Patent ID: 6638959
Filing Date: 2003-10-28
Classification: A01N,C02F

Abstract:
A method of achieving an effective â€œfree chlorineâ€  level in treating with a biocide water that is in contact with, or that comes into contact with, at least one iron or copper surface, which method comprises introducing into said water a biocidally effective amount of at least one biocide consisting essentially of 1,3-dibromo-5,5-dialkylhydantoin wherein said amount (i) provides in the water a biocidally effective â€œfree chlorineâ€  level that is within 90% of the â€œtotal chlorineâ€  level in the water thereby enabling the rate of said 1,3-dibromo-5,5-dialkylhydantoin biocide consumption to be reduced as compared to N,Nâ€²-bromochloro-5,5-dimethylhydantoin, and (ii) reduces the rate of corrosion of said iron or copper with which the water is or comes into contact as compared to N,Nâ€²-bromochloro-5,5-dimethylhydantoin, said at least one 1,3-dibromo-5,5-dialkylhydantoin that is introduced into said water being characterized in that one of the alkyl groups in the 5-position is a methyl group and the other alkyl group in the 5-position has in the range of 1 to 4 carbon atoms.