Method for generating oxygen from compositions comprising ionic liquids

Abstract

The present invention is directed to a method for generating oxygen comprising providing at least one oxygen source, providing at least one ionic liquid, providing at least one metal oxide compound, wherein the oxygen source is a peroxide compound, the ionic liquid is in the liquid state at least in the temperature range from 10 C. to +50 C., and the metal oxide compound is an oxide of one single metal or of two or more different metals, said metal(s) being selected from the metals of groups 2 to 14 of the periodic table of the elements, and contacting the oxygen source, the ionic liquid, and the metal oxide compound.

Claims

1. A method for generating oxygen comprising providing at least one oxygen source, providing at least one ionic liquid, providing at least one metal oxide compound, wherein the oxygen source is a peroxide compound, the ionic liquid is in the liquid state at least in the temperature range from 10 C. to +50 C., and the metal oxide compound is an oxide of one single metal or of two or more different metals, said metal(s) being selected from the metals of groups 2 to 14 of the periodic table of the elements, and contacting the oxygen source, the ionic liquid, and the metal oxide compound to generate breathable oxygen suitable for human breathing.

2. The method according to claim 1, wherein the oxygen source and the ionic liquid are provided as a first component, the metal oxide compound is provided as a second component, and the step of contacting comprises mixing the first and the second components.

3. The method according to claim 1, wherein the metal oxide compound and the ionic liquid are provided as a first component, the oxygen source is provided as a second component, and the step of contacting comprises mixing the first and the second component.

4. The method according to claim 1, wherein the oxygen source and the metal oxide compound are provided as a first component, the ionic liquid is provided as a second component, and the step of contacting comprises mixing the first and the second components.

5. The method according to claim 1, wherein the oxygen source is selected from alkali metal percarbonates, alkali metal perborates, urea hydrogen peroxide, and mixtures thereof.

6. The method according to claim 1, wherein the ionic liquid is at least one salt having a cation and an anion, wherein the cation is selected from the group consisting of imidazolium, pyrrolidinium, ammonium, choline, pyridinium, pyrazolium, piperidinium, phosphonium, and sulfonium cations, and wherein the cation may have at least one substituent, or wherein the ionic liquid is at least one salt having a cation and an anion, wherein the anion is selected from the group consisting of dimethylphosphate, methylsulfate, trifluoromethylsulfonate, bis(trifluoromethylsulfonyl)imide, chloride, bromide, iodide, tetrafluoroborate, and hexafluorophosphate.

7. The method according to claim 1, wherein the ionic liquid is selected from the group consisting of butyltrimethylammoniumbis(trifluoromethylsulfonyl)imide ([Me3BuN]TFSI) 1-butyl-3-methylimidazoliumtrifluoromethanesulfonate (BMImOTf), 1-butyl-3-methylimidazoliumdimethylphosphate (BMImPO4Me2), 1-butyl-3-methylimidazoliummethylsulfate (BMImSO4Me), 1,1-butylmethylpyrrolidiniumbis(trifluoromethylsulfonyl)imide (BmpyrTFSI), 1,3-dimethylimidazoliumdimethylphosphate (MMImPO4Me2), 1,3-dimethylimidazoliummethylsulfate (MMImSO4Me).

8. The method according to claim 1, wherein the metal oxide compound is at least one oxide containing one single metal, optionally in different oxidation states.

9. The method according to claim 1, wherein the metal oxide compound is one or more of MnO2, Co3O4, CrO3, Ag2O, CuO, and PbO2.

10. The method according to claim 1, wherein the metal oxide compound is at least on oxide containing at least two different metals.

11. The method according to claim 1, wherein the metal oxide compound is selected from spinel type metal oxides, ilmenite type metal oxides and perovskite type metal oxides.

12. The method according to claim 1, wherein the metal oxide compound is selected from mixed cobalt iron oxides, mixed copper iron oxides, mixed nickel iron oxides, mixed manganese iron oxides, mixed copper manganese oxides, mixed cobalt manganese oxides, mixed nickel manganese oxides, mixed nickel cobalt oxides, mixed lanthanum iron nickel oxides, mixed lanthanum strontium manganese oxide, and mixtures thereof.

13. The method according to claim 1, wherein at least one of the oxygen source and the metal oxide compound is in the form of at least one powder compact, or in the form of powder compacts having different degrees of compression.

14. The method according to claim 13, wherein the at least one powder compact has been compacted with a pressure in the range of 1 to 220 MPa.

15. The method according to claim 1, wherein the oxygen source is present in an amount ranging from 10 to 80 weight %, the ionic liquid is present in an amount ranging from 20 to 80 weight %, and the metal oxide compound is present in an amount ranging from more than 0 to 20 weight %.

