Making Bromine

[goldandsilver123]

Just took the morning today to make some Br2.

Used NaBr + H2SO4 + dripping H2O2.
Calculated to make 100 mL of Br2.

Start:


Beginning:



Running:


Finished:




Stored in glass with PTFE lined cap in the fridge:



There's a layer of water on top of it.



Let's see what it can do with HCl to PGMs!!

 

[orvi]

Bromine would certainly help, but i personally don´t like it, because it evaporates very quickly, stain the whole place and irritate the s**t out of your senses But it fascinate me everytime I see it, just looks very nice.
Also it produces bromine monochloride, when used with HCl together, but for dissolving purposes it should be good.
Stay safe

 

[Elemental]

A long time ago, I shared a lab with some microbiologists in high school. I was doing a bromine synthesis on ice to prevent fume generation. They had upped the temperature in the lab since they were incubating something. Needless to say, when I dismantled my apparatus, I was hit in the face with a full blast of bromine gas. Developed a bromine allergy that day. My university pool was cleaned with bromine and every time I went to swim, I felt sick the next day. It's been 20+ years and I still have the allergy to bromine.

Hate having to admit my mistake, but learn from my mistake and follow Orvi's advice and stay safe.

 

[butcher]

We used steam from boilers to make chilled water for air conditioning with bromine/bromide in the chillers.

Similar working principles to using a propane gas flame pilot and ammonia to refrigerate your food.

 

[goldandsilver123]

In a experimental organic chemistry class we were doing an experiment with bromide, don't really remember what reaction was, but it generated small amounts of bromine. The bromine smell was really really faint, but at the end of class I was talking like darth vader, my group thought I was joking, it lasted about 30 min.

This bromine was made inside a fume hood. The vapor exit of the glassware was directed to the air deflector at the bottom of the fume hood.

After every bit of glassware was washed with metabisulfite solution.

 

[Elemental]

@goldandsilver123, glad to hear I’m not the only victim of bromine. It’s some nasty stuff.

 

[Lou]

Usually I make bromine from sodium bromate and sodium bromide with the addition of sulfuric acid.

It can then be dried over concentrated sulfuric acid to get anhydrous bromine, but for the purposes of dissolving Pt and Pt, it doesn't matter. In fact, all that matters is a system with a very long, very cold condenser setup for reflux but with the capability to switch from reflux to distillation so that bromine can be removed with chlorine. Some bromine chlorine compounds that are very volatile (and highly objectionable, BrCl) are also formed with this, so there is never complete recovery of bromine. This only seems to happen with Br in the presence of Cl2, not with HCl.

It's a nice system for dissolving PGMs, and operates around 55-59 C in 6 M HCl. The Br2 itself should be kept cold and in bakelite-lidded glass bottles with at PTFE seal. That keeps the fumes escaping to a tolerable level. You can overpack it with a sodium thiosulfate "tea bag" and put in a heavy 6 mil bag. It prevents excessive rusting.

 

[Stibnut]

Back when I was doing a lot more chemistry at home and reading/occasionally posting on Science Madness, I tried several ways of making bromine. The bromide+bromate+acid method was easily the best in my experience too - it's very fast, simple, and high-yielding. The only downside was dealing with all the produced bromine. That stuff is interesting and almost beautiful but also very irritating, corrodes just about everything but glass and Teflon, and is of course dangerous. I don't have any desire to mess around with it anymore, except as very dilute bromine water for testing unsaturation in organics.

 

[orvi]

A long time ago, I shared a lab with some microbiologists in high school. I was doing a bromine synthesis on ice to prevent fume generation. They had upped the temperature in the lab since they were incubating something. Needless to say, when I dismantled my apparatus, I was hit in the face with a full blast of bromine gas. Developed a bromine allergy that day. My university pool was cleaned with bromine and every time I went to swim, I felt sick the next day. It's been 20+ years and I still have the allergy to bromine.

Hate having to admit my mistake, but learn from my mistake and follow Orvi's advice and stay safe.

Any synthesis could be done safely, so it could be done with bromine as well. I see very clean looking hood on the pictures. If it work as supposed, and does not leak the gas back to the room, you should be pretty much OK. When whole apparatus is dismantled inside the hood and immersed into bucket of sulfite solution for a night, it will by fine. But the risk is still there, flask could crack, or water from broken condenser could leak on the outside, creating heat shock to glass, rupturing apparatus... These could be mitigated to minimum probability, but you cannot eradicate the risks completely. Then it is up to you, if you consider the risks and despite them like to proceed with synthesis.

I classify the dangerous chemicals to two categories (for myself):
1. toxic, corrosive, carcinogenic no matter what combination of these - but it can be neutralized/reacted to form relatively harmless compounds easily. So as you follow all the safety basics and dont expose yourself by mistake, accident or ignorance, you can fully destroy any traces of it and you and your workplace should be fine. This is the bromine case - nasty stuff, but bisulfite or thiosulfate tame it nicely and completely.

2. toxic, corrosive, carcinogenic no matter what combination of these - but it can´t be neutralized/reacted easily that way it produce harmless compounds. To this category falls most of the nasty organic compounds like cyanates, chlorinated biphenyls stuff, organomercury compounds, stannanes, some organic hydrazines of poor water solubility... etc. And also some inorganic compounds - like all mercury, beryllium and thallium stuff. Decontamination is tedious, slow and often cannot be complete. Many times the waste created is order of magnitude less hazardous, but it still is - like precipitating mercury as sulfide with Na2S. You create relatively harmless precipitate of HgS, but it is still the mercury compound, hard to dispose properly and cost effectively.

Personally i opt not to work with compounds of the latter category in any manner.