Sciencemadness Discussion Board

Gas mask and why Hg ?

alexleyenda - 25-12-2013 at 19:16

Hi,
I have 2 questions, one about gas masks and one about mercury.

I was wondering if a gas mask was necessary to work outside with
common home chemist gas such as HCl, Cl2, I2 and NO2 during
medium sized reactions around maybe 50 to 500 mL of reagents.
I already searched a lot on the subject and found no clear answer,
so I make my own topic, I don't want to take the risk, especially
after I read about the possible effects of NO2 gas. I already
worked with small quantities of those gas without problem, staying
quite far away from the reactions, but I plan using nitric acid soon
in reactions in which I have to stay close to do manipulations so I
wonder if doing it outside and avoiding the NO2 fumes is fine or if
the danger justifies buying a gas mask. Same question for the other gas?

Edit: Should I worry about getting these gas on my skin or not? Of course i'll be protected but you know some parts as the neck are not covered.


Now for the Hg question:

I saw many topics discussing mercury compounds and how much some
people wanted mercury even if it is hard to obtain and dangerous and
I just can't figure out why? Are there really special/unique experiments
involving mercury that I missed or is it just for the fun of making Hg compounds?

Thank you


[Edited on 26-12-2013 by alexleyenda]

[Edited on 26-12-2013 by alexleyenda]

Zyklon-A - 25-12-2013 at 19:39

I have handled all those gasses without a gas mask, and I'm fine. Cl is not as toxic as you may think, and you'll run away gasping for breath long before you are in any danger of being poisoned. As for HCl you'll be fine, I2 is not a gas at STP, NO2 is very bad, maybe get a gas mask for that (and Chlorine). You can never go wrong with safety precautions.

I have never handled Hg, or any of it's compounds, but I would like to. liquid metals (at STP) are awesome, so ya, it's probably because it is ''just for the fun of making Hg compounds'', as far as I know.

[Edited on 26-12-2013 by Zyklonb]

alexleyenda - 25-12-2013 at 21:53

Yeah for Cl2 I already searched on it and heard lots of story of people breathing a lung full of it without too much damage, I2 sublimates quickly with little heat and NO2 really is the thing that scares me, I found stories of horrible damages, though the description of the exposure was not really clear. Anyways thank you for your answer, it gives me a rough idea, i'll wait for more answers of people completely sure of their answer, but i'll start looking at masks right now :p

hyfalcon - 26-12-2013 at 05:21

Just work with them outside and upwind. You'll know to change position from the least whiff of those gasses. It's almost like your legs have a mind of their own about putting distance between yourself and that horrible odor that just wafted up your nose.

plante1999 - 26-12-2013 at 06:00

Mercury is a liquid metal, which gives it unique properties exploited both in chemistry and in physics, barometer and mercury cell process for chlor-alkali production for example. It's chemical properties are also particular, many reaction can use it, amalgamation, hydromercuration, catalysis, and so on. Unless someone plan to play with it, it is not a beginner reagent.

Zyklon-A - 26-12-2013 at 07:46

Quote: Originally posted by alexleyenda  
Yeah for Cl2 I already searched on it and heard lots of story of people breathing a lung full of it without too much damage, I2 sublimates quickly with little heat and NO2 really is the thing that scares me, I found stories of horrible damages, though the description of the exposure was not really clear. Anyways thank you for your answer, it gives me a rough idea, i'll wait for more answers of people completely sure of their answer, but i'll start looking at masks right now :p


I actually like the smell of I2 at low concentrations:cool:,NO2 scares me to, I went through a phase where I tried to make a gas mask, never got to it, I might try again though.

[Edited on 26-12-2013 by Zyklonb]

Bot0nist - 26-12-2013 at 08:07

Quote: Originally posted by hyfalcon  
Just work with them outside and upwind. You'll know to change position from the least whiff of those gasses. It's almost like your legs have a mind of their own about putting distance between yourself and that horrible odor that just wafted up your nose.


Yes, but be extra carefull with oxides of nitrogen. Low concwntrations are not that irritating, but still very bad. Chlorine and hydrogen chloride will clear you out from thw area fast enough though, if your outside and the breeze changes.

alexleyenda - 26-12-2013 at 12:24

@ plante Thanks for the informations, I was not considering working with Hg anyways, I was just curious.

I think i'll try doing it outside a windy day and if I feel even a small exposure i'll just stop and get a gas mask. The more I read about this thing the less I like it. You only feel the damages after the exposure and I also made a connection that I should have done faster; nitrite salt such as NaNO2 are carcinogenic as they tend to make carcinogenic nitrosamines in our body... So NO2 gas of course do the same thing and I confirmed it with an msds (thought only 1 out of 3 mentioned it). It might not be the most cancinogenic thing as they put this sht (nitrite salt) in our meat to kill bacterias but still...

