Sciencemadness Discussion Board

Bromine Source and Synthesis

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Brom - 7-8-2015 at 18:14

Diggafromdover could you point me in the right direction where I could find a 500 ml heating mantle stirrer for anywhere close to the price you paid?

Dan Vizine - 10-8-2015 at 14:20

I also use the permanganate, NaBr & Sulfuric acid route. I maintain the reaction vessel considerable above the boiling point of Br2 by controlling the rate of acid addition to a soln. of KBr and KMnO4 in hot water. No external heat is needed. The Br2 and some water seems to come over. I wash the Br2 with H2O and dry over anhydrous NaBr. Distillation gives quite a nice product. I think I made ~900 g of distilled product in two runs in a 2 L RB. The cost was about $50.

DSCN0956.JPG - 1.5MB 30 g #35.jpg - 557kB



Bromine 0.9 Kg.jpg - 827kB



[Edited on 10-8-2015 by Dan Vizine]

Dan Vizine - 10-8-2015 at 14:44

Quote: Originally posted by Brom  
Diggafromdover could you point me in the right direction where I could find a 500 ml heating mantle stirrer for anywhere close to the price you paid?


Where else? e-Bay. Just watch patiently for a few weeks. The prices are usually not a giveaway, but if you're diligent in checking, great deals can be found. I got a practically new 2 L and 3 L mantle together for About $80.

Brom - 10-8-2015 at 18:24

Appreciated. I will look into it.

Dan Vizine - 11-8-2015 at 08:14

Don't forget that they don't plug into the wall outlet. A device, like a variac, is needed to control input power.

Brom - 11-8-2015 at 18:26

Thanks a lot for the advice. I wasn't aware of that. Could that be why the ones I was referring to before cost so much? Because they already have that built in and are ready to plug in?

Dan Vizine - 11-8-2015 at 19:12

Yes, there are hard-shelled units that are "plug'n'play" so to speak, they have control knobs. I'm not very familiar with these. Most that I've encountered were soft-shelled or aluminum-shelled and their maximum power requirements were clearly noted. An iron-constantan thermocouple is often built-in, and more frequently, ignored.

A variac is rarely very cheap.

Fleaker - 12-8-2015 at 12:29

I think the best way I ever made bromine was sodium bromide, sodium bromate, and sulfuric acid. Collect the distillate, separate the water, dry it with c. sulfuric and it's good to go!

j_sum1 - 12-8-2015 at 17:18

My next attempt will be passing Cl2 through a NaBr solution. I know there are issues with Cl2 but it is actually the most economic use of the reagents and equipment I have available.
I wish however that I had a good cheap OTC source of bromide salts around here. The only OTC source is Bromochlorodimethylhydantoin for spas, and even that is hard to come by. The presence of chlorine makes for a really good pool chemical, but pretty much useless as a bromine source.

Texium - 12-8-2015 at 20:17

Quote: Originally posted by Fleaker  
I think the best way I ever made bromine was sodium bromide, sodium bromate, and sulfuric acid. Collect the distillate, separate the water, dry it with c. sulfuric and it's good to go!
I'm planning on trying that once I have a functional bromate cell going. It looks like the most promising and clean method. I don't know if I ever posted it in this thread, but the first time I tried, over a year ago now, I used sodium bromide, potassium permanganate, and HCl. It got the job done and got me a somewhat wet element sample that I could be proud of at the time, but definitely wasn't clean or very efficient.

diggafromdover - 13-8-2015 at 12:28

Quote: Originally posted by Brom  
Diggafromdover could you point me in the right direction where I could find a 500 ml heating mantle stirrer for anywhere close to the price you paid?


Ah, but I did not find a mantle, I found a Fisher Thermix, which is a humungous hotplate with magnetic stirrer. I found it on Ebay from a surplus seller in Vermont. In other words, I stumbled around on eBay until I tripper over it.

Be patient, and keep checking.

Brom - 14-8-2015 at 12:07

Thanks for all the input. I'm going to keep watching eBay. Its past time for me to retire my heat gun back to the garage.
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