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flyingbanana
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Single Use Bromine Storage
What would be the best/safest way to store a small amount of bromine (<5ml) in a regular glass vial to minimize/keep vapors from forming? Bromine
under water? dissolved in acetic acid or dichloromethane or a better solvent for bromine? what concentration keeps vapors in?
This would be for easy single use in small scale reactions, just dump the entire contents of the vial into the solution, pure bromine would not be
required and contact with it would be minimized.
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neutrino
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What supplies do you have available?
If you have any glassworking skill, try making an ampoule. Start with a test tube, seal it off most of the way, let it cool down, add the bromine, and
quickly seal off the remaining part. Just make sure to use a borosilicate tube.
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evil_lurker
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Neutrino is right, except I would use an acetylene torch for heat (MAPP gas would probably be ok too, just a lil slower). I'd start by heating up a
part near the middle till the glass is soft all the way around and pull... creating a narrow spot in the glass tube leaving the top and bottom the
original diameter.
Allow to cool slowly... fill'r up, then heat up the narrow glass part again till soft. Twist off the top and melt the pointy part down to a nub...
instant ampule.
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garage chemist
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For continued storing of bromine, obtain a simple small glass bottle with screw cap and cut a round piece from a sheet of teflon. Then take out the
plastic thing in the screw cap which normally makes it airtight (it is not resistant against aggressive chemicals) and insert the round piece of
teflon sheet instead. This modified cap is completely resistant to bromine, as long as the bromine only comes in contact with the teflon.
Woelen has demonstrated it in another thread.
I will use bottles with such modified caps to store Oleum and PCl3.
If you want to store bromine as a solution in an organic solvent, only carbon tetrachloride will do the job. Every other solvent will react, even
chloroform (and dichloromethane even faster).
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flyingbanana
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thanks for all the suggestions. The teflon idea seems th emost feasible, and a bromine solution in CCl4.
Edit: apparently bromine is infinitely soluble in carbon tetrachloride. what is a good, standard concentration? I was thinking 10% v/v
[Edited on 31-3-2006 by flyingbanana]
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evil_lurker
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Keep it fully concentrated.
www.cynmar.com has safety coated, narrow mouth, amber glass bottles with PTFE/teflon lined caps for cheap.
They are not listed on the website, so you'll have to call and get a P/N...
They have sizes from 2 oz to 33 oz... last I bought of them costed $7.00 or so for the 33 oz size.
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leu
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It's quite easy to store bromine in narrow mouth glass bottles such as those that steak sauce is sold in, one simply makes a gasket out of ptfe tape
to protect the plastic cap 
Chemistry is our Covalent Bond
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Fleaker
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For a quick remedy for storing bromine, I just make a quick cap out of beeswax. The wax is not attacked by liquid bromine, but keep in mind, it's just
a quick solution for very temporary storage. Something I would like to mention to you all, any bromine you have stored in a PTFE capped bottle (make
sure it's not *just* teflon lined, the bromine will creep under it-personal experience here), I suggest sealing up with either paraffin or beeswax,
just melt it in a double boiler setup and dip it in a couple times. This keeps the bromine from slowly leaking out and destroying metal shelving,
computers, and other delicate metallic items. Of course, the wax seal is easily removed with a knife.
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neutrino
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What exactly do you mean by "under"? Are you referring to the space where the PTFE comes into contact with the glass? Also, define 'slowly'. I store
bromine and iodine in tightly-screwed vials with a PTFE insert in the cap and have yet to notice leakage.
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Fleaker
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I mean if you've stored bromine for about a year on your shelf and you notice that the area around it has started to rust. I mean under as in the
teflon insert on the black phenolic cap (at least that is the type of cap I have). As I alluded to, after about 30 days of room temperature storage,
enough bromine made it through to make a pea-sized hole in the cap. I plugged that with wax until I could find a bakelite cap for the bottle.
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neutrino
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In other words, your bromine diffused through the PTFE and attacked the cap on the other side.
How thick is your insert? Mine is rather thick (~1mm) and the brown color has not gone any significant distance through the cap. Only a brownish
circle is visible at the very surface of the insert (on the side exposed to bromine).
