OXYGEN GENERATOR AND METHOD FOR STARTING OR ACCELERATING THE OXYGEN PRODUCTION OF AN OXYGEN GENERATING COMPOSITION

An oxygen generator has a composition for generating oxygen and a basic compound. The composition for generating oxygen includes an oxygen source, an ionic liquid, a metal salt, and an optional basic compound. The oxygen source is a peroxide compound, the ionic liquid is in the liquid state at least in a temperature range from −10° C. to +50° C., the metal salt has one single metal or two or more different metals, and an organic and/or an inorganic anion. There is also described a method for starting or accelerating the oxygen production of an oxygen generating composition, and a device for generating oxygen in a controlled manner.

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Description
CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation, under 35 U.S.C. § 120, of copending International Patent Application PCT/EP2019/070423, filed Jul. 30, 2019, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of European Patent Application EP 18186432.3, filed Jul. 30, 2018; the prior applications are herewith incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to oxygen generators, compositions, methods and devices for generating oxygen in a controlled manner.

Humans cannot exist without oxygen. In many environments, however, oxygen supply is insufficient or there is a risk of emergency situations involving a shortage of oxygen, for example in SAR (search and rescue) applications, in submarines, in mines, in space capsules, and also in airplanes. Air pressure decreases with increasing flight altitude, and at cruising altitudes of many aircrafts, in particular long-range aircrafts, sufficient oxygen for human beings is no longer available. Therefore, the aircraft cabins are pressurized in order to ensure sufficient oxygen supply. In the case of a sudden de-pressurization of an aircraft cabin, oxygen masks must be available, which supply oxygen to crew and passengers until the aircraft reaches a flight level where sufficient oxygen is available.

The oxygen which is provided by these emergency systems is typically produced by so-called “chlorate candles” or “oxygen candles”. These chemical oxygen generators contain chlorates or perchlorates as an oxygen source, as well as various additives such as fuels, catalysts, binders and moderators. Chlorate candles are often in the form of cylindrical rods, i.e. they have a shape similar to candles. Chlorate candles are disclosed, for example, in international publication WO 97/43210.

Known chlorate candles require high temperatures at which the oxygen production takes place. Namely, in chlorate candles the decomposition reaction requires a temperature of about 350° C. for initiation, and the oxygen is released at temperatures between 450° C. and 700° C. Therefore, effective heat insulation of chlorate candles is required, resulting in a weight and size penalty. Furthermore, decomposition of chlorates and perchlorates tends to produce toxic side products, in particular chlorine, which must be removed from the oxygen stream, thus additionally adding size and weight. Furthermore, there is a risk of system failure. In chlorate candles the reaction zone is normally liquid, i.e. there is a liquid zone traveling through the candle, starting at the point of ignition. The liquid zone within the otherwise solid candle considerably destabilizes the candle such that mechanical shocks or even slight vibrations may result in the separation of the candle portions, thus interrupting the heat transfer and discontinuing the chlorate or perchlorate decomposition. In such a case, oxygen production may be interrupted, although oxygen is still vitally needed.

A different type of chemical oxygen generators uses peroxides as oxygen sources, for example sodium percarbonate, sodium perborate, or an urea adduct of hydrogen peroxide. Decomposition of the peroxides yields oxygen, and the decomposition reaction can be started by contacting the peroxide compounds with an appropriate enzyme or transition metal catalyst. Chemical oxygen generators of this type are disclosed in U.S. Pat. No. 2,035,896, international publication WO 86/02063, Japanese publication JPS 61227903, and German publication DE 196 02 149.

Many known peroxide-based oxygen generators use water for providing contact between the peroxides and the catalysts. Unfortunately, water freezes at 0° C. and, therefore, no oxygen can be produced below 0° C., while some emergency systems must be operational below 0° C. Also, the decomposition of peroxides in aqueous solutions may result in vehement effervescing of the reaction mixture. As a consequence, an oxygen generating device containing a peroxide-based oxygen generating composition must have a complicated structure.

A new concept is disclosed in our commonly assigned European patent applications EP 3 323 471 A1, EP 3 323 782 A1 and EP 3 323 783 A1. Those documents disclose devices, compositions and methods for generating oxygen from peroxides in ionic liquids. The compositions comprise at least one oxygen source, at least one ionic liquid, and at least one metal oxide compound, wherein the oxygen source comprises a peroxide compound, the ionic liquid is in the liquid state at least in a 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, the metal(s) being selected from the metals of groups 2 to 14 of the periodic table of the elements.

The use of ionic liquids provides for distinct advantages. Ionic liquids are environmentally friendly compounds. They are liquid over a broad temperature range and exhibit a low to non-existing vapor pressure. Moreover, these liquids are non-flammable and are even used as flame retardants which makes them highly attractive for the use in an airplane. Many of their other properties can be varied by changing their molecular structures. Their high heat capacity enables them to dissipate the reaction heat from the decomposition of peroxides to oxygen.

The compositions disclosed in the prior publications EP 3 323 471 A1, EP 3 323 782 A1 and EP 3 323 783 A1 produce breathable oxygen reliably and continuously in a wide temperature range, also including subfreezing temperatures. The oxygen produced is at a low temperature, such as below 150° C. or even lower. It is typically free from toxic or otherwise noxious components such as chlorine or carbon monoxide. The compositions are capable to produce oxygen over an extended period of time and with a significant flow rate, and promptly upon demand.

However, all oxygen generating compositions described above have in common that they produce oxygen at a flow rate inherent to the particular system, and once the decomposition reaction of the oxygen source has started, it cannot be stopped until all of the oxygen source has been decomposed. Thus, there may be situations, where oxygen is produced although it is not needed or not needed in the amount produced, while later, when oxygen or more oxygen may be needed again, there is no longer any oxygen or no longer enough oxygen available. Furthermore, there may be situations, where not enough oxygen per time unit is produced although it is needed, e.g. because the constitution of a specific person requires a higher oxygen production rate than an average person. Such situations occur frequently in SAR applications, in mining, submarine and space flight applications. If in a conventional oxygen generator the oxygen production is interrupted, intentionally or unintentionally (as may happen in chlorate oxygen candles), there is no possibility to restart the oxygen production. Furthermore, under phases of particularly severe physical strain of a user, there is temporarily more oxygen required, but prior art oxygen generators cannot provide an increased oxygen supply for a desired period of time.

BRIEF SUMMARY OF THE INVENTION

It would be beneficial to provide a solution to at least some of the problems of the prior art outlined above and to provide an oxygen generator allowing to modify the oxygen production rate, i.e., to increase or decrease the oxygen flow rate. It would be also beneficial to provide an oxygen generator which allows to stop the oxygen production when no oxygen is needed, and to restart the oxygen production whenever oxygen is needed. It would be particularly beneficial, when stoppage and restart of the oxygen production could be performed several times.

In addition, it would be beneficial if this oxygen generator would be capable of producing breathable oxygen reliably and continuously in a wide temperature range, and preferably including subfreezing temperatures. The oxygen produced should be at a low temperature, such as below 150° C. or even lower. Desirably, the oxygen should be free from toxic or otherwise noxious components such as chlorine or carbon monoxide. It would be also beneficial if the oxygen generator would be capable to produce oxygen over an extended period of time and with a significant flow rate, and preferably promptly upon demand.

With the above and other objects in view there is provided, in accordance with the invention, an oxygen generator, comprising:

a composition for generating oxygen including an oxygen source, an ionic liquid, and a metal salt, and

a basic compound for starting or accelerating oxygen production;

the oxygen source comprising a peroxide compound;

the ionic liquid being in the liquid state at least in a temperature range from −10° C. to +50° C.; and

the metal salt having one single metal or two or more different metals, and an organic and/or an inorganic anion.

