Sciencemadness Discussion Board

Nitric Acid

Anarchist - 26-12-2002 at 20:19

Where do you guys get nitric acid? I know it can't be bought in any OTC products. I was thinking of making it myself from KNO3 + H2SO4 but I don't have any kind of tubing that wouldn't get eaten away by the NO2 fumes. Is the only good place to get it from a lab?

trinitrotoluene - 27-12-2002 at 13:48

This is what I suggest get 2 flask and put rubber stopers on them one have 2 holes 1 for the tubing and 1 for the thermoneter. And the other stopper with only 1 hole. To make the stoppers resistant to HNO3 just wrap teflon on it. Do a good job on that and on both of the flasks. Then take aluminium or glass tubing and connect the two flask togeather. And the flask your planning to use as a condenser put it into a beaker into a ice bath.I guess this is as much as i want to explain.

Anarchist - 27-12-2002 at 14:46

thanks, I'll try it.

lucifer - 28-12-2002 at 06:57

I get my hno3 from a drugstore.
I always say I use it for etching
Copper. (like printed circuit boards).

Farmers use hno3 also for disaffection.
Maybe that will help you further.

Anarchist - 28-12-2002 at 10:19

I don't think my drugstore carries HNO3 unless they have it behind the counter where they keep the prescription stuff. I think you're supposed to use HCl for copper etching also. I will check it out though.

trinitrotoluene - 28-12-2002 at 23:30

I know the nearest drug store I went to last time I ask them for citric acid they said they dont have it but they can order it and they told me to wait a week. I can't freaking find citric acid i've went to many food stores and srug stores but I hope they will get me my citric acid soon. After that I will ask them can they order some nitric acid.I hope it wont be too expensive because it seems like chemicals from the drug store is pretty expensive like 112 grams of KNO3 it cost me $2.75

DeusExMachina - 4-1-2003 at 19:29

hey lucifer, what did you buy the HNO3 from the drug store as? I am desperately in need of some.

trinitrotoluene - 5-1-2003 at 23:30

Its much cheaper to make a nitric acid still and make your nitric acid. You will get a higher concentration too. Thats what I'm about to do. If you can do that then most stuff you can nitrate with H2SO4/KNO3, NH4NO3 or NaNO3. Also a cheap method. All I need is some High purity Al foil,a 2000 ml beaker a smaller beaker like 150 ml ,and some suport and i have a HNO3 still like brainfevers but more efficiect. I arieady have 454 grams of KNO3 8 lbs of NaNO3 and 300 grams on HN4NO3. I also have 1 liter of 93% H2SO4 but i can buy gallons at the local hardware store for $12.98 its the cheap kind thats dyed black.

DeusExMachina - 6-1-2003 at 15:45

thanks but I don't have any chems right now so I'd rather buy it than try to make it right now. PLus, I will have to by glass tubing and the way that madscientist told me how to do it over AIM, I would have to put holes in my stoppers :(

lucifer - 6-1-2003 at 16:54

DeusExMachina : I bought a blue can of 25 L 58% HNO3,
This is in holland, so maybe not that useful for you.
It also wasn’t that expensive about 2,5 Euro the liter.
This was about a year ago.

My Nitric acid and Nitric acid still.

trinitrotoluene - 18-1-2003 at 23:20

My nitric acid still: A 500ml erlin flask I add 300 grams of powdered Sodium Nitrate NaNO3 and mixed with 195ml of concentrated sulfuric acid (H2SO4). Then for rubber stoppers I make my own out of Al foil.And I brought a 3' Al tube at the local ace hardware its a large tube and it cost $1.99 per feet.So connect it to the flask anf homade stoppers out of Al foil and seal it with teflon tape, so the HNO3 vapor wont escape.On the other side I did the same Al made stoppers and teflon taping, and the flask is in a ice bath. Ok heat source is a hot plate. I also put soaked napkins on the Al tubing so the HNO3 will condense. So about 95% of the HNO3 condense in the Al tubing and the rest condense in the condensing and cooling flask. Today when I distilled HNO3 my yeald was 160ml of yellow HON3.I am pretty happy with my result. Oh BTW after you are done pour the foaming soloution out of the falsk quickly it will solidifly and will be a pain to get out of the flask. So pour that byproduct out when its in liquid form. My next goal is mass production using 900grams of powdered NaNO3 and 580ml of concentrated H2SO4. ANd I'm going to be using a 1000-1500ml flask. Hope my yeald will be 500ml! After that I plan on using kilograms and start producing liters of HNO3.

