Ionic liquid containing hydroxamate and N-alkyl sulfamate ions
View Patent ↗Embodiments of the invention are related to ionic liquids and more specifically to ionic liquids used in electrochemical metal-air cells in which the ionic liquid includes a cation and an anion selected from hydroxamate and/or N-alkyl sulfamate anions.
1. An ionic liquid comprising a cation and an anion selected from hydroxamate and N-alkyl sulfamate anions, wherein the hydroxamate anion has the following general formula:
wherein R is selected from hydrogen, linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 30 carbon atoms; oligoethylene glycol monoalkyl ethers of the form (R′—(O—CH 2 —CH 2 ) p —O—CH 2 —CH 2 ), wherein p represents a number of from 1 to 30 and R′ represents a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 30 carbon atoms; alkenyl; cycloalkyl; heteroaryl-C 1-6 -alkyl groups having from 3 to 8 carbon atoms in the aryl residue and at least one heteroatom selected from N, O, P, and S which may be substituted with at least one C 1-6 alkyl group and/or halogen atoms; and aryl-C 1-6 -alkyl groups having from 5 to 12 carbon atoms in the aryl residue which may be optionally substituted with at least one C 1-6 alkyl group and/or halogen atom; and
the N-alkyl sulfamate anion has the following general formula:
wherein R is selected from linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 30 carbon atoms; oligoethylene glycol monoalkyl ethers of the form (R′—(O—CH 2 —CH 2 ) p —O—CH 2 —CH 2 ), wherein p represents a number of from 1 to 30 and R′ represents a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 30 carbon atoms; alkenyl; heteroaryl-C 1-6 -alkyl groups having from 3 to 8 carbon atoms in the aryl residue and at least one heteroatom selected from N, O, P, and S which may be substituted with at least one C 1-6 alkyl group and/or halogen atoms; aryl-C 1-6 -alkyl groups having from 5 to 12 carbon atoms in the aryl residue which may be optionally substituted with at least one C 1-6 alkyl group and/or halogen atom.
2. The ionic liquid as claimed in claim 1 , wherein the cation is selected from one or more cations selected from the group consisting of:
Phosphonium cations of the general formula:
(PR 1 R 2 R 3 R) + ;
Quaternary ammonium cations of the general formula:
(NR 1 R 2 R 3 R) + ;
Imidazolium cations of the general formula:
Pyrazolium cations of the general formula:
Thiazolium cations of the general formula:
Pyridinium cations of the general formula:
Triazolium cations of the general formula:
Quinolinium cations of the general formula:
Morpholinium cations of the general formula:
and
Diazabicyclo[2,2,2]octonium cations of the general formula:
wherein R 1 , R 2 , and R 3 , are independently selected at each occurrence from the group consisting of hydrogen; linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having from 1 to 30 carbon atoms; oligoethylene glycol monoalkyl ethers of the form (R′—(O—CH 2 —CH 2 ) p —O—CH 2 —CH 2 ), wherein p represents a number of from 1 to 30 and R′ represents a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 30 carbon atoms; alkenyl; cycloalkyl; heteroaryl, heteroaryl-C 1-6 -alkyl groups having from 3 to 8 carbon atoms in the heteroaryl residue and at least one heteroatom selected from N, O, P, and S which may be substituted with at least one group selected from alkyl groups and/or halogen atoms; and aryl-C 1-6 -alkyl groups having from 5 to 12 carbon atoms in the aryl residue which may be optionally substituted with at least one C 1-6 alkyl group and/or halogen atom;
where R is selected from the group consisting of linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 30 carbon atoms; oligoethylene glycol monoalkyl ethers of the form (R′—(O—CH 2 —CH 2 ) p —O—CH 2 —CH 2 ), wherein p represents a number of from 1 to 30 and R′ represents a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 30 carbon atoms; alkenyl; cycloalkyl; heteroaryl-C 1-6 -alkyl groups having from 3 to 8 carbon atoms in the aryl residue and at least one heteroatom selected from N, O, P, and S which may be substituted with at least one C 1-6 alkyl group and/or halogen atoms; and aryl-C 1-6 -alkyl groups having from 5 to 12 carbon atoms in the aryl residue which may be optionally substituted with at least one C 1-6 alkyl group and/or halogen atom;
where n is 0, 1, 2, 3, or 4; and
where R 4 is selected from C 1-6 -alkyl, halogen, amino, cyan, C 1-4 -alkoxy, carboxylate, or sulfonate.
3. The ionic liquid as claimed in claim 1 , wherein the anion is a hydroxamate selected from the group consisting of acetohydroxyamate, benzohydroxamate, and mixtures thereof.
4. The ionic liquid as claimed in claim 1 , wherein the anion is N-(2-pyridylmethyl) sulfamate.
5. The ionic liquid as claimed in claim 1 , wherein the ionic liquid comprises one or more cation-anion pairs selected from the group consisting of N-ethyl-N-methylmorpholinium N-(2-pyridylmethyl) sulfmate; 1-methyl-1,4-diazabicyclo[2,2,2]octanium acetohydroxamate; 1-methyl-1,4-diazabicyclo[2,2,2]octanium benzohydroxamate, and mixtures thereof.
