bid plus a cushion must have ganged bids last hour.$43 w shipping for a high quality piece versus the same size chin junk for $51+shipping.
right size for the small amounts of nitric I could have used.

An excuse to move up to real equipment,24/40 jointed columns,collectors.3way dist adapters therm. etc.

[Edited on 15-6-2009 by grndpndr]

DJF90 - 15-6-2009 at 12:33

Quickfit is much more versatile than a retort, and you'll probably feel alot better about the whole issue when you get a nice set

Unfortunately it is expensive, and takes a while to build up a decent quantity.

entropy51 - 15-6-2009 at 15:29

grndpndr, sorry you lost the retort on e-bay. There's something very alchemic about making HNO3 the same way it was made 3 centuries ago.

I have plenty of standard taper glass, but for making HNO3 or Br2 I dust off one of my retorts. It's a shame that Pyrex retorts are becoming so difficult to find.

cobrasniper555 - 23-6-2009 at 11:32

@Formatik: May I ask, how is your setup going? I've developed a different method very similar to yours but with a "return" assembly to return the NO gases, when NO2 is dissolved in water, to the original reaction vessel. I also plan on maybe increasing the surface area of the copper in the main reaction vessel. I'm really big on this subject because if it becomes efficient, then this process may replace the constant purchasing of stump remover.

Thanks.

Formatik - 25-6-2009 at 09:00

I haven't worked on it since, it was really just a probe to see if ammonia oxidation is even successful under such conditions. To maximally optimise, one would have to most closely approach what is possible for conversion conditions, as the Ostwald process, in the industry at least is highly efficient.

froot - 26-6-2009 at 00:22

Just reading through the Perchloric acid topic Philou Zrealone mentions a reaction that may be worth considering for the production of concentrated HNO3 - or perhaps more correctly concentrating dilute HNO3 in a round about way.

Quote:

H-C#C-H + 2AgNO3 --> Ag2C2 + 2HNO3

AgNO3 can be wetted with 1 or 2 drops of water and then placed in an atmosphere of C2H2 to initiate the reaction, afterwhich C2H2 can be bubbled through until the reaction is complete. AgNO3 can be synthesised in dilute HNO3, the only trick would be to extract the Ag back out of the Ag2C2 in a controlled manner. Working with Ag2C2 in small batches while it's wet should be much less risky. The only question would be weather the acetylene/AgNO3 reaction would go ahead in extremely acidic conditions.

Any thoughts?

[Edited on 26-6-2009 by froot]

CMOS - 4-7-2009 at 02:09

Can I use NH4NO3 to making HNO3 ?

User - 4-7-2009 at 03:02

Please give some more explanation about what you are trying to say..
I combination with sulfuric acid and than distilling would not be that useful, the ammonium nitrate breaks down quite easily.

12AX7 - 4-7-2009 at 03:02

Yes, read the rest of this thread.

Tim

hissingnoise - 4-7-2009 at 04:42

Quote: Originally posted by CMOS

Can I use NH4NO3 to making HNO3 ?

Yes you can, but the acid will be dilute as oxidation of NH4NO3 by H2SO4 produces H2O + N2.
KNO3 and NaNO3 are more suitable---NaNO3, being very hygroscopic should be dried thoroughly before addition to H2SO4. . .

darel - 10-7-2009 at 00:05

mikkello mentioned saltpeter and sodium bisulfate make NO2. what is the complete reaction?

KNO3 + NAHSO4 + Heat = NO2 + ???

gnitseretni - 10-7-2009 at 10:28

Anyone ever tried reacting nitrogen dioxide with hydrogen chloride?

Formatik - 10-7-2009 at 11:47

Quote: Originally posted by darel

mikkello mentioned saltpeter and sodium bisulfate make NO2. what is the complete reaction?

KNO3 + NaHSO4 + Heat = NO2 + ???

I doubt NO2 forms as a direct result. So: 2 NaHSO4 + 2 KNO3 = 2 HNO3 + K2SO4 + Na2SO4

HNO3 then decomposes when heated.

Quote: Originally posted by gnitseretni

Anyone ever tried reacting nitrogen dioxide with hydrogen chloride?