non-dstillation method

a123x - 25-1-2003 at 11:49

Uh, just one question I have. How can Al tubing be used like that to distill nitric acid? Shouldn't the Al react with the acid to form aluminum nitrate and H2? Also if you look in the general chemistry section there's a thread on the production of nitric acid using calcium nitrate, strontium ad barium nitrate also work its just that it is easiest to make calcium nitrate. Calcium nirate and sulfuric acid make nitric acid and calcium sulfate which is insoluble. Rather than distill it you have to filter the calcium sulfate off of the nitric acid which should be doabl with a slightly modified fiberglass cloth(its not woven really tightly so you have to slide the threads over to make it nice and tight so the fine sulfate particals can't get through). With that method 98% H2SO4 could yield over 98% nitric acid.

Darkfire - 25-1-2003 at 12:12

The best way i have seen to distill HNO3 is by brainfever;

Use: 1 100ml beaker
1 150ml beaker
hot water bath
plastc that will with stand hot hno3
salt ice bath
h2so4 and Xno3

First: Take the 100ml beaker and place it on a stand in the middle of the 1000ml beaker.
Now fill the big flask with with the correct amount of the acid and nitrate, making sure not to go above the top of the stand.
Now place the plastic in the shape of a funnel so the tip is directly above the small beaker. Tie this on securly and add the salt ice bath on the plastic.
Place in the hot water bath and heat.
|\ ice / | | \ / | | | big beaker |_|sb|_|
Sb= small beaker

BASF - 25-1-2003 at 20:37

As i mentioned earlier, this is a widespread low-budget-method for purifying THC.
I was very surprised such a simple setup existed, and worked well.

(replaces expensive soxhlet extractors and professional distillation setups)

A cannabis-related homepage i´ve recently found, talks about 2-3 hours distillation time for organic solvents like ethanol and petrol ether.

DeusExMachina - 27-1-2003 at 19:52

hey darkfire, what type of rubber can stand hot HNO3? wouldn't the acid just eat right through it? anyways, this is how I'm gonna make my HNO3.

Please tell me if this will work... :(:o

PS- Don't make fun of me for my stupidness please :cool:

HNO3.jpg - 59kB

DeusExMachina - 27-1-2003 at 19:54

sorry for the double post (really, this edit button is pissing me off) but I forgot to include that I didn't find a rounded glass tube so this is why the flasks have to be on there side instead of standing up.

vulture - 28-1-2003 at 13:27

Rubber won't stand nitric acid for long. I give you 5-15 minutes before it will be destroyed.
Remember that your distilling setup has to cope with hot and almost pure HNO3 gas, which is ofcourse very reactive.

Pure Al will withstand conc HNO3 because of passivation, so will iron.

DeusExMachina - 28-1-2003 at 16:40

vulture, will my setup work? I have covered each rubber stopper with teflon.

vulture - 29-1-2003 at 13:12

Well, if you've sufficiently protected your stoppers it should work. I would advise you to cool the receiving flask because otherwise pressure build up might cause your setup to shoot out the glass rod or the flask.

Oh, and put the receiving flask on a lower stand than the distilling flask, this will improve condensation and flow.

