Sciencemadness Discussion Board - Made Bromine Tonight

Made Bromine Tonight

BobD1001 - 14-9-2013 at 16:46

Today I performed the most terrifying reaction I have ever done. The synthesis of elemental Bromine. Of course it was done outside with full protective gear and a respirator. After amoupling the small sample I made, I realized the ampoule didn't fully seal, and some bromine vapor was detectable, even got a very small whiff of it! Scary! So I went outside and resealed it properly. The Bromine ate up the rubber stopper used pretty quickly, but the whole apparatus was submerged in Sodium Thiosulfate solution to neutralize all bromine immediately after collecting enough Br for the element collection.

12AX7 - 14-9-2013 at 16:52

Cool!

Wait a minute, where's fluorine...?

elementcollector1 - 14-9-2013 at 17:07

Quote: Originally posted by 12AX7

Cool!

Wait a minute, where's fluorine...?

I think he got CaF₂ instead, judging from the photo...
Nice wooden Periodic Table!

BobD1001 - 14-9-2013 at 17:44

Quote: Originally posted by 12AX7

Wait a minute, where's fluorine...?

That's certainly an element that I'm "cheatingly" displaying for good! The little ampoule you see there is just full of compressed PTFE tape; about a half roll of it in that little ampoule! Bromine was plenty scary enough!

BobD1001 - 14-9-2013 at 20:39

Pretty embarrassing, I just realized in my bromine induced adrenaline rush, I put the Br where Cl belongs....

Its now resting in its correct place on the periodic table.

[Edited on 15-9-2013 by BobD1001]

12AX7 - 14-9-2013 at 22:31

Thought something looked out of place. Wasn't sure if you already had chlorine (cheating aside, fluorine isn't an easy one!).

Speaking of chlorine, you could ampoule it with the help of dry ice and acetone; think a few here have done it before.

Tim

BobD1001 - 14-9-2013 at 22:59

Tim, Thank you for the suggestion! I will certainly look into that! Do you happen to know what kind of pressure is generated from ampouling the chlorine when it returns to room temperature? I would be concerned about ampoule rupture as mine aren't very thick (just flame sealed pasteur pipettes).

elementcollector1 - 15-9-2013 at 09:09

Quote: Originally posted by BobD1001

Tim, Thank you for the suggestion! I will certainly look into that! Do you happen to know what kind of pressure is generated from ampouling the chlorine when it returns to room temperature? I would be concerned about ampoule rupture as mine aren't very thick (just flame sealed pasteur pipettes).

The full explanation is, you would generate a few drops of liquid chlorine, allow these to boil (the expanding chlorine gas is heavier than air and purges the ampoule), and seal it. Liquid chlorine would take much heavier ampoules.

woelen - 15-9-2013 at 09:22

BobD1001, you made a really beautiful display box for the elements. I love to see this kind of work. I myself ampouled bromine and chlorine as well and I found ampouling of both elements to be quite easy. The most important thing is that you have to make the elements in a REALLY dry state. I used H2SO4 for drying the Br2 and used a mix of CaCl2 and P4O10 for drying the chlorine:

This is the chlorine ampoule I made (gas only): http://en.wikipedia.org/wiki/File:Chlorine_ampoule.jpg

This is the bromine ampoule I made:

woelen - 15-9-2013 at 09:51

Indeed, it does not wet glass when dry. The following page contains two movies which demonstrate this effect.

http://woelen.homescience.net/science/chem/compounds/bromine...