NO2Cl forms next to Cl2 and NOCl by reaction of gaseous HCl with liquid NO2 at -22° (R. Müller, Lieb. Ann. 122 [1862] 1). The nitroxo chlorides do yield nitric or nitrous acid with water, but how would you isolate it from HCl (which reacts again)?

gnitseretni - 10-7-2009 at 12:11

Use NO2 gas, not liquid.

See patent 4557920

React HCl gas with NO2 gas, you get NOCl gas and HNO3 in the form of precipitated liquid droplets. No isolating anything.

Formatik - 10-7-2009 at 13:26

The usefulness is limited to depending on NO2 already made. Say if you made the NO2 from a metal nitrate directly, you can just treat with H2SO4 as usual and get the fuming nitric acid. If you get your NO2 from something like the Birkeland–Eyde process, then dry it first (silica gel) and then you can use that additional patent setup (more work than I would like to do, though).

hissingnoise - 12-7-2009 at 13:11

Quote: Originally posted by darel

mikkello mentioned saltpeter and sodium bisulfate make NO2.

Making HNO3 by distillation from KNO3/H2SO4 is by far the most practical method and the glassware needed is within everyone's reach.
There is no real need to go the NO2 route, and it never really works as well as the textbook examples, anyway. . .

darel - 12-7-2009 at 17:21

Like Centimeter, I to look for another means of producing nitric acid without he use of sulfuric acid. It is relatively expensive and you can't get the sulfuric acid back. I looked onto using HCL because it's 7$ gal vs 28 for sulfuric. My plan is to make NO2 and oxidize it with an ozone. Iam working on the generator. The absorbtion tower for the NO2 and water is inefficient. But N2O5 absorbs much better with water and concentrations can be made up to 100%.

But using sulfuric acid/ nitrate salt method, would it be possible to regenerate the sulfuric acid via:

H2SO4 + KNO3 = HNO3 + KHSO4

KHSO4 + 350C = K2S2O7 + H2O

K2S2O7 + C = K2S2O5 + CO2

K2S2O5 + 200C = K2O + 2SO2

The sulfur dioxide will be percolated through hydrogen peroxide or mixed with O3 and into water to make H2SO4.

hissingnoise - 13-7-2009 at 01:49

N2O5 dissolves readily in HNO3 and the resulting mixture is a more powerful nitrating agent than HNO3 alone. . .
Some members have used thermal decomposition of pyrosulphate;
Na2S2O7---> SO3 + Na2SO4, to produce oleum but with limited success.
You could though, look for cheaper drain-cleaner but in any case, $28 gal isn't exactly prohibitive---you'll distill quite a bit of HNO3 with a gallon.

[Edited on 13-7-2009 by hissingnoise]

darel - 17-7-2009 at 11:30

I have been using a vaccum pump with an absorbtion train and it does alright for protecting the pump from sucking in corrosive fumes. But I do get a similar result as the pictures Mr. Pyro shared. I am looking into an aspirator. what kind of water pressure is needed to pull a 30 mm hg vaccum?

I am also looking into using the same water instead of having the hose running for an hour. Contrabasso mentioned using a bilge pump for recirculation. I don't think these will work because the pressure behind these pumps aren't high. What about a pressure washer. Could those motors be rigged up for such an apparatus?

DJF90 - 17-7-2009 at 12:20

Hissingnoise - I believe garage chemist made fantastic progress on the production of SO3/Oleum from sodium bisulfate via the pyrosulfate, having a very good yeild indeed (I seem to remember ~20g SO3 from 100g NaHSO4?). This can hardly be called "limited success".

chloric1 - 17-7-2009 at 12:52

Quote: Originally posted by darel

Like Centimeter, I to look for another means of producing nitric acid without he use of sulfuric acid. It is relatively expensive and you can't get the sulfuric acid back. I looked onto using HCL because it's 7$ gal vs 28 for sulfuric. My plan is to make NO2 and oxidize it with an ozone. Iam working on the generator. The absorbtion tower for the NO2 and water is inefficient. But N2O5 absorbs much better with water and concentrations can be made up to 100%.

But using sulfuric acid/ nitrate salt method, would it be possible to regenerate the sulfuric acid via:

H2SO4 + KNO3 = HNO3 + KHSO4

KHSO4 + 350C = K2S2O7 + H2O

K2S2O7 + C = K2S2O5 + CO2

K2S2O5 + 200C = K2O + 2SO2

The sulfur dioxide will be percolated through hydrogen peroxide or mixed with O3 and into water to make H2SO4.

