MONO AND BIS-ESTER DERIVATIVES OF PYRIDINIUM AND QUINOLINIUM COMPOUNDS AS ENVIRONMENTALLY FRIENDLY CORROSION INHIBITORS

1 . A quaternary nitrogen-containing corrosion inhibitor of formula

wherein

is an aromatic, nitrogen-containing ring of 5 to 14 ring atoms, optionally containing an additional N, O or S ring atom and optionally substituted with one or more alkyl, alkenyl, aryl, arylalkyl, cycloalkyl, amino, aminoalkyl, alkoxy, hydroxylalkyl, or cyano groups, or a mixture thereof;

Y is a group of formula —OC(O)R 1 or —C(O)R 1 ;

L is C 1 -C 10 alkyl, C 2 -C 10 alkenyl or a group of formula —CH 2 CH(OR 2 )CH 2 —;

R 1 is C 8 -C 20 alkyl or C 8 -C 20 alkenyl;

R 2 is H or <(O)R 1 ; and

X is Br, Cl or I.

2 . The corrosion inhibitor of claim 1 wherein the aromatic, nitrogen-containing ring is selected from oxazole, thiazole, acridine, cinnoline, quinoxazoline, pyridazine, pyridine, pryimidine, quinazolinie, quinoline and isoquinoline.

3 . The corrosion inhibitor of claim 2 wherein L is C 1 -C 10 alkylene or C 2 -C 10 alkenylene.

4 . The corrosion inhibitor of claim 3 wherein L is methylene.

5 . The corrosion inhibitor of claim 2 wherein L is a group of formula —CH 2 CH(OR 2 )CH 2 —.

6 . The corrosion inhibitor of claim 1 wherein the aromatic, nitrogen-containing ring is selected from pyridine and quinoline.

7 . The corrosion inhibitor of claim 6 wherein L is C 1 -C 10 alkylene, C 2 -C 10 alkenylene or a group of formula —CH 2 CH(OR 2 )CH 2 —.

8 . The corrosion inhibitor of claim 7 wherein the pyridine or quinoline is substituted with 1-4 C 1 -C 6 alkyl, C 2 -C 6 alkenyl, or C 1 -C 6 aminoalkyl groups, or a mixture thereof.

9 . The corrosion inhibitor of claim 8 wherein L is methylene.

10 . The corrosion inhibitor of claim 1 of formula

wherein R 3 -R 6 are independently selected from H, alkyl, alkenyl, aryl, arylalkyl, cycloalkyl, amino, aminoalkyl, alkoxy, hydroxylalkyl, or cyano groups, or a mixture thereof, or any two of R 3 -R 6 taken together with the ring atoms to which they are attached may form a fused cycloalkyl.

11 . The corrosion inhibitor of claim 10 wherein R 3 -R 6 are independently selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, or C 1 -C 6 aminoalkyl, or a mixture thereof.

12 . The corrosion inhibitor of claim 1 of formula

wherein R 3 -R 6 are independently selected from H, alkyl, alkenyl, aryl, arylalkyl, cycloalkyl, amino, aminoalkyl, alkoxy, hydroxylalkyl, or cyano groups, or a mixture thereof, or any two of R 3 -R 6 taken together with the ring atoms to which they are attached may form a fused cycloalkyl or fused heterocyclyl ring.

13 . The corrosion inhibitor of claim 12 wherein R 3 -R 6 are independently selected from H, C 1 -C 6 alkyl, C 2 -C 6 alkenyl, or C 1 -C 6 aminoalkyl, or a mixture thereof.

14 . A corrosion inhibitor composition comprising 5 to 50 weight percent of the corrosion inhibitor of claim 1 dispersed or dissolved in one or more organic solvents.

15 . The corrosion inhibitor composition of claim 14 wherein the organic solvents are selected from alcohols, glycols and aliphatic and aromatic hydrocarbons.

16 . The corrosion inhibitor composition of claim 15 wherein the organic solvents comprise ethylene glycol monobutyl ether.

17 . The corrosion inhibitor composition of claim 16 comprising 5 to 20 weight percent of the corrosion inhibitor of claim 1 .

18 . A method of inhibiting corrosion of a metallic surface in contact with a fluid in oil and gas applications comprising adding to the fluid an effective corrosion-inhibiting amount of one or more quaternary nitrogen-containing corrosion inhibitors according to claim 1 .

19 . The method of claim 18 wherein the fluid comprises oil or gas and water.