16. The method according to claim 5, wherein the oxygen source is selected from the group consisting of one or more of Na.sub.2CO.sub.3 x 1.5 H.sub.2O.sub.2, NaBO.sub.3 x 4H.sub.2O, NaBO.sub.3 x H.sub.2O, and urea hydrogen peroxide.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be further illustrated by the following non limiting examples with reference to the accompanying drawings, wherein:

(2) FIG. 1 is a graph illustrating reproducibility of oxygen release from a composition of the present invention,

(3) FIG. 2 is a graph illustrating oxygen release from different amounts of UHP through metal oxides in MMImPO4Me2,

(4) FIG. 3 is a graph illustrating reaction temperatures for the decomposition reactions illustrated in FIG. 2,

(5) FIGS. 4a, 4b are graphs illustrating oxygen release from 1 g UHP in different ionic liquids by catalytic amounts of manganese (IV) dioxide,

(6) FIG. 5 is a graph illustrating oxygen release from 1 g UHP in MMImPO4Me2 by different metal oxides,

(7) FIG. 6 is a graph illustrating oxygen evolution from 10 g UHP using different catalyst concentrations,

(8) FIG. 7 is a graph illustrating oxygen release from mixtures of SPC and UHP in ionic liquids,

(9) FIG. 8 is a graph illustrating oxygen release from 1 g UHP in MMImPO4Me2 by different metal oxides,

(10) FIG. 9 is a graph illustrating oxygen release from 2 g UHP using different catalysts,

(11) FIG. 10 is a graph illustrating oxygen release from different amounts of UHP through a mixed metal oxide in MMImPO4Me2,

(12) FIG. 11 is a graph illustrating reaction temperatures of the decomposition reactions illustrated in FIG. 10,

(13) FIG. 12 illustrates oxygen release from 1 g UHP in different ionic liquids by catalytic amounts of mangenese (IV) dioxide,

(14) FIGS. 13 and 14 are graphs illustrating oxygen release from 2 g UHP using different catalysts and different concentrations,

(15) FIG. 15 illustrates oxygen release from UHP, SPC and mixtures thereof through Co2FeO4 in MMimPO4Me2,

(16) FIG. 16 illustrates oxygen release from 1 g UHP powder and 1 g UHP powder compact,

(17) FIG. 17 illustrates oxygen release from 2 g UHP powder and two different 2 g UHP powder compacts, and

(18) FIGS. 18 to 22 schematically illustrate several embodiments of devices for generating oxygen from compositions according to the invention.

DETAILED DESCRIPTION

(19) In all graphs illustrating oxygen evolution or reaction temperature, oxygen evolution (or reaction temperature, respectively) is plotted against runtime, wherein runtime is the time which starts running at the time point of contacting the oxygen source (formulation) and the ionic liquid (formulation) comprising an active ionic liquid.

EXAMPLE 1

(20) 10.0 g urea hydrogen peroxide adduct (UHP) were added to a dispersion of mol % (relative to UHP) MnO.sub.2 (0.184 g) in 5.0 g 1,3-dimethylimidazoliumdimethylphosphate (MMImPO.sub.4Me.sub.2), contained in a glass flask. The flask was closed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. The experiment was repeated three times. As FIG. 1 shows, the reaction profile was substantially identical in all experiments, proving that the decomposition reaction was reliably reproducible.

EXAMPLE 2

(21) Urea hydrogen peroxide (UHP) adduct in the amounts listed in table 1 was added to dispersions of 2 mol % (relative to UHP) MnO2 in MMImPO4Me2 (amounts listed in table 1) contained in a glass flask. The flask was closed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. In addition, the reaction temperature was measured. The results are illustrated in FIGS. 2 and 3.

(22) FIG. 2 shows that when varying amounts of peroxide compound are added to equivalently varying amounts of ionic liquid and catalyst, the amount of oxygen released by the decomposition reaction increases proportionally, thus proving that the decomposition reaction is scalable for different sizes of devices for generating oxygen.

(23) FIG. 3 shows that the reaction temperatures increase with increasing amounts of reaction mixture, but remain well below 150 C. even for the sample containing 20 g UHP.

(24) TABLE-US-00001 TABLE 1 mass peroxide peroxide mass MnO2 adduct adduct mass IL catalyst volume reaction time UHP 2.5 g 1.25 g 0.046 g 300 cm.sup.3 6.1 min UHP 5 g 2.5 g 0.092 g 700 cm.sup.3 5.9 min UHP 10 g 5 g 0.184 g 1455 cm.sup.3 5.9 min UHP 20 g 10 g 0.368 g 2970 cm.sup.3 6.1 min

EXAMPLE 3

(25) 1.0 g urea hydrogen peroxide adduct compound (UHP) was added to a dispersion of 5 mol % (relative to UHP) MnO2 catalyst in 0.5 g of different ionic liquids (IL) contained in a glass flask each. The ionic liquids used are listed below. The flask was closed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. The results are shown in FIGS. 4a and 4b. FIGS. 4a and 4b reveal that all ionic liquids worked well. The reaction speed is influenced to some extent by the particular ionic liquid used.

(26) Ionic Liquids: butyltrimethylammoniumbis(trifluoromethylsulfonyl)imide ([Me3BuN]TFSI) 1-butyl-3-methylimidazoliumtrifluoromethanesulfonate (BMImOTf), 1-butyl-3-methylimidazoliumdimethylphosphate (BMImPO.sub.4Me.sub.2), 1-butyl-3-methylimidazoliummethylsulfate (BMImSO.sub.4Me), 1,1-butylmethylpyrrolidiniumbis(trifluoromethylsulfonyl)imide (BmpyrTFSI), 1,3-dimethylimidazoliumdimethylphosphate (MMImPO.sub.4Me.sub.2), 1,3-dimethylimidazoliummethylsulfate (MMImSO.sub.4Me).

