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Author: Subject: Nitrogen Dioxide Smell
MagicJigPipe
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Nitrogen Dioxide Smell

I haven't messed with NO2 in a long time. Tonight I decided to do a simple nitric acid distillation with KNO3 and H2SO4.

I can barely remember what NO2 smells like (even though it's smell almost left me traumatized last time!). This time it has a weird plasticy smell to it. Now, this could be it reacting with PVC or the NO2 itself.

It's not really irritating but just your typical annoying plastic smell. I can smell it from about 15 feet away. Do you think this is the actual NO2 or just some oxidation(?) product of the PVC?

I wanted to know so I know if I'm going to die or not. It might be nice to know before it happens. (I haven't been breathing it directly but I also don't have a fume hood).

Oh yeah, I also have pretty good ventilation. Doesn't NO2 tend to "sink" to the ground because of it's density?

EDIT
Okay, I just got a BIG whiff of it. Now I remember! Oh my god it's the most horrible, awful, disgusting smell I have ever .... arrgggggg... It's more of a gut renching, lung crunching "feeling" than a smell.

Oh god... Now I'm paranoid. What are the symptoms of NOx overexposure? Can I check for pulmonary edema with a stethoscope?

[Edited on 28-3-2008 by MagicJigPipe]

"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
woelen

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If you have the feeling that your breathing capabilities are impaired, then you should seek medical attention immediately. NOx is not the stuff to think of too lightly.

If, however, you only had a single whiff of the stuff and then went away, then I believe that your discomfort more is something between your ears, than something real.

But in case of doubt, please go to a doctor and don't try to hassle around in attempts to self-diagnose.

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Want to wonder? Look at https://woelen.homescience.net
not_important
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It's filled with doctor lingo, still should tell you something

http://www.emedicine.com/EMERG/topic847.htm

 Quote: Nitrogen dioxide is a deep lung irritant that can produce pulmonary edema and fatality if inhaled at high concentrations. The effects of NO2 depend on the level and duration of exposure. Exposure to moderate NO2 levels (50 ppm) may produce cough, hemoptysis, dyspnea, and chest pain. Exposure to higher concentrations of NO2 (>100 ppm) can produce pulmonary edema that may be fatal or may lead to bronchiolitis obliterans. Some studies suggest that chronic exposure to nitrogen dioxide may predispose individuals to the development of chronic lung diseases, including infection and chronic obstructive pulmonary diseases. * Acute exposure - Symptoms may range from mild cough to mucous membrane irritation to sudden fatality. o Suspect methemoglobin in patients exposed to nitrogen dioxide gas who exhibit cyanosis or dyspnea. o The initial absence of significant symptoms does not exclude a subsequent development of serious disease. * Latency period - Following a delay of 2-48 hours, patients exposed to nitrogen dioxide may develop the following symptoms: o Dyspnea o Cough o Chest pain o Clinical manifestations of noncardiogenic pulmonary edema * Late sequelae - The following may develop 2-6 weeks after initial nitrogen dioxide exposure: o Bronchiolitis obliterans, manifested as fever, cough, and dyspnea o Diffuse reticulonodular or miliary pattern on chest x-ray Physical: Initial physical findings are sometimes mild but may progress over the following 72 hours to life-threatening respiratory distress. * Pulmonary symptoms are the most common manifestation of nitrogen dioxide toxicity. o Cough o Dyspnea o Chest tightness o Choking o Wheezing o Chest pain o Rales o Rhonchi o Decreased breath sounds o Stridor * Other acute symptoms o Light-headedness o Loss of consciousness o Restlessness o Agitation o Confusion o Irritation of mucous membranes, including the eyes o Conjunctival infection o Weakness o Fatigue o Nausea o Abdominal pain o Skin burns, in cases of liquid nitrogen tetroxide exposure * Delayed symptoms o Tachypnea o Headache o Fever, chills o Insomnia o Myalgias o Hemoptysis o Palpitations o Cyanosis o Coma

NO2 is roughly half again as heavy as air, if there's much of a draft that's not enough to prevent mixing.

I don't think it'd worth bothering to distill HNO3 if it will be oming inyo contact with PVC or other non-fluorocarbon plastics, you're likely to get all sorts of crap in the distillate. That's why a lot of old chem books have you distilling in a retort - to avoid contact between hot HNO3 and organics.

[Edited on 28-3-2008 by not_important]
MagicJigPipe
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Okay, so basically if it I develope coughing or other symptoms within the next 3 days, I should go to the doctor. Also, if I have a gut feeling I will go.

I just REALLY don't want to have to explain to the chemophobic what I was doing messing around with NOx.