6. The ionic liquid as claimed in claim 1 , wherein the ionic liquid has a melting point below 100° C.
7. The ionic liquid as claimed in claim 1 , wherein the ionic liquid has a dynamic viscosity ≦2.3 GPascals.
8. The ionic liquid as claimed in claim 1 , wherein the ionic liquid has a specific conductivity (Λ) of ≧100 μS/cm, when measured at 298K.
9. An electrochemical cell comprising:
a) a fuel electrode for oxidizing a fuel;
b) an air electrode configured to absorb and reduce gaseous oxygen; and
c) an ionic liquid comprising a cation and an anion selected from hydroxamate and N-alkyl sulfamate anions.
10. The electrochemical cell as claimed in claim 9 , wherein the hydroxamate anion has the following general formula:
wherein R is selected from hydrogen, linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 30 carbon atoms; oligoethylene glycol monoalkyl ethers of the form (R′—(O—CH 2 —CH 2 ) p —O—CH 2 —CH 2 ), wherein p represents a number of from 1 to 30 and R′ represents a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 30 carbon atoms; alkenyl; cycloalkyl; heteroaryl-C 1-6 -alkyl groups having from 3 to 8 carbon atoms in the aryl residue and at least one heteroatom selected from N, O, P, and S which may be substituted with at least one C 1-6 alkyl group and/or halogen atoms; and aryl-C 1-6 -alkyl groups having from 5 to 12 carbon atoms in the aryl residue which may be optionally substituted with at least one C 1-6 alkyl group and/or halogen atom; and
the N-alkyl sulfamate anion has the following general formula:
wherein R is selected from linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 30 carbon atoms; oligoethylene glycol monoalkyl ethers of the form (R′—(O—CH 2 —CH 2 ) p —O—CH 2 —CH 2 ), wherein p represents a number of from 1 to 30 and R′ represents a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 30 carbon atoms; alkenyl; heteroaryl-C 1-6 -alkyl groups having from 3 to 8 carbon atoms in the aryl residue and at least one heteroatom selected from N, O, P, and S which may be substituted with at least one C 1-6 alkyl group and/or halogen atoms; aryl-C 1-6 -alkyl groups having from 5 to 12 carbon atoms in the aryl residue which may be optionally substituted with at least one C 1-6 alkyl group and/or halogen atom.
11. The electrochemical cell as claimed in claim 9 , wherein the cation is selected from one or more cations selected from the group consisting of:
Phosphonium cations of the general formula:
(PR 1 R 2 R 3 R) + ;
Quaternary ammonium cations of the general formula:
(NR 1 R 2 R 3 R) + ;
Imidazolium cations of the general formula:
Pyrazolium cations of the general formula:
Thiazolium cations of the general formula:
Pyridinium cations of the general formula:
Triazolium cations of the general formula:
Quinolinium cations of the general formula:
Morpholinium cations of the general formula:
and
Diazabicyclo[2,2,2]octonium cations of the general formula:
wherein R 1 , R 2 , and R 3 , are independently selected at each occurrence from the group consisting of hydrogen; linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having from 1 to 30 carbon atoms; oligoethylene glycol monoalkyl ethers of the form (R′—(O—CH 2 —CH 2 ) p —O—CH 2 —CH 2 ), wherein p represents a number of from 1 to 30 and R′ represents a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 30 carbon atoms; alkenyl; cycloalkyl; heteroaryl, heteroaryl-C 1-6 -alkyl groups having from 3 to 8 carbon atoms in the heteroaryl residue and at least one heteroatom selected from N, O, P, and S which may be substituted with at least one group selected from alkyl groups and/or halogen atoms; and aryl-C 1-6 -alkyl groups having from 5 to 12 carbon atoms in the aryl residue which may be optionally substituted with at least one C 1-6 alkyl group and/or halogen atom;
where R is selected from the group consisting of linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 30 carbon atoms; oligoethylene glycol monoalkyl ethers of the form (R′—(O—CH 2 —CH 2 ) p —O—CH 2 —CH 2 ), wherein p represents a number of from 1 to 30 and R′ represents a linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl group having 1 to 30 carbon atoms; alkenyl; cycloalkyl; heteroaryl-C 1-6 -alkyl groups having from 3 to 8 carbon atoms in the aryl residue and at least one heteroatom selected from N, O, P, and S which may be substituted with at least one C 1-6 alkyl group and/or halogen atoms; and aryl-C 1-6 -alkyl groups having from 5 to 12 carbon atoms in the aryl residue which may be optionally substituted with at least one C 1-6 alkyl group and/or halogen atom;
where n is 0, 1, 2, 3, or 4; and
where R 4 is selected from C 1-6 -alkyl, halogen, amino, cyan, C 1-4 -alkoxy, carboxylate, or sulfonate.
12. The electrochemical cell as claimed in claim 9 , wherein the anion is a hydroxamate selected from the group consisting of acetohydroxyamate, benzohydroxamate, and mixtures thereof.
13. The electrochemical cell as claimed in claim 9 , wherein the anion is N-(2-pyridylmethyl) sulfamate.
14. The electrochemical cell as claimed in claim 9 , wherein the ionic liquid comprises one or more cation-anion pairs selected from the group consisting of N-ethyl-N-methylmorpholinium N-(2-pyridylmethyl) sulfmate; 1-methyl-1,4-diazabicyclo[2,2,2]octanium acetohydroxamate; 1-methyl-1,4-diazabicyclo[2,2,2]octanium benzohydroxamate, and mixtures thereof.