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Synthesis of Bromine


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#1 Mendelejev

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Posted 4 May 2005 - 06:29 PM

Does anyone knows how I could make some Bromine with Sodium Bromide and sulfuric acid and MnO2. I also need to know wich glassware I have to use. (It should be done in a lab).
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#2 Silencer

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Posted 4 May 2005 - 07:53 PM

Make a solution of the NaBr and do electrolysis.
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#3 Mendelejev

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Posted 4 May 2005 - 08:13 PM

Make a solution of the NaBr and do electrolysis.


Yes, that's a great idea. But isn't there another way to produce bromine ?
Would this work ? :

2 NaBr + MnO2 + 3 H2SO4 ==> Br2 + 2 NaHSO4 + MnSO4 +2 H2O

And what should I use of equipment ? Should I do a destillation or ... ??
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#4 blackout

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Posted 4 May 2005 - 09:33 PM

hey, look here:
http://www.sciencema...ead.php?tid=606

NaBr, H2O2 and H2SO4, simple!
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#5 H2SO4

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Posted 4 May 2005 - 09:41 PM

Id try bubbling chlorine through NaBr solution. Br might precipate out or form a pool of Br at the bottom.
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#6 akcapr

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Posted 4 May 2005 - 09:44 PM

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

#7 Mendelejev

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Posted 4 May 2005 - 09:48 PM

hey, look here:
http://www.sciencema...ead.php?tid=606

NaBr, H2O2 and H2SO4, simple!


Thanx ! That was just what I needed to know. :P
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#8 jdurg

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Posted 4 May 2005 - 09:49 PM

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.
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#9 budullewraagh

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Posted 4 May 2005 - 10:58 PM

you could bubble chlorine gas into a bromide solution.

you could also use H2SO4. really important factor: MAKE SURE THE H2SO4 IS ONLY 25% OR SO. anything above 30% and youre pushing your luck. you dont want H2S to be evolved.

btw, jdurg, while it isnt smart to mix H2SO4 and H2O2, it is smart to do the following:
NaBr+H2SO4-->HBr+NaHSO4
2HBr+H2O2-->Br2+2H2O
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#10 jdurg

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Posted 5 May 2005 - 12:24 AM

Yeah, that would work, but you'd still have to deal with an excess of heat generated with sulfuric acid as you'd need it to be somewhat concentrated to get the reaction working properly. (In dilute solution, sulfuric acid isn't a massively good oxidizer like hypochlorite or aqueous chlorine is). It's much better in terms of ease and yield if you can generate the bromine in one step as opposed to two or three. (I.E. go from 2Br- straight to Br2 as opposed to Br- + H+ -> HBr, then oxidizing HBr to Br2 while some of it escapes as pure gas or reverts back to H+ and Br-).
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#11 H2SO4

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Posted 5 May 2005 - 12:39 AM

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



It's bp is only slightly higher than room temp at normal atmospheric pressure. If done in an ice bath it might form a layer on the surface if the method where you bubble Cl through it. First we went from talking about makingf iodine to bromine. This is a trend or something. What have you started Akcapr!
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#12 jdurg

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Posted 5 May 2005 - 12:44 AM

Also, bromine has a density of about 3.17 g/mL, so it is 3 times as dense as water and will NOT form a layer on top of water.
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#13 akcapr

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Posted 5 May 2005 - 01:36 AM

lol- next ones gonna be Astatine
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:)

#14 H2SO4

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Posted 5 May 2005 - 01:36 AM

ok, a layer on the bottom which can then be sucked out with a tube
or something
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#15 H2SO4

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Posted 5 May 2005 - 01:37 AM

lol- next ones gonna be Astatine



Lol, or fluorine!
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#16 akcapr

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Posted 5 May 2005 - 01:38 AM

lol or chlorine! xcpet thats a sinch
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#17 budullewraagh

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Posted 5 May 2005 - 01:55 AM

astatine doesnt exist
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#18 akcapr

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Posted 5 May 2005 - 02:04 AM

so. its in the same group
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#19 H2SO4

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Posted 5 May 2005 - 02:07 AM

Astatine does exist.

It exists only for a few nano seconds at the most and can be found in the decay chain of i think uranium.

Its just that there cannot be enough of it to be visible.
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#20 budullewraagh

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Posted 5 May 2005 - 08:45 PM

h2so4, 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.
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