IP Library Granted Patent US 12,428,381
Granted Patent B2
US 12,428,381 · App. 17/220,206 · Granted Sep 30, 2025

Gas treating solutions containing imidazole-amine compounds and methods of making the same

Inventors: Jason E. Bara (Tuscaloosa, AL); Kathryn E. O'Harra (Tuscaloosa, AL)
Assignee: The Board of Trustees of The University of Alabama
C07D233/64B01D53/1456B01D53/1493C10L3/104B01D2252/20473C10L2290/542
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Quick Facts
Patent No.
US 12,428,381
App. No.
17/220,206
Granted
Sep 30, 2025
Kind
B2
Abstract

Systems comprising a composition where an imidazole is tethered to an amine and a solvent are described herein. Methods of their preparation and use are also described herein. The methods of using the systems include the reduction of volatile compounds from gas streams and a liquid stream.

Claims (41)

1. A method of reducing one or more volatile compounds from a stream, comprising:

contacting a stream with a solution consisting of an imidazole having formula (I) or a salt thereof, and a solvent,

wherein

R is selected from null, C 1-20 alkyl, C 2-20 alkenyl, C 1 -C 20 alkoxy, C 2-20 alkynyl, C 1-20 heteroalkyl, C 2-20 heteroalkenyl, C 2-20 heteroalkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, C 6 -C 14 aryloxy; wherein R is optionally substituted with C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, amino, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl; and

R 1 and R 2 are, independent of one another, hydrogen, C 1-20 alkyl, C 2-20 alkenyl, C 1 -C 20 alkoxy, C 2-20 alkynyl, C 1-20 heteroalkyl, C 2-20 heteroalkenyl, C 2-20 heteroalkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, C 6 -C 14 aryloxy, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl; wherein each R 1 or R 2 independent of each other is optionally substituted with C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, amino, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl;

R 3 is selected from hydrogen, C 1 -C 10 alkyl, C 1 -C 10 alkoxy, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, C 6 C 14 aryloxy, wherein R 3 is optionally substituted with C 1 -C 10 alkyl, C 1 -C 10 alkoxy, C 2 -C 10 alkenyl, C 2 -C 10 alkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, amino, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl;

R 4 and R 5 are each independent of the other, selected from hydrogen, C 1-20 alkyl, C 2-20 alkenyl, C 1 -C 20 alkoxy, C 2-20 alkynyl, C 1-20 heteroalkyl, C 2-20 heteroalkenyl, C 2-20 heteroalkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, C 6 -C 14 aryloxy, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl; wherein each R 1 or R 2 independent of each other is optionally substituted with C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, amino, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl; or wherein

R 4 and R 5 together form a 6 membered aromatic ring containing 6 carbon atoms, wherein the solvent consists essentially of water.

2. The method of claim 1 , wherein the imidazole of formula (I) forms at least one complex with the one or more volatile compounds, and wherein the method further comprises removing the at least one complex from the stream.

3. The method of claim 1 , wherein the imidazole of formula (I) is non-ionic under neutral conditions.

4. The method of claim 1 , wherein the one or more volatile compounds present in the stream comprise one or more of carbon dioxide, hydrogen sulfide, sulfur dioxide, nitrogen oxide, nitrogen dioxide, carbonyl sulfide, or carbon disulfide.

5. The method of claim 1 , wherein R is selected from —CH 2 —, —CH(CH 3 )—, —C(CH 3 ) 2 —, —CH 2 CH 2 —, —CH 2 CH(CH 3 )—, —CH 2 C(CH 3 ) 2 —, —CH 2 CH 2 CH 2 , —CH 2 CH 2 CH(CH 3 )—, or —CH 2 CH 2 C(CH 3 ) 2 —.

6. The method of claim 1 , wherein the imidazole of formula (I) is selected from

7. The method of claim 1 , wherein the imidazole of formula (I) is present in the solution in an amount from about 30 wt % to about 70%.

8. The method of claim 4 wherein when the volatile compound is carbon dioxide, the imidazole of formula (I) absorbs carbon dioxide in a ratio of 1:3.

