Retard-3000
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Available Bromine
Pool/Spa bromine granules consist of sodium bromide and sodium/potassium dichloroisocyanurate, my understanding is that when the granules come into
contact with water the dichloroisocyanurate slowly decomposes releasing chlorine gas which displaces the bromide ions forming elemental bromine. My
question is how much elemental bromine can be formed from these granules ?
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Mixell
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Stoichiometry is your friend.
If the limiting factor is the DCC salt, then for every mole of DCC a mole of Br2 forms.
If the sodium bromide is the limiting factor, then for every 2 moles of NaBr, 1 mole of Br2 forms.
But it does not sound like a viable way to produce bromine other than for its intended use- disinfection.
Better think about oxidation of bromide with H2O2 at acidic conditions or with HNO3. Or the reaction of bromate and bromide at acidic conditions.
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Retard-3000
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I ask because I can't find any information on the amounts of DCC or NaBr that make up the bromine granules and thought someone on here may have bought
them before. However I do agree that it probably is best left for it's intended use. I will probably go via the oxidation of bromide in acidic
conditions, Do you think sodium hypochlorite will suffice as the oxidizer ?
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Nicodem
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Quote: Originally posted by Retard-3000  | | Pool/Spa bromine granules consist of sodium bromide and sodium/potassium dichloroisocyanurate, my understanding is that when the granules come into
contact with water the dichloroisocyanurate slowly decomposes releasing chlorine gas which displaces the bromide ions forming elemental bromine.
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No, the bromide gets oxidized by the dichloroisocyanurate anion, which is a strong oxidant. It just is a simple redox reaction. Mind that a pH
dependent equilibrium forms which can limit the amount of precipitable/extractable bromine. Remember that bromine is soluble in basic aq. solutions
and that it can reversibly react with the cyanurate ions via N-bromination. You would have to reduce the pH with NaHSO4, H2SO4, H3PO4 or some other
nonoxidizable acid in order to precipitate bromine, as the reaction mixture itself is basic. Cyanuric acid would therefore also precipitate.
| Quote: Originally posted by Mixell | Stoichiometry is your friend.
If the limiting factor is the DCC salt, then for every mole of DCC a mole of Br2 forms.
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If the limiting reagent is the dichloroisocyanurate salt, then two equivalents of Br<sub>2</sub> form. Always count the electrons, when in
doubts.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Mixell
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Oh, I was building my answer on the assumption that the reaction proposed by retard is correct (The DCC releases a Cl2 molecules which in turn oxidize
two bromide ions). Anyway, I'm not the best thinker on empty stomach 
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