BobD1001 - 15-9-2013 at 09:56

Now I'm concerned about my small sample of Bromine... It looks to be relatively pure, however I did not dry it as I wanted to minimize the amount I was working with in addition to minimizing exposure. Is my ampoule in danger of being ruptured? The amount of Bromine I have in it is probably less than .1 mL

elementcollector1 - 15-9-2013 at 10:08

Quote: Originally posted by BobD1001

Now I'm concerned about my small sample of Bromine... It looks to be relatively pure, however I did not dry it as I wanted to minimize the amount I was working with in addition to minimizing exposure. Is my ampoule in danger of being ruptured? The amount of Bromine I have in it is probably less than .1 mL

No, not really. 'Wetting' just means leaving some sort of residue on the surface.
(woelen - accidentally deleted post to edit it)

kristofvagyok - 15-9-2013 at 10:32

Quote: Originally posted by BobD1001

I realized the ampoule didn't fully seal, and some bromine vapor was detectable, even got a very small whiff of it! Scary!

If you are so afraid of this compound, than why do you tickle the dragon's tail?

However it is pretty easy to work with bromine, it's not so dangerous, just do not pour it on yourself. If you do not need to store it for a long time, than it could be easily placed in a glass with teflon or ground joints:

Pyro - 15-9-2013 at 10:53

yes that's true. I made ampoules of wet Br2 once and it stuck to the glass. over time the water collected to a tiny drop at the bottom, then it stopped clinging to the glass. I gave those away and now have almost 0,5l of dry bromine

(used 2kg NaBr)

@Woelen: are those ampules prescored? where did you get them? ebay?
It looks like you twisted the end off to seal it, may I suggest that you heat it and gently pull the end off without twisting, that way the glass isn't stressed as much

[Edited on 15-9-2013 by Pyro]

[Edited on 15-9-2013 by Pyro]

BobD1001 - 15-9-2013 at 12:37

Quote: Originally posted by kristofvagyok

Quote: Originally posted by BobD1001

I realized the ampoule didn't fully seal, and some bromine vapor was detectable, even got a very small whiff of it! Scary!

I wouldn't consider it a fear so much as a very high level of respect, which I believe we all have towards these types of elements. I was comfortable tackling the reaction, and did so without issue. Yes I do have such Teflon stoppered and also pfte sealed cap bottles, however this was simply to display on my element collection as I did not need it for any future reactions. If I need it in the future I will simply isolate more, dry, and store in such a bottle.

softbeard - 15-9-2013 at 13:05

Maybe I'm nuts and had narrowly escaped pulmonary edema, but I've never found bromine vapour that bad. No mask, poor ventilation, just some ammonia water to snort as an antidote if I got too much of a whiff.
Far, far less irritating than chlorine, at least for me. Of course I don't know what it was really doing to my lungs...
Anyhow, nice pics.

woelen - 15-9-2013 at 23:17

@pyro: I purchased these ampoules on eBay, quite a few years ago. The seller is "sir_flacon". He still sells these ampoules occasionally, he has 20 ml, 10 ml, 5 ml, 2 ml and 1 ml ampoules and he has them with brown glass and colorless glass. If you order something from him, try tyo combine things, shipping is EUR 12 for 1 box of ampoules, but also EUR 12 for e.g. 5 boxes of ampoules or whatever you put in the package.

Btw, I am curious about what you intend to do with 500 ml of Br2. That is an awful lot of bromine. Please be careful with that. Imagine what can happen if that bottle breaks!

When I made that ampoule I had some trouble sealing it, because my torch was not sufficiently hot. I just managed to melt the glass with it. Now I have a better torch, which easily melts the glass of such ampoules. But the samples held up quite well. I made them yearts ago and they still are good. No loss of vapors!

MrHomeScientist - 16-9-2013 at 05:45

Quote: Originally posted by BobD1001

There is no risk at all of the vial breaking. Bromine doesn't develop nearly enough vapor pressure. I have two ampoules half full of Br liquid (about 20mL total) and I'm not concerned at all. Ampouling is about the only safe, permanent way to store bromine after all! Elementcollector1's method of ampouling chlorine is the procedure I was going to try, to ensure there's enough pressure to make the gas easily visible.

How did you prepare yours? Mine was made from electrolysis of sodium bromide spa chemical, procedure courtesy of woelen.

