Sciencemadness Discussion Board - Chlorine gas neutralization

Chlorine gas neutralization

Amos - 5-10-2014 at 20:00

I just acidified some sodium chromate solution with sulfuric acid in order to convert it into sodium dichromate. The solution had some leftover sodium hypochlorite in this, and when I did this outside a surprising amount of chlorine smell still made its way into my garage through the open door several feet away. I'm inside the house now but I'd like to try and get rid of any remaining chlorine in there. Should I assume it will react itself away on metal surfaces in there, or should I try to get rid of it some way? Ventilation won't be an option until the morning.

Brain&Force - 5-10-2014 at 20:03

Maybe leaving out a sulfite or thiosulfate compound will work? Or even just leave a faucet running, as the chlorine may dissolve somewhat in the water.

Amos - 5-10-2014 at 20:09

Quote: Originally posted by Brain&Force

Maybe leaving out a sulfite or thiosulfate compound will work? Or even just leave a faucet running, as the chlorine may dissolve somewhat in the water.

I've got water boiling on a hotplate in there, in an attempt to turn it into HCl. I'm just pretty scared of chlorine, it might come under the door to my basement.

bbartlog - 5-10-2014 at 20:57

Ammonia does a fair job of neutralizing chlorine fumes.

Amos - 5-10-2014 at 21:05

I actually just generated some anhydrous ammonia in there; I'd much rather have that than chlorine. Whatever the cause, I can no longer smell chlorine in there anymore, meaning it's unlikely that its at a hazardous level. Thanks for your help guys.

Zyklon-A - 6-10-2014 at 10:07

Quote: Originally posted by No Tears Only Dreams Now

I actually just generated some anhydrous ammonia in there.

Don't use that to neutralize chlorine, as this reaction occurs:

Cl₂ + 2 NH₃ → NH₄Cl + NH₂Cl

Chloramine is much more toxic than chlorine. Of course the ammonia will absorb water from the air, and then it might just neutralize it in an acid-base reaction, rather then the disproportion reaction above.

Amos - 6-10-2014 at 10:14

Quote: Originally posted by Zyklon-A

Quote: Originally posted by No Tears Only Dreams Now

I actually just generated some anhydrous ammonia in there.

Don't use that to neutralize chlorine, as this reaction occurs:

Cl₂ + 2 NH₃ → NH₄Cl + NH₂Cl

Even though my problem is solved, I don't see why we shouldn't talk about what and what not to do should this happen to anyone else. I read that chlorine can be fatal after just a few deep breaths at 0.1% concentration in air. Surely monochloramine can't be THAT dangerous, right?

AJKOER - 7-10-2014 at 08:13

In the future, add dilute H2O2 to the solution containing NaClO until the vigorous foaming stops. The oxygen formed is actually pleasant smelling. Also, the odor of the hypochlorite/hypochlorous acid is removed, and no chlorine will be generated upon adding H2SO4.

To remove the smell of Cl2 (and also Cl2O), I find that steam offer some help (steam from dilute H2O2 probably is even better if feasible). The reason is likely:

Cl2 + H2O = HCl + HOCl
HOCl + H2O2 ---) HCl + H2O+ O2 (g)

Or, on net:

Cl2 + H2O + H2O2 ---) 2 HCl + H2O + O2 (g)

thereby driving the normal equilibrium for chlorine water to the right with the release of gaseous oxygen.

[Edited on 7-10-2014 by AJKOER]

macckone - 7-10-2014 at 10:28

A more likely mechanism is that the hypochlorite is converted
to perchlorate. The perchlorate ion is not displaced by sulfuric
acid. The perchlorate is also stable in acid solution unlike
the hypochlorite ion. If insufficient hydrogen peroxide is
used the chlorate could be formed which is unstable
with acids.

*edit* Wiki is sometimes your friend
The actual mechanism is much simpler.
NaClO + H₂O₂ -> NaCl + H₂O + O₂

I imagine some hypochlorite is in fact converted to perchlorate
but this is would probably be the preferred reaction.
The bimolecular chlorine is unlikely to form in basic NaClO solution.

