METHODS OF USING IONIC LIQUIDS AS CORROSION INHIBITORS
Ionic liquid containing compositions may be used in the production, recovery and refining of oil and gas. In addition, they may be used to treat cooling water and/or to inhibit and/or prevent corrosion of metals.
1 . A method of inhibiting corrosion of a metallic surface in contact with an acidic or aqueous fluid comprising contacting the acidic or aqueous fluid with a corrosive inhibiting effective amount of an ionic liquid of the formula:
A + X − (I)
wherein A is or contains nitrogen, phosphorus or a heterocyclic ring thereof; and X is an anion selected from the group consisting of halides; hydroxyl; hydroxy containing nitrogen or sulfur compounds; carbonates; alkyl carbonates; bicarbonates; dithiocarbonates; trithiocarbonates; xanthates, thiocyanates; alkoxides; carboxylates; hydroxycarboxylates; amino fatty acids; anionic alkoxylated fatty acids; anionic metallic complexes, sulfur or silicon containing anions; anionic phosphate esters, anionic thiophosphate esters; anionic phosphonate esters; anionic thiophosphonate esters; alkyl substituted phosphines; anionic urea; anionic thiourea; anionic natural products; anionic thiols; anionic phenols; anionic phenol resins; anionic copolymers of alpha olefins and maleic anhydride, esters, amides, imides or derivatives thereof; anionic acrylamido-methyl propane sulfonate/acrylic acid copolymers; anionic polyacrylamide; anionic homopolymers, copolymers and terpolymers of one or more acrylates, methacrylates and acrylamides, optionally copolymerized with one or more ethylenically unsaturated monomers; phosphated maleic copolymers; an anionic homo or copolymer of an oxirane or methyloxirane and mixtures thereof or a zwitterion.
2 . A method of inhibiting corrosion of a metallic surface in contact with an acidic or aqueous fluid comprising contacting the acidic or aqueous fluid with a corrosive inhibiting effective amount of an ionic liquid of the formula:
R 1 R 2 R 3 R 4 A + X − (II);
R 1 R 2 R 3 A + R 8 A + R 5 R 6 R 7 X − (III)
wherein:
A in formula (II) is or contains nitrogen or phosphorus or a heterocyclic ring thereof and wherein each A in formula (III) is independently selected from nitrogen or phosphorus or a heterocyclic ring thereof; and
X is an anion selected from the group consisting of halides; hydroxyl; hydroxy containing nitrogen or sulfur compounds; carbonates; alkyl carbonates; bicarbonates; carboxylates; hydroxycarboxylates; dithiocarbonates; trithiocarbonates; xanthates, thiocyanates; alkoxides; anionic urea; anionic alkyl substituted phosphines; anionic amino fatty acids; anionic alkoxylated fatty acids; anionic acrylamido-methyl propane sulfonate/acrylic acid copolymers; anionic phosphated maleic copolymers; anionic homo or copolymers of an oxirane or methyloxirane; anionic metal complexes; sulfur or silicon containing anions; anionic phosphate esters; anionic thiophosphate esters; anionic phosphonate esters; anionic thiophosphonate esters; anionic thiols; anionic natural products; anionic phenols; anionic phenol resins; anionic polyacrylamides; anionic copolymers of alpha olefins and maleic anhydride, esters, amides, imides or derivatives thereof; anionic alkyl substituted phosphines; and anionic homopolymers, copolymers and terpolymers of one or more acrylates, methacylates and acrylamides, optionally copolymerized with one or more ethylenically unsaturated monomers; and mixtures thereof; and further wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 7 are independently selected from the group consisting of hydrogen; benzyl; alkylbenzyl, or oxyalkyl; a straight or branched alkyl group, an alkylbenzyl group, an arylalkyl group, a straight or branched chain alkenyl group, a hydroxyalkyl group or a hydroxyalkylbenzyl group; and a polyoxyalkylene group; and R 8 is a straight or branched alkylene group, an alkylene oxyalkylene, or an alkylene polyoxyalkylene or a zwitterion; and further wherein R groups may be joined to form a heterocyclic nitrogen or phosphorus containing ring.
