Dear educated bees, I am currently seeking an...

[k0dog]

Dear educated bees,

I am currently seeking an alternative to the bromonization techniques at hand, for turing 2C-H -->2C-B.
The techniques that I have seen have included:
-a methode via elemental bromine but where would a normal bee get such a material
-a methode via KBr + H2SO4 + H2O2

Now of these methode only one really stand out as the best one to really use and that is the elemental bromine; however this substance is hard to come by.  Essentially the other methodes are only around to circumvent the "need" to use elemental Bromine.

Now to my question, Swim has found normal HBr at his pool supply store (but it has other things in the mix).  Could swim just do like a gas generator to create the Br2?  Of course this would be done by neutralization (probably from Sodium Bicarbonate since it is less harmful than lye).  Will this work to create the Br2 (gas) which will them be bubbled threw my 2CH mixture or will the pressure created by the Br2 gas not be enough?

[wolfx]

In the Rhodium page, there is something on KBr + Oxone. I think this is better than the H2O2, but I don't know for sure. I don't have actual experience with 2CX's etc.

Maybe someone could confirm the Oxone + KBr is better than H2O2 + KBr or not.

[terbium]

Now to my question, Swim has found normal HBr at his pool supply store (but it has other things in the mix).  Could swim just do like a gas generator to create the Br2?  Of course this would be done by neutralization (probably from Sodium Bicarbonate since it is less harmful than lye).  Will this work to create the Br2 (gas)
No. HBr will only supply the bromine anion (Br^-) just like KBr. To convert either to elemental bromine you will need an oxidizing agent such as H2O2 or Oxone.

[dioulasso]

If you dont want to use elemental Br (albeit nasty, its not the worst thing... ), use NBS:

Post 71830 (missing)

(Rhodium: "2C-B and 2C-C with N-halosuccinimide", Methods Discourse)

And there are plenty of modifications around for halogenation of alkoxy subst. aromatics w/ halosuccinimides.


If you want to use your household HBr sol.   , than add the oxidizer of your choice (H2O2 sol., KMnO4, K2Cr2O7, MnO2), and condense the Br2 in a cold trap (fumes led outside ). Of course consider the concentration of the HBr sol, etc...

[gsus]

dioulasso is on it w/ oxidizers. i suggest separating the Br- from the "other things" 1st tho. Ag+ precips Br- as yellow AgBr which is insol in HNO3/sol in conc NH4OH. if you do use carbonate, hot persulfate soln will convert to Br2 which can b extracted w/CCl4 or CHCl3. adding conc H2SO4 to a bromide will give SO2, Br2, and HBr, but adding 50%H2SO4 to a bromide soln will give only HBr. keep in mind Br2 forms hydrates and has 3-4% sol in H2O, and is sol in HBr and bromide solns.