Method and systems for extracting oxygen employing electrocatalysts

Claim 3

A method as in claim 1, wherein the carrier compound in the carrier fluid is a metal ion chelated to a ligand selected from the group consisting of 1,4,7,10,13-pentaazatridecane; 1,9-bis(2-pyridyl)-2,5,8-triazanonane; 1,10-bis(2-pyridyl)-2,5,9-triazadecane; 1,11-bis(2-pyridyl)-2,6,10-triazaundecane; 1,12-bis(2-pyridyl)-2,6,11-triazadodecane; 1,11-bis(2-pyridyl)-6-methyl-2,6,10-triazaundecane; 1,9-bis(2-(6-methylpyridyl)-2,5,8-triazanonane; 1,11-bis(2-(6-methylpyridyl)-2,6,10-triazaundecane; 2,6-bis(3-(2-pyridyl)-2-azapropyl)pyridine; 2,6-bis(1-(4-(2-pyridyl)-2-azabutyl)pyridine; 2,6-bis(5-(1,4-diazapentyl))pyridine; and 2,6-bis(6-(1,5-diazahexyl))pyridine.

Claim 4

A method as in claim 1, wherein the electrocatalyst is mobile in the carrier fluid.

Claim 5

A method as in claim 1, wherein the electrocatalyst is immobilized on at least one of the electrodes.

Claim 6

A method as in claim 1, wherein the electrocatalyst is immobilized on a substrate other than an electrode, further comprising the step of circulating an electrocatalyst between the electrodes and the other substrate so that the immobilized electrocatalyst may be oxidized and reduced.

Claim 7

A method as in claim 1, wherein the electrocatalyst is selected from the group consisting of iodide ions and substituted ferrocene, where the ferrocene is substituted with carboxylic acid, substituted amino groups, lower alkyl groups and substituted lower alkyl groups, and salts thereof.

Claim 8

A method as in claim 6, wherein the electrocatalyst is selected from the group consisting of iodide ions, ferrocene monocarboxylic acid, 1,1'-ferrocenedicarboxylic acid, hydroxymethylferrocene, dimethylaminomethylferrocene, and the methylated quaternary ammonium bromide or chloride salt of dimethylaminomethylferrocene.

Claim 9

A method as in claim 1, wherein the carrier fluid is at a pH in the range from about 5 to 9.

Claim 10

A method as in claim 1, wherein the electrocatalyst is present at a concentration from about 0.01 mM to 1M.

Claim 11

A method as in claim 1, wherein a voltage is applied across the electrodes, said voltage being from about 0.1 to 0.5 volts less than the uncatalyzed cell potential of the oxygenated carrier compound under the conditions of the cell.

Claim 12

A method as in claim 1, wherein X is a substituted heterocyclic amine selected from the group consisting of 2,6-pyridyl, 2,6-piperidyl, 2,5-pyrrolyl, and 2,5-imidazolyl.

Claim 13

An improved method for extracting molecular oxygen from a fluid mixture feedstock of the type wherein a carrier fluid is circulated between a loading station and an electrochemical cell having a pair of electrodes, wherein said carrier fluid includes a carrier compound able in a first oxidation state of binding oxygen and in a second oxidation state of releasing bound oxygen, said carrier compound having the formula: ##STR3## where, each of R 1 and R 2 is independently an organic group including a nitrogen coordinated to M; each of m, n, o, and p is independently 1, 2, 3, or 4; t is 0 or 1; X is selected from the group consisting of substituted heterocyclic amines, --O--, --S--, >P--R 3 , and >N--R 3 , where R 3 is hydrogen, lower alkyl, or aralkyl; and M is a transition metal ion selected from titanium, manganese, chromium, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, osmium, iridium, and platinum; whereby the carrier compound is converted to the first oxidation state by one electrode of the electrochemical cell in order to bind oxygen at the loading station and the carrier compound is converted to the second oxidation state by the other electrode in order to release oxygen, said improvement comprising: providing an electrocatalyst selected from the group consisting of substituted ferrocenes and iodide ion, to promote electron transfer between said electrode and the carrier compound proximate at least one of the electrodes, whereby the energy required to oxidize or reduce the carrier compound is decreased.