9. A method for sweetening a natural gas feed stream, comprising:

a) contacting the natural gas feed stream with a solution consisting of an imidazole of formula (I) or a salt thereof, and a solvent,

wherein

R is selected from null, C 1-20 alkyl, C 2-20 alkenyl, C 1 -C 20 alkoxy, C 2-20 alkynyl, C 1-20 heteroalkyl, C 2-20 heteroalkenyl, C 2-20 heteroalkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, C 6 -C 14 aryloxy; wherein R is optionally substituted with C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, amino, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl; and

R 1 and R 2 are, independent of one another, hydrogen, C 1-20 alkyl, C 2-20 alkenyl, C 1 -C 20 alkoxy, C 2-20 alkynyl, C 1-20 heteroalkyl, C 2-20 heteroalkenyl, C 2-20 heteroalkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, C 6 -C 14 aryloxy, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl; wherein each R 1 or R 2 independent of each other is optionally substituted with C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, amino, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl;

R 3 is selected from hydrogen, C 1 -C 10 alkyl, C 1 -C 10 alkoxy, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, C 6 -C 14 aryloxy, wherein R 3 is optionally substituted with C 1 -C 10 alkyl, C 1 -C 10 alkoxy, C 2 -C 10 alkenyl, C 2 -C 10 alkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, amino, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl;

R 4 and R 5 are each independent of the other, selected from hydrogen, C 1-20 alkyl, C 2-20 alkenyl, C 1 -C 20 alkoxy, C 2-20 alkynyl, C 1-20 heteroalkyl, C 2-20 heteroalkenyl, C 2-20 heteroalkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, C 6 -C 14 aryloxy, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl; wherein each R 1 or R 2 independent of each other is optionally substituted with C 1 -C 20 alkyl, C 1 -C 20 alkoxy, C 2 -C 20 alkenyl, C 2 -C 20 alkynyl, C 6 -C 14 aryl, C 1 -C 13 heteroaryl, amino, carbonyl, ester, ether, halide, carboxyl, hydroxy, nitro, cyano, silyl, sulfo-oxo, sulfonyl, sulfone, sulfoxide, thiol, or phosphonyl; or wherein

R 4 and R 5 together form a 6 membered aromatic ring containing 6 carbon atoms,

wherein the solvent consists essentially of water;

b) forming a purified gas feed stream and a gas-rich solution; and

c) separating the purified gas feed stream and the gas-rich solution.

10. The method of claim 9 , wherein the imidazole of formula (I) is non-ionic under neutral conditions.

11. The method of claim 9 , wherein the natural gas feed stream comprises one or more volatile compounds comprising one or more of carbon dioxide, hydrogen sulfide, sulfur dioxide, nitrogen oxide, nitrogen dioxide, carbonyl sulfide, or carbon disulfide.

12. The method of claim 11 , wherein in step b) the one or more volatile compounds are transferred to the gas-rich solution.

13. The method of claim 11 , wherein the one or more volatile compounds form at least one complex with the imidazole of formula (I).

14. The method of claim 9 , wherein R is selected from —CH 2 —, —CH(CH 3 )—, —C(CH 3 ) 2 —, —CH 2 CH 2 —, —CH 2 CH(CH 3 )—, —CH 2 C(CH 3 ) 2 —, —CH 2 CH 2 CH 2 , —CH 2 CH 2 CH(CH 3 )—, or —CH 2 CH 2 C(CH 3 ) 2 —.

15. The method of claim 9 , wherein the imidazole of formula (I) is selected from

16. The method of claim 9 , wherein the imidazole tethered to an amine is present in the solution in an amount from about 30 wt % to about 70 wt %.

17. The method of claim 1 wherein the imidazole of formula (I) is present in the solution in an amount from about 50 wt % to about 90 wt %.

18. The method of claim 9 wherein the imidazole of formula (I) is present in the solution in an amount from about 50 wt % to about 90 wt %.

19. The method of claim 1 , wherein the imidazole having formula (I) is a basic salt.

20. The method of claim 1 , wherein the imidazole having formula (I) is an alkali salt.

21. The method of claim 1 , wherein the imidazole having formula (I) is a sodium salt.

22. The method of claim 9 , wherein the imidazole having formula (I) is a basic salt.

23. The method of claim 9 , wherein the imidazole having formula (I) is an alkali salt.

24. The method of claim 9 , wherein the imidazole having formula (I) is a sodium salt.

Assignments (2)
CONFIRMATORY LICENSE Recorded Jun 10, 2021
From: UNIVERSITY OF ALABAMA IN TUSCALOOSA
To: UNITED STATES DEPARTMENT OF ENERGY
Reel/Frame 056540/0018 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 15, 2021
From: BARA, JASON E.; O'HARRA, KATHRYN E.
To: THE BOARD OF TRUSTEES OF THE UNIVERSITY OF ALABAMA
Reel/Frame 055930/0381 →
Continuity (2)
Provisional Application 63032834 · Jun 1, 2020
Related Publication 20210371387A1 · Dec 2, 2021
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