Picric-A
National Hazard
Posts: 796
Registered: 1-5-2008
Location: England
Member Is Offline
Mood: Fuming
|
|
Pure Bromine from swimming pool Bromine tablets
For me bromine is a very hard element to get. i cant buy bromine anywhere, let alone buy bromide salts.
I got told by a friend that i could get potassium bromide from pool suppliers so i contacted my local supplier and i managed to buy 1kg of bromine
tablets for about £10. The label, to my dismay, said, instead of being Potassium bromide, it was Bromo-Chloro 5,5-Dimethylhydantoin. Now my knolage
on organic chemistry is rather limited so i had no idea of how to seperate the bromiine form it. The label says 'contact with acids liberates toxic
gas' so form this i decided to ru several tests. i first added dil. sulphuric acid to it. nothing happened. to a new sample, i added dil. hydrpchloric
acid, and again, nothing happend. Finally in vain I added conc. sulphuric and hydorchloric acids, and again nothing happened.
The acid tests obviously didnt work so i looked at the warning label for clues on how to seperate the bromine from it and i settled on the oxidising
label on it.
By now i had lost hope on how to extract the bromine form it so i decided to see what else i could do with this so i didnt spend £10 on nothing. I
mixed it with powdered sugar and light the mixture. i found it burnt rather like KNO3 and sugar mix and i watched as it gave off quite a lot of reddy
brown vapour. I cautiously smelt this gas and it resembled bromine i had smelt in my school lab. 
From this i decided to heat it in a test tube and run the vapors wich looked like pretty pure bromine into a second cooled tube. the vapoures
condensed nicely into a liquid wich seemed like bromine. when i left this liquid in a stoppered test tube at room temperature, it solidified. now i
knew this wasnt pure bromine as pure bromine wouldnt solidify at 20 degrees C!!!
Finally i have planned to lead the vapours into conc. sodium hydroxide. If this is anything like chlorine it should form sodium hypobromite and soidum
bromide. Then i will expose it to sunlight for about 3 hours to fully convert any soidum hypobromite to soidum bromide. then i will evaporate this
liquid and add conc. sulphuric acid to the solid to release Bromine/HBr mix and condense this to much purer Bromine liquid. Do you think all this
would work?
any help would be appreciated and i hope i have helped others in their search to find this hard to get element!
Picric-A
|
|
|
-jeffB
Hazard to Others
Posts: 185
Registered: 6-12-2007
Member Is Offline
Mood: No Mood
|
|
I don't think bromides are controlled in any sense, so you should be able to order them online, say through eBay.
This thread addresses the use of BCDMH:
http://sciencemadness.org/talk/viewthread.php?tid=6953
|
|
|
Picric-A
National Hazard
Posts: 796
Registered: 1-5-2008
Location: England
Member Is Offline
Mood: Fuming
|
|
so would bromine form the bromide when disssolved in an alkali?
|
|
|
Jor
National Hazard
Posts: 950
Registered: 21-11-2007
Member Is Offline
Mood: No Mood
|
|
Bromine dissolves in a alkali solution, forming bromide ions and hypobromite ios. Hypobromite ions decompose slowly at room temprature, and very rapid
when heated, to bromide and bromate.
Br2 + 2 OH- >>> OBr- + Br- + H2O
3 OBr- >>> 2 Br- + BrO3-
|
|
|
Picric-A
National Hazard
Posts: 796
Registered: 1-5-2008
Location: England
Member Is Offline
Mood: Fuming
|
|
cool thanks for the help 
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
Old industrial process for capturing bromine or iodine from dilute sources was to produce the free halogen, sweep it out of the reaction mix with air
or air+steam, run that through a train of absorption units filled with hot Na2CO3 solution. You noted when a unit was saturated by the appearance of
the colour of the free halogen; finally pushing the last of the halogen on out of it with just air+steam. Evaporate the Xomide + Xomate solution from
the saturated absorption unit(s), heat it to redness to decompose the oxy salt leaving just the sodium halide. This was then treated with MnO2 +
H2SO4 if the free dry halogen was wanted.
In the case of iodine it's fairly easy to separate the iodide and iodate by stirring the dry salts with acetone, which dissolves the iodide. Doesn't
work very well with bromine because NaBr is not very soluble in acetone; it still can be done if you're persistent.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