DeusExMachina - 29-1-2003 at 13:26

yup, that's what I'm doing. the recieving flask is bomex glass though. Can't it crackif it gets got and then I cool it/

Darkfire - 11-2-2003 at 20:59

Teflon will stand up to hno3 mabey PVC and i sure some others will, test peices before the experiment. Use Al as a backup then at least if the plastic does melt you can save your acid from the ice bath above long enought to fix the problem. H2so4 will however eat the al foil if temp get high enought to vapoize it.

A rubber stopper is a rubber stoper, its rubber so it wont hold up, so cover with a teflon sheet and then cover the hole where the glass tube comes in as well.


NERV - 16-2-2003 at 20:04

From my own experience HNO3 will react with PVC, which will cause major contamination of your acid. I would stick to Teflon, and Al tubes, although you could use PE (I think thats what it was) tubes, as from what I have herd they will stand up to HNO3 for a wile.

lucifer - 17-2-2003 at 14:43

Coating aluminum tubes with Teflon would be ideal I guess,
But is it possible to this at home?

PHILOU Zrealone - 26-2-2003 at 04:46

Al is good to make distillation setup, as long as the process doesn't use H2SO4!
HNO3 oxydises the Al into Al2O3 what forms a protective layer!

You should then use Mg(NO3)2 or Ca(NO3)2 dehydratant to distill the HNO3!

rikkitikkitavi - 26-2-2003 at 10:18

most efficient dehydrant nitrate is Al(NO3)3!
Check patent GB 975324,1001615 and 1146338
for more info about using various nitrates as dehydrants.
(Al,K,Na,Ru,Li,Ca, e tc )

Haggis - 26-2-2003 at 10:37

Deusexmachine- my reccomendation is that you bend the glass tubing. That way there is a less chance for the XNO3/H2SO4 to bubble while boiling and splash in the receiving vessel. To do this, hold your glass tubing over an alcohol lamp. Hold the tube firmly on each side of the flame, protecting your fingers with two handtowels. Hold the area to be bent over the flame and keep a firm but gentle pressure on the tube while heating. When the glass softens, it will start to bend. Take it slightly off the flame and continue with the 90 degree bend. Then let the tubing cool naturally (without dropping into cool water). Do the other side with the same method, taking care that they are perfectly level to eachother.

[Edited on 26-2-2003 by Haggis]

PHILOU Zrealone - 27-2-2003 at 16:31

I thought Al(NO3)3 is an explosive, easy hydrolysed salt?
If you can use Ru(NO3)2, then use Au(NO3)3 it's cheaper ;-)!Believe me, I have worked with Ruthenium chlorides!


PHILOU Zrealone - 27-2-2003 at 16:59

As a parenthese: relative freeable oxygen by weight available to burn a fuel
HNO3 (63,5% bw)
LiNO3 (58%)
NaNO3 (47%)
KNO3 (39,56%)
Be(NO3)2 (60,1%)
Mg(NO3)2 (53,94%)
Ca(NO3)2 (48,75%)
Sr(NO3)2 (37,8%)
Ba(NO3)2 (30,6%)
Ti(NO3)4 (54%)
Cr(NO3)3 (50,4%)
Mn(NO3)4 (52,8%)
Mn(NO3)3 (49,8%)
Fe(NO3)3 (49,6%)
Al(NO3)3 (56,34%)

Or put by oxygen efficience:
HNO3 (63,5% bw)
Be(NO3)2 (60,1%)
LiNO3 (58%)
Al(NO3)3 (56,34%)
Ti(NO3)4 (54%)
Mg(NO3)2 (53,94%)
Mn(NO3)4 (52,8%)
Cr(NO3)3 (50,4%)
Mn(NO3)3 (49,8%)
Fe(NO3)3 (49,6%)
Ca(NO3)2 (48,75%)
NaNO3 (47%)
KNO3 (39,56%)
Sr(NO3)2 (37,8%)
Ba(NO3)2 (30,6%)

Al(NO3)3 is amongst the bests!

osamafon - 28-2-2003 at 01:36

how fast is al picrate

PHILOU Zrealone - 2-3-2003 at 15:11

All picrates must have about the same VOD at an identical density (if it was what you asked?); the major difference are density and sensitivity!

