BCDMH

Template:Chembox header | BCDMH
BCDMH
Template:Chembox header | General
Systematic name	1-Bromo-3-Chloro-5,5-Dimethylhydantoin
Other names	bromochloro-5,5-dimethylhydantoin, BCDMH, agribrom, aquabrom, aquabrome, bromicide, di-halo, halogene T30, nylate, photobrome, slimicide 78P
Molecular formula	C5H6BrClN2O2
Molar mass	241.49 g/mol
Appearance	White solid
CAS number	[126-06-7]
Template:Chembox header | Properties
Density	1.9 g/cm3
Solubility in water	0.25 g/100 ml (25 °C)
Melting point	158 °C - 165 °C
Boiling point	n/a
Template:Chembox header | Hazards
MSDS	External MSDS
Main hazards	Flamability, Inhalation
NFPA 704	Template:NFPA 704
Flash point	Decomposes at 160°C
R/S statement	Template:S8, Template:S17, Template:S26, Template:S36, Template:S37, Template:S39, Template:S41, Template:S45

BCDMH is a chemical disinfectant used for recreational water and drinking water purification. It is a white crystalline compound with a slight bromine and acetone odor and is insoluble in water, but soluble in acetone. BCDMH is an excellent source of both chlorine and bromine as it reacts slowly with water releasing hypochlorous acid and hypobromous acid. Chemically, BCDMH works in the following manner:

The initial BCDMH reacts with water (R = Dimethylhydantoin):

BrClR	+	2 H2O	→	HOBr	+	HOCl	+	RH2
BCDMH		Water		Hypobromous acid		Hypochlorous acid		Dimethylhydantoin

Hypobromous acid partially dissociates in water:

HOBr	→	H+	+	OBr-
Hypobromous acid		Hydrogen ion		Hypobromite ion

Hypobromous acid produces bromide ions when disinfecting:

HOBr	+	Live pathogens	→	Br-	+	Dead pathogens
Hypobromous Acid				Bromide Ion

The bromide ions react with the hypochlorous acid that was formed from the initial BCDMH:

Br-	+	HOCl	→	HOBr	+	Cl-
Bromide ion		Hypochlorous acid		Hypobromous acid		Chloride ion

This produces more hypobromous acid. However, it should be noted that the hypochlorous acid itself does play in a direct role in the disinfectant process.

References

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