Darel, the stochiometry looks solid but in reality your reactions will never happen. Firstly, carbon will reduce sulfate ll the way to sulfide. Secondly, I have personally heated dry solid metabisulfite with the aim to make SO2 only to discover is that the salt goes through a redox decomposition. The results are sodium sulfate, sodium sulfide and very llittle SO2.

uchiacon - 18-8-2009 at 00:09

Hey guys, I've just purchased about $150NZD worth of vacuum distillation labware(1L to a 500ml boiling flask) and I plan to conc the 68% nitric azeotrope into 98% with concentrated battery acid.

Here in NZ(no, we aren't a state of australia) I can buy 25L of 68-70% nitric for $75NZD at the hydroponics shop. Can also buy 30-40% sulfuric acid(battery electrolyte) for $80NZD for 20L at the car battery shop, or $8-10/L in smaller amounts at the motorcycle shop. So at current exchange rates(70c US to $1 NZD) the nitric costs $44US and the sulfuric at $47 US. You guys obviously aren't looking hard enough, we're talking NZ here!

I plan to make a venturi vacuum pump with a 30PSI waterpump I bought recently. It pumps 46L/min so I might need a large container... does anybody have any plans or tips or guides?? I have no idea on how I'm going to make a aspirator to create the vacuum, or on any of the specifics of pipe sizing in the aspirator etc... should I buy one or make it ?

And lowering the vapour point of water increased vacuum(along with ice in the reseviour), and I heard ethylene glycol works, but that it causes froth. Anything else that might work?

And I have the choice of a water bath or heating mantle, I'd guess that I might want something cooler(waterbath) if I make a decent vacuum, around the area of 60 degrees to avoid decomposition.

Technically speaking, if I'm only concentrating the acid(and losing hardly anything to decomp), I should get a relatively high yield correct?

Oh, and goes anybody use vacuum grease? Supposedly you need to to keep a good vacuum, but my glassware is fairly airtight and thick. Where might I get it anyway?

And you guys might want to check out your pottery shops for glazes and colourants, its crazy the stuff some of them stock... Vanadium pentoxide(sulfuric synth), lithium compounds....

Cheers guys

[Edited on 04-07-09 by uchiacon]

JohnWW - 18-8-2009 at 00:49

Quote:

Uchiacon: Hey guys, I've just purchased about $150NZD worth of vacuum distillation labware(1L to a 500ml boiling flask) and I plan to conc the 68% nitric azeotrope into 98% with concentrated battery acid. (cut)

Where did you get that labware from, also the heating mantle?

Quote:

Uchiacon: I plan to make a venturi vacuum pump with a 30PSI waterpump I bought recently. It pumps 46L/min so I might need a large container... does anybody have any plans or tips or guides?? I have no idea on how I'm going to make a aspirator to create the vacuum, or on any of the specifics of pipe sizing in the aspirator etc... should I buy one or make it?

Although 30 psi would be enough if it were properly configured (normal atmospheric pressure being 14.7 psi), ordinary water-pumps are unsuitable for use as vacuum pumps because they have to be "primed" with water or other liquid. They would wear out in no time otherwise, and are not designed to operate as gas compressors. You need a proper vacuum pump, to run a vacuum line from; an old British brand of them with which I am familiar is Edwards.

Quote:

Uchiacon: Oh, and goes anybody use vacuum grease? Supposedly you need to to keep a good vacuum, but my glassware is fairly airtight and thick. Where might I get it anyway?

A brand of proper vacuum joint and stopcock grease with which I am familiar is "Apiezon L". Petroleum jelly a.k.a. Vaseline may be used to some extent as a cheap substitute, but it is somewhat less viscous; an automotive grease, sold in tins and in grease gun cartridges, would be better as a substitute. But a silicone grease would be preferable to a paraffin grease, from the points of view of flammability and volatility.

[Edited on 18-8-09 by JohnWW]

uchiacon - 18-8-2009 at 01:12

*facepalm*

The water pump is meant for use in a water aspiration station, i.e. instead of attaching a hydroaspirator to a tap, you attach it to a pipe leading off from the water pump... hence venturi vacuum pump lol. Ice in the resivour also allows you to bring down water temp more than with a household tap... and you recirculate water.