EXAMPLE 4

(27) 1.0 g urea hydrogen peroxide adduct compound were added to dispersions of different metal oxide catalysts in 0.5 g MMImPO4Me2 contained in a glass flask. The flask was closed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. The catalysts used are listed in table 2, and the reaction profiles are shown in FIG. 5.

(28) FIG. 5 reveals that both the onset of the reaction and the reaction velocity depend on the particular catalyst used. While in the case of CrO3 the reaction starts immediately after contacting peroxide compound and catalyst, and is finished within a few seconds, in the case of the other catalysts, the onset of the reaction is somewhat delayed, and the reaction velocity is slower.

(29) TABLE-US-00002 TABLE 2 peroxide adduct metal oxide catalyst mass catalyst volume UHP Co.sub.3O.sub.4 0.128 g 145 cm.sup.3 UHP CrO.sub.3 0.053 g 200 cm.sup.3 UHP MnO.sub.2 0.092 g 140 cm.sup.3 UHP PbO.sub.2 0.051 g 142 cm.sup.3 UHP Fe.sub.3O.sub.4 0.123 g 18 cm.sup.3

EXAMPLE 5

(30) 10.0 g UHP were added to dispersions of different amounts of MnO2 catalyst in 7.5 g MMImPO.sub.4Me.sub.2 contained in a glass flask. The amounts and concentrations (relative to UHP) of MnO.sub.2 are indicated in table 3. The flask was closed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. The reaction profiles are shown in FIG. 6.

(31) It is evident from FIG. 6 that the catalyst concentration can be varied over a broad range, and that it exerts a strong influence both on the reaction velocity and on the amount of oxygen released. The reaction velocity dramatically increases with increasing catalyst concentration.

(32) TABLE-US-00003 TABLE 3 peroxide catalyst adduct concentration mass catalyst volume Time1) UHP 1 mole % 0.092 g 863 cm.sup.3 55.0 min UHP 2 mole % 0.184 g 1253 cm.sup.3 24.6 min UHP 4 mole % 0.368 g 1488 cm.sup.3 5.7 min UHP 8 mole % 0.736 g 1365 cm.sup.3 2.0 min 1)time means time until complete release of all available oxygen

EXAMPLE 6

(33) Urea hydrogen peroxide (UHP), sodiumpercabonate (SPC), and mixtures thereof in the amounts listed in table 4 were added to dispersions of 2 mol % (relative to the peroxide compound) MnO.sub.2 in 5.0 g MMImPO.sub.4Me.sub.2. The reaction vessel was closed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. The results are illustrated in FIG. 7.

(34) FIG. 7 illustrates that the nature of the peroxide compound has only little influence on the course of the decomposition reaction. The somewhat longer reaction time and reduced oxygen generation can be attributed to the somewhat lower solubility of SPC, as compared to UHP, in the particular ionic liquid used in this experiment.

(35) TABLE-US-00004 TABLE 4 mass UHP mass SPC mass MnO.sub.2 volume time 10 g 0 0.184 g 1458 cm.sup.3 5.97 min 7.5 g 4.2 g 0.184 g 1343 cm.sup.3 5.53 min 6.7 g 5.4 g 0.184 g 1290 cm.sup.3 4.07 min 0 10 g 0.11 g 1005 cm.sup.3 6.60 min

EXAMPLE 7

(36) 2 g urea hydrogen peroxide adduct (UHP) were added to dispersions of 5 mol % (relative to UHP) of different mixed metal oxide catalysts in 1.0 g MMImPO.sub.4Me.sub.2 contained in a glass flask. The flask was closed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. All catalysts were mixed cobalt iron oxides, as listed in table 5. The reaction profiles are shown in FIG. 8.

(37) FIG. 8 reveals that all tested cobalt iron oxide catalysts behaved very similar. There was almost no difference in reaction velocity, time point of onset of the reaction, and oxygen volume generated.

(38) TABLE-US-00005 TABLE 5 peroxide adduct metal oxide mass catalyst volume UHP CoFe.sub.2O.sub.4 0.249 g 295 cm.sup.3 UHP Co.sub.1.5Fe.sub.1.5O.sub.4 0.251 g 290 cm.sup.3 UHP Co.sub.2FeO.sub.4 0.253 g 290 cm.sup.3

EXAMPLE 8

(39) 2 g urea hydrogen peroxide adduct (UHP) were added to dispersions of 5 mol % (relative to UHP) of different mixed metal oxide catalysts in 1 g MMImPO4Me2 contained in glass flasks. The flasks were closed, and the oxygen volume released by the decomposition reactions was measured with a drum gas meter. The particular catalyst used are listed in table 6, and the reaction profiles are shown in FIG. 9.

(40) In this example, in contrast to the results obtained in example 7, differences were found between the individual mixed metal oxide catalysts. While not wishing to be bound by this theory, it is believed that the different findings in example 7 and example 8 can be attributed to the fact that the mixed metal oxide catalysts used in example 7 contained the same transition metals, and only the relative amounts were varied, while the mixed metal oxide catalysts used in example 8 contained different transition metals, i.e. each mixed metal oxide contained a different combination of transition metals.

