Abstract: The corrosion of metals in contact with aqueous alkanolamine solution in acid gas removal units is inhibited by adding to the alkanolamine solution a corrosion inhibiting amount of a thiacrown ether compound. The compounds are monomeric or polymeric and have from 4 to about 10 sulfur atoms on each of the crown rings. The polymeric thiacrown ether ring structures are substituted with polymerized ethylenically unsaturated monomers and have from 4 to about 10 sulfur atoms on each of the crown rings. In some embodiments of the invention, a linkage “M” connects the thiacrown ether ring structures and the polymers and M is O; S; COO; C1 to C5 substituted or unsubstituted linear or branched alkylene wherein the substituent is OH, SH, F, Br, Cl, I, COOH, amine, mono- or di- C1 to C5 alkylamino, C1 to C3 lower alkanoylamino or nitro; or M is NR6 where R6 is H or C1 to C5 alkyl.

Abstract: The corrosion of metals in contact with aqueous alkanolamine solution in acid gas removal units is inhibited by adding to the alkanolamine solution a corrosion inhibiting amount of a sulfur containing heterocyclic ring compound. The ring compounds are useful for inhibiting the corrosion of metals in both the acid gas rich and the acid gas lean portions of the acid gas removal unit.

Abstract: The corrosion of metals in contact with an aqueous alkanolamine solution in an acid gas removal unit is inhibited by adding a corrosion inhibiting amount of an alkanemonothiol or alkanedithiol compound to the aqueous alkanolamine solution. The alkanemonothiol and alkanedithiol compounds are useful for inhibiting the corrosion of metals in both the acid gas rich and lean portions of the acid gas removal unit.

Abstract: The corrosion of metals in contact with aqueous alkanolamine solution in acid gas removal units is inhibited by maintaining in the alkanolamine solution a corrosion inhibiting amount of a thiodialkanol. The thiodialkanol is useful for inhibiting the corrosion of metals in both the acid gas rich and lean portions of the acid gas removal unit.

Abstract: The corrosion of metals in contact with aqueous alkanolamine solution in acid gas removal units is inhibited by maintaining in the alkanolamine solution a corrosion inhibiting amount of a compound having the formula: ##STR1## where R is S or O, and R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently H, C.sub.1 to C.sub.8 alkyl, C.sub.1 to C.sub.8 alkenyl, C.sub.6 to C.sub.10 aryl, C.sub.7 to C.sub.12 alkaryl, C.sub.7 to C.sub.12 aralkyl, C.sub.3 to C.sub.10 cycloalkyl, C.sub.1 to C.sub.8 thiophene, or amino groups. The alkanedithiol is useful for inhibiting the corrosion of metals in both the acid gas rich and lean portions of the acid gas removal unit.

Abstract: The corrosion of metals in contact with an aqueous alkanolamine solution in an acid gas removal unit is inhibited by adding a corrosion inhibiting amount of an alkanemonothiol or alkanedithiol compound to the aqueous alkanolamine solution. The alkanemonothiol and alkanedithiol compounds are useful for inhibiting the corrosion of metals in both the acid gas rich and lean portions of the acid gas removal unit.

Abstract: The corrosion of metals in contact with aqueous alkanolamine solution in acid gas removal units is inhibited by maintaining in the alkanolamine solution a corrosion inhibiting amount of a thiodialkanol. The thiodialkanol is useful for inhibiting the corrosion of metals in both the acid gas rich and lean portions of the acid gas removal unit.

Abstract: Compositions and methods of using the compositions to inhibit oxygen induced corrosion of metal exposed to aqueous solutions are disclosed. The compositions include hydroxybenzoic acid in formulations with imidazoline, heavy aromatic naphtha, polymerized tall oil fatty acid, alkanols, dimer trimer acids, alkanoic acid, alkanediols, and water. The compositions, when added to aqueous solutions, effectively inhibit oxygen induced corrosion of metal.

Abstract: Compositions and a method of using the compositions to inhibit corrosion. The compositions are water soluble n-alkyl morpholine, saturated dicarboxylic acid, optionally alkanol amine and optionally surfactant compositions which inhibit ferrous metal corrosion when added to aqueous oxygen-free solutions.