extracting bromine

[max.yevs]

i happen to have a good amount of these disinfecatry tablets which are 33% bromine by weight, as they release HOBr and HOCl in water...

 

anyways, is there any way to extract bromine from HOBr?

i have two ideas in mind- one is two electrolyse it-

[ce]HOBr -> H^+ + OBr^-[/ce]

[ce]2H^+ + 2e^- -> H^2[/ce]

[ce]2OBr^- -2e^- -> O^2 + Br^2[/ce]

 

one is too react it with hydrochloric acid-

[ce]HOBr + HCl -> H2O + BrCl[/ce]

except i don't know what to do with BrCl, although its boiling point is pretty high, 5 degrees celsius, so i could make it liquid

 

basically what i want to achieve is something like this

[UC]

I would greatly advise against this. I believe someone over on sciencemadness managed to get clean bromine out of 1-Bromo-3-chloro-5,5-dimethylhydantoin (which is what I think those tablets are) but they used precise amounts of appropriate acid and distilled the bromine off.

 

Halogens are all pretty horrible and I doubt you have the proper equipment to handle them. On the other hand, there is a fairly simple way to make bromine on woelen's site that even a beginner could probably follow.

[max.yevs]

yeah halogens are pretty hazardous, althought there are at least several different ways to make chlorine (i.e. HCl + bleach/HOCl/MnO2 or by electrolysis), but yeah i can't do anything interesting with it because im at a loss for apparatus.

 

iodine is pretty awesome, i made it once from NaI (NaI + HCl > NaCl + HI; 2HI + H2O2 > 2H2O + I2)... reacts with aluminum very similarly to bromine- and with a nice purple smoke of gaseous I2... but it wasn't very efficient since I had to make out of tincture instead of NaI crystals...

 

i can't find how woelen makes bromine, i assume its either out of NaBr or KBr- maybe bubbling chlorine through it? unfortunately i'm at a loss here in both apparatus and bromide salts.

 

 

**

sorry UC, no turning back now. I've already set it up to react with HCl tomorrow... I'll post a picture if it works. (although I wouldn't be making bromine, i'll probably be making bromine monochloride)... i don't know if electrolysis is better, but it's such a drag i'll rather just do it with acid.

Edited March 26, 2009 by max.yevs

[YT2095]

we Have threads on how to make elemental Br2 here, but simply, NaBr and NaBrO3 (I forgot the ratio) will liberate Br2 when a strong acid is added like Sulphuric for instance.

that`s how I make mine except I distill it afterwards.

[hermanntrude]

bromine IS one of the most dangerous naturally occuring elements. it is frighteningly reactive and incredibly bad for the lungs

[max.yevs]

i've currently got it running, i'll say what results i got later

 

but can anyone tell me, which of these reactions is favorable?

[ce]HCl + HOCl -> H2O + Cl2[/ce]

or

[ce]HCl + HOBr -> H2O + BrCl[/ce]

?

[hermanntrude]

i'd venture to guess that Cl2 will be the favoured product since the bond between a Cl and a Cl is stronger

[max.yevs]

SUCCESS!

 

I've successfully made bromine monochloride from those 1-Bromo-3-chloro-5,5-dimethylhydantoin tablets...

 

first of, those tablets are 100g, 33g bromine and 37g chlorine... they release HOBr and HOCl...

 

100g tablet in a small 280ml bottle, about 200ml HCl added... Although the tablets turned slightly brown originally, it quickly turned yellow and kept releasing chlorine for about 2 hours... as you predicted hermanntrude.

 

then i realized... i have only added about 40g HCl, and maybe the reaction

[ce]

HCl + HOCl -> H2O + Cl2

[/ce]

is favorable over

[ce]

HCl + HOBr -> H2O + BrCl

[/ce]

 

this would leave practically no HCl to react with the HOBr. Losing all hope, i decide to put pieces of aluminum in there. Aluminum reacts very nicely with it, more quickly and powerfully then with the same 20%HCl i used for it. After putting in big chunks of aluminum, i noticed that a brownish gas began to form, pretty rapidly...i collected some in two bottles (picture 2).