(41) TABLE-US-00006 TABLE 6 catalyst catalyst mass volume CuFe.sub.2O.sub.4 0.254 g 243 cm.sup.3 Cu.sub.1.5Mn.sub.1.5MnO.sub.4 0.315 g 385 cm.sup.3 NiMnO.sub.3 0.172 g 285 cm.sup.3 NiCo.sub.2O.sub.4 0.256 g 295 cm.sup.3 Co.sub.2MnO.sub.4 0.252 g 265 cm.sup.3 La.sub.0.5Sr.sub.0.5MnO.sub.3 0.125 g 223 cm.sup.3 LaFe.sub.0.25Ni.sub.0.75O.sub.3 0.245 g 45 cm.sup.3

EXAMPLE 9

(42) Urea hydrogen peroxide adduct compound in the amounts listed in table 7 were added to dispersions of 2 mol % (relative to UHP) Co1.5Fe1.5O4 in corresponding amounts (see table 7) of MMImPO4Me2 contained in glass flasks. The flasks were sealed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. In addition, the reaction temperatures were measured. The results are illustrated in FIGS. 10 and 11.

(43) FIG. 10 shows that when varying amounts of peroxide compound are added to equivalently varying amounts of ionic liquid and mixed metal oxide catalyst, the amount of oxygen released increases proportionally, thus proving that the decomposition reaction is scalable for different sizes of devices for generating oxygen.

(44) FIG. 11 shows that the reaction temperatures increase with increasing amounts of the reaction mixtures. However, the reaction temperatures always remained below 110 C. In the case of example 2 wherein manganese (IV) oxide was used as a catalyst, i.e. an oxide containing only one single transition metal rather than mixed metals, was used as a catalyst, the maximum reaction temperatures appeared to be somewhat higher, thus suggesting a tendency towards lower reaction temperatures with mixed metal oxide catalysts than with single metal oxide catalysts.

(45) TABLE-US-00007 TABLE 7 peroxide adduct mass peroxide mass IL mass catalyst volume time UHP 2.5 g 1.25 g 0.046 g 300 cm.sup.3 6.1 min UHP 5 g 2.5 g 0.092 g 700 cm.sup.3 5.9 min UHP 10 g 5 g 0.184 g 1455 cm.sup.3 5.9 min UHP 20 g 10 g 0.368 g 2970 cm.sup.3 6.1 min

EXAMPLE 10

(46) 1.0 g urea hydrogen peroxide adduct was added to dispersions of 10 mol % (relative to UHP) Fe.sub.1.5Co.sub.1.5O.sub.4 in 0.5 g of different ionic liquids contained in glass flasks. The ionic liquids used are listed below. The flasks were closed, and the oxygen volume released by the decomposition reactions were measured with a drum gas meter. The results are shown in FIG. 12.

(47) FIG. 12 reveals that all ionic liquids worked well. The reaction velocity was influenced to some extent by the particular ionic liquid used.

(48) Used Ionic Liquids:

(49) 1-butyl-3-methylimidazoliumtrifluoromethanesulfonate (BMImOTf)

(50) 1,1-butylmethylpyrrolidiniumbis(trifluoromethylsulfonyl)imide (BMpyrTFSI)

(51) 1,3-dimethylimidazoliumdimethylphosphate (MMImPO.sub.4Me.sub.2)

(52) 1,3-dimethylimidazoliummethylsulfate (MMImSO.sub.4Me)

EXAMPLE 11

(53) 2 g urea hydrogen peroxide adduct (UHP) were added to dispersions of different amounts of NiCo2O4 catalyst and CoFe2O2 catalyst, respectively, in 1 g MMImPO4Me2 in a glass flask. Amounts and concentrations (relative to UHP) of the catalysts are indicated in table 8. The flasks were closed, and the oxygen volume released by the decomposition reaction was measured with a drum gas meter. The reaction profiles for NiCo2O4 are shown in FIG. 13, and the reaction profiles for CoFe2O4 are shown in FIG. 14.

(54) It is evident from FIGS. 13 and 14 that the catalyst concentration can be varied over a broad range and exerts a strong influence both on the reaction velocity and on the amount of oxygen released. The reaction velocity dramatically increases with increasing catalyst concentration.

(55) TABLE-US-00008 TABLE 8 peroxide concentration mass adduct catalyst catalyst catalyst volume time UHP NiCo.sub.2O.sub.4 2 mol % 0.152 g 92 cm.sup.3 41.1 min UHP NiCo.sub.2O.sub.4 5 mol % 0.382 g 290 cm.sup.3 12.5 min UHP NiCo.sub.2O.sub.4 8 mol % 0.612 g 305 cm.sup.3 9.1 min UHP CoFe.sub.2O.sub.4 1 mol % 0.050 g 67 cm.sup.3 47.6 min UHP CoFe.sub.2O.sub.4 2 mol % 0.100 g 203 cm.sup.3 41.5 min UHP CoFe.sub.2O.sub.4 5 mol % 0.250 g 303 cm.sup.3 3.9 min UHP CoFe.sub.2O.sub.4 8 mol % 0.399 g 293 cm.sup.3 2.3 min

EXAMPLE 12

(56) Urea hydrogen peroxide adduct (UHP), sodium percarbonate (SPC), and mixtures thereof in the amounts listed in table 9 were added to dispersions of 0.505 g Co.sub.2FeO.sub.4 in 5 g MMImPO.sub.4Me.sub.2. The reaction vessels were closed, and the oxygen volume released by the decomposition reactions were measured with a drum gas meter. Amounts of oxygen generated as well as the reaction times are shown in FIG. 15.

