US 6,187,227 B1Granted

Thiacrown ether compound corrosion inhibitors for alkanolamine units

AssigneeBetzDearborn Inc.

InventorsLjiljana V. Minevski, Janet A. Gaboury

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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.

Claims17

Dependent claims

A method for inhibiting corrosion of metals in contact with an aqueous alkanolamine solution in an acid gas removal amine unit comprising adding to the aqueous alkanolamine solution an effective corrosion inhibiting amount of at least one of thiacrown ether compound or polymeric thiacrown ether compound effective as a corrosion inhibitor wherein the at least one of thiacrown ether compound or polymeric thiacrown ether compound is selected from one or more of the following formulas:

where Y is an integer of 1 to 7 and Z is an integer of 1 to 4 with the proviso that Y+Z cannot be greater than 8;
M is a linkage group and is selected from O;
COO where the carbon atom is attached to P, P1 and P2;
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;
or M is S with the proviso that P, P1 and P2 are not polyethyleneimine;
P, P1 and P2 are polymers or oligomers in formulas 4 and 5;
P1 and P2 are selected from H, polymers, or oligomers in formula 3;
and
X1 and X2 are independently H;
SH;
F;
Cl;
I;
substituted or unsubstituted C1 to C10 linear or branched alkyl or alkenyl group;
substituted or unsubstituted C6 to C10 aryl;
amine;
mono- or di- C1 to C10 lower alkylamino;
C1 to C10 lower alkanoylamino;
nitro;
cyano;
COOH;
OCOR1 wherein R1 is C1 to C10 alkyl or alkenyl group;
OR2COOR3 wherein R2 is substituted or unsubstituted C2 to C5 linear or branched alkyl group and R3 is substituted or unsubstituted C1 to C10 linear or branched alkyl group or alkenyl group;
OR4 where R4 is substituted or unsubstituted C1 to C10 linear or branched alkyl or alkenyl group;
or SR5 wherein R5 is substituted or unsubstituted C1 to C10 linear or branched alkyl or alkenyl group;
wherein the substituents of the X1 and X2 moieties are independently OH, SH, F, Br, Cl, I, COOH, amine, mono- or di- C1 to C10 alkylamino, alkanoylamino or nitro and with the proviso that both X1 and X2 cannot both be H.

24 more elements

An aqueous acid gas removal solution inhibited against acid gas promoted corrosion of metals comprising:

a) alkanolamine;
b) an effective corrosion inhibiting amount of at least one of thiacrown ether compound or polymeric thiacrown ether compound;
and
c) water, wherein the at least one of thiacrown ether compound or polymeric thiacrown ether compound is selected from one or more of the following formulas:
where Y is an integer of 1 to 7 and Z is an integer of 1 to 4 with the proviso that Y+Z cannot be greater than 8;
M is a linkage group and is selected from O;
COO where the carbon atom is attached to P, P1 and P2;
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;
or M is S with the proviso that P, P1 and P2 are not polyethyleneimine;
P, P1 and P2 are polymers or oligomers in formulas 4 and 5;
P1 and P2 are selected from H, polymers, or oligomers in formula 3;
and
X1 and X2 are independently H;
SH;
F;
Cl;
I;
substituted or unsubstituted C1 to C10 linear or branched alkyl or alkenyl group;
substituted or unsubstituted C6 to C10 aryl;
amine;
mono- or di- C1 to C10 lower alkylamino;
C1 to C10 lower alkanoylamino;
nitro;
cyano;
COOH;
OCOR1 wherein R1 is C1 to C10 alkyl or alkenyl group;
OR2COOR3 wherein R2 is substituted or unsubstituted C2 to C5 linear or branched alkyl group and R3 is substituted or unsubstituted C1 to C10 linear or branched alkyl group or alkenyl group;
OR4 where R4 is substituted or unsubstituted C1 to C10 linear or branched alkyl or alkenyl group;
or SR5 wherein R5 is substituted or unsubstituted C1 to C10 linear or branched alkyl or alkenyl group;
wherein the substituents of the X1 and X2 moieties are independently OH, SH, F, Br, Cl, I, COOH, amine, mono- or di- C1 to C10 alkylamino, alkanoylamino or nitro and with the proviso that both X1 and X2 cannot both be H.

28 more elements

Dependencies are inferred from the claim text.