Abstract: There is disclosed diamines of the formula ##STR1## wherein R.sub.6 is H, Cl, or CH.sub.3 ; andR.sub.8 " is H, Cl, or CH.sub.3, with the provisos that(a) if R.sub.8 " is H or CH.sub.3, R.sub.7 " is CH.sub.3 ; and(b) if R.sub.8 " is Cl, R.sub.7 " is F; and(c) if R.sub.6 and R.sub.8 " are both H, R.sub.7 " is any of CH.sub.3, F, CF.sub.3, trifluoromethoxy, trifluoromethylsulfonyl, cyclohexyl, C.sub.2 -C.sub.10 alkyl, p-chlorophenoxy or p-chlorophenyl alkyl having 7 or 8 carbon atoms. The diamines have algicidal activity.

Abstract: There is disclosed N-(2-cyclohexylphenyl)-N', N'-diethyl-ethylene diamine. The compound is useful as an algicide. Compositions containing the compound and methods of use of the compositions are disclosed also.

Abstract: Algicidal composition comprising in an algicidally effective amount a diamine of the formula ##STR1## wherein R.sub.1 is hydrogen or up to three substituents such as halogen, alkyl, phenoxy, phenylthio, or halogen substituted alkoxy, R.sub.2 is hydrogen or a substituent such as alkyl, phenyl, halogen substituted phenyl or a trifluoromethyl-substituted phenyl group, R.sub.3 is an alkylene of 2 to 6 carbon atoms, R.sub.4 is hydrogen or alkyl of 1 to 4 carbon atoms, R.sub.5 is alkyl of 1 to 6 carbon atoms or R.sub.4 and R.sub.5 are together tetramethylene or pentamethylene or R.sub.2 and R.sub.5 are together ethylene and where R.sub.1 is other than three halogen atoms.