Bromine from NaBr

The KMnO4 + NaBr + H2SO4 reaction seems the best way to go. The heat to drive the reaction is provided by the dropwise acid addition, no interhalogens are produced and making a kilo of bromine at once is easy with small glassware.

Quote: Originally posted by symboom

Non chlorine shock for pools contains potassium monoperoxysulfate once added to sodium bromide bromine liquid is created. Works for iodide bromide chloride it is strong enough to form chlorine have not tried liberating fluorine gas from fluoride that and I dont think it is not strong enrrough oxidizer for fluorine

With regards to Br2 contamination with interhalogens, I would think that this should not be a problem if preparing Br2 by bubbling Cl2 through an aqueous solution. If bromine monochloride forms at all, it could only be as a transient species, since the interhalogens are very prone to hydrolysis. I'm not sure about those containing fluorine, but the fluorinated interhalogens I've avoided preparing, for fairly obvious reasons. I've read what chlorine trifluoride for example, is capable of, and it does not make for reading that is of a nature which encourages one to muck about with it. Protective clothing and gas mask won't cut it there, given how it will, oh, set concrete ablaze for example

Whilst I've no direct experience with bromine monochloride yet (iodine bromides are next on my interhalogen to-do list. BTW-does I2 form a tribromide as well as a monobromide? and does BrCl3 or BrCl5 exist? are they stable, if so?) I do with iodine monochloride and have prepared a smaller quantity of iodine trichloride.

The speed of hydrolysis is rapid, near enough instantaneous. A drop of ICl permitted to fall into cold water dissociates more or less instantaneously into a puff of chlorine gas and the iodine with which the interhalogen was formed then falls through the water in finely dispersed form.

I should think that even if any did make it through a distillation, distilling the Br2 from H2O would efficiently remove any bromine chlorides present.

Thats strange, although I was going on visual examination. It certainly appeared to evolve a pale yellow-greenish gas. I took this to be Cl2 perhaps too hastily, knowing that ICl hydrolyzes in H2O.

I was under the impression that the acid produced on reaction of ICl with HCl(g) was of the composition HICl2 not HICl4. The rxn with ICl3/H2O could be useful, looks like a very expedient way to produce periodic acid and if desired, thence periodate salts.

How come BrCl3 does not exist? One might intuit that a hypothesis for the reason, were it ICl3 that did not exist, might be due to the large ionic radius and atomic mass of iodine and this contributing to steric effects retarding either formation of, stability of, or both, of ICl3. But a bromine atom is smaller than an iodine so this obviously is not the case.

Is it rather, that bromine is too electronegative to form a trichloride, whilst iodine just about comes within the range of its being possible, especially seeing as how the interatomic bonding in interhalogens is less strong than the parent halogens as mono-elemental diatomic molecular species . But that doesn't fit, again, with the fact that both iodine and bromine, as well as chlorine form trifluorides, although.

Interestingly, there are it seems, on looking up periodic acid in more detail, not solely the orth- and meta-periodic acids, but orthoperiodic acid forms salts where in for example the sodium cation and presumably other group I metal cations form acid salts, orthoperiodate being of the stoichiometry M5IO6, but there also exists a sodium hydrogen periodate where three of the cations are replaced by hydrogen, giving M2H3IO6.

Does metaperiodic acid also form acid hydrogen containing salts at all?

And, if heated past 100 'C, periodic acid can be dehydrated to the anhydride of iodic acid iodine pentoxide. I2O5 That looks like an interesting chemical, that might be worthy of an attempt to synthesize some. I could spare the ICl since I have a bottle of the stuff sitting in the fridge waiting for a use (the synthesis of the ICl itself was primarily a means to satisfy my thirst for knowledge and exploration, and an excuse to head to the bench and start tinkering, to slake the urge that comes to all mad scientists when we feel the siren song calling and the red (or at least ruddy orangey brown of bromine) mist come down

I2O5 looks interesting, since it can form hypervalent oxyions where the negative charge is on the halogen, in the form of iodyl salts (IO2+ and iodosyl salts (IO+) with SO3 and concentrated H2SO4 respectively. anybody care to suggest experiments or syntheses which might be done with iodic anhydride? Most iodine oxides are highly unstable, but tetraodine nonoxide is reportedly stable up to 75 'C and diiodine tetroxide is reportedly stable up to 100 'C. Any ideas on how the tetroxide is prepared, or what might be interesting to do with it? tetraiodine nonoxide can reportedly be prepared by treating I2 with ozone gas. What are its known properties/uses? and do interhalogens of any kind form mixed dihalogen nonoxides of the stoichiometry XYO9 where X and Y are Cl, Br or I, respectively?

According to wikipedia these lesser known iodine oxides (it seems only the pentoxide, iodic anhydride is well known) are poorly studied. Which to me sounds as good a reason as any to go do some studying



And this paper https://sci-hub.ac/10.1002/jrs.1250160611 also makes mention of an iodic anhydride hydrate other than iodic acid, of the formula HI3O8. Are salts of this acid known? what a peculiar structure.



[Edited on 14-6-2017 by tsathoggua1]

If I had copious quantities of permanganate salts, I would use them for preparing bromine, but I have less than 500 grams of potassium permanganate on hand, and it's not cheap. Concentrated hydrogen peroxide is not available everywhere, but I can easily purchase it from garden stores. It's also very convenient to use a bromate salt, which can be prepared from a bromide salt.

[Edited on 15-6-2017 by JJay]