Claim 14

An improved method for extracting molecular oxygen from a fluid mixture feedstock of the type wherein a carrier fluid is circulated between a loading station and an electrochemical cell having a pair of electrodes, wherein said carrier fluid includes a carrier compound able in a first oxidation state of binding oxygen and in a second oxidation state of releasing bound oxygen, said carrier compound having the formula: ##STR3## where, each of R 1 and R 2 is independently an organic group including a nitrogen coordinated to M; each of m, n, o, and p is independently 1, 2, 3, or 4; t is 0 or 1; X is selected from the group consisting of substituted heterocyclic amines, --O--, --S--, >P--R 3 , and >N--R 3 , where R 3 is hydrogen, lower alkyl, or aralkyl; and M is a transition metal ion selected from titanium, manganese, chromium, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, osmium, iridium, and platinum; whereby the carrier compound is converted to the first oxidation state by one electrode of the electrochemical cell in order to bind oxygen at the loading station and the carrier compound is converted to the second oxidation state by the other electrode in order to release oxygen, said improvement comprising: providing an electrocatalyst selected from the group consisting of substituted ferrocenes and iodide ion, to promote electron transfer between said electrode and the carrier compound proximate at least one of the electrodes, whereby the energy required to oxidize or reduce the carrier compound is decreased.

Claim 15

An improved method as in claim 12, wherein the carrier compound in the carrier fluid is a metal ion chelated to a ligand selected from the group consisting of 1,4,7,10,13-pentaazatridecane; 1,9-bis(2-pyridyl)-2,5,8-triazanonane; 1,10-bis(2-pyridyl)-2,5,9-triazadecane; 1,11-bis(2-pyridyl)-2,6,10-triazaundecane; 1,12-bis(2-pyridyl)-6,11-triazadodecane; 1,11-bis(2-pyridyl)-6-methyl-2,6,10-triazaundecane; 1,9-bis(2-(6-methylpyridyl)-2,5,8-triazanonane; 1,11-bis(2-(6-methylpyridyl)-2,6,10-triazaundecane; 2,6-bis(3-(2-pyridyl)-2-azapropyl)pyridine; 2,6-bis(1-(4-(2-pyridyl)-2-azabutyl)pyridine; 2,6-bis(5-(1,4-diazapentyl))pyridine; and 2,6-bis(6-(1,5-diazahexyl))pyridine.

Claim 16

An improved method as in claim 12, wherein the electrocatalyst is mobile in the carrier fluid.

Claim 17

An improved method as in claim 12, wherein the electrocatalyst is immobilized on at least one of the electrodes.

Claim 18

An improved method as in claim 12, wherein the electrocatalyst is immobilized on a substrate other than an electrode, further comprising the step of circulating an electrocatalyst between the electrodes and the other substrate so that the immobilized electrocatalyst may be oxidized and reduced.

Claim 19

An improved method as in claim 12, wherein the electrocatalyst is selected from the group consisting of iodide ions and substituted ferrocene, where the ferrocene is substituted with carboxylic acid, substituted amino groups, lower alkyl groups and substituted lower alkyl groups, and salts thereof.

Claim 20

An improved method as in claim 12, wherein the electrocatalyst is selected from the group consisting of iodide ions, ferrocene monocarboxylic acid, 1,1'-ferrocenedicarboxylic acid, hydroxymethylferrocene, dimethylaminomethylferrocene, and the methylated quaternary ammonium bromide or chloride salt of dimethylaminomethylferrocene.

Claim 21

An improved method as in claim 12, wherein the carrier fluid is at a pH in the range from about 5 to 9.

Claim 22

An improved method as in claim 12, wherein the electrocatalyst is present at a concentration from about 0.01 mM to 1M.

Claim 23

An improved method as in claim 12 wherein a voltage is applied across the electrodes, said voltage being from about 0.1 to 0.5 volts less than the uncatalyzed cell potential of the oxygenated carrier compound under the conditions of the cell.

Claim 24

A method as in claim 12, wherein X is a substituted heterocyclic amine selected from the group consisting of 2,6-pyridyl, 2,6-piperidyl, 2,5-pyrrolyl, and 2,5-imidazolyl.