In other words, exemplary embodiments of the invention include an oxygen generator comprising a composition for generating oxygen comprising an oxygen source, an ionic liquid and a metal salt, and a basic compound for starting or accelerating oxygen production, wherein the oxygen source comprises a peroxide compound, the ionic liquid is in the liquid state at least in a temperature range from −10° C. to +50° C., the metal salt comprises one single metal or two or more different metals, and an organic and/or an inorganic anion. Metal(s) of the salt mean(s) here and in the following metal ion(s). The metal salt as such is not able to catalyze decomposition of the peroxide and therewith oxygen production. For starting oxygen production, the metal(s) of the metal salt has/have to be oxidized. This occurs automatically when the basic compound is added. Presumably, the peroxide serves as oxidizing agent for the metal(s). The metal(s) of the metal salt of the present invention may be selected from the metals of groups 2 to 14 of the periodic table of the elements. The periodic table has 18 groups (see: Pure and Applied Chemistry, vol. 60, 3, pages 431-436).

Starting oxygen production may be a first starting of oxygen production from an oxygen generating composition or a further starting, i.e., a restart, after an interruption of oxygen generation by addition an acidic compound.

Further exemplary embodiments of the invention include a composition for generating oxygen comprising an oxygen source, an ionic liquid, a metal salt, and a basic compound, or, if the ionic liquid is a basic ionic liquid or the oxygen source is basic, comprising an oxygen source, an ionic liquid and a metal salt, wherein the oxygen source comprises a peroxide compound, the ionic liquid is in the liquid state at least in a temperature range from −10° C. to +50° C. and the metal salt comprises one single metal or two or more different metals, and an organic and/or an inorganic anion.

Further exemplary embodiments of the invention include a method for starting or accelerating oxygen production of an oxygen generating composition. In the sense of the invention an oxygen generating composition is a composition already generating oxygen but also a composition for generating oxygen in which oxygen generation still has to be started. The method comprises providing an oxygen source, providing an ionic liquid, providing a metal salt, contacting the oxygen source, the ionic liquid and the metal salt, and starting or accelerating the oxygen production by adding a basic compound to the oxygen source, the ionic liquid and/or the metal salt, wherein the oxygen source comprises 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 salt comprises one single metal or two or more different metals and an organic and/or an inorganic anion. Addition of the basic compound to the oxygen source, the ionic liquid and/or the metal salt may occur before, during or after contacting of the oxygen source, the ionic liquid and the metal salt. If it occurs before, it is sufficient to add it to one or two out of the oxygen source, the ionic liquid and the metal salt.

Further exemplary embodiments of the invention include a device for generating oxygen in a controlled manner, the device comprising a reaction chamber housing a composition for generating oxygen, the composition comprising a combination of constituents consisting of an oxygen source, an ionic liquid, and a metal salt, at least one dosing device housing a basic compound and, optionally, at least one dosing device housing an acidic compound, the dosing device(s) being adapted to introduce the basic compound and, optionally, the acidic compound into the reaction chamber, means for maintaining at least one of the oxygen source, the ionic liquid and the metal salt physically separated from the remaining constituents, means for establishing physical contact of the oxygen source, the ionic liquid and the metal salt, and means for allowing oxygen to exit the reaction chamber, or, in particular if the ionic liquid is an acidic compound or contains an acidic compound, a reaction chamber housing a composition for generating oxygen, the composition comprising a combination of constituents consisting of an oxygen source, an ionic liquid, and a metal salt, means for allowing oxygen to exit the reaction chamber, at least one dosing device housing a basic compound and, optionally, at least one dosing device housing an acidic compound, the dosing device(s) being adapted to introduce the basic compound and, optionally, the acidic compound into the reaction chamber, wherein the metal salt comprises a single metal or two or more different metals, and an organic and/or an inorganic anion, the oxygen source comprises a peroxide compound, and the ionic liquid is in the liquid state at least in the temperature range from −10° C. to +50° C. In said device for generating oxygen the oxygen production rate is adjusted by adding the basic compound or, optionally, the acidic compound to the composition for generating oxygen. If oxygen production shall be increased, started or restarted this occurs by the addition of the basic compound and if it shall be decreased or stopped this occurs by the addition of the acidic compound. Since oxygen generation starts only after oxidation of the metal of the metal salt and this oxidation takes only place under basic conditions, it may be not required to provide means for maintaining at least one of the oxygen source, the ionic liquid and the metal salt physically separated from the remaining constituents and means for establishing physical contact of the oxygen source, the ionic liquid and the metal salt if conditions are not basic. However, the composition of the oxygen source, the ionic liquid and the metal salt may be basic as such, e.g. if the ionic liquid or the oxygen source is basic.

Each of the dosing devices may be adapted to introduce the basic compound or the acidic compound by providing a feed line leading from a reservoir housing the basic compound or the acidic compound to the reaction chamber. The feed line may be equipped with a valve the opening of which allows the basic compound or the acidic compound to flow, e.g. due to gravity, into the reaction chamber. When closed or if the valve is a one-way valve the valve may also prevent flow of fluid or oxygen from the reaction chamber into the feed line or even in the reservoir. The reservoir may be equipped with a piston or slide bar for pressing the basic compound or the acidic compound via the feed line into the reaction chamber. The counterpressure provided by the piston or slide bar can prevent that fluid or generated oxygen passes the feed line from the reaction chamber into the reservoir such that a valve is not absolutely required, in particular when the feed line has a small diameter.

Technical implementations of the inventive concept as claimed herein include a composition for generating oxygen, an oxygen generator comprising a composition for generating oxygen, a method for generating oxygen, a method for starting or accelerating the oxygen production of the oxygen generator, and a device for generating oxygen in a controlled manner.

In the method of this invention, oxygen is produced from the composition for generating oxygen, and the oxygen production is accelerated or started by adding a basic compound.

As can be easily understood, the constituents of the composition for generating oxygen are corresponding, irrespective of which technical implementation of the invention is contemplated. Therefore, any disclosure provided for a particular implementation, such as composition, oxygen generator, method or device is analogously applicable to the other implementations of this invention.

A composition for generating oxygen, an oxygen generator (including a composition for generating oxygen and an acidic compound and/or a basic compound), a method for starting or accelerating the oxygen production, and a device for generating oxygen in the sense of this invention is a composition, generator, method or device for generating gaseous, in particular breathable, oxygen in particular in an amount and at an oxygen production rate sufficient to maintain breathing of a human being for a limited time. Any composition, generator, method or device yielding oxygen as a side reaction product, in particular in an amount and at an oxygen production rate not sufficient to maintain breathing of a human being for a limited time, does not constitute a composition, a generator, a method or device in the sense of this invention.

The oxygen generator, the composition, the method for accelerating or starting the oxygen production and the device for generating oxygen in a controlled manner enable acceleration or starting of oxygen production. This enables to provide a composition containing all constituents other than the basic compound and to start oxygen production just by adding the basic compound. It is also possible to restart oxygen production after it had been stopped by addition of an acidic compound. Furthermore, accelerating oxygen production allows adaption of the oxygen production rate to its real need such that at least the required amount of oxygen per time unit but not more oxygen per time unit than required is produced. Due to the possibility to adapt oxygen production to the need of oxygen the oxygen generator, the composition, the method and the device according to the invention allow for a longer provision of sufficient oxygen for a human being and therewith a longer survival of the human being in an emergency situation than with oxygen generators, compositions, methods and devices providing oxygen in an uncontrolled manner.

The invention enables a precise adjustment of the oxygen production rate. If oxygen has to be provided for a defined time, the oxygen generator or the device can contain a smaller amount of the oxygen generating composition than oxygen generators and devices providing oxygen in an uncontrolled manner. Thus, the weight of such an oxygen generator or device comprising the oxygen generating composition can be lower than the weight of an oxygen generator or device known in the art. This is important, e.g. if the oxygen generator or the device is used as an emergency system in an airplane.

The compositions for generating oxygen according to further exemplary embodiments of the invention comprise at least the following constituents: a peroxide compound as an oxygen source, a metal salt as a catalyst triggering the oxygen release reaction, an ionic liquid as a carrier for providing contact between the oxygen source and the catalyst, and for dissipating the heat generated during the peroxide decomposition reaction and, if the ionic liquid is not a basic ionic liquid or the oxygen source is not basic, a basic compound for starting or accelerating oxygen production. In exemplary embodiments the metal salt is soluble in the ionic liquid. The term “soluble” means that essentially the complete amount of the metal salt of a particular oxygen generating composition can be dissolved in the amount of ionic liquid used in this particular composition. The ratio of oxygen source:ionic liquid:metal salt can be varied, however, due to space constraints and also for economical reasons it is advantageous to keep the amount of ionic liquid reasonably small. Therefore, for the purpose of this invention, “soluble” means a solubility of at least 10 nmol (nanomol) metal salt in 1 g ionic liquid. In further exemplary embodiments, the metal salt is only partially soluble or insoluble in the ionic liquid. Typically, the metal salt catalysts have at least some solubility, i.e. are partially soluble.