[Edited on 7-10-2014 by macckone]

CuReUS - 8-10-2014 at 09:05

Quote: Originally posted by Zyklon-A

Quote: Originally posted by No Tears Only Dreams Now

I actually just generated some anhydrous ammonia in there.

Don't use that to neutralize chlorine, as this reaction occurs:

Cl₂ + 2 NH₃ → NH₄Cl + NH₂Cl

also the ammonium chloride will fill the room with a dense white fume

CuReUS - 8-10-2014 at 09:11

Quote: Originally posted by No Tears Only Dreams Now

Quote: Originally posted by Zyklon-A

Quote: Originally posted by No Tears Only Dreams Now

I actually just generated some anhydrous ammonia in there.

Don't use that to neutralize chlorine, as this reaction occurs:

Cl₂ + 2 NH₃ → NH₄Cl + NH₂Cl

chlorine is not that dangerous ,read bromic acid's story of being "chlorinated" and living to tell the tale
http://www.bromicacid.com/mistakes.htm

although your lungs will burn for a long time
i got nitrated(inhaled too much NO₂ )once while trying to do my first nitration reaction,because i didnt use a fume hood or any sort of protection

my lungs burned for five days

drinking coffee and taking antioxidants(lemon juice ,anything rich in vitamin C and E) helps to reduce the pain somewhat

Amos - 8-10-2014 at 09:47

Quote:

my lungs burned for five days

drinking coffee and taking antioxidants(lemon juice ,anything rich in vitamin C and E) helps to reduce the pain somewhat

Wow, compared to BromicAcid in his youth I feel like a freakin' professional. That is pretty reassuring, as I imagine at most I only generated a couple of grams of Cl2. It's good to work with dilute things first before you step it up(As soon as my SS spoon is finished dissolving I will be making sodium dichromate out of the whole thing)

[Edited on 10-8-2014 by No Tears Only Dreams Now]

blargish - 8-10-2014 at 10:28

Quote: Originally posted by CuReUS

i got nitrated(inhaled too much NO₂ )once while trying to do my first nitration reaction,because i didnt use a fume hood or any sort of protection

my lungs burned for five days

drinking coffee and taking antioxidants(lemon juice ,anything rich in vitamin C and E) helps to reduce the pain somewhat

NO₂ is no fun at all. I inhaled quite a bit more than I should have the first time I synthesized fuming nitric acid and tested the product... Was sick for a week.

Chlorine is not as bad, as I have heard it has a good warning level (the point at which you begin coughing and feeling uncomfortable coincides with the point at which you should get the heck out of there), as opposed to NO₂, which is pretty bad at almost any threshold.

CuReUS - 9-10-2014 at 08:51

Quote: Originally posted by Zyklon-A

Quote: Originally posted by No Tears Only Dreams Now

I actually just generated some anhydrous ammonia in there.

Don't use that to neutralize chlorine, as this reaction occurs:

Cl₂ + 2 NH₃ → NH₄Cl + NH₂Cl

but according to this wiki page http://en.wikipedia.org/wiki/Respirator under chemical warfare
during word war 1 ,when germans released chlorine gas into the trenches,a canadian soldier(he was actually a doctor) told the soldiers to hold urine soaked cloth to cover their nose and mouth ,he though that chlorine would react with the ammonia in the urine and get neutralised.then if chloramine is toxic,the soldiers would have died

although i have read somewhere else that will form dichlorourea so i am not sure

xfusion44 - 9-10-2014 at 10:39

Quote: Originally posted by blargish

Quote: Originally posted by CuReUS

i got nitrated(inhaled too much NO₂ )once while trying to do my first nitration reaction,because i didnt use a fume hood or any sort of protection

my lungs burned for five days

drinking coffee and taking antioxidants(lemon juice ,anything rich in vitamin C and E) helps to reduce the pain somewhat

