Synthesis of Bromine

[jdurg]

Again, I still say that it would be easier, cheaper, and more efficient to do this with calcium hypochlorite, sodium bromide, and hydrochloric acid. Plus, all three can be found in one place (your local pool and spa store) and you don't need to do anything with the three items other than mix them together. (I.E. you don't need to dilute anything, concentrate anything, or purify anything).

[blackout]

H2SO4 will be better than HCl if you distill the bromine cause H2SO4 won't come with Br2

[budullewraagh]

oleum will.

 

but anyway, it's not so bad; the bromine should be under the water anyway, so when you want to distill it and dry it, you can just transfer your mixture to another apparatus

[jdurg]

Yeah. HCl is very water soluble so it's not going to be escaping from the bromine which should remain as a dark liquid on the bottom of the water.

[budullewraagh]

well, there shouldnt be much HCl at all. just a small amount from potential fumes

[entropydave]

h2so4' date=' that isnt true; think of schrodinger's cat.

 

half-life of 210 At is actually 2 minutes. if you get an active enough alpha source you can produce enough of it to see; it's black. in fact, researchers have produced enough to perform some tests on it.[/quote']

... I found "Astatine's most stable isotope, astatine-210, has a half-life of 8.1 hours" at http://education.jlab.org/itselemental/ele085.html

 

I am amazed - I didn't think that there was anything morethan a few nanograms in the Earths crust at any one time.... but I guess if you sythesize it, there's no real limit to the amount you could make... never thought abut that.....

[MagicJigPipe]

I have found the H2O2, NaBr, H2SO4 method to be easier in practice. It's not dumb (unless you consider making Br2 dumb) and since the reagents are so cheap a little loss isn't bad.

[YT2095]

all you need is a Bromide and a Bromate mixed, Then add your acid.

 

no need for H2O2 at all.

[hermanntrude]

br would go up as a gas... it may be dense but not as dense as water

 

bromine is a liquid, and much more dense than water.

 

I expect you all know this, but bromine is nasty stuff. I've worked with it before and it can RUIN people's lungs. Be careful. Read the MSDS here

[thedarkshade]

You can get bromine by electrolysis of HBr, or reacting in KBr with Cl by the followring equation:

 

[ce]2KBr + Cl2 -> 2KCl + Br2[/ce]

 

or there are other ways to:

 

[ce]2KMnO4 + 16HBr -> 2KBr + 2MnBr2 + 5Br2 + 8H2O[/ce]

 

[ce]MnO2 + 4HBr -> MnBr2 + Br2 + 2H2O[/ce]

[Runninfarmer]

I electrolyzed an aqueous solution of NaBr with a graphite anode and it appeared to be workin, but it was producing a yellowish color that was spreading throughout the solution. I was worrried that it was going to come out of soln. and into the air. Do you just have to run it longer so it starts to collect at the bottom or are you going to run into the hazard of fumes coming out of the soln. before it starts to collect?

[YT2095]

the Ideal in Any halate cell is to keep the soln Moving.

left stationary even with Cathode bubbles as the agitator isn`t sufficient, and the raw halogen will be evolved.

Happily in the case of Br2 it`s very heavy and most will sink in the soln.

[Runninfarmer]

So if I keep it running and stir it, all the Br2 produced will stay in soln and eventuallly collect towards the bottom? I was just worried some of the vapors would come out.

 

Thanks for the info

[insane_alien]

some vapours will come off it. do it utside or with the window open, if you can smell it, stop the reaction, walk away and wait for the fumes to clear.

[YT2095]

you`ll find very little will come out, and it`s quite safe to do indoors in a lab, I`v made liters of the stuff in here, yes you do get a slight smell, but not enough to cause you damage.

the Cl2 in the air at a swimming baths is Higher!

[ars3n]

I would doubt you would have to deal with HBr in this case. The greatest danger here is still Bromine and maybe H2O2 if someone foolish enough to use highly concentrtaed H2O2 for this purpose.

However such mixture wouldnt give a good yield of Br2 beacuse a significant amount of O2 will also be generated.

 

Mixing NaBr, H2O2 and H2SO4 is one of the dumbest things you could ever do, and most scientists are quite smart enough to know that you should never do that. NEVER mix hydrogen peroxide and sulfuric acid. When you do that, you will lose a good deal of bromine in the form of HBr gas which will bubble out, and the extremely high temperature of the reaction vessel will cause any bromine you have to instantly vaporize away. In addition, the sulfuric acid will form a very nasty and dangerous compound with the hydrogen peroxide, and may itself be reduced into choking, toxic sulfur oxides. There is absolutely no benefit in producing elemental bromine in that manner. In fact, if you try it that way you'll most likely wind up wasting a lot of time, money, and your health.