What about skin exposure? I guess it's not so bad and in the worst case just a wash after the experiment will do the trick, am I right? Of course in msds it's a big deal like if I went to live in a room full of NO2 for a day but everything in msds is a big deal and they give no details, I hate them for that. They even say to avoid contact with NaCl so yeah ... What about the reality of small exposures for maybe 30 min max?

Bot0nist - 26-12-2013 at 12:31

As far as NOx goes. If you can smell it, its to much. Chlorine and HCl will make you move before damage is done usually. NOx can be insidious, and inhalation is a big threat. Just use sense. If you can see and smell orange/red, or brown gas, dont inhale it.

Hexavalent - 26-12-2013 at 12:37

Quote: Originally posted by Bot0nist  
NOx can be insidious, and inhalation is a big threat. Just use sense. If you can see and smell orange/red, or brown gas, dont inhale it.


A method I frequently use which can be effective is the use of a scrubber/gas trap. For NOx, I'd use concentrated, ice-cold potassium hydroxide solution, in sufficient volume to absorb all of the nitrogen dioxide you anticipate will be generated. This may eliminate the need for a respirator on small scales, but for larger reaction volumes, I'd wear one, just in case. Using multiple gas traps in a row is ideal, but, if your equipment availability is limited, just use one larger one. Be careful, however, especially if you are heating and then cooling your reaction system, to avoid suckback <img src="../scipics/_warn.png" />, which can cause the absorbing solution to react violently with your reaction mixture, be sprayed everywhere, or even destroy your product; having an empty flask between your reaction flask and scrubber, as demonstrated by NurdRage in his video on the preparation of hydrochloric acid <img src="../scipics/_yt.png" </img> , is ideal, but an inverted funnel, the top immersed a few centimetres into your scrubbing solution, is also a good choice.

(1500th post ;) )


[Edited on 26-12-2013 by Hexavalent]

Bot0nist - 26-12-2013 at 12:41

I agree hex. If you can rig it, a exhaust scrubbing line is a great idea, even with proper ventilation. Plus you can recover your nitrates... and yes. Watch for suckback. It sucks amd can cause catastrophic effects quickly.

[Edited on 26-12-2013 by Bot0nist]

Pyro - 26-12-2013 at 15:09

Cl2 is nasty shit, just like Br2. But you will vomit at 30ppm, at 60ppm it kills you. Pulminary edema. But you wont stick around so long.
NO2 really isnt so bad, ive worked with it a lot. Inhaling it will make you feel sick, but not much more.
a moist rag will keep most of those gasses away.

as for Hg, it will be clear when you feel it for the first time. Salts of it are veerrry heavy and some are very colorful.

HeYBrO - 26-12-2013 at 15:25

I recently made sodium nitrate via ammonium nitrate and sodium hydroxide and scrubbers are a blessing. I did not note once the scent of ammonia ( except when i was cleaning ) and i didn't release it into the air (environmental concerns) thanks to the scrubber. I agree 100 % with Hex, at very least use a scrubber and always take safety and disposal into account before you run a synthesis it is not fun sitting with toxic chemical waste.

alexleyenda - 26-12-2013 at 15:31

I'll definitely try the gas/suckback trap if possible and thank you for the suckback warning and link to probably one of the only nurdrage video I didn't watch because HCl is so easy to get OTC, I heard of the suckback before but now how it happens has become clear, that'll really help!

The only concern I have now is that I can make a such setting, but i'll have to use rubber stoppers, the only ground joint glassware I have is my distillation glassware and I can't really use it for bubling.. I know nitric acid attacks rubber stoppers, but is it safe to use them only to contain the NO2 fumes coming from the reaction as long as it doesn't reach nitric acid,s boiling point?

Bot0nist - 26-12-2013 at 19:32

Yes it does. Al foil over a nitrating bath or nitric acid corrodes badly. That is mosinformation. UTFSE. It has bwen covered a lot.

alexleyenda - 26-12-2013 at 21:23

I used TFSE and found absolutely nothing about NO2 fumes on rubber, only infos about hot Nitric acid vapors that destroys rubber but I already knew that. So Al foil over a nitrating bath corrodes, but is it because of nitric acid vapor only or also because of NO2 gas ? If it's caused by some nitric acid vapors only I could use a distillation set up and condensate the acid so i'm left only with NO2 for the bubling.

Edit: Hmmm in fact I just thought about that... I could use very cold water and a graham condenser to make liquid NO2 as it boils at 20°C and then easily neutralise it. I would need a lot of ice but it could be done. In fact I could even make solid NO2 as it freezes around -11°C and the temperature often drops under that atm during winter where I live. That could be interesting.

[Edited on 27-12-2013 by alexleyenda]