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Author: Subject: HBr in acetic acid from BCDMH
genuinterest
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[*] posted on 13-6-2012 at 09:33
HBr in acetic acid from BCDMH


I have been considering how to make a HBr/Acetic Acid solution. Ideally one would add NaBr to acetic acid and conc sulphuric acid, unfortunately NaBr is unavailable. After reading the various threads on producing elemental bromine, it seems BCDMH (1-Bromo-3-chloro-5, 5-dimethylhydantoin) may be a viable replacement for NaBr, if HCl production can be avoided.

I was thinking that if a large amount of BCDMH was crushed and mixed with phosphoric acid, HBr would leave solution as gas and could be passed into acetic acid.
The problem is that I think HCl would also be produced, maybe it would be recaptured by the excess BCDMH before it left solution, but maybe not.

Does anyone have any ideas to remove HCl from the produced gas if it is formed (without NaBr)?

Maybe pass gas through BCDMH?

[Edited on 13-6-2012 by genuinterest]
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watson.fawkes
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[*] posted on 13-6-2012 at 10:27


Quote: Originally posted by genuinterest  
BCDMH
UTFSE officially stands for Use The Forum Search Engine. Sometimes "Forum" is replaced by other vernacular.

There's a quite adequate procedure already worked out, with experimental details, elsewhere on this site.
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genuinterest
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[*] posted on 13-6-2012 at 10:56


I have read many threads about production of elemental bromine and a few posts on making Hbr. But I couldn't find the thread/post detailing how to produce clean HBr from BCDMH.

Sorry, i guess.

Thank you for the suggestion Hexavalent but unfortunately NaBr is unavailable.

[Edited on 13-6-2012 by genuinterest]

[Edited on 13-6-2012 by genuinterest]
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genuinterest
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[*] posted on 13-6-2012 at 13:22


I had a thought, HBr gas generated could be lead into a flask containing mainly dry NaOAc and a small amount of water or acetic acid.

NaBr is partially soluble in acetic acid, but maybe treatment with H2SO4 would remove most of it as NaHS04. I don't have my merck index handy...
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genuinterest
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[*] posted on 14-6-2012 at 04:29


This is the idea i've come up with, will hopefully get a chance to see if it will work on weekend.

[If what I would like to be true actually was true] HCl from acid will displace the bromine from BCDMH making HBr, HCl from generator will produce HBr in excess of what can be solved in H20 in reaction vessels 1 & 2. HBr and perhaps some HCl will react with NaOAc in vessel 3 producing acetic acid and NaX, when the NaOAc is used up the HX will be dissolved in the acetic acid until saturation. Any HCl in solution will react with the formed NaBr. When NaOAc in vessel 4 is moderately used up it will be reasonably certain that the acetic acid in vessel 3 is saturated with HBr. This can be confirmed by titration.

Still mulling this idea over, and have yet to work out stoichiometry, but it seems like a reasonable method to me at this point.

Maybe people can discuss purchasing NaBr in a different thread?


hbr acetic acid.JPG - 17kB

[Edited on 14-6-2012 by genuinterest]

[Edited on 14-6-2012 by genuinterest]
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ScienceSquirrel
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14-6-2012 at 05:22
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14-6-2012 at 05:27
Nicodem
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[*] posted on 14-6-2012 at 10:24


Quote: Originally posted by genuinterest  
HCl from acid will displace the bromine from BCDMH making HBr, HCl from generator will produce HBr

What is the reference for such an unreasonable claim? Since when is HCl a reductor strong enough to reduce bromoimides to bromides? I think you should revise your knowledge of redox reactions if you have any genuine interest in chemistry. For the beginning it would do you good to actually read the thread on the topic of bromine synthesis from BCDMH, rather to just pretend of having read it. Some members put a lot of effort into that discussion and seeing how you manage to ignore it certainly doesn't please them. Then, after you read it and learn something, you might be able to devise a reaction of BCDMH that could potentially give HBr as one of the products.
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14-6-2012 at 10:24
genuinterest
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[*] posted on 14-6-2012 at 11:22


you are mainly right. I have read those threads, but it is true my grasp of redox and chemistry in general is sporadic, i probably missed or skipped over many pertinent details. Thank you for steering me back to text books, i will do as you suggest.

[edit] It appears i missed this thread: http://www.sciencemadness.org/talk/viewthread.php?tid=13380
when originally doing my searches. As nicodem said, there is much in there for me to learn from.

The other thread: https://www.sciencemadness.org/whisper/viewthread.php?tid=69... I will re-read and try to make sense of the things i don't understand.


[Edited on 14-6-2012 by genuinterest]
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