Well, with both Cl2 and NO2 I have some bad experiences I've done everything outside, except some electrolysis of brine. I can't say which would be more toxic, but it happened to me, that I inhaled too much of both of them and neither was fun, but this happened to me more times with chlorine, so I may think, that the chlorine is more nasty than nitrogen dioxide. Other than smell, experience was pretty much the same (burning in nose, throat, coughing...) This happens, when Cl2 or NO2 reacts with water in throat and nose to produce HCl or HNO3, that's why it burns... If you inhale too much, it becomes too acidic in lungs and lungs try to adjust the pH with more liquid (water I think, but I'm not sure), when this happens, you can drown in your own liquid if breathing of those gasses isn't stopped soon enough. Once it happened to me, that I inhaled a lot of chlorine, while doing electrolysis of brine (I wasn't sure that it works and I sticked my nose into the beaker

), than I coughed for an hour and It burned extremely when I inhaled it

Regarding of this topic I think it would help spraying the water in the room where chlorine is (so that it would react with it).

AJKOER - 31-10-2014 at 14:22

Quote: Originally posted by Zyklon-A

Quote: Originally posted by No Tears Only Dreams Now

I actually just generated some anhydrous ammonia in there.

Don't use that to neutralize chlorine, as this reaction occurs:

Cl₂ + 2 NH₃ → NH₄Cl + NH₂Cl

Reading the current Wikipedia article on NH2Cl (link: http://en.m.wikipedia.org/wiki/NH2Cl ) appears to profess its great benefit over Cl2 as a water purification agent. This claim is not fully supported, in my opinion, as while Chloramine does have a higher half life in the water supply, the claim of reduced tendency to produce chlorocarbons, is perhaps dubious as the safest way to reduce THMs, according to the World Health Organization (WHO), is to remove the organic matter from the water first through prefiltration before disinfection. Also, Chloramine is known to be much weaker/less effective disinfectant than Chlorine to begin with (see another perspective on Chloramine at http://www.chloramine.org/chloraminefacts.htm ) especially with respect to viruses. The Wikipedia article does, with some balance, report the increase in Pb absorption by Chloramine and possible fatalities from Lead with children.

My prior readings on Chloramine gives some insight of the elevated poisonous behavior with respect to Lead. Apparently, NH2Cl can magnified poisonous properties (as to how precisely this is effected, I will let biochemist comment). There was a cited example of the accidental mixing of chlorine bleach and ammonia in a factory setting (forming NH2Cl) in contact with Methyl alcohol, whereupon a mass blinding of workers ensured. Normally, such exposure to CH3OH vapors will not blind one rapidly. Also, with the recent increase of unwanted nitrates (various American States post warning on the web relating to particular dangers to newborns with respect to nitrates) and chlorates in the water supply (thanks apparently to the photocatalytic ability of nitrates acting on Hypochlorous acid), NH2Cl may be a more problematic purification agent (in my opinion, as on hydrolysis, it forms NH3 and notably HOCl, which, with its extended life span, is potentially more likely to actually undergo photolysis forming chlorates).

Interestingly, not another reference in Wikipedia to its potential poisonous behavior until the very end of the relatively long article where to quote:

"Chloramine has been implicated as a mutagen and as a toxic agent for aquatic life, hence the US EPA proposes to prohibit its use in drinking water.[4]"

where, after tauting the script of politicians pushing it as a superior water chlorinating agent (over the very vocal, at times, public disapproval of the substance), some lip service is served up to the interest of the fishing industry as it apparently is quite fatal to fish and marine life (as I understand it, via the disruption of the biochemistry of oxygen absorption from the water, with a similar effect on gaseous oxygen absorption by red blood cells for humans, per the prior link.) As such, reports on the increase/aggravation of respiratory illness by Chloramine treated swimming pools (again, prior link) should not be surprising.

I find amusing the current Wikipedia article as I remember what the old Wikipedia article use to say, before its limited implementation as a water purification agent. It was really scary stuff per my recollection. Also curiously, many MSDSs on NH2Cl, citing its toxic nature, appear to have just vanished over time.

[Edited on 1-11-2014 by AJKOER]