 

A better method of producing bromine is to oxidize the bromide ion via chlorine gas production. In fact, one trip to a pool supply store will get you everything you need. You can either generate the chlorine gas separately, or you can just generate it in-situ which is probably the easier thing to do. Just get some powdered super shock (Caldium hypochlorite), sodium bromide tablets, and hydrochloric (muriatic) acid. Mix the hypochlorite and sodium bromide in some water so that everything will be nicely dissolved. Then slowly add the hydrochloric acid. You will notice that the solution will start turning a reddish color as free bromine is liberated. You want to add the HCl slowly so that the solution doesn't overheat and you don't generate too much chlorine gas at one time. You will also want to have an excess of acid so that the bromine will remain as the free element. Then all you have to do is cool off the solution and suck out the bromine from the bottom of the beaker with a pipette. Just make absolutely sure you do this outside.

[Tealman535]

How exactly do I know when to stop adding HCl?

I understand all the safety procedures and everything. I have carefully read this entire thread.

How much of calcium hypochlorite and sodium bromide do I add initially?

(as much as will dissolve?)

Basically when does the reaction stop yielding bromine?

 

Additional questions:

- What should I store the bromine in?

- If I keep the bromine very cool, will it evaporate more slowly?

- What do you recommend to suck the bromine out of the bottom of the beaker?

 

Thanks for your help.

 

 

Tim Ambrose: Teenage Inventor/Scientist

[nitric]

Store the bromine in glass under sulfuric acid,Don't let it freeze or boil,and suck it out with a glass pipette.

[Tealman535]

Just a few simple questions.

- Why exactly do I store it under sulfuric acid?

- Why won't the bromine react with the acid?

- Will the bromine be diluted in the acid or will it stay separated at the bottom of the glass bottle?

- I have some 10% sulfuric acid, will this work?

- If not, how do I concentrate it safely?

 

I appreciate your help. Thanks.

 

 

Tim Ambrose: Teenage Inventor/Scientist

[YT2095]

- Why exactly do I store it under sulfuric acid?

- Why won't the bromine react with the acid?

- Will the bromine be diluted in the acid or will it stay separated at the bottom of the glass bottle?

- I have some 10% sulfuric acid, will this work?

- If not, how do I concentrate it safely?

 

1. to keep the Br2 absolutely dry (you don`t have to do this however)

2. why should it? there`s no mechanism for a reaction.

3. it`ll stay separate for the most part.

4. No.

5. careful heating to drive off all the water, Or the addition of sulpher trioxide.

[Tealman535]

Thank you for the reply.

Further info:

- How thick should the layer of sulfuric acid be that I float on top of the liquid bromine? (is there a volume or weight ratio to figure it out?)

- Can anyone provide a link or instructions on the consentrating of sulfuric acid by the heating method?

>> What kind of vessel should be used to do the heating?

>> How can I do this without a bunsen burner?

(This is what I do have)

http://www.chefdepot.net/graphics8/portable_electric_burner.jpg

portable_electric_burner.jpg

(I have beakers and flasks and even an alcohol burner) http://www.unitednuclear.com/alc1.jpg

However I do not have a support stand to properly use the alcohol burner. http://www.unitednuclear.com/tripod.jpg

Perhaps there is still a way I can use the burner if anyone knows a make-shift way.

 

Thanks Again.

 

 

Tim Ambrose: Teenage Inventor/Scientist

[hermanntrude]

I've got 17 identical bottles of bromine in my lab, none of which are stored under sulfuric acid. I think it's OK to omit that part

[Tealman535]

That's what I was beginning to wonder.

Thanks for the info.

However, I would like to know the specs on those bottles please.

- Are they amber bottles?

- Do they have plastic screw caps?

- How much does it help to tightly close the bottles with teflon tape?

 

I would appreciate it a lot if you could tell me these specs.

Thanks in advance.

 

 

Tim Ambrose: Teenage Inventor/Scientist

[frosch45]

You don't need an amber bottle in this case because Br2 will not decompose when put into contact with sunlight, it just needs to be glass.

 

If you have just plain old plastic as your cap, then I definately wouldn't use those. When I first tried making some bromine, I just had these little bottles with actual teflon caps. It didn't really wear anything away, although, after I emptied the bottle to stabalize the bromine (well actually react it with some aluminum, and anyone who knows anything about bromine knows about this reaction. yes, it was quite spectacular ) the bottle stunk quite badly. Teflon is a very good idea in this case.

[Tealman535]

What about this kind of bottle?

http://dbhs.wvusd.k12.ca.us/webdocs/AcidBase/Lab-AcidBaseTitration/Bottle-GlassStopper.JPG

Bottle-GlassStopper.JPG (JPEG Image, 640x480 pixels)

 

Again I submit my question that nobody answered:

- Which method is recommended for making bromine? (Electrolysis of sodium bromide solution or carefully adding HCl to a solution of sodium bromide and calcium hypochlorite?)

 

Tim Ambrose: Teenage Inventor/Scientist