I got my labware for labwarehouse.co.nz, the guy is very reasonable. Just give him a phonecall or something and tell him Logan referred you.

I plan on making the heating mantle and magnetic stirrer with help from this thread www.sciencemadness.org/talk/viewthread.php?tid=6764#pid76986

Hey, but John, got nitric?

Another Way

hodges - 18-8-2009 at 17:22

I was watching chemistry videos on YouTube and ran across what appears to be an interesting new idea for making nitric acid. Basically if you have hydrochloric acid and a nitrate, you mix the two to get nitrate ions. This mixture can attack copper, producing various oxides of nitrogen as a byproduct. You collect the oxides and bubble them through H2O2 or even water and you get nitric acid.

http://www.youtube.com/watch?v=2yE7v4wkuZU

This is an interesting and novel technique assuming it works as shown in the video.

Back when I was in high school, I wanted nitric acid but could not get it. I thought along the same lines as the author of the above video - I wanted to generate nitrogen oxides so I could bubble them through water, but all I had was HCl. So I always tried to reduce my potassium nitrate to nitrite, using pyro compositions. Never had much luck though. As I recall, only if I poured HCl on the nitrite while it was still very hot would I get any brown gas, even even then just a trace. To think all I would have had to do to use copper with my HCl and KNO3....

Hodges

Rich_Insane - 19-8-2009 at 08:50

Would Ca(NO3)2 work well? This yields two NO3 ions.

If I added 100 gm of Ca(NO3)2 and just as much H2SO4, I would get double the HNO3. The only problem is the concentration, and the fact that I only have an Ahlinn Condenser without any joints or adapters (hence the fact that I would have to build something or use some other method).

Does this sound efficient?

DJF90 - 19-8-2009 at 12:14

Think again. CaSO4 will form a protective layer on the calcium nitrate. One reason why H2SO4 doesnt eat concrete very well (And HCl does a marvellous job...). Ca(NO3)2 does thermally decompose quite easy to give NO2 that can be used as in the above video to give nitric acid of similar quality.

2Ca(NO3)2 => 2CaO + 4NO2 + O2

The NO2 should dissolve in water to give nitric acid. The O2 produced should help the process.

4NO2 + O2 +2H2O => 4HNO3

WOW! The gas mix just happens to have the right stoichiometry! Arent you in luck. Thermal decomp occurs at about 400C IIRC, well within reach. Make sure the evolved gases have a long path through the water to ensure maximum absorbsion.

uchiacon - 3-9-2009 at 23:07

Hey guys,
I haven't seen many people bother with a magnetic stirrer for their distillations under vacuum. I was told bumping would be a problem, but is it even needed? I mean, in a 1L boiling flask filled with 250mls of nitric and sulfuric, will bumping be a problem at like 30torr? Would it be possible to fill it up to 1/2 way without too much bumping?

Will a magnetic stirrer speed up the distillation? I'm thinking of making a basic hotplate with a light dimmer and nicrhome wire, and if I keep that thin (1-2cm thick) I should be able to put my mag stirrer underneath to mix up the acids. I have an aluminium plate and some refractory cement that I could probably use, and if I get a N42 neodymium magnet on the motor I would assume that it'd be able to turn it though the hotplate. Also tested out that aluminium and obscuring of magnetic fields thing; it does obscure the field but its almost unnoticable. I'll use a water bath to provide the heat too.

User - 4-9-2009 at 01:10

Although a water bath would seem quite ideal I would personally prefer a heating mantle in this case.
One of the reason is to squeeze the last nitric acid out of the mixture by adding more heat at the end, this can be considered the second fraction.
Somehow the reaction seem to never be actually ended ( might sound stupid but let me explain).
I've done a synthesis a while ago with SA & KNO3 and let te reaction run for couple of hours at same temp until not much more HNO3 was distilled.
Then raised the temp to aprox. 140 degrees. even more was collected ( lower purity)
For some reason I stored the mixture that was still in the flask and put the bottle away.
After a couple of days the mixture was sweating nitric acid and heavy condensing was found on the walls.
This flask is standing now for a month or something and it keeps doing the same thing.
Even tough I used quite much extra heat there was still NA remaining.