Peroxide compounds such as hydrogen peroxide adduct compounds, can be decomposed in ionic liquids by contacting them with metal salts in a similar manner as metal salts in aqueous solution, but without the disadvantages of reactions catalyzed by metal salts in aqueous solutions. Exemplary compositions of this invention do not contain any water or at least only traces of water contained in the constituents of the composition. In particular, decomposition of peroxide compounds in ionic liquids yields breathable oxygen at low temperatures, and without requiring bulky thermal insulations for the oxygen generating device.

This can be attributed to the use of ionic liquids as a medium for providing contact between the oxygen source and the catalyst.

Ionic liquids are salts in the liquid state. Therefore, any salt that melts without decomposing or vaporizing yields an ionic liquid. Sometimes, salts which are liquid below the boiling point of water are considered as ionic liquids. Technically interesting are in particular those ionic liquids which are in the liquid state at relatively low temperatures such as at room temperature or even below room temperature.

An ionic compound is considered as an ionic liquid herein when it is in the liquid state at least in a temperature range from −10° C. to +50° C. (at standard pressure of 105 Pa). Exemplary ionic liquids are in the liquid state at least from −30° C. to +70° C., and further exemplary ionic liquids are in the liquid state in an even broader temperature range such as from −70° C. to +150° C. All temperatures referring to the liquid state of ionic liquid given herein particularly refer to the ionic liquid at standard pressure of 105 Pa.

The properties of ionic liquids can be modified and adapted to the particular needs by varying the chemical structure. Typically, ionic liquids are thermally stable, have wide liquid regions, a high heat capacity and nearly no vapor pressure. Most of them are incombustible. They can be even used as flame retardants. Reference is made to US 2011/0073331 A1 disclosing ionic liquid flame retardants, and quoting literature disclosing preparation methods (paragraph 0127).

As indicated above, the ionic liquids used in the present invention should be in the liquid state at a low temperature, such as down to −10° C., or down to −30° C. or even below. Such ionic liquids are salts consisting of organic cations and organic or inorganic anions, and both cations and anions are bulky. In exemplary embodiments, they are bulky and asymmetric. As a general rule, the melting temperature decreases with increasing bulkiness and decreasing symmetry of cations and anions. Combinations of highly bulky and asymmetric cations and anions may not freeze down to temperatures as low as −120° C. Many ionic liquids are available which are liquid at −70° C. and above.

Suitable cations are, for example, imidazolium, pyrrolidinium, ammonium, pyridinium, pyrazolium, piperidinium, phosphonium, and sulfonium cations. The cations may or may not have substituents. Particularly, the cations may have one or more substituents, for example alkyl side chains such as methyl, ethyl or butyl side chains. The substitution may be symmetric or asymmetric.

Suitable anions include, for example, dimethylphosphate, methylsulfate, ethylsulfate, trifluoromethylsulfonate, bis(trisfluoromethylsulfonyl)imide, chloride, bromide, iodide, tetrafluoroborate, hexafluorophosphate, acetate, and but-3-enoate. In the case of “small” anions such as chloride, bromide, and iodide, particularly bulky cations can be selected, in order to provide for the desired low temperature liquidity.

Some exemplary ionic liquids are

    • 1-butyl-3-methylimidazoliumdimethylphosphate ([BMIM][PO4Me2]),
    • 1,3-dimethylimidazoliumdimethylphosphate ([MMIM][PO4Me2]),
    • 1-butyl-3-methylimidazoliumacetate ([BMIM][OAc]),
    • 1-ethyl-3-methylimidazoliumethylsulfate ([EMIM][EtSO4]),
    • tetraethylammonium but-3-enoate ([NEt4][but-3-enoat]),
    • 1,3-dimethylimidazoliummethylsulfate ([MMIM][MeSO4]),
    • 1-butyl-3-methylimidazoliummethylsulfate ([BMIM][MeSO4]),
    • 1,1-butylmethylpyrrolidiniumbis(trifluoromethylsulfonyl)imide ([BMPyrr][TFSI]),
    • butyltrimethylammoniumbis(trifluoromethylsulfonyl)imide ([Me3BuN][TFSI]),
    • 1-butyl-3-methylimidazoliumtrifluoromethanesulfonate ([BMIM][OTf]),
    • 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]),
    • tetrabutylammonium arginine ([TBA][Arg]),
    • trimethylammonium propanesulfonic acid hydrogen sulfate ([TMPSA][HSO4]),
    • 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate ([SBMIM][HSO4]),
    • diethylmethylammonium methanesulfonate ([NEt2MeH][MeSO3]), and
    • 1-ethyl-3-methylimidazolium hydrogen sulfate ([EMIM][HSO4]).

[NEt4][but-3-enoate], [EMIM][OAc] and [TBA][Arg] are basic ionic liquids, and [TMPSA][HSO4], [SBMIM][HSO4], [NEt2MeH][MeSO3] and [EMIM][HSO4] are acidic ionic liquids.

Further ionic liquids can be found in “Neue Anwendungen für ionische Flüssigkeiten in der Technik and Medizintechnik” (New Applications for Ionic Liquids in Technology and Medical Technology), Dissertation by F. Stein, University of Rostock, Germany, 2014, at page 43.

The ionic liquids usable herein are, however, not particularly limited. It is only required that they are liquid and stable (i.e. they do not decompose) in the desired temperature range. Of course, the ionic liquids should not react with any constituents of the oxygen generating composition, the acidic compound and the basic compound. The ionic liquids may be used singly or in combinations of two or more. Thus, in exemplary embodiments, this invention uses ionic liquid formulations containing one or more ionic liquids and, optionally, contain further additives which do not detrimentally interfere with the peroxide decomposition reaction.

As an oxygen source, peroxide compounds, in particular solid hydrogen peroxide adduct compounds are used. Solid hydrogen peroxide adduct compounds constitute suitable and stable substituents for liquid hydrogen peroxide, are easily storable, long term stable and safe to work with. Exemplary oxygen sources are alkali percarbonates, e.g. sodium percarbonate (Na2CO3×1.5H2O2), alkali perborates, e.g. sodium perborate (NaBO3×4H2O, NaBO3× H2O), and urea hydrogen peroxide (UHP). In UHP urea and hydrogen peroxide are present in a molar ratio of about 1:1.

The peroxide compounds are not particularly limited, as long as they are stable under usual storage conditions. Exemplary peroxide compounds are stable also at elevated temperatures, for example in the vicinity of a fire. The peroxide compounds can be soluble or partially soluble or insoluble in the ionic liquids. The peroxide compounds can be used singly or in combinations of two or more, i.e. as oxygen source formulations containing, optionally, further additives which do not detrimentally interfere with the peroxide decomposition reaction.

In exemplary embodiments, the decomposition reaction of the peroxide compound is catalyzed by metal salts. The metals salts comprise one single metal or two or more different metals and an organic and/or an inorganic anion.

In exemplary embodiments the metal salt is soluble in the ionic liquid, and in further exemplary embodiments, the metal salt is not soluble or partially soluble in the ionic liquid. Selecting a metal salt and an ionic liquid such, that the desired amount of metal salt is completely dissolved in the desired amount of ionic liquid provides the advantage that the metal salt and the ionic liquid can be provided in the form of one single homogeneous component. The solutions are stable, and even during long term storage, no sedimentation takes place. Providing the metal salt and the ionic liquid in the form of a homogeneous solution simplifies the design of oxygen generating devices, results in a higher activity of the mixture of catalyst and ionic liquid and, in turn, reduces the required amount of catalyst. A further advantage is the prolonged shelve life of the compositions, as compared to compositions containing the catalyst in suspended form.

The solubility behavior of metal salts in ionic liquids is, at least roughly, analogous to the solubility behavior in water. Therefore, if readily soluble catalysts are desired, metal salts known to be readily soluble in water can be used, and if hardly soluble catalysts are desired, metal salts known to be hardly soluble in water can be used.

