Methods of treating aqueous systems with treatment compositions including non-triazole derivatives of imidazoline and/or amide compounds are provided that are effective to inhibit corrosion of corrodible metal surfaces in the aqueous systems. The non-triazole imidazoline and/or amide compounds show comparable or better corrosion inhibition as compared to conventional triazole corrosion inhibitors, and have low toxicity and good stability in the presence of halogens such as halogen-containing biocides or free chlorine.

Compounds, compositions and methods are provided for reducing, inhibiting, or preventing corrosion of a surface, using a corrosion-inhibiting composition comprising a dispersant having the structure of Formula 1 and a corrosion inhibitor having the structure of Formula 2:

##STR00001##

wherein X.sub.1 is hydroxyl, OC(O)R.sub.1; X.sub.2 is hydroxyl, or OC(O)R.sub.2; X.sub.3 is hydroxyl or OC(O)R.sub.3; R.sub.1, R.sub.2, and R.sub.3 are independently C.sub.10 to C.sub.30 alkyl or alkenyl; m, n, and o are independently integers from 1 to 10; R.sub.20, R.sub.21, R.sub.22, R.sub.23, and R.sub.24 are independently hydrogen or C(O)R.sub.31; R.sub.31 is C.sub.10 to C.sub.30 alkyl or alkenyl; p is an integer of 0 or 1; q is an integer of 1 to 4; r is an integer of 0 or 1; s is an integer of 0 or 1; t is an integer from 1 to 4; and p1, q1, r1, r2, s1, and t1 are independently integers from 1 to 6; wherein when p, r, and s are 0, q+t is an integer from 4 to 8 and at least one of R.sub.20, R.sub.21, R.sub.22, R.sub.23, and R.sub.24 is C(O)R.sub.31.

Disclosed are alkyl lactone-derived hydroxyamide and alkyl lactone-derived hydroxyester used in compositions and methods for inhibiting corrosion. The alkyl lactone-derived hydroxyamide and alkyl lactone-derived hydroxyester are reaction products of an alkyl lactone and an amine, and an alkyl lactone and an alcohol, respectively.

A method for inhibiting corrosion of a corrodible metal surface that contacts a water stream in a geothermal well system. The method includes introducing into the water stream a corrosion inhibitor composition comprising: (i) a cationic surfactant, such as an imidazoline and/or a fatty amine ethoxylate, and (ii) an anionic surfactant.