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Topic: How Do You Store Bromine?  (Read 33526 times)

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Offline AfromOz

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How Do You Store Bromine?
« on: December 23, 2006, 01:14:56 AM »
My small amount is decreasing weekly. :(

I currently have it in a glass flask with a glass stopper and wads of Parafilm wrapped around the junction.

It's slowly escaping. Shame as I need it for educational purposes....plus it just looks so cool.

There has to be an relatively easy way?

Cheers,

Adam
If it goes pop, OK.
If it goes KABOOM, better.

Offline EccentricHeather

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Re: How Do You Store Bromine?
« Reply #1 on: December 23, 2006, 01:32:29 AM »
The only good way I know of is to seal it in an ampoule.  Bromine will eat through just about every attempt at containment.  I haven't tried to make ampoules; I bought my sample already in one, so I didn't have to worry about it.

Heather

Offline Ψ×Ψ

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Re: How Do You Store Bromine?
« Reply #2 on: December 23, 2006, 03:09:52 AM »
store it as NBS?  just a thought...

Offline AfromOz

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Re: How Do You Store Bromine?
« Reply #3 on: December 23, 2006, 03:58:59 AM »
^^NBS =?

I was just wondering what chemical companies sell the stuff in. If I remember correctly, the sample I got came out of a plain, dark plastic bottle with a plastic top.

Nothing too exotic in that except you can't see the stuff.

Cheers,

Adam
If it goes pop, OK.
If it goes KABOOM, better.

Offline Ψ×Ψ

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Re: How Do You Store Bromine?
« Reply #4 on: December 23, 2006, 02:00:54 PM »
NBS = N-bromosuccinimide.  It's used to brominate things.  A little heating/vacuum and bromine comes off.

Offline AfromOz

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Re: How Do You Store Bromine?
« Reply #5 on: December 24, 2006, 01:28:02 AM »
Thanks for that.

Just looked it up and it decomposes after a while. :(

Thinking of getting Teflon spray for the glass stopper in my flask and doing the Teflon tape wrap.

Just wondering how I could make an ampoule out of it as I think getting one into Australia would be next to impossible.

My sample is in the fridge (well stored and protected) to try and slow the vapourisation process. Was going to freeze it but the MSDS sheet says not to.

Oh, bloody bromine! Why do the room temperature liquid elements have to be so toxic and problematic?

Cheers,

Adam
« Last Edit: December 24, 2006, 01:33:28 AM by AfromOz »
If it goes pop, OK.
If it goes KABOOM, better.

Offline EccentricHeather

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Re: How Do You Store Bromine?
« Reply #6 on: December 24, 2006, 11:33:05 AM »
If I remember correctly, bromine will even eat teflon, so the teflon tape wrap may not work.  However, anything is worth a try.  It looks like you need to do some research on making ampoules if you want to preserve your bromine.

If you do lose your bromine, there are ways of making more.  Before I found a way to buy a good sample, I was looking for ways to make it and I found this article.  The chemicals needed (potassium bromide and potassium hydroxide) should not be too difficult to obtain.

http://www.crscientific.com/article-bromine.html

If you try this, please carefully read and understand the warning.  It looks like a very dangerous procedure.  Since I was able to buy some bromine in an ampoule, I probably won't ever attempt this.

Heather

Offline AfromOz

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Re: How Do You Store Bromine?
« Reply #7 on: December 25, 2006, 02:07:51 PM »
Thanks for the link, Heather.

Looks a bit scary to me! :o

As I said before, I must find out what is so special about the seemingly innocuous black bottle it all originally came in.

Shame I'm on summer holidays  :-\ Won't have access to the lab for another month.

Will get that bottle and save my bromine.

Any bromine ampoule sellers in Australia? ???

Cheers,

Adam
If it goes pop, OK.
If it goes KABOOM, better.

Offline jdurg

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Re: How Do You Store Bromine?
« Reply #8 on: December 26, 2006, 10:44:00 PM »
Bromine is a b$*%( to store indefinitely.  When you purchase it from a supplier, it comes in a brown amber glass vial/bottle with a Teflon lined cap.  Still, the Br2 will find a way to seep through the Teflon and the cap and corrode everything around it.  This is why in all labs you'll see the area that Bromine is stored in will be fairly well corroded and have that faint Bromine odor to it.

The only way to safely keep bromine stored away at room temperature without it escaping away is to seal it in a glass ampoule and then cast that ampoule into an acrylic resin block.  Even keeping it in a glass ampoule isn't enough to stop the bromine.  Over a long period of time it will slowly leach through the glass thusly weakening the glass.  I had some bromine stored in a glass tube for a good two years, I think it was, before I noticed a strong bromine odor coming from the tube.  When I went to get it re-ampouled, I noticed that the glass had become tissue-paper thin over that timeframe.  As a result, I got my bromine as well as all my other halogens re-sealed in glass ampoules and then had all those ampoules resealed in a cast acrylic resin block.  They look REALLY sweet now and I know that the bromine won't leach out.  (As the friend of mine who sealed it had cast a bromine ampoule in resin about three years ago, and even though the glass vial within had broken, the bromine has not leaked out).
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Offline woelen

