The Dow Chemical Company

Robert G Asperger

Robert C Clouse

Leroy S Krawczyk

Giffin D Jones

Billy D Oakes

Smallwood Holoman Jr

A graft copolymer of an episulfide and the reaction product of a polyalkylenimine and a lower ketone is water-soluble or water-dispersible. The copolymer is made by adding an episulfide to the polyalkylenimine dissolved in a lower ketone and heating below the boiling point of the solvent. The resulting graft copolymer is a corrosion inhibitor.

Polyalkylenimine-alkylene sulfide graft copolymer and method of making

A copper based corrosion inhibitor composition and a method for employing the same to prevent corrosion of metal in contact with acid-gases, i.e., hydrogen sulfide, carbonyl sulfide and carbon dioxide. Copper, or a copper compound and sulfur or a sulfur compound, is maintained in solution in contact with the metal under conditions of operation, particularly the thermal regeneration, which provide copper ions and sulfur atoms, particularly polysulfide moieties at the surface of the metal, e.g. copper sulfide is dissolved in an aqueous alkanolamine, monoethanolamine, solution used as an absorbent for acid-gas removal from sour-gas. The copper and sulfur moieties may be formed in situ or prepared and added in solution. The inhibitor has particular utility in protecting metal surfaces which are subject to corrosion as an incidence of the acid-gas content of either natural or synthetic gases.

Method and composition for inhibiting the corrosion of ferrous metals

The corrosion of iron and steel by an aqueous sour gas conditioning solution used to remove CO.sub.2 from a gas stream is effectively inhibited by a combination of a quaternary pyridinium salt and an organic thioamide, a water-soluble sulfide or a water-soluble thiocyanate.

Inhibitor for gas conditioning solutions

The corrosion of iron and steel by an aqueous sour gas conditioning solution used to remove CO.sub.2 from a gas stream is effectively inhibited by a combination of a quaternary pyridinium salt and an organic thioamide or water-soluble thiocyanate. The addition of a small amount of a water-soluble cobalt salt to the inhibitor combination improves its effectiveness.

Cobalt-containing inhibitor for sour gas conditioning solutions

The corrosion of iron and steel by an aqueous sour gas conditioning solution used to remove CO.sub.2 and H.sub.2 S from a gas stream is effectively inhibited by a combination of a quaternary pyridinium salt and a lower alkylenepolyamine or corresponding polyalkylenepolyamine.

Quaternary salt-polyamine inhibitor for sour gas conditioning solutions

An aqueous organic amine acid gas scrubbing system, particularly an aqueous N-methyldiethanolamine or diethanolamine acid gas scrubbing system having incorporated therein (1) a compound or mixture of compounds having the formula ##STR1## wherein n is an integer from 1 to 3, m is an integer from 2 to a number sufficient to yield a molecular weight of about 800, R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each independently selected from the group consisting of --H, --C.sub.n' H.sub.2n' OH, --C.sub.n' H.sub.2n'+1, --C.sub.n' H.sub.2n' N(R.sub.3)R.sub.4 wherein n' is an integer from 1 to 2 and wherein R.sub.1 -R.sub.3 and R.sub.2 -R.sub.4 may be joined to form cyclic amines when n is 2; said compound being present in about 10 to about 2000 parts per million parts of treating solution; (2) copper or a copper ion yielding compound in from 0 to 1000 ppm; and (3) sulfur or a sulfur atom yielding compound in from 0 to 1000 ppm.

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Midland, MI, United States of America

Robert G Asperger