Sciencemadness Discussion Board

Chromyl bromide

Bedlasky - 19-7-2020 at 07:32

Hi.

I read this discusion today:

https://chemistry.stackexchange.com/questions/95286/why-do-c...

Pure CrO2Br2 is purple solid stable at - 70°C, solutions in chlorinated solvents are purple (just like permanganate in water).

It would be interesting experiment. DCM or chloroform can be used instead of CCl4, CrO3 can be made from potassium dichromate and HBr from KBr/H2SO4 generator. Chromyl bromide is stable at low temperatures, so acetone/dry ice bath can be used for cooling.

DraconicAcid - 19-7-2020 at 09:35

Are you sure DCM would be usable? I know from experience that Mn2O7 will react vigorously with DCM, and can ignite it. I know chromyl compounds are less oxidizing than manganese(VII), but it's still something I'd be careful about.

Bedlasky - 19-7-2020 at 10:04

They say that chromyl bromide is soluble in chlorinated solvents, so I assume that it don't react with it. But for sure I'll find more sources. I can try add drop of DCM or chloroform on solid chromium trioxide if they catch fire.

DraconicAcid - 19-7-2020 at 10:07

Quote: Originally posted by Bedlasky  
They say that chromyl bromide is soluble in chlorinated solvents, so I assume that it don't react with it. But for sure I'll find more sources. I can try add drop of DCM or chloroform on solid chromium trioxide if they catch fire.


Come to think of it, the favoured solvent for pyridinium chlorochromate is dichloromethane, so it will probably be okay.