Claim 25

An electrochemical system for extracting molecular oxygen from a fluid mixture feedstock, said system comprising: an oxygen loading station; an electrochemical cell including a pair of electrodes; a voltage source connected to the electrodes; a carrier fluid which circulates between the electrodes of the electrochemical cell and the oxygen loading station, said carrier fluid including a carrier compound able in a first oxidation state of binding molecular oxygen and in a second oxidation state of releasing bound oxygen, said carrier compound having the formula: ##STR4## where, each of R 1 and R 2 is independently an organic group including a nitrogen coordinated to M; each of m, n, o, and p is independently 1, 2, 3, or 4; t is 0 or 1; X is selected from the group consisting of substituted heterocyclic amines, --O--, --S--, >P--R 3 , and >N--R 3 , where R 3 is hydrogen, lower alkyl, or aralkyl; and M is a transition metal ion selected from titanium, manganese, chromium, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, osmium, iridium, and platinum; and an electrocatalyst in proximity to at least one of the electrodes, said electrocatalyst selected from the group consisting of substituted ferrocenes and iodide ion.

Claim 26

An electrochemical system for extracting molecular oxygen from a fluid mixture feedstock, said system comprising: an oxygen loading station; an electrochemical cell including a pair of electrodes; a voltage source connected to the electrodes; a carrier fluid which circulates between the electrodes of the electrochemical cell and the oxygen loading station, said carrier fluid including a carrier compound able in a first oxidation state of binding molecular oxygen and in a second oxidation state of releasing bound oxygen, said carrier compound having the formula: ##STR4## where, each of R 1 and R 2 is independently an organic group including a nitrogen coordinated to M; each of m, n, o, and p is independently 1, 2, 3, or 4; t is 0 or 1; X is selected from the group consisting of substituted heterocyclic amines, --O--, --S--, >P--R 3 , and >N--R 3 , where R 3 is hydrogen, lower alkyl, or aralkyl; and M is a transition metal ion selected from titanium, manganese, chromium, iron, cobalt, nickel, copper, ruthenium, rhodium, palladium, osmium, iridium, and platinum; and an electrocatalyst in proximity to at least one of the electrodes, said electrocatalyst selected from the group consisting of substituted ferrocenes and iodide ion.

Claim 27

An electrochemical system as in claim 23, wherein the oxygen loading station includes an oxygen-permeable membrane.

Claim 28

An electrochemical system as in claim 23, wherein the carrier compound in the carrier fluid is a metal ion chelated to a ligand selected from the group consisting of 1,4,7,10,13-pentaazatridecane; 1,9-bis(2-pyridyl)-2,5,8-triazanonane; 1,10-bis(2-pyridyl)-2,5,9-triazadecane; 1,11-bis(2-pyridyl)-2,6,10-triazaundecane; 1,12-bis(2-pyridyl)-2,6,11-triazadodecane; 1,11-bis(2-pyridyl)-6-methyl-2,6,10-triazaundecane; 1,9-bis(2-(6-methylpyridyl)-2,5,8-triazanonane; 1,11-bis(2-(6-methylpyridyl)-2,6,10-triazaundecane; 2,6-bis(3-(2-pyridyl)-2-azapropyl)pyridine; 2,6-bis(1-(4-(2-pyridyl)-2-azabutyl)pyridine; 2,6-bis(5-(1,4-diazapentyl))pyridine; and 2,6-bis(6-(1,5-diazahexyl))pyridine.

Claim 29

An electrochemical system as in claim 23, wherein the electrocatalyst is mobile in the carrier fluid.

Claim 30

An electrochemical system as in claim 23, wherein the electrocatalyst is immobilized on at least one of the electrodes.

Claim 31

An electrochemical system as in claim 23, wherein the electrocatalyst is bound to a support outside of the electrochemical cell, and non-bound electrocatalyst is circulated between the electrochemical cell and the immobilized electrocatalyst in order to effect oxidation and reduction of the immobilized electrocatalyst.

Claim 32

An electrochemical system as in claim 23, wherein the electrocatalyst is selected from the group consisting of iodide ions and substituted ferrocene, where the ferrocene is substituted with carboxylic acid, substituted amino groups, lower alkyl groups and substituted lower alkyl groups, and salts thereof.

Claim 33

An electrochemical system as in claim 29, wherein the electrocatalyst is selected from the group consisting of iodide ions, ferrocene monocarboxylic acid, 1,1'-ferrocenedicarboxylic acid, hydroxymethylferrocene, dimethylaminomethylferrocene, and the methylated quaternary ammonium bromide or chloride salt of dimethylaminomethylferrocene.

Claim 34

An electrochemical system as in claim 23, wherein X is a substituted heterocyclic amine selected from the group consisting of 2,6-pyridyl, 2,6-piperidyl, 2,5-pyrrolyl, and 2,5-imidazolyl.