(57) TABLE-US-00009 TABLE 9 mass UHP mass SPC volume time 2 g 0 260 cm.sup.3 5.9 min 1.3 g 1.0 g 275 cm.sup.3 6.2 min 0 2 g 265 cm.sup.3 7.6 min

(58) FIG. 15 illustrates the nature of the peroxide compound has only little influence on the course of the decomposition reaction.

EXAMPLE 13

(59) In a first experiment, 10 g urea hydrogen peroxide adduct (UHP) in powder form were added to a dispersion of 0.184 g MnO2 in 5.0 g MMImPO4Me2 contained in a glass flask.

(60) In a second experiment, 10 g of the same UHP powder which was used in example 1, were pressed into a powder compact by applying a compaction pressure of 38 MPa. The pellet was added to a dispersion of MnO2 in MMImPO4Me2, as used in experiment 1.

(61) The flasks were closed, and the oxygen volumes released by the decomposition reactions were measured with a drum gas meter. The results are shown in table 10 and FIG. 16.

(62) It is obvious that the reaction velocity was considerably reduced and the time of oxygen production considerably extended, respectively, by compacting the hydrogen peroxide adduct compound.

(63) TABLE-US-00010 TABLE 10 peroxide adduct compaction (form) mass pressure volume time UHP (powder) 10 g 1460 cm.sup.3 7 min UHP (powder 10 g 38 MPa 1120 cm.sup.3 58 min compact)

EXAMPLE 14

(64) In a first experiment 2 g urea hydrogen peroxide adduct (UHP) in powder form were added to a dispersion of 0.074 g Co1.5Fe1.5O4 in 1.0 g MMImPO4Me2 contained in a glass flask.

(65) In a second experiment, 2 g of the same UHP powder which was used in the first experiment, were pressed into a powder compact by applying a compaction pressure of 38 MPa. The pellet was added to a dispersion of Co1.5Fe1.5O4 in MMImPO4Me2 as used in experiment 1.

(66) In a third experiment, 2 g of the same UHP powder which was used in the first and the second experiment, were pressed into a powder compact by applying a compaction pressure of 220 MPa. The pellet was added to a dispersion of Co1.5Fe1.5O4 in MMimPO4Me2 as used in experiments 1 and 2.

(67) The flask was closed, and the oxygen volume released by the decomposition reactions was measured with a drum gas meter. The results are shown in table 11 and FIG. 17. It is obvious that the reaction velocity was considerably reduced and the time of oxygen generation was considerably extended, respectively, by compacting the hydrogen peroxide adduct compound into pellet form. The effect increases with increasing compaction pressure.

(68) TABLE-US-00011 TABLE 11 peroxide compaction mass adduct (form) mass pressure Co.sub.1.5Fe.sub.1.5O.sub.4 volume time UHP (powder) 2 g 0.074 g 280 cm.sup.3 7 min UHP (powder 2 g 38 MPa 0.074 g 263 cm.sup.3 29 min compact) UHP (powder 2 g 220 MPa 0.074 g 142 cm.sup.3 90 min compact)

(69) Thus, examples 13 and 14 prove that reducing the accessible surface area of the peroxide compound, for example by pressing, constitutes a simple measure for extending the time of oxygen release, i.e. for extending the time span wherein breathable oxygen is available.

(70) An exemplary device for generating oxygen from compositions as described above which use ionic liquids for dissolving or dispersing a hydrogen peroxide adduct compound as an oxygen source, and for dispersing a catalyst and bringing the catalyst into contact with the oxygen source, is specifically designed. An exemplary device for generating oxygen has at least one reaction chamber for storing the composition in a condition where not all constituents of the composition are in physical contact. Such physical contact of all constituents of the composition is established at the very moment when oxygen is required. The device is equipped with suitable means for allowing the constituents to contact each other at that very moment. Furthermore, the device allows that the generated oxygen exits the reaction chamber. Some exemplary devices are illustrated in FIGS. 18 to 22, wherein like reference numerals designate like components. The description of such exemplary embodiments shall not be construed as limiting the invention in any manner.