Well to shorten a long, somewhat pointless story.
You would be well off with a little extra heat to spare.
This way one could also take the second fraction, just not to throw it away.
And also a water bath would mean a nightmare bedtime story when your flask breaks.

[Edited on 4-9-2009 by User]

dann2 - 7-9-2009 at 05:02

Hello,

Came accross this. It may be useful reading for the Nitric acid from Ammonium Nitrate dabblers.
Hope it has not been posted before.
Dann2

Attachment: Dehydration of Ammonium Nitrate.pdf (221kB)
This file has been downloaded 607 times

chloric1 - 7-9-2009 at 13:41

@dann2-Great article co-authored by Davis L. Tenney none the less :cool:

About heating calcium nitrate- this might be a good route if your calcium nitrate is not the calcium ammonium nitrate double salt. For this, you will need a slight excess of Ca(OH)2 to turn it all to calcium nitrate. Also, calcium oxide is a component of many glasses. Could the proceedure of heating calcium nitrate in pyrex be safely carried out? It is stated the 400°C is all that is need to start decomposition. But if we learned anything from garage chemist and his sulfur trioxide, it would be that the decomposition would be complete at a significantly higher temperature. I will have to check this out for myself. I actually have a tiny amount of calcium nitrate beads left.

NOTE: A local hobbyist supply house carried chemicals in the day and I remember seeing some OLd calcium nitrate that formed a solid cake in its bottle and it was BROWN!

If this nitrate breaks down that easy maybe the temperature does not need to be high at all.

Picric-A - 7-9-2009 at 14:34

I have made (very weak!) HNO3 from decomposing Ca(NO3)2 before.
The problem with doing this on a large scale is similar to producing benzene via decarboxylation of a benzoate with NaOH.
The CaO produced formes a hard insulating mass which prevents the mix decomposing furthur.
It works well on test tube scale though. Im not sure why your solid nitrate turned brown but you do need to heat it fairly well, i used roaring bunsen flame which proceeded to completion (on 2g scale) Nitrate was tested by dissolving in water (not completly-CaO/OH = fairly insoluble) adding some NaOH then adding Al granules, no NH3 noted.

[Edited on 7-9-2009 by Picric-A]

entropy51 - 7-9-2009 at 15:06

Quote: Originally posted by Picric-A

I have made (very weak!) HNO3 from decomposing Ca(NO3)2 before.

Oh did you now? How exactly does that work?

Quote: Originally posted by Picric-A

Nitrate was tested by dissolving in water (not completly-CaO/OH = fairly insoluble) adding some NaOH then adding Al granules, no NH3 noted.

WTF? Is this supposed to be a test for nitrate? Or what? Your chemistry seems to be as confused as your spelling.

Picric-A - 7-9-2009 at 15:11

yea ACTUALLY, NaOH + NO3- + Al does give off ammonia as a test for nitrate.

how does it work?? well you could not be lazy and read the thread, but i guess i could tell you. I heated a copper tube full of Ca(NO3))2 beads with Nichrome wire then passed the evolved gasses through a series of bubblers.
Added NaOH to the resulting solution till a neutral solution was obtained then boiled off to find out roughly how much nitric i made (not a lot).

And yes my spelling is rather off, dislexia and quick typing, but i dont see how that sentence was confusing in any way?!?!?!?

[Edited on 7-9-2009 by Picric-A]

entropy51 - 7-9-2009 at 15:21

Quote: Originally posted by Picric-A

Added NaOH to the resulting solution till a neutral solution was obtained then boiled off to find out roughly how much nitric i made (not a lot).

And yes my spelling is rather off, dislexia and quick typing, but i dont see how that sentence was confusing in any way?!?!?!?

I guess I'm just slow (I too have dyslexia, but I learned how to spell) but is that supposed to describe a titration? How does boiling off tell you how much nitric you made (not any).

By how does that work, I meant a balanced equation with Gibbs free energies and equilibrium constants that might suggest something at work besides your imagination.

Come to think of it, I think you were misdiagnosed. It isn't "dislexia", whatever that is. It's a combination of arrogance and ignorance.

If you can't play in the yard with the big dogs, it might be better if you stayed on the porch with the other puppies.

For someone who claims to have a license to buy chemicals, it seems odd that you're mucking aroung trying to make HNO3 using some crazy scheme to decompose calcium nitrate fertilizer. I'll wager that you'll have just as much success as you did with your (alleged) contact process plant for sulfuric.

