Sciencemadness Discussion Board

Brominating granules containing mostly Sodium Dichloro-S-Triazinetrione

SuperOxide - 24-11-2020 at 10:25

I was looking to isolate some elemental bromine from some sodium bromide containing pool/spa sanitizing chemicals, and I found a product by SpaTime with Brominating Granules in big bold letters on the front which I ended up purchasing a while ago (for a pretty decent price, too).

When I get home and look up the SDS document to look at the contents:

  1. Sodium bromide - 18%
  2. Sodium Dichloro-S-Triazinetrione - 82.5%

I was going to test out how much bromine can actually be extracted from this, but I'm not too familiar with the sodium Dichloro-S-Triazinetrione that this product mostly contains (other than what I read from this fact sheet).

Any suggestions? Would the bromine be contaminated with something from the Dichloro-S-Triazinetrione? (perhaps chlorine?) Or is the Dichloro-S-Triazinetrione of any use if that can be extracted on its own?

Thanks in advance.

Antigua - 24-11-2020 at 10:28

Didn't Tom from Explosions and Fire use a similar compound? I think it was the hydantoin then. Anyways, yes, you will get some bromine contaminated heavily with chlorine (something like 30%). So it is viable, but kind of awful too if you want bromine.

woelen - 24-11-2020 at 10:51

You can get liquid Br2 from this, but with quite some BrCl dissolved in it. Its appearance will be like bromine, the color of the BrCl will be totally overwhelmed by the color of the bromine, but when you use it for synthesis (e.g. for organics), then you will get mixes of chlorinated and brominated organics.

You can purify Br2, contaminated with BrCl by adding this to a solution of NaBr, but you must be careful not to use excess NaBr. If you use too much NaBr, then a lot of the Br2 will go into solution as Br3(-) and then you will not be able to isolate it from the solution, unless you are willing to distill the bromine.

Separating Br2 from BrCl by distillation is not a good idea. Separation will be poor.

SuperOxide - 24-11-2020 at 11:44

Quote: Originally posted by Antigua  
Didn't Tom from Explosions and Fire use a similar compound? I think it was the hydantoin then. Anyways, yes, you will get some bromine contaminated heavily with chlorine (something like 30%). So it is viable, but kind of awful too if you want bromine.


His video was extracting bromine from BCDMH, which has the Cl/O bonded to a 5 membered ring, where as the Dichloro-S-Triazinetrione (or Dichlor) has a 6 membered ring. But other than that, I think it's pretty similar (though I think even his product had more sodium bromide than mine did :( )
Quote: Originally posted by woelen  
You can get liquid Br2 from this, but with quite some BrCl dissolved in it. Its appearance will be like bromine, the color of the BrCl will be totally overwhelmed by the color of the bromine, but when you use it for synthesis (e.g. for organics), then you will get mixes of chlorinated and brominated organics.

You can purify Br2, contaminated with BrCl by adding this to a solution of NaBr, but you must be careful not to use excess NaBr. If you use too much NaBr, then a lot of the Br2 will go into solution as Br3(-) and then you will not be able to isolate it from the solution, unless you are willing to distill the bromine.

I see... And if I'm going to react the Br/BrCl with NaBr, I may as well just find NaBr and extract the bromine from that to begin with, lol.
Quote: Originally posted by woelen  
Separating Br2 from BrCl by distillation is not a good idea. Separation will be poor.

Right, I agree distillation wouldn't be idea for separating the Br2/BrCl. I found a neat article on Sci-Hub that covers The Separation of Chlorine and Bromine by means of Hydrogen Peroxide:
Quote:

In a previous communication (ANALYST, 31, 127) the author described a method of separating iodine from chlorine and bromine, by treating the solution of the mixed salts with acetic acid and hydrogen peroxide, and showed the possibility of also separating bromine from chlorine by means of hydrogen peroxide in a solution containing free sulfuric acid


[Edited on 24-11-2020 by SuperOxide]

SuperOxide - 24-11-2020 at 12:06

I was planning on synthesizing anthranilic acid, and I know you can use either sodium hypobromite (Br2+NaOH) or sodium hypochlorite - Do you think the Br2/BrCl mixture would actually work for that or would the BrCl cause some problems? (Honestly, I think that since I wouldn't be able to determine the ratio of Br2/BrCl in the end product, I probably couldn't determine how much I would need to use anyways).

Edit: NVM, I don't think this would work. I think the BrCl would yield HBrO when reacted with the NaOH (BrCl + NaOH => NaCl + HBrO), and pretty sure the hypobromous acid would hog the hypobromite, and act as a buffer. But if I'm wrong on that, lmk.

[Edited on 24-11-2020 by SuperOxide]

Texium - 25-11-2020 at 08:15

I doubt that it would cause any problems. Hypobromous acid is not very stable, and under these basic conditions hypobromite will be strongly favored. Since you have a strong base (NaOH) in there, any buffer effects will be negligible. You could also just use hypochlorite bleach for the anthranilic acid synthesis though.

Also, as a side note, sodium dichloro-S-triazinetrione, also known as sodium dichloroisocyanurate (NaDCC), is also sold in pure form as chlorinating granules and makes for an excellent source of chlorine for experiments when mixed with HCl.