(71) FIG. 18 illustrates a device for generating oxygen 1 having one single reaction chamber 2 for storing the composition for generating oxygen. In such a single reaction chamber 2 at least one of the constituents of the composition for generating oxygen must be enclosed in a receptacle in order to avoid contact with the remaining constituents of the composition contained in the reaction chamber 2. In the embodiment shown in FIG. 18, two receptacles 5, 6 are arranged in the reaction chamber. Receptacle 5 contains an intimate mixture of the oxygen source 7 and the decomposition catalyst 9, for example in powder form or compressed into pellets, in a thoroughly dried condition. Receptacle 6 contains the ionic liquid 8. Alternatively, there may be only one receptacle for enclosing the peroxide/catalyst mixture, while the ionic liquid is free within reaction chamber 2, or ionic liquid 8 may be enclosed within a receptacle, while the peroxide/catalyst mixture is not enclosed in a separate receptacle. It is, in principle, also possible to enclose only the catalyst within a separate receptacle, while the ionic liquid and the peroxide are not enclosed. It is only necessary to avoid contact between all three constituents during storage of the device for generating oxygen.

(72) It is desirable to store the peroxide 7, the ionic liquid 8 and the catalyst 9 within the reaction chamber 2 in such an arrangement that all constituents will be able to get intimately mixed once oxygen generation is required. When, for example, the catalyst and the ionic liquid are provided in one receptacle, and the peroxide in another receptacle, the catalyst may settle within the ionic liquid during storage, and proper mixing with the peroxide may be inhibited. Quick and perfect mixing of all constituents can be achieved when the peroxide and the catalyst are intimately mixed in advance in a dry condition, optionally compacted into moulds, and filled either into the reaction chamber 2 or into a separate receptacle 5 to be placed within the reaction chamber 2, and the ionic liquid is provided in a separate receptacle 6. Placing the ionic liquid in a separate receptacle, although this is not absolutely necessary in a case where peroxide and catalyst are placed in a receptacle 5, constitutes an advantageous precautionary measure against accidental mixing of the constituents in case of receptacle 5 leakage or breakage. Care must be taken, when UHP and catalyst are mixed, because UHP is highly hygroscopic.

(73) In a situation where oxygen shall be generated, receptacle 5, or receptacles 5 and 6, respectively, are destroyed by a breaking device 18. In FIG. 18, breaking device 18 has the form of a plate, however, means for destroying the receptacle(s) are not limited to plates, and other means are known to persons skilled in the art, for example firing pins or grids. Movement of plate 18 can be achieved by a spring 19 or another activation mechanism. During storage of the device for generating oxygen, spring 19 is under tension and holds plate 18 at a position distant from receptacles 5, 6. Once the tension is released by a suitable trigger mechanism (not shown), spring 19 moves plate 18 towards receptacles 5, 6, and plate 18 destroys receptacles 5, 6. Such a trigger may be, for example, pulling an oxygen mask towards a passenger in an airplane. Another exemplary trigger mechanism is an oxygen sensor sensing a low oxygen condition.

(74) Receptacles 5, 6, and plate 18 are made from materials which guarantee that receptacles 5, 6 will be broken or ruptured when hit by plate 18. Exemplary materials are plastic foils or glass for receptacles 5,6, and thicker plastic material or metal for plate 18.

(75) Destruction of receptacles 5, 6 causes mixing of peroxide, ionic liquid, and catalyst, and initiates oxygen generation. In order to allow that the oxygen exits reaction chamber 2, reaction chamber 2 has an opening. In the illustrated embodiment, the opening is sealed with a gas permeable membrane 16. The opening may be at a different position than shown in FIG. 18, or there may be more than one opening. This applies analogously to all devices for generating oxygen of the invention.

(76) The oxygen generated in the devices of this invention may be passed through a filter or other purification means as known in the art. The devices may be equipped with such means.

(77) The oxygen generating reaction is an only slightly exothermic process, and proceeds at low temperature, i.e. well below 150 C. Therefore, reaction chamber 2 does not need to resist high temperatures, and may be made from lightweight, low melting materials such as plastic. In addition, any bulky insulation is not required. This is particularly advantageous in all cases where weight must be saved and/or space is limited, for example in the case of oxygen masks which shall be installed in an aircraft.

(78) FIG. 19 illustrates an alternative embodiment of an exemplary device 1 for generating oxygen. In the embodiment of FIG. 19, the reaction chamber 2 has two compartments, a first compartment 3, and a second compartment 4, which are separated by a gastight membrane 17. The first compartment 3 contains one or more constituents of the composition for generating oxygen. Compartment 3 is equipped with a cutting device 20 having cutting edge 20, and the cutting device is arranged in a position that allows cutting edge 20 to cut through membrane 17 separating the first compartment 3 and the second compartment 4.

(79) Compartments 3, 4 have openings sealed by membranes 15 and 16, respectively. Membranes 15, 16 are gas permeable, thus allowing the oxygen generated during the oxygen generating reaction to exit reaction chamber 2.

(80) An activation mechanism 19, for example a spring, is provided for moving cutting device 20 towards membrane 17, and through membrane 17. Such a mechanism is described in DE 10 2009 041 065 A1. As explained in connection with FIG. 18, spring 19 is under tension during storage of device 1, and once the tension is released by a trigger mechanism (not shown), spring 19 moves receptacle 5 towards membrane 17, cutting edge 20 destroys membrane 17, and first compartment 3 and second compartment 4 are combined into one single reaction chamber 2.

(81) In the embodiment illustrated in FIG. 19, a mixture of peroxide 7 and catalyst 9 is contained in the first compartment 3, and ionic liquid 8 is contained in second compartment 4. Upon destruction of membrane 17, the peroxide/catalyst formulation falls into the second compartment 4, and mixes with ionic liquid 8. The oxygen generated exits the reaction chamber 2 through membranes 15, 16.