As regards inorganic anions, anions such as chlorides, sulfates, carbonates, hydroxides, and nitrates are known to provide water solubility, and as regards organic anions, anions such as chelating agents, i.e. anions forming coordination complexes with metals, are known to provide water solubility.

Accordingly, in exemplary embodiments, the metal salt is at least one selected from the group consisting of chlorides, sulfates, carbonates, hydroxides, and nitrates. Metal salts having these inorganic anions are generally well soluble in many ionic liquids.

In further exemplary embodiments, the metal salt is at least one selected from the group consisting of acetates, acetylacetonates, oxalates, tartrates, and citrates. Metal salts having these chelating organic anions are generally well soluble in many ionic liquids.

In further exemplary embodiments, a fraction of the organic or inorganic anions is substituted by oxygen anions, thus yielding mixed catalysts, i.e. metal compounds comprising both oxidic anions and inorganic anions or organic anions, or even metal compounds comprising oxidic anions, inorganic anions, and organic anions.

The metal salt, in exemplary embodiments, contains one single metal, optionally in different oxidation states, the metal being selected from the metals belonging to groups 5 to 14 and periods 4 to 6 of the periodic table of the elements. The periodic table has 18 groups and 7 periods (see: Pure and Applied Chemistry, 1988, Vol. 60, No. 3, pages 431-436).

In further exemplary embodiments, the metal salt comprises at least two different metals, with at least one metal being selected from the metals belonging to groups 5 to 14 and periods 4 to 6 of the periodic table of the elements.

In all embodiments, each metal may be present in one single oxidation state or in different oxidation states.

The metal salts may be used singly or in combinations of two or more different metal salts. The salts may have different cations or different anions or both different cations and different anions. The metal salts may be provided in the form of metal salt formulations, i.e. the catalyst may be one single metal salt or a combination of two metal salts, and optionally additives which do not detrimentally interfere with the peroxide decomposition reaction may also be contained.

The metal salt comprises at least one metal in an oxidation state allowing a reaction with hydrogen peroxide, assuming basic conditions in aqueous reaction media, i.e. the redox potential of the oxidation state transition which the metal undergoes during the catalytic reaction must allow a reaction with hydrogen peroxide.

Exemplary metal salt catalysts include salts of vanadium, chromium, manganese, iron, cobalt, copper, molybdenum, ruthenium, iridium, and lead. Exemplary oxidation states are +2 for vanadium, +3 and +6 for chromium, +2 and +3 for manganese, +2 and +3 for iron, +2 for cobalt, +1 and +2 for copper, +6 for molybdenum, +3 for ruthenium, +3 for iridium, and +2 and +4 for lead.

As exemplary inorganic salts catalyzing the peroxide decomposition reaction may be mentioned: PbCl2, CrCl3, CoCl2, CoCO3, CoSO4, IrCl3, MnCl2, VCl2, KCr(SO4)2, FeCl3, CuCl2, and their respective hydrates.

As exemplary organic salts catalyzing the peroxide decomposition reaction may be mentioned: Mn(OAc)2, Mn(OAc)3, Mn(acac)2, Mn(oxalate), Pb(acac)2, Pb(OAc)2, Pb3 (citrate)2, Pb(tartrate), Co(OAc)2, MoO2(acac)2, Ru(acac)3. and their respective hydrates. OAc means acetate and acac means acetylacetonate.

The above listed inorganic and organic salts constitute active catalysts in many ionic liquids.

The acidic compounds according to exemplary embodiments are inorganic acids, organic acids, acidic salts, or ionic liquids with acidic properties.

Examples for inorganic acids are hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid; examples for organic acids are acetic acid, succinic acid, citric acid, and benzoic acid, examples for acidic salts are sodium hydrogen sulfate and monopotassium phosphate, and examples for ionic liquids with acidic properties are 1-ethyl-3-methylimidazolium hydrogen sulfate ([EMIM][HSO4]), trimethylammonium propanesulfonic acid hydrogen sulfate ([TMPSA][HSO4]), 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate ([SBMIM][HSO4]) and diethylmethylammonium methanesulfonate ([NEt2MeH][MeSO3]).

In the oxygen generators of the present invention, the acidic compounds (“acids”) may be provided in liquid form. Liquid forms include the pure liquid compound, concentrated or diluted solutions of liquids or gases (for example concentrated or diluted solutions of hydrochloric acid or acetic acid), and solutions and dispersions of solid acids or acidic salts in a solvent or dispersing agent. Acids in liquid form can be, e.g., usual mineral acids such as hydrochloride acid, sulfuric acid, nitric acid and phosphoric acid. Acids in liquid form may also be solutions of acidic salts such as succinic acid, sodium hydrogen sulphate, potassium dihydrogen phosphate or crotonic acid. The acid may also be a pure liquid compound such as acetic acid or valeric acid.

Exemplary solvents or dispersing agents are water and ionic liquids. Ionic liquids having high viscosity can be used, for example, in admixture with ionic liquids having lower viscosity.

In exemplary embodiments, the acidic compounds are provided in solid form, for example in the form of a powder, of pellets or beads. Acidic compounds that may be provided in a solid form are solid acids such as succinic acid, citric acid or benzoic acid, and acidic salts such sodium hydrogen sulfate or monopotassium phosphate.

The basic compounds (“bases”) according to exemplary embodiments are provided in solid form, for example in the form of a powder, of pellets or of beads. It is also possible that the basic compound is not added from outside to the running oxygen generating reaction but from one or more tuner compact(s) that are added to the oxygen generating composition before or at the beginning of the reaction. Tuner compacts are pellets comprising the basic compound in solid form and having two or more layers that are able to release the basic compounds at a predetermined time after start of the oxygen generating reaction such that the basic compound is added to the composition for generating oxygen by release from the tuner compact(s). Optionally, it is also possible that the tuner compact comprises at least one layer releasing the acidic compound at another time than the basic compound, wherein the acidic compound is also present in solid form. In this way it is possible to release the basic compound and, optionally, the acidic compound without access to the composition for generating oxygen from outside. This allows to adjust oxygen production rate such that no extrema arise. According to further exemplary embodiments the basic compounds are provided in the form of the pure liquid compounds, or in the form of concentrated or diluted solutions or dispersions in a solvent or dispersing agent.

Exemplary solvents or dispersing agents are water and ionic liquids. Ionic liquids having high viscosity may be used, for example, in admixture with ionic liquids having lower viscosity.

Exemplary bases are hydroxides such as potassium hydroxide, sodium hydroxide and calcium hydroxide, basic salts such as potassium phosphate, sodium acetate, sodium percarbonate, potassium carbonate, basic oxides such as calcium oxide, and ionic liquids with basic properties, such as 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), tetrabutylammonium arginine ([TBA][Arg]), and tetrabutylammonium but-3-enoate ([NEt4][but-3-enoate]).

In the context herein, the term “composition” includes embodiments wherein all constituents of the composition are mixed, i.e., they are in contact with each other, as well as embodiments wherein the constituents are not in contact with each other, i.e., they are physically separated, or wherein some but not all constituents are in contact with each other. It must be considered that a mixture comprising an ionic liquid, a peroxide compound dissolved or dispersed therein, and a metal salt as catalyst, is not stable, unless the ionic liquid is an acidic compound or contains an acidic compound or the ionic liquid is not a basic compound and does not contain any basic compound. When ionic liquids having basic functionality are used, the decomposition of the peroxide compound starts as soon as the catalyst comes into contact with the peroxide compound, in the ionic liquid, or at least shortly thereafter. Therefore, the constituents of the composition for generating oxygen must be stored in a condition wherein the catalyst cannot trigger the release of oxygen from the peroxide compound. This can be achieved by providing the composition for generating oxygen in the form of a “kit of parts”, i.e. as a combination of at least two components, the two components comprising the at least one oxygen source, the at least one ionic liquid, and the at least one catalyst compound. In the at least two components, at least one of the three constituents (the oxygen source(s), the ionic liquid(s), and the catalyst is not in contact with the other constituents of the composition for generating oxygen.