3 . The method claim 2 , wherein A both occurrences of A in (III) are or contain nitrogen and R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 7 are independently selected from the group consisting of hydrogen; benzyl; oxyalkyl; a straight or branched C 1-30 alkyl group; a C 7-30 alkylbenzyl group; a C 7-30 arylalkyl group; a straight or branched C 3-30 alkenyl group; a C 1-30 hydroxyalkyl group; a C 7-30 hydroxyalkylbenzyl group; and a polyoxyalkylene group and further wherein R groups may be joined to form a heterocyclic nitrogen or phosphorus containing ring; and R 8 is a straight or branched C 1-30 alkylene, an alkylene oxyalkylene, or an alkylene polyoxyalkylene.
4 . The method of claim 3 , wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 and R 7 of (II) and (III) are independently selected from —H, a C 1-20 alkyl, —CH 2 CH 2 OH, and CH 2 CH(CH 3 )OH.
5 . The method of claim 1 , wherein X is a hydroxide, halide, bicarbonate, carbonate, alkyl carbonate, alkoxide, carboxylate or a hydroxycarboxylate.
6 . The method of claim 3 , wherein X is selected from the group consisting of —Cl, —Br, —F or —I.
7 . The method of claim 1 , wherein X is selected from the group consisting of anionic phosphate esters, anionic thiophosphate esters, anionic phosphonate esters; anionic thiophosphonate esters; anionic diphosphonic acids, 2-mercaptoethyl mercaptide, anionic 2-sulfanylethanol; anionic 2-sulfanyl, propan-1-ol; anionic 2-sulfanylbutan-2-ol; anionic 1-sulfanylbutanol-2-ol; and anionic glucaric acid and mixtures thereof.
8 . The method of claim 1 , wherein A is selected from the group consisting of an imidazolium or pyridinium.
9 . The method of claim 8 , wherein the pyridinium is an alkylpyridinium.
10 . The method of claim 8 , wherein the ionic liquid is of the structure:
wherein R is a C 12 -C 18 alkyl or alkenyl group and X is —OH, NH 2 or C(═O)R.
11 . The method of claim 7 , wherein the ionic liquid is a phosphate ester or thiophosphate ester of the structure (IIA) or (IIB):
wherein R is an alkyl or RO(CH 2 CH 2 O) n CH 2 CH 2 ) and R″ and R′″ are independently selected from —H and a C 1 -C 20 alkyl.
12 . The method of claim 1 , wherein the ionic liquid is a quaternary ammonium halide.
13 . The method of claim 12 , wherein the quaternary ammonium halide is of the structure:
wherein the alkyl group contains from 1 to 20 carbon atoms.
14 . The method of claim 1 , wherein the ionic liquid is an alkyl pyridine quat.
15 . The method of claim 14 , wherein the alkyl pyridine quat contains more than one pyrindyl ring.
16 . The method of claim 14 , wherein the alkyl pyridine quat is of the structure:
wherein R is a C 1 -C 18 alkyl or benzyl.
17 . The method of claim 1 , wherein X is selected from the group consisting of anionic thiazoles, anionic triazoles and anionic thiadiazoles.
18 . The method of claim 1 , wherein X is a carboxylate selected from the group consisting of formate, acetate, propionate, benzoate, n-butyrate, isobutyrate, pivalate, octanoate, laurate or is an anion of a C 18 fatty acid.
19 . The method of claim 1 , wherein X is a hydroxycarboxylate selected from the group consisting of glycolate, lactate, citrate, glucarate, gluconate and tartrate.
20 . The method of claim 1 , wherein the ionic liquid is present in a treatment composition containing a second corrosion inhibitor and further wherein the second corrosion inhibitor is not an ionic liquid.
21 . The method of claim 20 , wherein the anion of the ionic liquid is the same as the counter anion of the second corrosion inhibitor.
22 . The method of claim 1 , wherein the acidic or aqueous liquid is crude oil, petroleum fuel or oil, a condensate, a distillate or cooling water.