(82) Of course, it is also possible to place ionic liquid 8 into the first compartment 3 and the peroxide/catalyst formulation into the second compartment 4, or to use any other arrangement wherein at least one of the constituents is separated from the remaining constituents.

(83) As a material for the cutting device 20, any material may be used which may cut membrane 17, for example a metal sheet. The first compartment 3 and the second compartment 4 can be formed from the same materials as the single reaction chamber 2 illustrated in FIG. 18.

(84) Another embodiment of an inventive device 1 for generating oxygen is illustrated in FIG. 20. In the embodiment of FIG. 20, the reaction chamber 2 is equipped with an injection device 21, for example a syringe or another dosing device.

(85) Reaction chamber 2 and injection device 21 are connected, or constitute separate units which can be connected, to form one single unit. An opening, or several openings, in the wall of reaction chamber 2 allow that oxygen generated during the peroxide decomposition reaction exits reaction chamber 2. The openings are sealed in the embodiment shown by gas permeable membranes 16. In the embodiment illustrated in FIG. 20, the openings are provided at the junction of reaction chamber 2 and injection device 21.

(86) The exemplary injection device of FIG. 20 comprises a slide bar 22, a spike 23, and an injection lance 24. The injection device is adapted for holding one or several constituents of the composition for generating oxygen, in the illustrated example the ionic liquid 8. Ionic liquid 8 is contained in a receptacle 5 made from a material which can be easily ruptured, for example a plastic foil. A mixture of peroxide 7 and catalyst 9 is contained in reaction chamber 2. Alternatively, catalyst 9 may be contained in ionic liquid 8. In a device as illustrated in FIG. 20, any settlement of the catalyst within the ionic liquid during storage does not constitute a disadvantage because the catalyst will be re-dispersed during the injection step.

(87) Slide bar 22 can be actuated in an analogous manner as the breaking device 18 in FIG. 18, and the cutting device 20 in FIG. 19. Once actuated, slide bar 22 pushes receptacle 5 towards spike 23, receptacle 5 is ruptured, and ionic liquid 8 is injected through injection lance 24 into reaction chamber 2. Preferably, injection lance 24 is provided with several holes (not shown) in order to provide uniform distribution of ionic liquid 8. Ionic liquid 8 soaks the mixture of peroxide 7 and catalyst 9, or alternatively the mixture of ionic liquid 8 and catalyst 9 soaks peroxide 7, and the peroxide decomposition reaction starts, generating oxygen. The oxygen leaves reaction chamber 2 via membranes 16.

(88) Analogously to the embodiments described above, the arrangement of peroxide 7, ionic liquid 8, and metal oxide catalyst 9 may be different from the arrangement illustrated in FIG. 20. In particular, if not a liquid, but solid matter is contained in the injection device or dosing unit 21, no receptacle 5 is required, and means for destroying the receptacle, such as spike 23, and an injection lance are also not required.

(89) FIG. 21 depicts an embodiment of the device 1 for generating oxygen which is similar to the embodiment depicted in FIG. 18. Different from the embodiment of FIG. 18, the device for generating oxygen of FIG. 21 is contained in a container 10 surrounding and protecting reaction chamber 2. In this case, the oxygen generated is not directly released into the environment, but rather enters into a gas space 11 between gas permeable membrane 16 and an upper wall of container 10. The oxygen exits gas space 11 via a gas outlet 12 which may be, for example, provided with a filter.

(90) A device 1 as shown in FIG. 21 typically does not need any further thermal insulation. Rather, container 10 provides for sufficient insulation. If desired, a thin layer (for example, having a thickness of about 1 to 3 mm) of an insulating material may be placed between the outer wall of reaction chamber 2 and the inner wall of container 10. Such an insulating material may also serve the additional purpose of holding reaction chamber 2 tightly fixed in place within container 10. No insulating material should be provided between membrane 16 and the container wall opposite to membrane 16, i.e. in gas space 11.

(91) Housing the reaction chamber within a container is advantageous both in devices for generating oxygen having only one reaction chamber, and in devices for generating oxygen having more than one reaction chamber, for example two reaction chambers or a plurality or multitude of reaction chambers 2. An embodiment having eight reaction chambers 2 is illustrated in FIG. 22.

(92) In the device for generating oxygen illustrated in FIG. 22, reaction chambers 2 are shown schematically. Generally, the construction of reaction chambers 2 is not limited in any manner. For example, reaction chambers as illustrated in FIGS. 18 to 20 can be used. Furthermore, the arrangement of the reaction chambers is not limited to the arrangement shown in FIG. 22. Rather, the reaction chambers may be arranged within the container 10 in any appropriate manner.

(93) Oxygen generation within reaction chambers 2 is initiated upon activation of reaction chambers 2. In the embodiment shown in FIG. 22, all reaction chambers 2 are activated simultaneously by a common activation mechanism 19, such as a spring, designed for pushing a plate 18 towards reaction chambers 2, as described in connection with FIG. 18. Alternatively, each reaction chamber may be activated individually, i.e. may have its own activation mechanism, or several reaction chambers may be arranged to groups, each group having its own activation mechanism. For example, in the embodiment of FIG. 22, the eight reaction chambers might be arranged into two groups of four chambers, each group having its own activation mechanism.

