[Monoamine]

Hi, so I tried to make some HBr the other day, using NaBr and H₂SO₄ as precursors. I measured out 2 molar equivalent of NaBr, and 1 molar equivalent of H₂SO₄. I then dissolved the NaBr in distilled H₂2O (maybe a bit too much), and then slowly dripped the sulphuric acid into the solution (to keep the temperature below about 60°C. 

So far so good...

Next I tried to distill off the excess water, which worked fine at first, but after a while the solution being distilled turned cherry red! Its pH was below 0 and the pH of the clear solution in the collection flask had pH about 1.

At this point I stopped the experiment. I tried to pour the red solution into a bottle for storage, but as I was pouring it immediately crashed out of solution (looking a bit like an orange slushy). Adding more water helped it dissolve the slushy again and made its colour more yellow.

Could anybody help me understand what had happened? (As you can tell I still have much to learn...  )


My plan for now is this: Distill everything off at about 125°C and collect it (this should be aqueous HBr). The red slushy that will be left over will likely be Na₂SO₄.
Since Br₂ has its uses I wouldn't mind collecting it... its soluble in organic solvents so maybe I can rinse it with ether or something, since ether has a lower boiling point than Br₂. That way I could keep some.

Alternatively if people think this isn't a good idea I would also be curious how one can properly get rid of Na₂SO₄ contaminated with Br₂?

Any avice would be greatly appreciated, since I certainly don't just want to flush it down the drain 

[chenbeier]

Using NaBr and sulfuric is not a good idea, because Bromide will oxidised by the sulfuric.This works only with flouride or chloride.
Better is to use PBr3 and water.

[Monoamine]

Thank you for the advice!

[Monoamine]

Quick update: I ended up continuing the distillation at about 120°C. When the liquid was almost distilled off, it reverted back to a yellow and then almost clear colour. At the bottom of the flask remained a solid, which I would assume to be Na₂SO₄.

So I think I'll just collect all the distillate and redistill it at about 100°C to concentrate the HBr acid.