Pyro - 16-9-2013 at 07:35

Woelen: It is more like 450ml, It is stored in a 500ml DURAN bottle with a GL45 cap lined with teflon.
I just like to have it available for when its needed. I also keep about 5 ampules of it for small quantities.

I also like to freak out people who ask about my lab.
my chem teacher asked me:''so what kinds of things do you do in your lab?" "oh, I do many things, I have half a litre of Br2 that I made myself, look here *shows picture*"
just watch the expression and enjoy

BobD1001 - 16-9-2013 at 17:38

Quote: Originally posted by elementcollector1

No, not really. 'Wetting' just means leaving some sort of residue on the surface.
(woelen - accidentally deleted post to edit it)

Thank you Element Collector, I was somewhat concerned that the bromine may have been able to attack the glass if residual water was contaminating it.

@ Woelen, I truly appreciate the kind comments regarding the display!

@Pyro, what method did you utilize to make that sort of quantity of Bromine? I'm assuming the distillation method?

woelen - 16-9-2013 at 23:14

The presence of water in the ampoules is not an issue of safety, but it is an issue of pleasing display. The first ampoule of chlorine I made had some humidity left. On cooling down below 15 C I saw condensed water inside the ampoule and this ruins the nice display of it. It simply looks ugly.
An ampoule with wet bromine is equally ugly. You get all kinds of smears and little blobs on the glass and the bromine wets the glass. The nice effect, which is shown in the videos of my website and the nice clean looking surface are not present when even tiny amounts of water are present. Then you have all kinds of 'dross' floating on the bromine, and that looks ugly.

@Pyro: If you store it in a GL 45 capped bottle with a red teflon lines cap, then it is quite safe. I can imagine that the teacher at school is quite surprised if you show him your 450 ml of home brew bromine. Others brew beer, you brew bromine

[Edited on 17-9-13 by woelen]

Pyro - 17-9-2013 at 07:06

@Bob:it's almost 1kg. I used an adapted version of UC's. KMnO4, NaBr and H2O in a flask with H2SO4 added through a pressure equalized addition funnel.

My way is to have a 1l flask of KMnO4, NaBr and H2O in an ice bath, on top of that a 500ml pressure equalized addition funnel with H2SO4. Next I add the H2SO4 to the flask with vigorous stirring so that the temperature didn't rise too much. when all the H2SO4 is added, close the stopcock and add another 50ml of 98% H2SO4. then I put on a 50cm allihn condenser and heated the water bath. The Br2 boils in the flask, moves up the sidearm of the addition funnel (this acts as a reflux) and then travels up into the condenser where is condenses and drips down under the H2SO4. The dripping into H2SO4 dries it, there is almost no heat evolved.
when there is no Br2 left in the flask, stop the reaction and let everything cool down. then remove the condenser and drain the Br2 into a storage bottle.

@Woelen: It is a Blue GL45 cap to which I added a teflon liner from a different bottle. this is an old pic of it from the good old days when I could find my camera

, the brown residue on the teflon is unknown to me, I tried H2SO4, various solvents,... but it doesn't do any harm.

wet Br2 in an ampule fixes itself. the water forms a blob at the bottom and the Br2 becomes dry.

[Edited on 17-9-2013 by Pyro]

Metacelsus - 17-9-2013 at 11:00

Why use expensive KMnO4 when you can just electrolyze the solution to form NaBrO3 and use that as the oxidizer? This last weekend, I myself made bromine by this process:

103 g of 99% NaBr (spa pool treatment) and 0.5 g K2CR2O7 were dissolved in distilled water such that the solution volume was 175 mL. Next, the solution was placed in an electrolytic cell and electrolyzed at 3 A for 10 hours using a MMO anode and titanium cathode. The contents of the cell, which were now around 125 mL due to loss of water, and cloudy, probably due to precipitated KBrO3, were placed in a 500 mL 24/40 two-necked flask. On one of the necks was placed a Liebig condenser arm with ice water pumped through it; on the other neck was placed an addition funnel with 30 mL of 96% H2SO4 (Rooto drain cleaner). The flask was warmed on a water bath to approximately 60 C, at which point the acid was slowly added. Over the next few minutes, bromine collected in the condenser; I collected the first 25 milliliters of bromine, as that was all my ampule could comfortably hold (I was expecting lower yields). The bromine was dried with more H2SO4 and sealed in an ampule. Enragingly, as I was sealing it, water vapor produced by the torch flame condensed on the inside of the ampule, thus making the bromine stick to the sides. (Pictures coming soon.) The rest remained dissolved in the acid solution, and was neutralized with NaHCO3.

Quote:

wet Br2 in an ampule fixes itself. the water forms a blob at the bottom and the Br2 becomes dry.

This is not the case. Bromine is denser than water; holding my ampule feels like holding a roll of quarters. The dissolved water in bromine causes it to wet glass, which is a good way to tell if bromine is dry or not.

Pyro - 17-9-2013 at 11:32

trust me cheddite, this is the case. here is a picture that shows that on the bottom

I believe it stays at the bottom because of surface tension, I am aware that Br2 is 3,1X heavier than water. The bromine in this ampule doesn't stick to the glass. note:see that whiteish line? that's where the level of the Br2 is, it seems to be very slowly eating the glass (it has been there about 8 months)

and KMnO4 costs 30EUR/kg. with a bit under 1kg I made all my bromine. I am too lazy to wait for electrolysis and I HATE it, I HATE it, I HATE it! My way I can make about 100ml of Br2 in +-2hrs

woelen - 17-9-2013 at 11:47

I agree with Cheddite Cheese. I like the electrolysis very much and this is also how I made my bromine. As acid I used cheap and easy to obtain NaHSO4 (pH minus for swimming pools). The waiting time for the electrolysis is not an issue to me, just switch it on and let it brew for a day or so.

@Cheddite Cheese: Didn't you have any pitting corrosion of the titanium parts of your anode? I also tried to use my MMO anode for making KBrO3, but this resulted in formation of flocculent stuff from the uncovered titanium mesh of my MMO anode, so I quit the electrolysis. I did not want to destroy/erode the anode.

@pyro: The white line inside your ampoule is not from eating of the glass. Bromine does not eat glass, wet bromine also does not eat glass. Most likely you have some impurity in your bromine, which sticks to the glass. I have an ampoule and it already is many years old and still there is not a single line of residue sticking to the glass. This ampoule has been lying in the same position for many many months. It is most noticeable that the line is exactly at the border of the liquid bromine and the vapor and I think that hence the impurity must be floating on the bromine.

I think that for experimental purposes your bromine is perfectly fine, but for an element sample I am very critical (maybe a little bit too critical) and I put a lot of effort in getting the samples very pure and I do not want to see any crap like dirt, condensed water or solid particles floating on the bromine.

Pyro - 17-9-2013 at 12:47

Hmm,
I read somewhere that over time Br2 attacks glass over long time exposure, maybe it was at higher temperatures. now that I think about it it is most likely NaBr as that sample was from the small amount I salvaged from the accident.

Metacelsus - 17-9-2013 at 17:58

Quote: Originally posted by woelen

@Cheddite Cheese: Didn't you have any pitting corrosion of the titanium parts of your anode? I also tried to use my MMO anode for making KBrO3, but this resulted in formation of flocculent stuff from the uncovered titanium mesh of my MMO anode, so I quit the electrolysis. I did not want to destroy/erode the anode.

None of the non-coated portion of my anode was below the surface of the liquid in the cell, so I had no trouble with it. It's plausible that it could damage exposed Ti, but I'm not inclined to find out.

12AX7 - 20-9-2013 at 14:08

I can verify bromide attacks 6Al-4V titanium alloy as anode.

Tim