Thanks guys. And you're right woelen, I'm pretty sure most of this is just anxiety because I feel much better now. I will be vigilant, though.

EDIT
I was using the clear PVC tube to vent the excess (uncondensed) NOx into NaOH solution.

[Edited on 28-3-2008 by MagicJigPipe]

"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
Jor
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When you're exposed, stop experimenting, to avoid the inhalation of other irritant gasses.

Make sure you rest, dont run or do other sports.
YT2095
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another thing to be vigilant about with NO2 gas and others like HCl is that if your Not doing it outside or in a fume cupboard but in a room, you will Drastically reduce the life span of of any TVs or Monitors that happen to be in there as well.
these gases are not only corrosive but the HT circuitry for CRTs acts like a Magnet for these particles and when they condense around this area its only a matter of time before it corrodes something essential for the normal operation these.

I`ve found this out to my cost several years ago when I got through 3 Monitors in a 5 month span!

\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
MagicJigPipe
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Just wanted to say thanks again for the responses. I feel fine now and just had some anxiety. NO2 does that to me because I hate the "smell" so much and I just "feel" like I've been poisoned when I smell it like that.

I'm doing a titration today to determine the concentration of the acid.

"There must be no barriers to freedom of inquiry ... There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors. ... We know that the only way to avoid error is to detect it and that the only way to detect it is to be free to inquire. And we know that as long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost, and science can never regress." -J. Robert Oppenheimer
TechnologicallyRetarded
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NOx Elimination

I've searched for some time for a thread addressing the dangers and removal of NOx, so far this is the closest. I can sympathise - as I'm sure most of us can - with MagicJigPipe and his incident.

I recently attempted a TNP synthesis and being aware of the toxicity of NOx I did my best to get rid of most of it.

I have no fume hood. It is regrettable, but an ongoing goal nonetheless.

My set-up was quickfit and the synthesis was done outside. The NOx was led through a solution of 25g Sodium Metabisulfite (Wine brewing grade) and 15g NaOH in 200ml water and much crushed ice. Much was dissolved, but a layer of faint red rested on top.

Then suddenly a massive surge of this scrubbing solution travelled back into by barely nitrated Phenol! Most upsetting.

Can we collaborate forces to solve this problem? NOx has always been a problem to me, and will continue to be till I get it nailed. I'm still sure that an Iced scrubbing solution is the way, but how will we do this without get any sucked up?

Flicking through Google I saw articles referring to NH3 and Sulfide as scrubbing agents too.

Tr
chemoleo
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14-9-2009 at 14:30
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Do it outside or invest in a fumehood.

[Edited on 14-9-2009 by Mossydie]
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If you are releasing NOx indoors, or any acidic gasses, for that matter, then also releasing ammonia can make it less harmful. Ammonium sulphate and NaOH in a bowl will do the trick.

The body can deal with a little ammonia, wheras it cannot with little NOx.

Acidic gasses, if not neutralized, can seep into wood and be slowly released over time where their residues can condense on metallic surfaces and lead to rapid rusting and corrosion. So best avoided if you have your tools hung up in racks.
chloric1
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Well some industries bubble NOx in sodium carbonate to make sodium nitrate/nitrite. They are more carefull with the NO2 to NO ratios to get higher nitrite output. But If you do not get much nitrite just titrate the scrubber solution with sulfuric acid/potassium permanganate until a slight permanent pink remains then discharge the excess permanganate with metabisulfite. Or better use nitric acid with the permangante and discharge excess permanganate with H2O2 so your solution is all nitrate then boil to concentrated and add saturated barium chloride to reclaim nitrate!

In the theater of life its nice to know where the exit doors are located.
12AX7
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 Quote: Originally posted by Paddywhacker Acidic gasses, if not neutralized, can seep into wood and be slowly released over time where their residues can condense on metallic surfaces and lead to rapid rusting and corrosion. So best avoided if you have your tools hung up in racks.

Not to mention hydrolyze the wood, weakening it significantly (sulfuric acid is great at this).

Tim

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ctrlphreak
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You can readily see it when it comes up, dark brown colored gas.

It's smell is very metallic, doesn't burn in small quantities, but once you smell and acrid, disgusting smell, look for that cloud, stop the reaction, seperate the reactants if possible, vent the room and leave.
chloric1
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Had a moment! Duh! No need to isolate the nitrate anion with barium the solution shoule consist of potassiu, sodium and manganese nitrates. Sodium or potassium carbonate would suffice and more nitric acid could be isolated from the mixed alkali nitrates.

On the subject of acid on wood. For some strange reason, the combination of pine wood and HCl smells GREAT to me. I find pure HCl disagreeable though Go figure!