(94) Container 10 provides a gas space 11 receiving oxygen from all reaction chambers 2, and the oxygen collected within gas space 11 exits gas space 11 via gas outlet 12. Alternatively, gas space 11 may be divided into a plurality of compartments. A separate compartment, having its own gas outlet, may be attributed to each reaction chamber 2, or one compartment may provide a common gas space for a group of reaction chambers 2. For example, container 10 may provide two gas spaces 11, and each gas space 11 may collect oxygen from four reaction chambers 2.

(95) A device for generating oxygen having several reaction chambers 2 allows to extend oxygen generation over a long time span. As explained above, the reaction time of the peroxide decomposition reaction as well as the onset of the decomposition reaction can be manipulated by choosing appropriate metal oxide catalysts, by varying catalyst amounts and, in particular, by minimizing or maximizing the accessible surface area of the peroxide compound, for example by milling the peroxide compound to a fine powder or by pressing the peroxide compound into powder compacts. The higher the compacting pressure, the higher the density of the resulting powder compacts will be, thus minimizing the accessible surface area of the peroxide compound.

(96) In a device as illustrated in FIG. 22, each of the eight reaction chambers 2 may be charged with a different composition for generating oxygen. A first chamber may be charged for example, with a composition comprising the peroxide compound in fine powdered form, and a high catalyst concentration. This chamber will generate oxygen immediately upon activation, and with a high reaction rate. Thus, breathable oxygen will be available immediately, but only for a short time span.

(97) Three further reaction chambers 2 may be charged also with peroxide compound in fine powdered form, and with catalyst concentrations decreasing from chamber to chamber. In these reaction chambers oxygen generation will be slower, thus extending the time span wherein breathable oxygen is available.

(98) The remaining four reaction chambers may be charged with peroxide compound which has been pressed into powder compacts, the compacting pressure increasing from chamber to chamber. In these chambers, the onset of the decomposition reaction will be delayed, the delay increasing with increasing compaction pressure. This measure further extends the time span wherein breathable oxygen is available.

(99) A similar result can be achieved with only one reaction chamber 2 by charging the single reaction chamber with different oxygen generating compositions, for example with different metal oxide catalysts and/or with oxygen sources in powder form and/or compressed with different compacting pressures.

(100) Since the decomposition reactions are scalable to different reactor sizes, it is easily possible to charge an oxygen generating device with an oxygen generating composition in a sufficient amount to provide for the desired oxygen flow rate. For emergency systems it is generally desired to produce at least 4 1 oxygen per minute.

(101) Of course, also different numbers of reaction chambers than those disclosed by way of example can be advantageously used.

(102) The devices for generating oxygen may be designed as disposable devices (single use) filled with a composition for generating oxygen or compositions for generating oxygen, respectively, or as reusable devices which can be recharged after use with another composition for generating oxygen. Therefore, the constituents of the compositions for generating oxygen can be provided in the form of components suitable for recharging a device for generating oxygen, for example in cartridges.

(103) In an exemplary embodiment, one component comprises a metal oxide compound formulation and an ionic liquid formulation, and another component comprise an oxygen source formulation.

(104) In another exemplary embodiment one component comprises an oxygen source formulation and a metal oxide compound formulation, and another component comprises an ionic liquid formulation.

(105) In a further exemplary embodiment, one component comprises an oxygen source formulation, another component comprises an ionic liquid formulation, and still another component comprises a metal oxide compound formulation.

(106) The term oxygen source formulation means that the oxygen source may be one single peroxide compound, but may be as well a combination of two or more peroxide compounds, and may optionally contain any additives not detrimentally interacting with the peroxide decomposition reaction.

(107) The term ionic liquid formulation means that the ionic liquid may be one single ionic liquid, but may be as well a combination of two or more ionic liquids, and may optionally contain any additives not detrimentally interacting with the peroxide decomposition reaction. The ionic liquids themselves shall not react with any of the constituents of the compositions for generating oxygen, or with any intermediate products generated during the decomposition reaction.

(108) The term metal oxide compound formulation means that the catalyst may be one single metal oxide compound, but may be as well a combination of two or more metal oxide compounds, and may optionally contain any additives not detrimentally interacting with the peroxide decomposition reaction.

(109) The devices for generating oxygen according to the present invention are not sensitive to interruptions of the oxygen production process, in contrast to chlorate candles which can be easily destabilized, for example by shaking. Shaking a device for generating oxygen according to the present invention enhances mixing of the constituents of the oxygen generating composition and, therefore, promotes the oxygen generation reaction.

(110) The inventive devices can be construed in such a manner that the orientation of the inventive devices for generating oxygen in the gravity field of the earth is arbitrary. To this end, several oxygen outlets (sealed by gas permeable membranes or other structures allowing passage of oxygen, while blocking passage of non gaseous substances) must be provided in the walls of reaction chamber(s) 2, and the openings must be arranged in such a manner, that there is always an opening which is not covered by ionic liquid, irrespective of the orientation of the device.