photosyn
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Bromine vs. bromine in DCM
Elsewhere on this forum I have asked for advice about an organic synthesis that requires in one step the addition of 160g bromine (1mol) in 200ml of
DCM (for the given quantity described.)
Given that I am considering producing the bromine myself, from sodium bromide/HCl/trichloroisocyanuric acid, would there be simpler handling (and
reduced hazard) if the wet bromine gas evolved is condensed directly into chilled DCM, which could then be dried with and separated from conc.
sulphuric acid ?
[Edited on 3-1-2025 by photosyn]
[Edited on 3-1-2025 by photosyn]
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Keras
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You can try.
Maybe, since water and DCM are immiscible, you won’t even have to dry your bromine?
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Texium
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Thread Moved
3-1-2025 at 10:59 |
photosyn
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According to online data, DCM will hold between 1% and 2% water, which is not particularly dry.
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Keras
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Oh ok. I hadn’t checked, makes sense. I wonder what other drying agent could serve here, barring sulphuric acid. I suppose most of the classical
ones would react?
EDIT: Patent US3615265A discloses that the content of water in bromine is inversely proportional to the temperature. If you heat bromine near its
boiling point, residual water should separate and the final result is about 10 ppm water? No need for sulphuric acid, but for a darn good refrigerant.
You put your bromine in a sep funnel atop which you attach the refrigerant, then you heat your bromine gently using a hair dryer. When it begins to
boil you open the stopcock and let the water run down, and then put the whole thing to cool.
[Edited on 4-1-2025 by Keras]
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