Sciencemadness Discussion Board

Warning about extracting HNO3 with DCM

vulture - 19-9-2003 at 11:09

I've been extracting HNO3 with DCM today, with very promising results. Drops of DCM/HNO3 vaporize in less than a minute into thick white smoke.

However, nitrating cellulose with HNO3/DCM/H2SO4 turned out to be a nightmare.

I added 53ml of HNO3/DCM and 30ml of H2SO4 and cooled it in a freshly prepared NH4NO3 bath.

After that I added a significant amount (approx 5-10g) of cellulose. The cellulose became gooey and yellow, as I expected. When I returned 2min later, the mixture was boiling vigorously, spewing large clouds of deep red NO2 gas. :o

So apparently, DCM/HNO3 is too concentrated for NC.

BTW, what's the best way to treat NO2 poisoning? I've got a very sore throat now...:(

[Edited on 19-9-2003 by vulture]

Bodansky - 19-9-2003 at 11:37

From Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, 2002

" Nitrogen Dioxide. Nitrogen dioxide is an irritant gas. Its MAK value is 5 ppm (9 mg/m3 ), TLV-TWA 3 ppm (5.6 mg/m3 ), TLV-STEL 5 ppm (9.4 mg/m3 ). Inhalation of nitrogen dioxide causes pulmonary edema which may result in death (lethal dose 200 ppm). The substance is only slightly water-soluble but highly lipid-soluble. It therefore penetrates the alveoli where it damages the capillary walls resulting in exudative inflammation. The respiratory tract is obstructed due to formation of foam. Concentrations exceeding 60 ? 150 ppm produce coughing and a burning sensation in the chest. Pulmonary edema becomes apparent after 2 ? 24 h. The patient suffers respiratory distress and insomnia. Chronic exposure to low doses results in coughing, headache, loss of appetite, and gastrointestinal disorders. Patients should be kept under clinical observation. Inhalation of ammonia from ammonium hydrogen carbonate is recommended.
If the presence of nitrous gas is to be expected a gas mask should be worn (NO filter). "

...and from Casarett & Doull's Toxicology - The Basic Science of Poisons

" Nitrogen dioxide, like O3, is a deep lung irritant that can produce pulmonary edema if it is inhaled at high concentrations. It is a much less potent irritant and oxidant than O3, but NO2 can pose clear toxicologic problems. Potential life-threatening exposure is a real-world problem for farmers, as sufficient amounts of NO2 can be liberated from silage. Typically, shortness of breath ensues rapidly with exposures nearing 75 to 100 ppm NO2, with delayed edema and symptoms of pulmonary damage, collectively characterized as silo-filler's disease. "

" Toxic pulmonary edema represents an acute, exudative phase of lung injury that generally produces a thickening of the alveolar-capillary barrier. Edema fluid, when present, alters ventilation-perfusion relationships and limits diffusive transfer of O2 and CO2 even in otherwise structurally normal alveoli. Edema is often a sign of acute lung injury. The biological consequences of toxic pulmonary edema not only induce acute compromise of lung structure and function but also may include abnormalities that remain after resolution of the edematous process. After exposure to some toxic agents in which the alveolar-capillary surface is denuded (such as alloxan), recovery is unlikely, whereas in situations of more modest injury (such as histamine administration), full recovery is readily archievable. Between these two extremes there are forms of severe lung injury accompanied by amplified infammatory damage and/or exaggerated restorative-reparative
process (e.g., after paraquat ingestion). In these severe forms, the extensive interstitial and intraalveolar inflammatory exudate resolves via fibrogenesis, an outcome that may be beneficial or damaging to the lung. Accumulation and turnover of inflammatory cells and related immune responses in an edematous lung probably play a role in eliciting both mitogenic activity and fibrogenic responses. "

" Certain gases and vapors stimulate nerve endings in the nose, particularly those of the trigeminal nerve. The result is holding breath or changes in breathing patterns, to avoid or reduce further exposure. If continued exposure cannot be avoided, many acidic or alkaline irritants produce cell necrosis and increased permeability of the alveolar walls. Other inhaled agents can be more insidious; inhalation of HCL, NO2, NH3 or phosgene may at first produce very little apparent damage in the respiratory tract. The epithelial barrier in the alveolar zone, after latency period of several hours, begins to leak, flooding the alveoli and producing a delayed pulmonary edema that is often fatal. "

[Edited on 19-9-2003 by Bodansky]

vulture - 19-9-2003 at 12:42

You're post is not really comforting, now is it? :D

Anyways, my sore threat is almost gone, I feel fine. Let's see how things work out tomorrow morning.

See a doctor!

Rhadon - 19-9-2003 at 14:56

I don't know how much NO<sub>2</sub> you got, but the chance to get a pulmonary oedema is not to be underestimated. I know that one doesn't like to see a doctor in such a case and probably I wouldn't like to do it either, but it'd be the best thing you could do.