Skean Dhu - 12-4-2003 at 08:34

ok, i tried to make some HNO3 today, but the still didn't work.
i had a glass beverage bottle with about 50-70ml of H2SO4+KNO3 in a hot oil bath, and then for the tubing i had 3ft of Al tubing with a PB jar full of ice saltwater (about 4" away from the bend)to condense the fumes. the tubing was bent at 50degrees, put through the bottle cap(it was a resealable type) and then coated in many layers of teflon tape.

the still stood up to the heat and fumes fine however nothing but the occasional puff of NOx came out the end (which was about 4-6' lower than the bottle)

is the tubing too long, at too steep of an incline or what,

aldo how do you post a picture(ie; paintbrush) i want to give a general schematic of what my still looks like

Mendeleev - 25-12-2003 at 15:30

Darkfire, I agree that brainfever's method is the best but why do you use such small quantity beakers? I use 20 L stainless steel stockpots and get 2-4 L of nitric acid after several days distilling at 65 degrees Celsius, density 1.5 g/mL. Your way would give you about 100-150 mL that's not even enough for a kilogram of nitroglycerin.

[Edited on 25-12-2003 by Mendeleev]

Another Idea

hodges - 7-1-2004 at 15:26

I was just thinking about this thread and have another idea for getting HNO3. I have not tried it, so don't know if it would work.

I seem to recall that HNO3 reacts with copper to form various oxides of nitrogen. Why not create a solution of HNO3 by adding H2SO4 to a nitrate. Even though there will now be a sulfate salt in that solution, I would expect the HNO3 to still react with copper. So drop in some copper. Bubble the NO2 produced into another flask with water, and you have HNO3.

Maybe I'm all screwed up, so don't take my word on this. But it seems like it would work.


Mendeleev - 7-1-2004 at 15:35

The Copper process would be redundant. XNO3 + H2SO4 gives you XHSO4 + HNO3, so all you have left to do is distill, and no copper step. Plus the NO2 + H2O would give you a lot of water in you HNO3 I think due to equilibrium issues, low concentration. Distilling from XNitrate gives you 90% to 100% concentration depending on the sophistication of your methods. Industrially nitric acid is made by reacting NO2 with H2O and the concentration achieved is about %50. The NO2 is gotten from the NO + O2 reaction, and the NO is gotten from the NH3 + O2 reaction.

[Edited on 7-1-2004 by Mendeleev]

[Edited on 7-1-2004 by Mendeleev]

[Edited on 7-1-2004 by Mendeleev]

axehandle - 5-2-2004 at 17:59

Anyone know if 50% nitric acid concentration is the maximum obtainable by bubbling NO2 through water, or if it's just for economical reasons (time) the industrial yield is only 50%?

Mendeleev - 7-2-2004 at 15:20

You can probably get higher concentrations using NO2 + H2O, but the reason they don't in the industry is that they recycle everything. The process is three step.

4 NH3 + 5 O2 ---> 4 NO + 6 H2O
2 NO + O2 ---> 2 NO2
3NO2 +1 H2O ---> 2HNO3 + 1 NO

As you can see there is originally more water formed in the first reaction, and less water than NO2 used in the third reaction thus more is left over which is why the concentration is only 50% by mass. They just heat up the tank after the second step is finished so that the water is a gas and reacts with the NO2 gas more. This most likely requires a catalyst. I was actually wondering, since in the industry it is unlikely that they use glass for 100,000 liter vats of nitric acid, what materials are there besides glass which are both heat resistanct and nitric acid resistant, and have enough structural integrity to hold 100,000 liters?

[Edited on 7-2-2004 by Mendeleev]

rikkitikkitavi - 7-2-2004 at 23:09

stainless steel ...
above 95 % aluminium..