For example, the composition may comprise a first component and a second component, the first component comprising the oxygen source and the catalyst, and the second component comprising the ionic liquid or the first component comprising the oxygen source and the ionic liquid, and the second component comprising the catalyst or the first component comprising the ionic liquid and the catalyst, and the second component comprising the oxygen source.

The situation may be different when the ionic liquid has acidic properties or when the ionic liquid contains a compound having acidic properties.

The inventors have found that the peroxide decomposition reaction does not proceed or is at least decelerated in an acidic or neutral environment. Therefore, in compositions for generating oxygen which contain an acidic or neutral ionic liquid, the peroxide, the catalyst and the ionic liquid do not need to be stored physically separated, but can be in contact with each other, e.g. mixed. The inventors have further found, that in compositions for generating oxygen comprising an acidic or neutral ionic liquid, the peroxide decomposition reaction can be started by adding a basic compound to the ionic liquid, the catalyst and the peroxide.

Accordingly, an exemplary composition for generating oxygen comprises an oxygen source, a metal salt as a catalyst, an acidic ionic liquid (an ionic liquid which is acidic itself, or which is acidic because it contains an acidic compound) or a neutral ionic liquid and a basic compound. The oxygen source comprises a peroxide compound, the ionic liquid is in the liquid state at least in a temperature range from −10° C. to +50° C., and the metal salt comprises one single metal or two or more different metals, and an organic and/or an inorganic anion.

An exemplary oxygen generator comprises the above composition for generating oxygen and a further acidic compound for decelerating or stopping the oxygen production.

A further exemplary composition for generating oxygen comprises an oxygen source, a metal salt as a catalyst, and an ionic liquid (a neutral ionic liquid or a basic ionic liquid, i.e. an ionic liquid which is basic itself or which is basic because it contains a basic compound). The oxygen source comprises a peroxide compound, the ionic liquid is in the liquid state at least in a temperature range from −10° C. to +50° C., and the metal salt comprises one single metal or two or more different metals, and an organic and/or an inorganic anion.

A further exemplary oxygen generator comprises the above composition for generating oxygen and a basic compound for starting or accelerating oxygen production.

The compositions for generating oxygen may comprise from about 10 to 80 weight % of one or more oxygen sources, from about 20 to 80 weight % of one or more ionic liquids, and from more than 0 up to about 15 weight % of one or more metal salt catalysts. In exemplary embodiments, the oxygen source or mixture of oxygen sources constitutes from 40 to 70 weight %, the ionic liquid or mixture of ionic liquids constitutes from 30 to 60 weight %, and the catalyst or mixture of catalysts constitutes from more than 0 up to about 10 weight % of the composition. In some embodiments, the oxygen source may constitute up to 98 weight % of the composition, with the amounts of ionic liquid and catalyst being present in amounts as low as about 1% by weight, each. Optionally, further constituents may be present, for example silicon dioxide (as a heat sink) and/or radical scavengers, such as resorcinol, 2-methylhydrochinone, eugenol, phenol, and 4-propylphenol, all of which reduce the peroxide decomposition rate. In some embodiments, the amounts of such additional constituents do not exceed about 20 weight % of the composition. All constituents together add up to 100 weight %.

In the case of acidic ionic liquids, exemplary compositions also comprise a basic compound. The basic compound may be added in an amount which is at least sufficient to neutralize the ionic liquid. The amounts of the remaining constituents of the compositions are lessened proportionally.

An exemplary method for generating oxygen comprises providing an oxygen source, providing a basic ionic liquid, providing a metal salt, and generating oxygen by contacting the oxygen source, the ionic liquid and the metal salt. 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 salt comprises one single metal or two or more different metals, and an organic and/or inorganic anion.

According to an exemplary embodiment, the catalyst 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 component and the second component.

According to a further exemplary embodiment, the oxygen source and the catalyst are provided as a first component, the ionic liquid is provided as a second component, and the step of contacting comprises mixing the first component and the second component.

When the oxygen source and the catalyst are provided as one single component, i.e. in an admixed state, both the oxygen source and the catalyst should be thoroughly dried before mixing. Otherwise, the oxygen source may be decomposed inadvertently. In the absence of any mediator, for example water or an ionic liquid, the solid oxygen source and the solid catalyst constitute long-term stable mixtures.

According to a further exemplary embodiment, the oxygen source and the ionic liquid are provided as a first component, the catalyst is provided as a second component, and the step of contacting comprises mixing the first component and the second component.

A further exemplary method for generating oxygen comprises providing an oxygen source, providing an acidic ionic liquid, providing a metal salt, providing a basic compound, and generating oxygen by contacting the oxygen source, the ionic liquid, the metal salt and the basic compound. 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 salt comprises one single metal or two or more different metals, and an organic and/or inorganic anion.

According to an exemplary embodiment, the oxygen source, the catalyst and the ionic liquid are provided as a first component, the basic compound is provided as a second component, and the step of contacting the oxygen source, the ionic liquid, the catalyst and the basic compound comprises mixing the first component and the second component.

According to a further exemplary embodiment, the oxygen source is provided as a first component, the ionic liquid and the catalyst are provided as a second component, and the basic compound is provided as a third component, and the step of contacting comprises mixing the first component, the second component and the third component.

In the above methods for generating oxygen, the oxygen is produced with a particular production rate and for a particular time. The production rate and time can be influenced to some extent by appropriately selecting the type and amounts of the constituents, however, each oxygen generator having a particular combination of constituents produces oxygen at a rate inherent to that particular combination. There is no possibility to influence a running decomposition reaction.

The present invention provides the possibility to stop the peroxide decomposition reaction before the whole amount of oxygen is released. Alternatively, the oxygen production rate may be not stopped, but only decreased. Those effects can be achieved by adding an appropriate amount of an acidic compound. Depending on the type and the amount of acid, the oxygen production is stopped or is only decreased to a greater or lesser extent. The interruption or deceleration of the oxygen production may be observed instantaneously upon addition of the acid to the oxygen generating composition.

The present invention provides also the possibility to start a decomposition reaction or to restart an interrupted decomposition reaction or to increase the oxygen production rate of a running decomposition reaction. These effects can be achieved by adding an appropriate amount of a basic compound to the composition for generating oxygen. Start or restart of the oxygen production or acceleration of the oxygen production may be observed instantaneously upon addition of the basic compound to the composition for generating oxygen. After restart of an interrupted decomposition process, the pristine oxygen production rate may be achieved within a few seconds. Depending on the type and amount of the basic compound the oxygen production can be accelerated to a greater or lesser extent.

An exemplary method for starting or accelerating the oxygen production of an oxygen generator comprises providing an oxygen source, providing an ionic liquid (acidic or neutral), providing a metal salt, contacting the oxygen source, the ionic liquid and the metal oxide compound, and starting or accelerating the oxygen production by adding a basic compound to the oxygen source, the ionic liquid and/or the metal salt.

A further exemplary method for accelerating or starting the oxygen production of an oxygen generator comprises providing an oxygen source, providing an acidic ionic liquid, providing a metal salt, providing a basic compound, generating oxygen by contacting the oxygen source, the ionic liquid, the metal salt and the basic compound, and starting or accelerating the oxygen production by adding a further basic compound to the oxygen source, the ionic liquid, the metal salt and the basic compound.

Oxygen production interruption and restart of the oxygen production can be performed multiple times over the course of the decomposition reaction. Thus, it is possible to adapt the oxygen production rate to the particular needs. In situations where a user needs more oxygen, he may increase the oxygen flow rate, and in situations where he needs less oxygen he may save oxygen by decreasing or even interrupting the oxygen production. The inventive method for controlling the oxygen production rate of an oxygen generator supplies oxygen in a manner similar to a liquid oxygen supply system or a pressurized oxygen tank.

It goes without saying that in the above methods the acidic compound and the basic compound are not added simultaneously, but rather at the respective time when stop or decrease of oxygen production, or start, restart or increase of oxygen production, respectively, are desired.

The oxygen source, the ionic liquid, the metal salt, the acidic compound and the basic compound are as described above.

In an exemplary method, the oxygen production is decelerated or interrupted after a desired time interval by adding an acidic compound to the oxygen source, the ionic liquid and the catalyst. After a further desired time interval, the oxygen production may be accelerated or restarted by adding a basic compound or a further basic compound to the oxygen source, the ionic liquid, and the catalyst.