You must know that pulmonary oedema are often only noticed after it's already too late and the first symtoms will appear many hours after exposure!

I translate (roughly) from Hunnius:
"After a symptom-free interval of 8-10 hours a pulmonary oedema can appear"

Really, the best thing would be to see a doctor. If you don't want to do that, the next best thing might be to lay down, keeping your legs low and your upper body high. Breath calmly. Move as few as possible. But I cannot guarantee for these measures, it's only what I think I remember from having read long ago.

If you want further suggestions it might be an idea to look what they do on phosgene poisoning. Since the latter can also cause a pulmonary oedema the treatment might be similar, but again this is just an assumption.

[Edited on 19-9-2003 by Rhadon]

BromicAcid - 19-9-2003 at 16:29

One of the first things I did when I started doing chemistry at home long ago was try and obtain all the common acids eg HCl, H2SO4, HClO4, H3PO4, and of course HNO3 so I tossed some sodium nitrate in a 1 L round bottom and added significant amounts of H2SO4 and started heating. Long story short, too much heat, too much H2SO4 and I ended up distilling off NO2 which condensed and my yeild was about 60ml. Mind you I thought this was nitric acid. So I would use it in my experiments like it was HNO3. I eneded up using the whole bottle in over the course of a couple months but every time I used it I would get a sore throat and headache and start getting "The Shakes" it wasn't till sometime later that I learned what I had created. Kinda funny really but it still sucked.

Wrong cellulose

Mephisto - 20-9-2003 at 04:56

The HNO3 wasn’t to concentreted and I think the DCM wasn’t the fault too. I had exactly the same problem: I used only 65% HNO3 and it starts to boil and getting black, when I add the cellulose. Also a lot of NO2 fumes evolved. The boiling acid damaged a cupboard when it boils over. The cellulose was the fault. It wasn’t 100% cellulose. The synthetic additions cause the boiling of the acid. When I used 100% cellulose without additions, there was no boiling and no fumes. And the nitrocellulose works. You should buy these pads, which are used to take off make-up. These consists of 100% cellulose.

vulture - 20-9-2003 at 08:26

You could be right, considering I used some low tech tissue paper.

I'll try cotton pads, which are available in vast quantities, since I happen to be "blessed" with a mother and a sister going through puberty. :D

KABOOOM(pyrojustforfun) - 22-9-2003 at 19:04

when using DCM-HNO3-H2SO4 you have a DCM-HNO3 layer @ the top and H2SO4 @ bottom (right?) when you add cellulose if any reaches to the bottom layer before complete reaction, the H2SO4 carbonizes cellulose. the carbon is then oxidized by conc H2SO4 cerating SO2 witch reacts with HNO3 forming HSO3NO2, this reacts with water in the mix, forming H2SO4 and HNO2 ...
please correct me if I'm wrong.
and is NC soluble in DCM?

vulture - 23-9-2003 at 02:17

NC doesn't seem to be soluble in DCM.

As long as the DCM fase doesn't have a aqeous layer on top, the sulfuric acid does mix with the HNO3/DCM.

Carbonisation was insignificant and mostly not observed.

Mephisto - 23-9-2003 at 08:26

vulture: With how many parts DCM you extract the HNO3 from one part of the low concentrated HNO3 and H2SO4 mixture? I know the patent says you can use up to seven parts DCM, but how much you use?

Just BTW, (DCM + HNO3 from Ullmann's):
Nitrating systems which achieve a high degree of nitration without degradation of the cellulose chain are of special scientific interest. This process is known as polymer analogous nitration. After a critical examination of all known nitrating mixtures, the nitric acid/acetic acid/acetic anhydride system in a ratio of 43:32:25 at 0 °C [42] was recommended for determining the molecular mass of native celluloses of such solutions by using absolute methods and the intrinsic viscosity number [43]. The system anhydrous nitric acid in dichloromethane also allows the application of such polymer analogous reactions at temperatures between 0 and -30 °C [44]. Other authors [45] prefer the system nitric acid/phosphoric acid/phosphorus pentoxide.

[42] C. F. Bennett, T. E. Timell, Sven. Papperstidn. 58 (1955) 281-286.
[43] D. A. J. Goring, T. E. Timell, Tappi 45 (1962) 454-460.
[44] K. Thinius, W. Thümmler, Makromol. Chem. 99 (1966) 117-125.
[45] M. Marx-Figini, Makromol. Chem. 50 (1961) 196-219.