[Edited on 7-9-2009 by entropy51]

[Edited on 7-9-2009 by entropy51]

[Edited on 8-9-2009 by entropy51]

Picric-A - 7-9-2009 at 15:24

Nope it wasnt supposed to describe a titration, hence i put 'roughly' in there...
By working out how much alkali i added (approx) then working out how much nitrate i made (approx) from that how much nitric i made (approx)

Guess i proved you wrong about the nitrate test... i should of mentioned Devarda's alloy is normally used for this but aluminium wokrs just as well and is 1/10 of the price.

Whatever, FUCK YOU!

Picric-A - 7-9-2009 at 15:26

[/rquote] If you can't play in the yard with the big dogs, it might be better if you stayed on the porch with the other puppies. [/rquote]

I think you should take your own advise there, not knowing a simple test for NO3-...

[Edited on 7-9-2009 by Picric-A]

entropy51 - 7-9-2009 at 15:29

Quote: Originally posted by Picric-A

By working out how much alkali i added (approx) then working out how much nitrate i made (approx) from that how much nitric i made (approx)

Whatever, FUCK YOU!

How did you work it out? Sounds like you had constipation.

I see you can spell adolescent obscenities when you want to spell. I guess "dislexia" comes and goes, like your alter egos saber and labxyz.

Picric-A - 7-9-2009 at 15:33

Something called wheight gained... again i quote 'If you can't play in the yard with the big dogs, it might be better if you stayed on the porch with the other puppies'

'I see you can spell adolescent obscenities when you want to spell. I guess "dislexia" comes and goes, like your alter egos saber and labxyz. ' made no sence

entropy51 - 7-9-2009 at 15:41

Quote: Originally posted by Picric-A

I think you should take your own advise there, not knowing a simple test for NO3-...

It sounds really, really sensitive too. If the NH3 doesn't sting your eyes, there's no nitrate present and your reaction went "to completion".

Thanks for the pointer, but I think I'll stick to the nitrate tests that I knew before being instructed by Picric, saber and labxyz.

Picric-A - 7-9-2009 at 15:48

You are so dumb... its called damp litmus paper... its funny you are trying to find any small detail to stab at me but it just isnt working... pathetic!
What test it that? brown ring?

entropy51 - 7-9-2009 at 15:56

Quote: Originally posted by Picric-A

You are so dumb... its called damp litmus paper...

A sensitive analytical instrument indeed. Thanks for the chemistry lesson kid. Shouldn't you be working on your homework instead of interrupting adult conversations? Does your mum know you're on your computer when you should be learning how to spell?

Picric-A - 7-9-2009 at 15:58

Doesnt need to be sensitive, there is either ammonia there or not, NO3- present or not...

Jesus, your so funny, you should consider that as a job, its probably the only thing your good at!

DJF90 - 7-9-2009 at 15:58

The "brown ring" test it is. I think it is a superior test than that using NaOH and Aluminium metal (or Devarda's alloy" because it will not give a false result if ammonium salts are present.

And

Quote:

I see you can spell adolescent obscenities when you want to spell. I guess "dislexia" comes and goes, like your alter egos saber and labxyz.

makes perfect sense.

panziandi - 7-9-2009 at 15:59

Entropy51 loves the brown ring test for bullshit!

Picric-A - 7-9-2009 at 16:04

Quote: Originally posted by panziandi

Entropy51 loves the brown ring test for bullshit!

whose that a stab at?

DJF90 - 7-9-2009 at 16:09

This is chemistry, we dont do stabbing... Thats for the biologists and medics

Picric-A - 7-9-2009 at 16:11

again a crazy joke!

panziandi - 7-9-2009 at 16:11

It was a general joke and play on words relating to analytical chemistry and linking it to the entropy51-saber situation, well... the now entropy51-picricA situation.

Anyway, your method of preparing "nitric acid" will produce nitrogen dioxide, which dissolves in water forming nitrous and nitric acids, dissolving nitrogen oxides to make nitric acid is not the way to go really. Should have double decomposed your calcium nitrate it with sodium/potassium sulphate, used the sodium/potassium nitrate to react with sulphuric acid giving concentrated nitric acid.

entropy51 - 7-9-2009 at 16:11

Quote: Originally posted by Picric-A

Quote: Originally posted by panziandi

Entropy51 loves the brown ring test for bullshit!

whose that a stab at?