According to further exemplary methods, acceleration and/or deceleration of the oxygen production is performed stepwise by adding several portions of a basic compound or a further basic compound or an acidic compound or a further acidic compound, respectively, with time intervals between the individual addition steps.

In another exemplary method, the process of decelerating or interrupting the oxygen production and the process of accelerating or restarting the oxygen production are performed several times.

Many compositions for generating oxygen do not produce constant oxygen flow rates, but rather show increasing or decreasing oxygen flow rates. In other oxygen generating compositions, oxygen flow rates fluctuate during the peroxide decomposition reaction. Fluctuating or increasing or decreasing oxygen flow rates, however, are undesirable. The present invention offers a possibility to influence the decomposition reaction, i.e. to accelerate the reaction when the oxygen flow rate decreases, and to decelerate the reaction when the oxygen flow rate increases, thus rendering the oxygen flow rate constant over the course of time.

In the context of this invention, a liquid is regarded neutral if its pH is in a range from 6.5 to 7.3 (because they contain an ionic liquid having a pH in this range intrinsically, or because they contain an ionic liquid having a pH in a different range, but the pH has been adjusted by adding an acidic or a basic compound, respectively).

In the context of this invention, a liquid is regarded acidic if its pH is in a range below 6.5. In ionic liquids having a pH below 6.5 (because they contain an ionic liquid having a pH below 6.5 intrinsically, or because they contain an ionic liquid having a different pH, but the pH has been adjusted by adding an acidic compound), the peroxide decomposition reaction proceeds slower than at a pH of 6.5 or above. The lower the pH value, the slower the decomposition reaction, and an increasingly higher amount of peroxide compound remains as an undecomposed residue. For the ability to stop oxygen production, the pKa-value of the acidic compound and/or the further acidic compound has been found to be important. In an embodiment of the invention the pKa-value of the acidic compound and/or the further acidic compound is below 5, in particular below 4.5, in particular below 4, in particular below 3.5, in particular below 3, in particular below 2.5, in particular below 2, in particular below 1.5, in particular below 1, in particular below 0.5, in particular below 0. The pKa-values are always given for 25° C. as standard condition. The pKa-value is an intrinsic feature of the acidic compound and/or the further acidic compound. Usually, pKa-values of known acidic compounds or known further acidic compounds are known in the art. The pKa-values can be determined by methods well-known in the art, e.g. by means of titration.

The acidic compound and/or the further acidic compound and the amount of acidic compound and/or the further acidic compound where the peroxide decomposition does not proceed at all, depends on the types of ionic liquid, peroxide and catalyst, and can be easily found for each particular system by a few routine experiments.

In the context of this invention, a liquid is considered basic if its pH is in a range above 7.3. In ionic liquids having a pH above 7.3 (because they contain an ionic liquid having a pH above 7.3 intrinsically, or because they contain an ionic liquid having a different pH, but the pH has been adjusted by adding a basic compound), the peroxide decomposition reaction proceeds faster than at a pH of 7.3 or below. The higher the pH value, the faster the peroxide is decomposed, i.e. the shorter the time period needed for complete decomposition of the peroxide. Again, reaction speeds somewhat vary depending on the types of ionic liquid, peroxide and decomposition catalyst, but a desired reaction speed for a particular system can be easily found by a few routine experiments. For the ability to start oxygen production, the pKb-value of the basic compound has been found to be important. In an embodiment of the invention the pKb-value of the basic compound and/or the further basic compound is below 10, in particular below 9.5, in particular below 9, in particular below 8.5, in particular below 8, in particular below 7.5, in particular below 7, in particular below 6.5, in particular below 6, in particular below 5.5, in particular below 5. The pKb-values are always given for 25° C. as standard condition. The pKb-value is an intrinsic feature of the basic compound and/or the further basic compound. Usually, pKb-values of known basic compounds or known further basic compounds are known in the art. The pKb-values can be determined by methods well-known in the art, e.g. by means of titration.

In an embodiment of the method of the invention the amount of the basic compound and/or the further basic compound comprised by the oxygen generator is sufficient for allowing complete oxidation of the metal ion of the metal salt by at least one oxidation state, in particular by two oxidation states. Such an oxidation may be caused by the peroxide as oxidizing agent.

In an embodiment, the oxygen generator according to the invention comprises an amount of the basic compound sufficient for allowing complete oxidation of the metal ion of the metal salt by at least one oxidation state, in particular by two oxidation states. This amount can be easily calculated or experimentally determined. For example, if the basic compound is NaOH and the metal salt is MnCl2 the metal is completely oxidized when the solution or suspension obtained brown color of MnO2 which color does not further increase in intensity.

Herein, the pH value of an ionic liquid is determined in an 100 mM aqueous solution (distilled water) of the ionic liquid at 20° C. The pH value can be adjusted as desired by adding acids or bases, respectively, e.g. 1 M HCl or 1 M NaOH.

An exemplary device for generating oxygen in a controlled manner is specifically adapted for housing the components of the composition for generating oxygen in a physically separated state, and for bringing them into physical contact once generation of oxygen is desired, and for housing at least one acidic compound and, optionally, at least one basic compound in such a manner that the acidic compound and the basic compound can be added to the composition when desired.

In an exemplary embodiment, a device for generating oxygen comprises a reaction chamber housing a composition for generating oxygen, the composition comprising a combination of constituents consisting of an oxygen source, an acidic ionic liquid and a metal salt, means for allowing oxygen to exit the reaction chamber, and a dosing device housing a basic compound, the dosing device being adapted to introduce the basic compound into the reaction chamber.

In another exemplary embodiment, a device for generating oxygen in a controlled manner comprises a reaction chamber housing a composition for generating oxygen, the composition comprising a combination of constituents consisting of an oxygen source, an acidic ionic liquid, and a metal salt, means for allowing oxygen to exit the reaction chamber, at least one dosing device housing a basic compound and at least one dosing device housing in acidic compound, the dosing devices being adapted to introduce the basic compound and the acidic compound into the reaction chamber.

In a further exemplary embodiment, a device for generating oxygen in a controlled manner comprises a reaction chamber housing a composition for generating oxygen, the composition comprising a combination of constituents consisting of an oxygen source, a neutral or basic ionic liquid, and a metal salt, at least one dosing device housing an acidic compound and at least one dosing device housing a basic compound, the dosing device(s) being adapted to introduce the basic compound and optionally the acidic compound into the reaction chamber, means for maintaining at least one of the oxygen source, the ionic liquid and the metal salt physically separated from the remaining constituents, means for establishing physical contact of the oxygen source, the ionic liquid and the metal salt, and means for allowing oxygen to exit the reaction chamber.

The oxygen source, the ionic liquid, the metal salt, the acidic compound and the basic compound are as described above.

Devices for housing the components of the composition for generating oxygen in a physically separated state and for bringing them into physical contact once generation of oxygen is desired, are described in EP 3 323 782 A1, in particular in paragraphs [0053] to [0057] and [0106] to [0127], and are illustrated in FIGS. 18 to 22 of EP 3 323 782 A1. The entire document and the specific disclosure is incorporated herein by reference.

A device for generating oxygen according to the present invention may be designed, for example, as illustrated in FIGS. 19 and 20 of EP 3 323 782 A1, however, in the device of present invention, reaction chamber 2 or compartment 4, respectively, would be filled with an oxygen source, and acidic ionic liquid, and a metal salt, and injection device 21, or compartment 3, respectively, would be filled with a basic compound.

In order to be suitable as a device for generating oxygen in a controlled manner according to the present invention, the devices disclosed in EP 3 323 782 A1 must be modified by including dosing devices for housing basic compounds and optionally (further) acidic compounds, the dosing devices being adapted to introduce the basic compounds and optionally the acidic compounds into the reaction chamber. Exemplary devices are described with reference to FIGS. 11 and 12 below.

In exemplary embodiments the ionic liquids described above are used as dispersants or solvents and as heat sinks in the oxygen generator described above.

The disclosed generators, methods and devices may take advantage of any of the materials describe above in relation to compositions and vice versa.

All references herein to “comprising” should be understood to encompass “including” and “containing” as well as “consisting of” and “consisting essentially of”.