Microtek - 24-9-2003 at 04:44

Vulture: Are you sure that H2SO4 mixes with the DCM/HNO3 ? As I understood it, the entire point of using DCM to extract the HNO3 from a H2SO4/HNO3/H2O mix was that it didn't extract anything else.

more complicated reactions

palpy - 25-10-2003 at 12:17

sounds interesting, using a mix of HNO3 and DCM for nitration, but i would be careful with more complicated reactions...
i'm wondering if it could be used in the Bachmann's method or method K (both for RDX)
does somebody know if DCM could react with acetic anhydride (or anything else involved) some undesirable way?

vulture - 25-10-2003 at 12:59

Vulture: Are you sure that H2SO4 mixes with the DCM/HNO3 ? As I understood it, the entire point of using DCM to extract the HNO3 from a H2SO4/HNO3/H2O mix was that it didn't extract anything else.

As I said before, it depends on the conditions.

If there's a water phase the sulfuric acid will mix with that because of it's great affinity for water and become immiscible with the DCM.

However, when you've extracted your HNO3 with DCM you've got a nearly anhydrous mix. The sulfuric acid mixes with it because it's polar aswell.

I tried both these things.


simsalabin - 30-10-2003 at 09:04

i have got fertilizer grade an prilled.
i thinks it is coated with dolomite or some kind of silice... mixed with water is sediments no problem..but it take lot to of time..

can i boil it with sulfuric acid straight away
or do i have first to extract pure an ?
does the coating interfere with nitric acid fomation ?

vulture - 30-10-2003 at 09:47

What the hell has this got to do with this thread??

Please search, your questions could have easily been answered by a simple search.


froot - 22-5-2004 at 14:39

Today I had a go at HNO3 extraction using DCM :-
I have 55% HNO3 and pure DCM. I never had any MgNO3 as advised yet.
1) 50ml HNO3 and 200ml DCM. The mixture was agitated for a couple of minutes and then separated. No great differences in volume of seperated components was noticed. The DCM was boiled down to next to nothing but a couple of acidic fumes.
2) The same as above but the mixture was heated to about 30 deg hoping that HNO3 solubility improved. A greater difference in volumes was noticed. The HNO3 azeotrope was less, so was the DCM, probably from evaporation.
3) 100ml H2SO4 was added to 100ml 55% HNO3. When mixed the DCM turned yellow. After seperation the H2SO4/HNO3 lost about 25ml. The seperation funnel was left full of brown NOx gas. The DCM fumed when blown at.
4) This is weird! This idea evolved from an idea mentioned to me by Vulture a while ago. About 3g hexamine was added to the DCM/HNO3 and left on a stirrer to dissolve. It took a while and no significant temp increase. The solution went milky. Eventually I heated the soln and boiled away the DCM until I reached 80deg. When the remnants were dumped in cold water there was no precipitate but the water went milky and it had the same sweet smell as when you add toluene to HNO3/H2SO4??!?

I have a feeling I'm doing something wrong, and I think I'm not using enough DCM but at what concentration HNO3 in DCM must one have to execute a successful nitration?

[Edited on 22-5-2004 by froot]

vulture - 23-5-2004 at 03:38

You need to add H2SO4 or some other dehydrating agent to the DCM/HNO3 mixture. This greatly improves separation and extraction.

For exact figures, check the patents.

Ramiel - 4-6-2004 at 09:37

The patents suggest as close to 70% as possible for Nitric and as close to 98% as possible for sulphuric. So it seems one could just find the azeotrope of each.

The patent I have simply says to seperate from the aqueous acid by liquid seperation techniques. Could they be any more vague?! :mad:

Decanting, distillation, Mosesation - all of them conventional, but which one do they mean? :(

please help me
*puppy dog eyes*
- Ramiel

vulture - 4-6-2004 at 11:16

Separation funnel...

Marvin - 7-6-2004 at 10:31

Out of curiosity, why didnt you drown and discard when it went gooey?

vulture - 7-6-2004 at 11:33

Because it was looking still fine and the gooeyness is typical for nitrated cellulose.

Marvin - 10-6-2004 at 04:18

Errm, no it isnt. The cellulose should look almost exactly the same as it did before the experiment, though some yellowing is usual, probably as a result of nitric acid acting on residual protein.

Gooeyness means the polymer is being destroyed, usually by a mixture of oxidation and hydrolysis and produces simple sugars which can then cause furthur problems.

Most of my failiers were due to my packing cotton into the nitrating mixture to get as much as possible in (classic newbie mistake). The ones that went sucessfully had only a little cotton in a lot of mixture and it was impossible to tell any nitration was going on until the cotton was removed/washed/dried and then ignited.

vulture - 10-6-2004 at 12:24

In my experience it always got kinda gooey and returned to normal when neutralized. I barely used 2g of paper in 50ml of DCM extract.

Bob - 28-6-2004 at 12:33

suppose that after doing the DCM extraction and distilling off some DCM, you end up with stuff that does NOT mix with sulfuric easily but forms a second phase? I think it unlikely that there is water in the HNO3/DCM phase so what else can be wrong?