If you want pure bromine, see if your pool store carries pure sodium bromine. The one that I went to a few years ago sold it in 4 pound containers at a very affordable price, right around the corner from the 27% hydrogen peroxide.

SuperOxide - 25-11-2020 at 10:06

Quote: Originally posted by Texium (zts16)  
I doubt that it would cause any problems. Hypobromous acid is not very stable, and under these basic conditions hypobromite will be strongly favored. Since you have a strong base (NaOH) in there, any buffer effects will be negligible. You could also just use hypochlorite bleach for the anthranilic acid synthesis though.

Noted, I will keep this in mind if I end up using it for this. I realize that bleach can be used, but it seems like using bromine gives a slightly better yield (but that's just based on some of the tutorials/videos I've watched and articles I've read).
Quote: Originally posted by Texium (zts16)  
Also, as a side note, sodium dichloro-S-triazinetrione, also known as sodium dichloroisocyanurate (NaDCC), is also sold in pure form as chlorinating granules and makes for an excellent source of chlorine for experiments when mixed with HCl.

If you want pure bromine, see if your pool store carries pure sodium bromine. The one that I went to a few years ago sold it in 4 pound containers at a very affordable price, right around the corner from the 27% hydrogen peroxide.

I figured it may be a good source of chlorine, but then the chlorine may be contaminated with bromine, lol.

What do you think about just separating the NaDCC and NaBr? Is there any reason I can't just do a simple extraction? I haven't looked up the ideal solvents to use for either, but I would think this can be done with the right solvents.

woelen - 26-11-2020 at 00:42

Quote: Originally posted by SuperOxide  
[...]
I see... And if I'm going to react the Br/BrCl with NaBr, I may as well just find NaBr and extract the bromine from that to begin with, lol.[...]

Still, this can be useful. You now already have your mixed product with NaBr and NaDCC in it. Using this strategy allows you to make good use of your mixed product and if you also get pure NaBr, then you will need less of your pure NaBr to get bromine.

Sometimes I use this kind of seemingly inefficient strategies to make good use of impure hardware store chemicals if in a later stage I obtain pure reagents and have no other uses anymore for the impure hardware store chemicals.

[Edited on 26-11-20 by woelen]

SuperOxide - 26-11-2020 at 10:16

Quote: Originally posted by woelen  
Quote: Originally posted by SuperOxide  
[...]
I see... And if I'm going to react the Br/BrCl with NaBr, I may as well just find NaBr and extract the bromine from that to begin with, lol.[...]

Still, this can be useful. You now already have your mixed product with NaBr and NaDCC in it. Using this strategy allows you to make good use of your mixed product and if you also get pure NaBr, then you will need less of your pure NaBr to get bromine.

Sometimes I use this kind of seemingly inefficient strategies to make good use of impure hardware store chemicals if in a later stage I obtain pure reagents and have no other uses anymore for the impure hardware store chemicals.


Interesting... ok, two questions

1) If I process the NaBr/NaDCC to get the Br2/BrCl mixture, whats the best way to determine the ratio of each in the product? Would just getting the density (after filtering and drying it properly) be enough to determine the concentration of each? Or does this reaction have other side products that could make analyzing it more difficult?

2) Is there any reason I can't separate the NaBr and NaDCC using solvent extraction? It would seem to me that one could just separate the NaBr and NaDCC in the Brominating Granules product using the appropriate solvents for each, then I would have some NaBr I could process for bromine and NaDCC I could use for reactions I need chlorine in. Is there some reason that this wouldn't be sufficient? (I only ask because the fact that some chemists have to deal with the contaminated end products somewhat implies that maybe there was a reason they couldn't have separated the NaBr/NaDCC in the original product that I'm unaware of).

unionised - 26-11-2020 at 11:11

Quote: Originally posted by SuperOxide  


2) Is there any reason I can't separate the NaBr and NaDCC using solvent extraction?

NaDCC will react with many- perhaps most- solvents.
In the presence of a suitable solvent, it will also react with NaBr.
An interesting approach would be to ensure a large excess of chlorine- so all the bromine is oxidised to BrCl.

Then you can measure that and add enough bisulphite (or some such) to reduce it to Br2.
It's only possible in very cold weather- of course.

SuperOxide - 26-11-2020 at 11:48

Quote: Originally posted by unionised  
NaDCC will react with many- perhaps most- solvents.
In the presence of a suitable solvent, it will also react with NaBr. [...]

Yeah, I figured that was the case.
Quote: Originally posted by unionised  
[...]
An interesting approach would be to ensure a large excess of chlorine- so all the bromine is oxidised to BrCl.

Then you can measure that and add enough bisulphite (or some such) to reduce it to Br2.
It's only possible in very cold weather- of course.

Actually, I was just going to ask that very thing, lol. Since the product is like 80% NaDCC, which is where the Cl comes from, and only 18% NaBr, wouldn't that pretty much guarantee an excess of Cl? Wouldn't it be a safe assumption that the Br2 that does get created would be saturated with BrCl?

But regardless, no worries. You have me convinced that this product is more suitable for chlorine generation than a source of bromine (which seems obvious, guess I just needed someone else to tell me).

[Edited on 27-11-2020 by SuperOxide]