iodine and bromine

[nitric]

Can someone tell me a good method to make iodine and bromine.....

with potassium iodine and potassium bromide

[ChemSiddiqui]

Lets just say heat with con.Sulphuric Acid. By the way if you are trying to prepare it look at the safety measures FIRST ALWAYS! if its a wee-bit dangerous leave it out altogether!

[YT2095]

no, doing the above will make the halide Acid, not the Element itself.

 

displacement with Cl2 works though.

Edited June 17, 2008 by YT2095

[hermanntrude]

or electrolysis of a concentrated solution of KI will give iodine.

 

Halogens are very highly dangerous, though. Inhalation can cause a delayed pulmonary oedema

[John Cuthber]

"no, doing the above will make the halide Acid, not the Element itself"

Want to bet?

You may not get a brilliant yield, but it certainly works.

If you want HI or HBr you are better off using phosphoric acid- sulphuric oxidised the halide to the free halogen

[ChemSiddiqui]

no, doing the above will make the halide Acid, not the Element itself"

Want to bet?

You may not get a brilliant yield, but it certainly works.

If you want HI or HBr you are better off using phosphoric acid- sulphuric oxidised the halide to the free halogen

 

I'd say Halide acid is formed but since the reducing ability increases from flourine to iodine, Iodide ions in the halide acid are oxidised and reduces sulphuric acid to sulphur and sulphur dioxide.

[YT2095]

a mix of of the halide and halate salt with sulphuric will work well, but sulphuric acid alone is crap, I have tried it.

although not with Conc acid... maybe that makes the difference?

[DeanK2]

There is some use for both. By using sulfuric acid to liberate bromine from KBR would be the quickest, cheapest and least dangerous method. The oxidation stops when bromine is produced. If you are intersested, this is a two part reaction:

 

1.) KBr + H2SO4 -------> KHSO4 + HBr (sulfuric acid acts as an acid)

2.) 2HBr + H2SO4 ------> Br2 + SO2 + 2H2O (sulfuric acid acts as an oxidising agent)

Excess acid must be used

 

Hydrogen iodide proceed to further react with sulfuric acid, so Iodine is completely obtained from reacting with sulfuric acid, but other reactions take place that produce substances that take more time to safely remove (yet all Iodine will be liberated).

 

1.)KI + H2SO4 ---------> KHSO4 + HI

2.)2HI + H2SO4 -------> I2 + SO2 + 2H2O

3.)6HI + H2SO4 -------> 3I2 + S + 4H2O

4.)8HI + H2SO4 -------> 4I2 + H2S + 4H2O

 

To obtain Iodine, a simple redox reaction can be performed. Simply add the KI with chlorine.

2KI + Cl2 --------> 2KCl + I2

 

Best of luck.

However, these are extremely harmful and potentially problematic chemicals.

[frosch45]

or.....

 

if your really cool

 

you could also use f2 to displace it

[hermanntrude]

or.....

 

if your really foolish

 

you could also use f2 to displace it

 

I think you mistyped your post, hs. I corrected the mistake

[frosch45]

lol

[John Cuthber]

F2 would have been daft. f2 is just plain wrong.

[frosch45]

I understand that, I realize that F2 would be stupid to use in actual practice, but in theory it would work. in that sense, it is not wrong, definitely stupid and unnecessary when you have access to the more safe but still incredibly toxic chlorine, but it would work

 

its not like some amateur lab would be able to whip out a liter with no problem....

 

I seriously doubt nitric (the thread originator) would have access to something like fluorine if he was asking a question like this

[John Cuthber]

Since F2 reacts with I2 and Br2, it's hardly a sensible choice for making them.

[frosch45]

Alright guys, sorry I wasn't clear enough.

 

Here is what I ment.

 

Flourine gas has the potential to replace chlorine and bromine and iodine because it is a stonger oxidizing agent.

 

In this sense, It would replace the I and Br from KI and KBr. You would obviously have the side reactions then occur.

 

I did not mean for this to be the actual method by any means.

[John Cuthber]

Never take advice from someone who can't spell fluorine.

 

"Flourine gas has the potential to replace chlorine and bromine and iodine because it is a stonger oxidizing agent."

[frosch45]

come on guys

 

I get it. It wouldn't have worked. I was wrong and you guys were right.

 

I did spell it right in the previous posts, I was typing too fast.

 

None the less, I will agree with you that Fluorine gas would not work in this instance or many others. All that I meant was that it would have the potential to kick I2 and Br2 out of the KI and KBr.

[nitric]

just made some bromine and iodine with: KI,KBr+KMnO4+H2SO4.

!

[YT2095]

it`s cleaner if you use the a Bromate or Iodate as the oxidiser though, the Bromine synth becomes really nice then as you can premix these 2 powders and store them away without incompatibility issues, and just add acid when ever you want the bromine.

It saves a lot trouble with storage issues too.

[verode]

iodine pure with iodate and bisulfite

with chlorine you may get interhalogens compounds

you may get bromine with HNO3 water nitrite and any bromide

the temperature around 0ºC

[nitric]

actually nitric acid is a very active oxidizer and a strong acid so i would not need to use any toxic nitrites in the mix. why 0*C?

[verode]

because bromine is very easy to make gas at 20ºC and they are very toxic

you must use any nitrite for start the reaction.

 

I've use pure HNO3 with bromides and nothing happend

but if you put some nitrite on it

wov

may be is the NO2 intermedie

[YT2095]

I use a KBr (sometimes LiBr) and 10% nitric acid soln quite regularly and when I make the reagent up there really isn`t anything apparent happening, but if left to stand for a while (a few weeks to months in my case) there is a slight Br2 smell and discoloration.