The research lab license, the contact sulfuric plant, the ripping off of fellow forum members.

And 95% of your so-called posts.

Quote: Originally posted by Picric-A

Doesnt need to be sensitive, there is either ammonia there or not, NO3- present or not...

Spoken like a true chemist! One who has trouble with math in school.

[Edited on 8-9-2009 by entropy51]

Picric-A - 7-9-2009 at 16:15

Quote: Originally posted by panziandi

It was a general joke and play on words relating to analytical chemistry and linking it to the entropy51-saber situation, well... the now entropy51-picricA situation.

Anyway, your method of preparing "nitric acid" will produce nitrogen dioxide, which dissolves in water forming nitrous and nitric acids, dissolving nitrogen oxides to make nitric acid is not the way to go really. Should have double decomposed your calcium nitrate it with sodium/potassium sulphate, used the sodium/potassium nitrate to react with sulphuric acid giving concentrated nitric acid.

Yep that would def. be the better way of doing it but this thread was geared towards decomposing calcium nitrate to produce ntiric acid so i followed along that path then entropy decided to start an argument...

DJF90 - 7-9-2009 at 16:16

Yes don't you have school in the morning picric-A? I'm sure your teachers won't appreciate you falling asleep in class... And panziandi, thats a very clever idea. React sat. solutions of each Calcium nitrate and Potassium sulfate, yielding a ppt. of Calcium sulfate and a solution of Potassium nitrate, which, when decanted from the ppt, will crystallise nicely into "needles" of KNO3. But why bother when KNO3 is even more available than the Calcium salt?

And the title is Nitric acid synthesis, so to me that means anything goes, so long as HNO3 is the product. Read the first page

[Edited on 8-9-2009 by DJF90]

[Edited on 8-9-2009 by DJF90]

[Edited on 8-9-2009 by DJF90]

Picric-A - 7-9-2009 at 16:21

Yep i do but i prefer rinsing Entropy off the face of the earth

@ DJ - Where i live you cant buy KNO3 OTC but you can buy sack of Nitrochalk for like £3 for 5kg.
Both potassium and sodium sulphate arnt the most soluble so only dilute (K/Na)NO3 solutions could be made so a lot of boiling would be needed.

entropy51 - 7-9-2009 at 16:23

Is it just me, or are all these esoteric methods of making HNO3 (as opposed to following 5 centuries of tradition with metal nitrates and H2SO4) just manifestations of pre-pubertal mental masturbation for people who are afraid to go buy some H2SO4? Even 14 year olds can buy it in a hardware store, assuming they don't have one of them fancy chemical licenses like our three-named friend.

But methods to use available OTC nitrates to get to the classical method are definitely of interest.

[Edited on 8-9-2009 by entropy51]

[Edited on 8-9-2009 by entropy51]

[Edited on 8-9-2009 by entropy51]

panziandi - 7-9-2009 at 16:24

I suppose Picric-A probably meant a post in the thread asked specifically about calcium nitrate, I would peronally go that route. OR saturated calcium nitrate solution and add sulphuric acid (fairly strong if not concentrated) that would ppt CaSO4 and leave with a fairly storng nitric acid solution which could be filtered and distilled. It would be better with Ba(NO3)2 this is the method of choice for preparing chloric and perchloric and other acids from barium salts. Should give these methods a go P-A and see how they compare?

DJF90 - 7-9-2009 at 16:27

100g of water will dissolve nearly 50g Na2SO4 at about 32C. See the solubility curve for sodium sulfate. Solubility of NaNO3 is irrelevant as you would evaporate to dryness.

Picric-A - 7-9-2009 at 16:27

Quote: Originally posted by entropy51

Is it just me, or are all these esoteric methods of making HNO3 (as opposed to following 5 centuries of tradition with metal nitrates and H2SO4) just manifestations of pre-pubertal mental masturbation for people who are afraid to go to the hardware store and buy some H2SO4?

Unless of course you're Fritz Haber and need to save the bacon in World War I.

[Edited on 8-9-2009 by entropy51]

Im a chemist- i prefer to buy Reagent grade 98% sulphuric acid or 69% Nitric acid if i want it, not crappy 'drain opener' like you probably do!

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