Mendeleev - 8-2-2004 at 16:57

Are you sure stainless steel stands up to nitric acid? Aluminum is the least acid resistant metal I know, and what about sulfuric, can stainless steel stand up to sulfuric acid? After all they distill the nitric acid using sulfuric to get high purity.

axehandle - 8-2-2004 at 19:07

I recently researched suitable materials for nitric, so here is from the top of my head:

Aluminum forms a protective oxide layer on contact with nitric acid (which is a very strongly oxidizing acid), and is indeed a suitable replacement for glass tubing if you're going to distill nitric acid and are building a condenser.

If the acid is hot though, it WILL eventually eat through.

Modern stainless steel can supposedly withstand nitric acid up to 70%, if memory serves me right.

Oh, and PVC also is resistant to nitric acid (any concentration) as long as it's not hot.

About stainless and sulfuric I'm not sure. I would construct the tank out of teflon or pvc coated stainless as they are both resistant.

This link may be of use, it's a chart of the resistances against a multitude of acids w.r.t. various plastics/polymers.

Mendeleev - 8-2-2004 at 20:04

Interesting, yet when nitric acid is distilled it is hot. Perhaps the insides of the tank have a glass coating? I was also wondering about titanium.

axehandle - 9-2-2004 at 04:10

Porcelain enamel has had a great comeback in industry as protective coating. As I understand it, it can, using modern techniques, be applied to almost any metal substrate.

I'm wondering if huge reactor vessels nowadays consist of cheap, mild steel with an also cheap porcelain enamel coating? It would make both technological and economical sense... hmmmmm.

rikkitikkitavi - 9-2-2004 at 11:03

PVC is NOT resistant to concentrated nitric acid. It is resitant to cold conc sulfuric acid < 40 C, and hydrocloric acid.

Stainless steel is not resistant to sulfuric or hydrocloric acid .

axehandle, sometimes they make reaction vessels like that. A few caveats though:

i plants, worker tend to use force and various tools in contact with the eqipment
(for example banging a sledge hammer at a silo ,when the product is stuck in the bottom, banging it broken that is...)

second, it is sometimes difficult to match the
temperature expansion of both materials.

But there is a few areas , fex in the pharmacutical industry where the clean surfaces of enameld steel is used.

The extra cost for enamelling often doesnt justify the use of a cheaper steel. Also consider the fact that corrosive chemicals has a tendency to be found outside the equipment, mostly where they do most harm... (Murphys Law as applied to a chemical engineers everyday headache)


[Edited on 9-2-2004 by rikkitikkitavi]

axehandle - 12-2-2004 at 01:25

Then pray tell why Oxford University would list PVC as nitric acid resistant. When coming to think of it, I've seen it listed as resistant in several other places.

Can you cite a reputable source saying otherwise?

And, btw, and this is not meant as a flame, but I researched porcelain enamel for another pet project of mine that you don't want to know about --- the modern porcelain enamels have a very high tolerance to impulse as well as tensile stress; basically, anything that doesn't deform the substrate won't deform or crack the enamel.

[Edited on 2004-2-12 by axehandle]

Mumbles - 12-2-2004 at 14:49

Does it specifically say concentrated Nitric Acid though? The way I understand is it is resistant to nitric acid at normal temps. At elevated it doesn't stand a chance. Just because it is resistant to it doesn't mean it can hold it. It might hold up for a week or so, but it will be eaten away eventually. Look at section X

I did see a lot more saying it was resistant to, than not though.

axehandle - 12-2-2004 at 20:54

Yes, it does. Actually is say "resistant" both for <30% >70% and "concentrated".

But I agree that PVC wouldn't stand a a snowball's chance in hell at elevated temperatures...:)

The chart I'm referring to is for gloves for emergency spill sanitation. PVC might not stand up to long time exposure, like e.g. storing andydrous nitric in a PVC canister....:o

The info in your link doesn't say if PE-HD is resistant. I would like it to be once my first batch of nitric is ready, since I really HATE glass. Glass breaks, plastics don't.

[Edited on 2004-2-13 by axehandle]

[Edited on 2004-2-13 by axehandle]