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Re: How Do You Store Bromine?
« Reply #9 on: December 27, 2006, 04:41:21 PM »
Before I found a way to buy a good sample, I was looking for ways to make it and I found this article.  The chemicals needed (potassium bromide and potassium hydroxide) should not be too difficult to obtain.

http://www.crscientific.com/article-bromine.html
This is quite a nice experiment, but it is useless for making bromine. You only get bromine, dissolved in water, and it is a pain to isolate it from the water. I make my bromine as follows:

Take 5 grams of KBr and dissolve in as little as possible of water. You may need 5 ml of water or so, but not more. Carefully add 2.5 ml of concentrated sulphuric acid. Do this drop by drop, very slowly and stir after every few drops. The solution may turn orange a little, but that does not matter. Let all cool down and you will see that nice glistering crystals are formed. These are mostly KHSO4 and/or K2SO4. Keep the liquid and remove the crystals.

Now add 1.4 grams of KBrO3. That latter chemical can be made easily at home. I wrote a webpage about that:

http://woelen.scheikunde.net/science/chem/exps/KBrO3_synth/index.html

The KBrO3 need not be purified if you only want to make bromine. Just use the crude material with bromide remains and possibly some carbon/chromate remains.

The 1.5 grams of KBrO3 must be added in small amounts. You will see that copious amounts of bromine are formed and quickly a thick drop of bromine settles. When all of the KBrO3 is added and has dissolved (this takes a lot of time), then you'll have more than 4 grams of pure (but crude) bromine.

Now carefully pipette away as much of the aqueous layer as possible, but assure that the bromine remains covered by a thin layer of water. Add 5 ml of clean water and shake a little. Any undissolved crystals of KBrO3 now can dissolve. Again pipette away the water and again add 5 ml of water. Now, the last traces of acid, dissolved in the bromine, will dissolve in the water and any salts will dissolve in the water.

Finally, pipette away the bromine from under the water. It does not matter if some water is pipetted with it as well. The water will float on top of the bromine in the pipette. Take the bromine from the water, assure the outside of the pipette is free of water drops and then transfer the bromine to a separate small clean and dry container. From the pipette, the bromine can easily be separated from the water. Just take care not to drop the water in the bromine, just leave a single drop of bromine in the pipette, just below any water in it.

Bromine obtained in this way is quite pure. It also is amazingly dry (IIRC, water hardly dissolves in bromine, only 0.05%, while on the other hand, bromine dissolves quite well in water, approximately 3% by weight). The bromine in the little vial was made in this way:

http://woelen.scheikunde.net/science/chem/compounds/bromine.html

This bromine is so dry, that it does not react with Mg, nor with Na. Both metals simply float on top of the bromine and do nothing. As soon as a tiny drop of water is added, a violent reaction starts.

If you attempt to do this synthesis of bromine, then do this outside or in a good fumehood. Also be careful with the pipetting of bromine. Bromine is a very mobile liquid with very low viscosity. It is really hard to keep it in a pipette without spilling some of it. Do the transfer with the two bottles very close to each other, and even then, be prepared to spill a drop or two. Absolutely assure that no drop of bromine can touch your hand.
When the safety precautions are taken into account and when you work outside, or in a good fumehood, then you can have hours of fun with your home-made bromine. It is such cool stuff....
Want to wonder? See http://www.oelen.net/science

Offline AfromOz

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Re: How Do You Store Bromine?
« Reply #10 on: December 28, 2006, 01:57:57 AM »
^^ Interesting that. May give it a shot!

Tried an experiment. Put my slowly decreasing mass of bromine into the freezer for hours.

Freezer is at -17ºC..

My bromine failed to freeze. >:(

The vapours didn't even reduce. >:(

Now, just what is in that bottle??

Cheers,

Adam
If it goes pop, OK.
If it goes KABOOM, better.

Offline jdurg

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Re: How Do You Store Bromine?
« Reply #11 on: December 28, 2006, 02:29:50 PM »
^^ Interesting that. May give it a shot!

Tried an experiment. Put my slowly decreasing mass of bromine into the freezer for hours.

Freezer is at -17ºC..

My bromine failed to freeze. >:(

The vapours didn't even reduce. >:(

Now, just what is in that bottle??

Cheers,

Adam

I would check that freezer and make sure that it is actually at -17 Celcius.
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Offline Ψ×Ψ

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Re: How Do You Store Bromine?
« Reply #12 on: December 28, 2006, 02:32:45 PM »
Is the container you're storing it in airtight?  Could be a pressure drop as the temperature decreases, maybe.

Offline AfromOz

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Re: How Do You Store Bromine?
« Reply #13 on: December 31, 2006, 12:52:55 AM »
To the two above.

Yes, my freezer is at -17C, I measured it with a thermometer.

And, my container is obviously not 100% airtight as some bromine occasionally escapes  :(

Why does the MSDS form recommend not freezing bromine? Perfect way to preserve it.

Cheers,

Adam
If it goes pop, OK.
If it goes KABOOM, better.

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