Abstract: A method and corrosion inhibitor for inhibiting corrosion of metal equipment in an aqueous medium comprising components selected from the group consisting of Skeletonema costatum, fish, other algae, and a combination thereof. The method comprises incorporating into the medium a corrosion inhibiting amount of a water soluble corrosion inhibitor comprising an N-ethoxy, 2-substituted imidazoline. The N-ethoxy substituent comprises a quantity of ethylene oxide effective to render the imidazoline water soluble. The corrosion inhibitor is rendered more environmentally compatible by shortening the number of carbon atoms in the fatty acid chain at the 2-position of the imidazoline. The fatty acid chain consists essentially about 18 carbon atoms or less, preferably about 10 carbon atoms or less, most preferably from about 6 to about 8 carbon atoms.

Abstract: A method for inhibiting corrosion of a metal surface bearing a corrosion product including ferrous ions is disclosed. The method comprises applying to the surface a salt of an ethoxylated amine and a reaction product of an alcohol and a fatty acid maleic anhydride adduct produced by a reaction between maleic anhydride and an unsaturated fatty acid. Related compositions are also disclosed.