 

I assume i made bromine chloride- when chlorine was being made before, it was almost colorless greenish yellow with no red tinge.

 

Despite being great that its an interhalogen. Oh and its quite irritating if you breath it. Its like chlorine, but instead of giving you one pungent whiff, it keeps irritating your nose/throat. But it's not too bad...

 

Oh and I did it very unefficiently. Simply to prove the concept. Those tablets could have yielded 50 grams BrCl, about 15 liters (gas).

After spending a little time in ice, you can see a bit of liquid bromine chloride (picture 3).

 

I realize for all the chemists here, this is a very simple experiment... maybe they can explain why the aluminum did what it did...

Edited March 27, 2009 by max.yevs

[max.yevs]

actually, BrCl could be more useful then chlorine, i guess... after pouring those couple drops on a piece of aluminum foil, it started fizzing quite a bit... and i don't think evaporating is really much more of a problem then with bromine...

 

i think if i had a decent quantity i might have seen some flashes, after all, it is more reactive then bromine...

 

i will probably pursue a decent quantity of Br2 or BrCl sometime... Iodine monochloride is another interesting interhalogen, thats liquid or solid at room temp, i suppose it could be made similarly by

[ce]NaI + HCl -> NaCl + HI[/ce]

[ce]HI + HOCl -> H2O + ICl[/ce]

 

Actually I might try that one pretty soon.

Edited March 27, 2009 by max.yevs

[hermanntrude]

max, these chemicals can very seriously harm you, and you're not even sure what they are.

[YT2095]

I just wonder how long he expects those rubber seals to hold out!

[hermanntrude]

i'm wondering what the lids are made of. They may react with the unholy mixture of halogens in there

[max.yevs]

lids are made of metal, probably aluminum . but i used up the BrCl very quickly, as soon as i cooled it down to a liquid. Only a tiny bit of corrosion present on their surface, which doesn't surprise me... have you ever tried reacting aluminum with chlorine? almost impossible... and chlorine is more reactive then BrCl

 

And don't worry, i'll stop posting projects on sfn, i've started a free website, i'll just post them there and maybe refer to them when needed, like woelen does. and save this forum for actual questions .

 

unholy mixture of halogens

i like the way that sounds, lol.

 

max, these chemicals ... you're not even sure what they are.

oh, im pretty sure its Bromine monochloride (with some chlorine). Unless you're referring to my iodine monochloride idea, then im not sure if its a solid or liquid because there are two 'polyphorms', one of which melts at 13 degrees C, and the other at 27.

Edited March 28, 2009 by max.yevs

[hermanntrude]

i suspect the reason aluminum doesn't easily react with chlorine is the aluminum oxide on its surface because bromine definitely does react with aluminum and very violently, too.

 

and no, you're NOT sure what they are. You can never be sure without at least a few tests. You're probably right that you've made some BrCl, but you probably also made a few other things and you don't know much about the quantities or purities. Some of the reactants and by-products could still be in there and all of these possibilities add to the chances of some unexpected happening, right in your face.

 

In future, I'd feel a lot better if you kept halogens away from metal lids, and read the MSDS sheets for everything and anything you might or do make, and all the reactants too. At least then you'll have a clue what the hazards are and perhaps think again before rushing in. I don't want to quell the spirit of investigative science in you but I must remind you that people hurt themselves by either a lack of knowledge or by a lack of preparedness. For instance, what would you do if there was a fire in your "laboratory"? where is the nearest fire extinguisher? what type is it? Who would you call if you spilt some of your BrCl mixture on your skin? Would you be able to overcome your pride and admit it when somethign went wrong?

Edited March 28, 2009 by hermanntrude

[max.yevs]

i don't know, all the halogens reacts violently with aluminum - after pouring the couple drops I had on a piece of foil, it started fizzing just until the brcl ran out... but it is very hard to

a gas... and chlorine is slightly more reactive then bromine monochloride...

 

but there's a special danger to bromine in the fact that its liquid- i mean aluminum will never burn in oxygen, right? but if you use liquid oxygen, the aluminum

into sparks. my whole idea in this experiment was to try to make a very corrosive liquid- if not bromine, then brcl... which if you look at the first post i planned to cool it from the beginning.