In the theater of life its nice to know where the exit doors are located.
TechnologicallyRetarded
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Re: NOx Elimination

 Quote: Well some industries bubble NOx in sodium carbonate to make sodium nitrate/nitrite. They are more carefull with the NO2 to NO ratios to get higher nitrite output. But If you do not get much nitrite just titrate the scrubber solution with sulfuric acid/potassium permanganate until a slight permanent pink remains then discharge the excess permanganate with metabisulfite. Or better use nitric acid with the permangante and discharge excess permanganate with H2O2 so your solution is all nitrate then boil to concentrated and add saturated barium chloride to reclaim nitrate!

Indeed that would be a fine method for Nitrogen reclamation, but personally I don't mind being a little wasteful of reagents -my only concern is my neighbors, my family and myself. I do kind of like/need my lungs and other bits affected by NOx.

What I'm trying - and spectacularly failing - to articulate is this: I wish to remove NOx in it's entirety from my reaction.

As I posted above, I did try to use a scrubbing bath consisting of basic Na2S2O5, but I had a major case of suck-back which completely wrecked my nitration:
 Quote: Then suddenly a massive surge of this scrubbing solution travelled back into by barely nitrated Phenol! Most upsetting.

It did however remove the majority of NOx, which is good. Perhaps there are other ways of removing it. Passing it through a smoky flame or cold-trapping it. Does anyone have info./experience with this?

Tr

hissingnoise
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I've never had a problem with the small quantities of NO2 released during nitric acid distillation, or found the smell offensive, but I now cool the receiver in an ice-bath just to be sure.
The thick cloud roiling from a runaway nitration is a different thing, though, and for that reason I can't see myself nitrating phenol or producing MF this side of getting a hood.
My doctor tells me I have a 'touch' of emphysema but I put that down to a smoking habit.
If I hadn't been told it I wouldn't have known.
Breathing traffic fumes on a busy street is probably as bad as inhaling in a stinky lab. . .
JohnWW
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Nitrogen oxides, mostly the lower ones, are generated in substantial amounts by automobile engines, which intake air (21% O2, 78% N2, 1% Ar, and traces of other gases) and use it to burn fuels (vaporized hydrocarbons, or CH4, or H2). Gasoline-type engines, in which combustion of an heated and compressed vapor-air mixture takes place with the aid of a spark produced by an alternator, are likely to produce more nitrogen oxides than diesel engines, in which combustion is obtained simply by extreme adiabatic compression of the mixture to above the flash-point. These oxides, along with SO2 from any sulfur-containing compounds in the fuels, being acidic and fairly toxic, constitute the most dangerous (and corrosive) part of automobile smog.

[Edited on 16-9-09 by JohnWW]
S.C. Wack
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It took very little to give me edema, which I did not seek medical attention for. Went away after a couple days. It's a freaky sensation, feeling your lung area rattle when you move. I've literally puked out of my lungs from a cold turning to bronchitis/mild pneumonia - which was less freaky.

So I don't advise smelling it.
Jor
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In a busy street, especially if there are busses, I can smell NO2 all the time. I really like the smell of NO2, it smells like chlorine or bromine but nicer.

I have once got a breath of NO2 wich actually hit me in the nose. I guess the concentration was fairly high as NO2 doesn't irritate at low concentrations. I aborted experimenting and took a good rest for a day, and I was fine.

Also one day, I inhaled too much bromine. I had some irritation in my chest, and a little bit of pain. But again, I took a day rest (sleeping, watching TV, etc).

If you inhale too much of a lung irritant, take a day rest, and try to analyse yourself how much you inhaled for how long (at least that's what I did). For example the levels of bromine were slightly irritating in my nose and I was exposed for about 20 minutes. So that can't be lethal, I think it was average 5ppm (with peaks of 10ppm) for 20 minutes, while LD50 is about 150ppm for 1 hour. Before you start work, know what concentrations are dangerous, and know what is the detection level/irritation level.
If you inhaled too much go see a doctor immediately. You don't have to fear losing your lab, when you overexposed yourself to a lung irritant, as you can tell the doctor that you inhaled lots of chlorine while mixing bleach and HCl when cleanign the toilet. Or say you inhaled too much HCl from hardware store 30% HCl. Enough stories you can make up.

Those exposures were in my unwise times. I now always work in a fume hood, and without one, I think I wont experiment again with gasses like NO2 and Br2. Trust me, having a fume hood is one of the best things to have in a lab, it makes you feel so comfortable, sometimes too comfortable that you overlook the dangers of skin contact
hissingnoise
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 Quote: Originally posted by Jor You don't have to fear losing your lab, when you overexposed yourself to a lung irritant, as you can tell the doctor that you inhaled lots of chlorine while mixing bleach and HCl when cleanign the toilet.