The term “a” means “at least one.”

The term “oxygen,” as a product, primarily pertains to oxygen gas in a concentration and amount that is useful and sufficient for human breathing. Oxygen is also produced by the novel process and device for technical and other industrial purposes.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIGS. 1-6 are graphs illustrating start of decomposition of UHP (urea hydrogen peroxide) by addition of basic compounds which decomposition is catalyzed by dissolved metal salts as catalysts,

FIG. 7 is a graph summarizing data deducted from the results given in FIGS. 1 to 6 showing the amount of basic composition required for starting reaction in dependence from strength of the basic compound,

FIG. 8 is a graph summarizing data deducted from further experiments for determination of the amount of basic composition required for starting reaction in dependence from strength of the basic compound,

FIGS. 9 and 10 are graphs illustrating acceleration of decomposition of UHP, which decomposition is catalyzed by dissolved metal salts and started by addition of a basic compound and which acceleration is caused by further basic compound,

FIG. 11 is a sectional view of an embodiment of a device for generating oxygen according to this invention, and

FIG. 12 is a sectional view of another embodiment of a device for generating oxygen according to this invention.

 DETAILED DESCRIPTION OF THE INVENTION

In all graphs illustrating oxygen release, oxygen flow rate and volume are plotted against runtime, wherein runtime is the time which starts running at the time point of contacting the oxygen source, the ionic liquid, the metal salt with a basic compound. “Volume” is the oxygen volume released in total. Oxygen flow rate (I/h) and volume released (I) by each decomposition reaction where measured with a drum gas meter in each of the experiments of examples 1 to 3, throughout the experiments.

Example 1

In example 1 different basic compounds were added to oxygen generating compositions comprising ionic liquid, a Mn2+-salt and UHP for evaluating conditions required for starting oxygen generation. In general, 100 g urea hydrogen peroxide (UHP) were mixed with 1 mol % MnCl2 with respect to the amount of UHP which MnCl2 was dissolved in 30 g of an ionic liquid which was [EMIM][EtSO4] or [MMIM][PO4Me2]. The resulting mixture generated no oxygen. After 10 minutes given for equilibration a solution of a basic compound in 10 g [EMIM][EtSO4] or [MMIM][PO4Me2] was added to the mixture. The kind of basic compound and the amount of basic compound were varied in these experiments. Volume of the oxygen produced in the reactions was measured by means of the gas meter.

Since the oxygen generating mixture needed some time for starting in some cases released volume of oxygen was only assessed 50 minutes after addition of the basic compound. The reaction was considered as started when more than 0.5 g UHP were degraded after 50 minutes. The amount required for starting the reaction was determined from the experimental data by linear approximation.

In experiments 1 to 17 the types and amounts of compounds given in below tables have been used.

TABLE 1 Catalyst Peroxide IL Base n(Base)/ n(Base)/ Experiment (Mass) (Mass) (Mass) (Mass) n(IL) n(MnCl2) 1 MnCl2 UHP [MMIM][PO4Me2] TRIS (325.0 mg) in 10 g 0.0149 0.252 (1.34 g) (100 g) (30 g) [MMIM][PO4Me2] 2 MnCl2 UHP [EMIM][EtSO4] TRIS (81.3 mg) in 10 g 0.00390 0.0630 (1.34 g) (100 g) (30 g) [MMIM][PO4Me2] 3 MnCl2 UHP [MMIM][PO4Me2] TRIS (40.6 mg) in 10 g 0.00190 0.0315 (1.34 g) (100 g) (30 g) [MMIM][PO4Me2]

Results are given in FIG. 1.

TABLE 2 Catalyst Peroxide IL Base n(Base)/ n(Base)/n Experiment (Mass) (Mass) (Mass) (Mass) n(IL) (MnCl2) 4 MnCl2 UHP [EMIM][EtSO4] Imidazole (340 mg) in 10 g 0.0295 0.469 (1.34 g) (100 g) (30 g) [EMIM][EtSO4] 5 MnCl2 UHP [EMIM][EtSO4] Imidazole (170 mg) in 10 g 0.0148 0.234 (1.34 g) (100 g) (30 g) [EMIM][EtSO4] 6 MnCl2 UHP [EMIM][EtSO4] Imidazole (85 mg) in 10 g 0.00738 0.117 (1.34 g) (100 g) (30 g) [EMIM][EtSO4]

Results are given in FIG. 2.

TABLE 3 Catalyst Peroxide IL Base n(Base)/ n(Base)/n Experiment (Mass) (Mass) (Mass) (Mass) n(IL) (MnCl2) 7 MnCl2 UHP [EMIM][EtSO4] 2-Methylpyridine (3 g) 0.190 3.02 (1.34 g) (100 g) (30 g) in 10 g [EMIM][EtSO4] 8 MnCl2 UHP [EMIM][EtSO4] 2-Methylpyridine (0.6 g) 0.0381 0.605 (1.34 g) (100 g) (30 g) in 10 g [EMIM][EtSO4] 9 MnCl2 UHP [EMIM][EtSO4] 2-Methylpyridine (0.3 g) 0.0190 0.302 (1.34 g) (100 g) (30 g) in 10 g [EMIM][EtSO4] 10 MnCl2 UHP [EMIM][EtSO4] 2-Methylpyridine (0.1 g) 0.00634 0.101 (1.34 g) (100 g) (30 g) in 10 g [EMIM][EtSO4]

Results are given in FIG. 3.

TABLE 4 Catalyst Peroxide IL Base n(Base)/ n(Base)/n Experiment (Mass) (Mass) (Mass) (Mass) n(IL) (MnCl2) 11 MnCl2 UHP [EMIM][EtSO4] p-Toluidine (4 g) in 10 g 0.221 3.51 (1.34 g) (100 g) (30 g) [EMIM][EtSO4] 12 MnCl2 UHP [EMIM][EtSO4] p-Toluidine (2 g) in 10 g 0.110 1.75 (1.34 g) (100 g) (30 g) [EMIM][EtSO4] 13 MnCl2 UHP [EMIM][EtSO4] p-Toluidine (1 g) in 10 g 0.0551 0.876 (1.34 g) (100 g) (30 g) [EMIM][EtSO4]

Results are given in FIG. 4.

TABLE 5 Catalyst Peroxide IL Base n(Base)/ n(Base)/n Experiment (Mass) (Mass) (Mass) (Mass) n(IL) (MnCl2) 14 MnCl2 UHP [EMIM][EtSO4] Aniline (5 g) in 10 g 0.317 5.04 (1.34 g) (100 g) (30 g) [EMIM][EtSO4] 15 MnCl2 UHP [EMIM][EtSO4] Aniline (2 g) in 10 g 0.127 2.02 (1.34 g) (100 g) (30 g) [EMIM][EtSO4]

Results are given in FIG. 5.

TABLE 6 Catalyst Peroxide IL Base n(Base)/n n(Base)/n Experiment (Mass) (Mass) (Mass) (Mass) (IL) (MnCl2) 16 MnCl2 UHP [EMIM][EtSO4] 2,6-Dimethylaniline (8 g) 0.390 6.20 (1.34 g) (100 g) (30 g) in 10 g [EMIM][EtSO4] 17 MnCl2 UHP [EMIM][EtSO4] 2,6-Dimethylaniline (5 g) 0.244 3.87 (1.34 g) (100 g) (30 g) in 10 g [EMIM][EtSO4]

Results are given in FIG. 6.

From the results of experiments 1 to 17 a relation between the strength of the added basic compound and the amount required for starting oxygen production by peroxide decomposition according to the above definition can be seen. The stronger the basic compound, e.g. the lower the pKb-value, the smaller is the amount of the basic composition required for starting the reaction. Basic compounds having a pKb-value above 10 are only able to accelerate oxygen production but not to start oxygen production. The results are summarized in FIG. 7 and below Table 7.