 

i know that like bromine left in a bottle, its vapors can eventually destroy the cap if its rubber... but i used brcl after maybe 10 minutes, as soon as it condensed. I wouldn't think of storing it! and by the way, that gas is at about normal pressure...

 

in any case, i realize i shouldn't have posted those pictures here (or maybe even this whole experiment). i wanted to show how cool brcl is, not to get everyone worried...

 

I like the way they did it in 1950s. Look at the picture on the bottom, he's holding NO2/N2O4 between 2 glasses... nobody is yelling: what if he knocks them over? And they're giving you easy instructions on to how to make some at home, without excessive warnings. Why? Because they know a glass full of NO2 wont kill you. A glass full of chlorine won't kill you. Because if someone accidently releases some, they wouldn't put their face right up to it and breathe it until they died. It's a pretty interesting article by the way, find it here, its 3 pages.

 

I wish my popsci subscription still had pages like these. But times change, people are afraid of 'dihydrogen monoxide'.

 

Sometimes i wish i lived in 1950s America.

Edited March 28, 2009 by max.yevs

[max.yevs]

Sorry, I didn't mean to be rude in that post. I would edit it if i still could. But you have to admit halogens are awesome. They're the most reactive elements, save for oxygen.

 

Except I don't like fluorine and astatine. You think rubber seals are a problem for bromine? Fluorine will eat through glass and plastic. And even its salts are poisonous. Astatine- well I'm sure only a few people in the world have handled it, its the second most radioactive element after Francium.

 

But chlorine, bromine, and iodine- they're the perfect trio. All very corrosive, one gas, one liquid, and one solid. Chlorine i've dealt with many times, it doesn't deserve half the bad rep it gets. Iodine i've made only once, but it was very nice. Reacted with aluminum scraps without even asking it to. Bromine is actually the only one i've never handled, its corrosiveness can be hazardous.

 

Although the liquid BrCl is even more corrosive. What was really good about this experiment is that I have found a decent way of making monohalide interhalogens. This includes BrCl, IBr, and ICl. The ones with fluorine are not only too dangerous, but wouldn't work. Fluorine hydrolyzes completely regardless of solubility.

Edited March 29, 2009 by max.yevs

[Theophrastus]

Yeah, a further problem with astatine is that its half life, is just a little under 7 hours. Flourine is incredibly dangerous and reactive. In fact, its reactivity meant that it wasn't isolated until the late 19th century, and the chemist who did so, was awarded the nobel prize. If you look up incompatible compounds in the CRC handbook of chemistry and physics, you'll find the following to be true:

 

Flourine incompatible with: everything

 

ps: I agree, that you have to use all- glass apparatus when handling halogens. Certain types of rubber, based on the time of the experiment, and a low effusion rate, can also be used. Cheers

[max.yevs]

its like you know how chlorine doesn't eat at pvc... because polyvinyl chloride already has chlorine in it...but it also doesn't eat at glass because it cant replace oxygen in SO2

 

fluorine eats at glass, so pretty much the only thing you can store fluorine in is Teflon...

 

oh i just got what you said yt, "rubber seals"... lol that was duct-tape., i let it let some air out just to avoid the risk of overpressurizing... on second thought I should have just used a baloon to collect the gas.

 

---

Merged post follows:

Consecutive posts merged

I think bromine could be made out of bromine monochloride (after all, this thread is called extracting bromine) with the use of sodium iodide and chlorine.

 

[ce]BrCl + 2NaI -> NaBr + NaCl + I2[/ce]

[ce]Cl2 + 2NaBr -> 2NaCl + Br2[/ce]

 

I'm pretty sure this would work. Before anybody points this out, yes i know excess Cl2 in the second equation is technically capable of reacting with the Br2 to make BrCl again. However, I don't think they react that easily. If that was true, then the I2 from the first equation could also be part of a variety of interhalogens. (IBr, ICl, ICl3)... which i suppose is very possible actually.

 

But I'll save that experiment for some other time... I'm sure all of you are tired of hearing about halogens.

Edited March 30, 2009 by max.yevs
Consecutive posts merged.