Collecting/storing chlorine gas

[rthmjohn]

Anybody got a good method of effectively collecting the chlorine gas from a bleach/HCl reaction into a glass ampoule. I can't figure out how to minimize the loss of Cl2 into the atmosphere.

[akcapr]

r u trying to collect it from the ampule or are you trying to collect it in the ampule?

[calbiterol]

And even more important, why do you want to collect it? Trying to get blacklisted by the FBI, now are we? It's extremely dangerous stuff, so be careful.

[budullewraagh]

no it isnt. it's very difficult to kill yourself with chlorine. the smell becomes unbearable LONG before you get anywhere near a lethal concentration. i got a full lungful once and coughed for 3 minutes and i was fine. didnt even get pulmonary edema. well, maybe a very mild case but it wasnt bad at all. plus, the fbi isnt worried about chlorine.

 

anyway, i'd explain, but im sure jdurg would rather do so, as he seems to loove ampouling gases:D

[calbiterol]

I was under the impression that concentrated chlorine gas is very dangerous. It was, after all, one of the first chemical weapons (used a LOT in WWI) and was responsible for many, many deaths on the battlefield there. Seeing as it has the potential to kill, IMHO, you should treat it as if it can always kill you. Anyways, that's just me. The FBI thing was a joke. The kind of things I've heard about getting on the FBI watchlist... I once was told that if you buy a copy of Hitler's Mein Kampf you are put on the list. For some reason, I kind of doubt that...

[budullewraagh]

yes, it was used in world war I. it also killed very few people. in the first world war, trenches were used. the chlorine wasnt pleasant, so people would leave the trenches, coughing, at which time, they would be mowed down by machine gun fire. chlorine gas itself is responsible for a very small percentage of fatalities in combat.

 

a quote from wikipedia:

at second battle of ypres: " "90 men died from gas poisoning in the trenches; of the 207 brought to the nearest dressing stations, 46 died almost immediately and 12 after long suffering."

 

Chlorine was inefficient as a weapon. It produced a visible greenish cloud and strong odour, making it easy to detect. It was water-soluble so the simple expedient of covering the mouth and nose with a damp cloth was effective at reducing the impact of the gas. Chlorine required a concentration of 1,000 parts per million in order to be fatal, destroying tissue in the lungs. However, despite its limitations chlorine was an effective terror weapon and the sight of an oncoming cloud of the gas was a continual source of dread for the infantry."

 

and while it's "dangerous," consider everything in moderation. basically, one would have to lock one's self in a room with significant amounts of chlorine gas in order to die. if you do an experiment outside and you stand 5 feet from a reaction vessel that spews a few moles of chlorine upwards, you wont die. you'll cough a little. you MAY get pulmonary edema. still, again, the smell becomes unbearable before concentrations become high enough to cause any significant damage, so you'll know when to run.

[akcapr]

once u find out the hard way, usually u understand it better.

[budullewraagh]

i've been exposed to chlorine gas on numerous occasions. a half-lungful made me cough for a few minutes and then i didnt get pulmonary edema. the other time i smelled the gas and coughed maybe three times.

[rthmjohn]

into the ampoule

[jdurg]

Yeah, my first attempt at making chlorine gas didn't seem to be working, so I opened up my reaction vessel and got a nice noseful of Cl2 gas. It burned for a little while and I coughed a little bit, but that was really the extent of it.

 

For collecting chlorine gas, the best way to do it is to have the outlet from your reaction going right into the test tube/ampoule that you are collecting it in. (It is also important to make sure that it has been cleaned by running the Cl2 through cool water and then dried by running it through anhydrous NaHCO3). What you will do is generate enough chlorine gas so that your ampoule is overflowing. It's easy to see when you've reached this point if your tube is in front of a white piece of cardboard since the Chlorine will be green in color and easy to see that it's flowing out of the tube.

 

In a separate area, what you'll want to do is set up three welding torches. Set them up so that the three flames converge in one area. This is where the tube will be melted shut. (You will also need two sets of tongs to hold the tube in two places). With the flame set up for sealing the glass shut, you'll need to go back to your overflowing test tube of Chlorine gas with some Teflon Tape. Cl2 is much denser than air, so most of it will stick around in the tube unless you turn it upside down. Wrapping the open end in Teflon tape so that the opening is covered will keep the vast majority of it in there, but not make it airtight. At this point, using one of the tongs you want to grab the tube near the bottom. Now move this tube into the area where the three flames converge. Using the other tongs, quickly grab some glass near the top of the tube and begin to pull upwards a little bit. The area in the flame should be melting by now, and by pulling upwards you'll cause it to melt shut. While it's still molten, you can use the tongs to "flatten" and smooth out the melted portion of the tube. Your chlorine gas will now be locked into the tube and you'll still be able to see the nice pale-green color of it.

[Mendelejev]

Aren't there some sites with photo's ? Couse it's really difficult to imagine !! And could you also use this method for hydrogen, oxygen, nitrogen, etc. ?

[jdurg]

When I get some free time I'll try and upload a diagram that could help out. With hydrogen, it probably would not work as well since the hydrogen is quite flammable and may have a tendency to ignite when it comes in contact with the flame. You'd probably need to use some other heating method and do it in an atmosphere completely free of oxygen in order to prevent the hydrogen from burning. With oxygen and nitrogen, that should work just fine. (Though you'll never really be 100% sure that it's the nitrogen or oxygen in there since they are transparent gases).