DBDMH is an organic compound derived from the heterocycle called dimethylhydantoin

Hydantoin

Hydantoin, which is also known as glycolylurea, is a heterocyclic organic compound that can be thought of as a cyclic "double-condensation reaction" product of glycolic acid and urea...

. This white crystalline compound with a slight bromine

Bromine

Bromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...

 odor is widely used as a disinfectant used for drinking water purification

Water purification

Water purification is the process of removing undesirable chemicals, materials, and biological contaminants from contaminated water. The goal is to produce water fit for a specific purpose...

, recreational water treatment, as a bleaching agent in pulp and paper mills, and for treating industrial/commercial water cooling systems. Its action does not involve the use of hypochlorous acid

Hypochlorous acid

Hypochlorous acid is a weak acid with the chemical formula HClO. It forms when chlorine dissolves in water. It cannot be isolated in pure form due to rapid equilibration with its precursor...

.

Mechanism of action

DBDMH is a source of bromine, which is equivalent to hypobromous acid (HOBr).

Br₂X + 2 H₂O → 2 HOBr + H₂X

(Where H₂X is 5,5-dimethylhydantoin)

With a pK_a of 8.6, hypobromous acid partially dissociates in water:

HOBr H⁺ + BrO^-

Hypobromous acid serves as a source of "Br⁺," which produces bromide ions in the process of disinfection:

HOBr + live pathogens → Br^- + dead pathogens

The resulting bromide ions can then undergo oxidation to hypobromous acid in the presence of an oxidizer of sufficient strength e.g. ozone

Ozone

Ozone , or trioxygen, is a triatomic molecule, consisting of three oxygen atoms. It is an allotrope of oxygen that is much less stable than the diatomic allotrope...

, hypochlorous acid

Hypochlorous acid

Hypochlorous acid is a weak acid with the chemical formula HClO. It forms when chlorine dissolves in water. It cannot be isolated in pure form due to rapid equilibration with its precursor...

, potassium monopersulfate

Persulfate

The term persulfate refers to ions or compounds with more oxygen than normal sulfates.These do not have sulfur in a different oxidation state; rather, they contain peroxide units, where two oxygens take the place of one in a normal sulfate; the oxygen atoms are in oxidation state −1.The main forms...

. This reoxidation process is commonly called "activation" of the bromide ion:

Br^- + HOCl → HOBr + Cl^-