Abstract: Method for disinfecting a liquid medium or hard surface containing undesired halogen-sensitive micro-organisms by treatment with substituted N-halo derivatives of imidazolidin-4-ones having substituents at the 2 and 5 positions of the imidazolidin-4-one ring, including N-chloro, N-bromo, N,N'-dichloro, N,N'-dibromo, and N,N'-bromochloro derivatives of imidazolidin-4-ones having substituents selected from hydrogen, alkyl, alkoxy, hydroxy, phenyl, substituted phenyl, or spiro-substitution at the 2 and 5 positions on the ring. These N-halo compounds are stable, noncorrosive biocides which are resistant to direct sunlight, and are useful as disinfectants, sanitizers, and algae inhibitors.

Abstract: Substituted N-halo derivatives of imidazolidin-4-ones having substituents at the 2 and 5 positions of the imidazolidin-4-one ring are described. More particularly, there are described N-chloro, N-bromo, N,N'-dichloro, N,N'-dibromo, and N,N'-bromochloro derivatives of imidazolidin-4-ones having substituents selected from hydrogen, alkyl, alkoxy, hydroxy, phenyl, substituted phenyl, or spiro-substitution at the 2 and 5 positions on the ring. These N-halo compounds are stable, noncorrosive biocides which are resistant to direct sunlight, and are useful as disinfectants, sanitizers, and algae inhibitors.