But if the irritant is NO2, it would be wise to be up-front about it as one's health should be more important than a lab. . .
You have, though, put your finger on the fact that society's chemophobia can have an actual bearing on the health of chemistry hobbyists.
I, however, have always had a resistance to doctors visits much to my wife's annoyance.
entropy51
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Hissingnoise makes a good point, but depending on their circumstances some people would probably follow Jor's advice. For an NOx exposure you could say you were cleaning antique copper coins with HNO3 or some other plausible story.

In most cases it probably wouldn't help to tell the doctor that you were nitrating phenol, or whatever. The medical treatment for all the pulmonary irritant gases is essentially the same and will be determined based on chest x-ray finding, arterial blood gas measurments, and clinical symtomology. There are no specific antidotes for the pulmonary irritants so there is no need for the doctor to know its identity. Jor's story about bleach and ammonia in the toilet bowl is an excellent one. Emergency departments see a case of that probably once a week in a busy hospital so it will arouse no suspiscion but will result in the appropriate medical evaluation and treatment.

There are of course specific antidotes for cyanide, so if you inhaled HCN and are conscious, which is doubtful, tell them it was HCN you were using to test a sample in your mineral collection.

I would call the paramedics if I developed shortness of breath, extreme chest tightness, coughing up of blood or watery fluid, or cyanosis (blue color) of lips or skin following an inhalational exposure to a toxic gas.

I strongly recommend not treating yourself with a home-made antidote. But do get to fresh air as fast as you can to stop the exposure.

[Edited on 16-9-2009 by entropy51]

Better to remain silent and appear a fool than to open your mouth and remove all doubt.
TechnologicallyRetarded
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All this information is great, but no-one has addressed the methods of gas extraction, except for the mention of a fume hood.

Has anyone used/heard of NOx elimination methods for those of whom a fume-hood is for whatever reason impossible?

Thanks, Tr.
ewalcacer
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This is an old thread but it was one of the top results for my search on google. I was making elemental silver from silver nitrate a few minutes ago by decomposing the nitrate in a muffle furnace at 1100º C in order to also melt the silver after decomposition. Since it couldn't be done in the fume hood here (work lab) all NO2 produced infected the lab. The ammount of silver nitrate I used was something arround 10 grams.
I'm very worried because I could really smell the sweet, chlorine like, odor in the whole lab. I left the lab for a few minutes and kept the door opened to help ventilation.
Since I got a flu yesterday, it's going to be impossible to cough and know that it's probably from the NO2... Right now I'm feeling great but I'm freaking terrified that I can get sick from this. Should I really be worried since I'm feeling great right now?
Thanks.
Endimion17
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 Quote: Originally posted by ewalcacer This is an old thread but it was one of the top results for my search on google. I was making elemental silver from silver nitrate a few minutes ago by decomposing the nitrate in a muffle furnace at 1100º C in order to also melt the silver after decomposition. Since it couldn't be done in the fume hood here (work lab) all NO2 produced infected the lab. The ammount of silver nitrate I used was something arround 10 grams. I'm very worried because I could really smell the sweet, chlorine like, odor in the whole lab. I left the lab for a few minutes and kept the door opened to help ventilation. Since I got a flu yesterday, it's going to be impossible to cough and know that it's probably from the NO2... Right now I'm feeling great but I'm freaking terrified that I can get sick from this. Should I really be worried since I'm feeling great right now? Thanks.

No, there's no need to worry. The described low concentration and the short duration of exposure can't cause any problems unless you suffer from rare illnesses.
NO2 is not the boogeyman of gases. Like chlorine, it's way too corrosive to the pulmonary system to be foolishly neglected. It can cause pulmonary oedema if the concentrations are higher and if you somehow inhale a visibly brown cloud, you'd probably start choking and fall on the floor twitching in shock.
However, it's always a good thing to avoid inhaling it.

In your case, freaking out is a lot worse option.

hissingnoise
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I'd say you're OK!
It kinda depends on the amount of space your lab has.
And while NO2 is detectable by smell at very low concentrations I'd advise a quick visit to a doctor just to be sure . . .

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 Sciencemadness Discussion Board » Fundamentals » Miscellaneous » Nitrogen Dioxide Smell Select A Forum Fundamentals   » Chemistry in General   » Organic Chemistry   » Reagents and Apparatus Acquisition   » Beginnings   » Responsible Practices   » Miscellaneous   » The Wiki Special topics   » Technochemistry   » Energetic Materials   » Biochemistry   » Radiochemistry   » Computational Models and Techniques   » Prepublication Non-chemistry   » Forum Matters   » Legal and Societal Issues