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Fleaker
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I apparently need to take a picture of this type of cap. I don't think it was diffusion. The cap is thick enough to prevent that (about ~1mm thick as
well).
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mick
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I have just read some of 'Hermeticity of electronic packages".
Sad but
mick
It gives a lot of information on how long it takes for air or water to get through a seal.
[Edited on 18-5-2006 by mick]
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neutrino
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Sound interesting. Where might one find this book?
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Zinc
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Could bromine be stored in a glass bottle with a ground glass stopper?
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BromicAcid
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Zinc, I've had my bromine stored in a glass bottle with a ground glass stopper now for about two years. The only problem that I have had is that the
stopper pops out when the temperature gets too hot. This problem is rectified by using some teflon tape to effectively tie down the stopper, I.e.,
wrapping the tape around the stopper itself and some around the neck of the bottle so that it holds it all in place. An additional tip is to store
your bromine under sulfuric acid. This really cuts down on bromine fumes when you are opening your bottle and taking bromine out of it, just use a
pipette to get beneath the sulfuric acid layer.
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Jdurg
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I had thought that I had my bromine stored safely in a sealed glass ampoule, but after about a year of storage I noticed a bleach-like odor inside my
element storage cabinet. Apparently, the bromine slowly ate away at the borosilicate glass at the top where it was the thinest. I had a friend of
mine re-seal the glass ampoule, and when he barely even touched the top part of the ampoule it instantly fell apart. The Br2 did a damn good job of
eating through the glass after about a year. Bromine IS the Houdini of chemicals.
Now, I have the bromine re-sealed in a glass ampoule and then cast inside a block of an acrylic resin. It absolutely can not escape. The friend who
made it for me showed an cylinder he made a few years ago where the glass vial broke during the casting process. The Br2 remained in the void left by
the glass and hasn't leached through the resin. I finally feel comfortable having my bromine around.
\"A real fart is beefy, has a density greater than or equal to the air surrounding it, consists of the unmistakable scent of broccoli, and usually
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Zinc
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I have a 20-30 years old sample of bromine sealed in a glass ampoule and it still holds fine.
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chemrox
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Consider a VOA. These are cylindical 20ml bottles with Teflon disks in the cap. They're free to cheap from an environmental lab. Long term storage,
go the ampoule route as detailed above.
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garage chemist
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What does VOA stand for, chemrox?
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not_important
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| Quote: | Originally posted by garage chemist
What does VOA stand for, chemrox? |
Volatile Organic Analysis
http://www.labhut.com/products/vials/by_type/voa.php
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ScienceHideout
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I am very sorry for bumping an old topic, but I have a question relating to this.
We just talked about pure, elemental bromine... but what about a bromine solution... bromine water.
Will that attack glass, metal, plastic, etc?
hey, if you are reading this, I can't U2U, but you are always welcome to send me an email!
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plante1999
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ive store 15% bromine water in glass bottle with Phenolic cap for about 1 year , and no probleme have occured. prety nasty stuff.... i keep it at 5
degree centigrade.
I never asked for this.
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HydroCarbon
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The PTFE insert on a cap will only provide partial protection against your bromine leaking. I have seen iodine stored in a glass vial with a thick
PTFE lined cap escape. The vial was wrapped in toilet paper, which was placed in a plastic bag, placed in a jar. After a few months the toilet paper
turned brown, and the jar smelled of iodine. Granted, not much escaped, but it was definitely not sealed. I would expect bromine to be much worse
than iodine.
I like the idea of a jar/vial with a PTFE lined cap with wax laid around the cap to seal it. Either that or a well constructed ampuole will be the
safest route.
Storing halogens is not easy.
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MrHomeScientist
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I made a small amount of bromine water to store for my element collection, and despite my best efforts it eventually escaped my container. I had it in
a glass vial with a plastic screw cap. Before I screwed the cap on, I covered the opening with yellow PTFE gas tape and wrapped some more around the
threads. I screwed the cap on, wrapped more PTFE tape around the outside, and wrapped a few layers of electrical tape over top of that. The bromine
still escaped. The color slowly lightened over time and after about 3 weeks it's completely gone and now I just have a well-sealed vial of
water. This stuff is hard to store. I have ampoules now so I'll try that next time I make some Br.
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