TABLE 7 pKb- n(Base) n(Base)/ n(Base)/ Base Value [mmol] n(IL) n(MnCl2) TRIS 5.94 0.250 1.38E−3 0.0233 Imidazole 6.95 2.07 12.6E−3 0.194 2-Methylpyridine 8.06 1.51 9.25E−3 0.147 p-Toluidine 8.92 15.8 0.0932 1.48 Aniline 9.13 19.4 0.115 1.83 2,6-Dimethylaniline 10.05 66.0 0.390 6.20 Dimethylphosphate 12.71 180 1.00 16.9

FIG. 7 shows as a function of the strength of the basic compound how many equivalents of the basic compound in relation to MnCl2 are required for starting peroxide decomposition. Filled squares symbolize start of peroxide decomposition by addition of the given amount of basic compound. Crosses indicate that the amount of the added basic compound did not result in a start of the reaction. The dotted curve is a calculated curve fitted to the calculated values.

Example 2

In example 2 another approach for determining the influence of the strength of a basic compound on peroxide decomposition has been used. In general, 20 g UHP were given in a flask. In 10 g of ionic liquid [MMIM][PO4Me2] 1 mol % MnCl2 with respect to the amount UHP and a defined amount of a basic compound were dissolved. This solution was then given into the flask containing the UHP. Kind and amount of the basic compound dissolved in the ionic liquid were varied. 3 days after start of reaction a sodium hydroxide solution was added to the reaction mixture. If not-degraded peroxide was still present in the flask it was then degraded. The volume of produced oxygen was measured by means of the gas meter. The reaction was considered as started if no peroxide could be detected in the flask 3 days after start of the reaction. The amount of basic compound required for start of the reaction has been determined from experimental data by linear approximation.

FIG. 8 shows the amount of basic compound required for start of the reaction according to the above definition in dependence from the strength of the basic compound. Filled circles symbolize the amount of basic compound in relation to the amount of ionic liquid sufficient for start of the oxygen generation. The empty circle refers to a start of peroxide decomposition, wherein the amount of basic compound is given for the first pKb-value of the dibasic disodium malonate.

The results show the relation between the pKb-value of the basic compound and the amount of this basic compound required for start of the reaction. The results confirm the results obtained with experiment 1.

Example 3

For determining the effect of addition of a basic compound to a running oxygen production 2 g Sodium acetate and 1.57 g Mn(OAc)2*4H2O were dissolved in 30 g of ionic liquid [MMIM][PO4Me2] and given to 100 g UHP in a flask. This resulted in peroxide decomposition and release of oxygen within a short time. Oxygen production rate rose up to 25 I/h and then decreased continuously. 16:30 minutes after start of the reaction a solution containing 16.5 mmol of a basic compound in 10 g of ionic liquid [MMIM][PO4Me2] were added. Type and amount of the different compounds of the compositions are given in below table 8.

TABLE 8 Catalyst Peroxide 1st Base 2nd Base strength of Base Experiment (Mass) (Mass) (Mass) (Mass) (pKb) 18 Mn(OAc)2*4 UHP [MMIM][PO4Me2] TRIS (2.00 g) 5.94 H2O (100 g) (30 g) + in 10 g (1.57 g) Sodium acetate (2 g) [MMIM][PO4Me2] 19 Mn(OAc)2*4 UHP [MMIM][PO4Me2] Imidazole (1.12 g) 6.95 H2O (100 g) (30 g) + in 10 g (1.57 g) Sodium acetate (2 g) [MMIM][PO4Me2] 20 Mn(OAc)2*4 UHP [MMIM][PO4Me2] Pyridine (1.30 g) 8.94 H2O (100 g) (30 g) + in 10 g (1.57 g) Sodium acetate (2 g) [MMIM][PO4Me2] 21 Mn(OAc)2*4 UHP [MMIM][PO4Me2] Sodium acetate 9.25 H2O (100 g) (30 g) + (1.35 g) (1.57 g) Sodium acetate (2 g) in 10 g [MMIM][PO4Me2]

The volume of oxygen produced is shown in FIG. 9 and the flow rate is shown in FIG. 10. The data show that basic compounds having a bigger strength of base, i.e. a smaller pKb-value, result in a bigger acceleration of peroxide decomposition.

FIG. 11 illustrates an exemplary device 1 for generating oxygen in a controlled manner, the device 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 can be enclosed in a receptacle in order to avoid contact with the remaining constituents of the composition contained in the reaction chamber 2. The device is particularly suitable for use with neutral and basic ionic liquids. In the embodiment shown in FIG. 11, 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. Further alternatively, the catalyst may be dissolved (soluble metal salts) or partly dissolved (partly soluble metal salts) or dispersed (insoluble metals salts or metal oxide compounds) in the ionic liquid. This alternative is particularly advantageous. 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.

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, an insoluble or only partly soluble metal salt is used as a catalyst, and this 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. In such a case proper mixing with the peroxide may be inhibited. Quick and perfect mixing of all constituents can be achieved when the peroxide and the soluble or insoluble catalyst are intimately mixed in advance in a dry condition, optionally compacted into molds, 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. Quick and perfect mixing can also be achieved when the catalyst is soluble in the ionic liquid, and is essentially dissolved therein. Placing the ionic liquid (or the ionic liquid and the catalyst) in a separate receptacle, although this is not absolutely necessary in a case where peroxide and catalyst (or the peroxide alone) 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.

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. 11, 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.

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.

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. 11, or there may be more than one opening.

In exemplary embodiments, the oxygen generated in the device described herein may be passed through a filter or other purification means as known in the art. The device may be equipped with such means.

The oxygen generating reaction is an only slightly exothermic process, and proceeds at low temperature, i.e. below 150° C., or even below 120° C. or below 100° C. Therefore, reaction chamber 2 does not need to resist high temperatures, and may be made from lightweight, low melting materials such as plastics. 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.

The exemplary device illustrated in FIG. 11 is equipped with two injection devices 11, 11′, for examples syringes or other dosing devices. Openings 17, 17′ fluidly connect the interior spaces of reaction chamber 2 and of injection devices 11, 11′ respectively.

The injection device 11 comprises a receptacle 12, a slide bar 13 and a spike 14. The injection device 11′ comprises a receptacle 12′, a slide bar 13′ and a spike 14′. Spikes 14, 14′ are held in place by fixtures 15, 15′. Receptacles 12, 12′ are made from a material which can easily be ruptured, for example bags made from plastic foils. Receptacle 12 contains an acidic compound and receptacle 12′ contains a basic compound.

In the exemplary embodiment illustrated in FIG. 11, slide bars 13, 13′ can be actuated in an analogous manner as the braking device 18. Once actuated, slide bar 13 pushes receptacle 12 towards spike 14, receptacle 12 is ruptured and acid is injected through opening 17 into reaction chamber 2. Similarly, once actuated, slide bar 13′ pushes receptacle 12′ towards spike 14′, receptacle 12′ is ruptured and base is injected through opening 17′ into reaction chamber 2.

Actuation of braking device 18 starts the peroxide decomposition reaction in reaction chamber 2. Without interference, the decomposition reaction proceeds until all peroxide compound has been decomposed. The device illustrated in FIG. 11 allows a user to stop the peroxide decomposition reaction by actuating slide bar 13, and to save the peroxide not yet decomposed for later use. Whenever oxygen is needed again, the user may actuate slide bar 13′, thus starting the peroxide decomposition reaction again.

The device illustrated in FIG. 11 has only one injection device 11 containing an acidic compound, and one injection device 11′ containing a basic compound. Such a device allows to stop and to restart the peroxide composition reaction only once. Providing reaction chamber 2 with several injection devices containing an acid, and with several injection devices containing a base allows to stop and to restart the peroxide decomposition several times. For example, a device 1 for generating oxygen having three injection devices containing acidic compounds and having three injection devices containing basic compounds, allows a user to interrupt and to restart the oxygen production three times, or at least until all of the oxygen source has been decomposed.

If desired, a device as illustrated in FIG. 11 can be also used for reducing or increasing the oxygen flow rate by injecting an acidic compound or a basic compound, respectively into reaction chamber 2, for example when leveling out increasing or decreasing or fluctuating oxygen flow rates shall be achieved.

It is also possible to provide only injection devices filled with acid, or only injection devices filled with base. In such a case, oxygen generating device 1 will only allow to reduce the oxygen flow rate, or to increase the oxygen flow rate, respectively.

An alternative exemplary device for generating oxygen in a controlled manner is illustrated in FIG. 12. In FIG. 12 the same reference numerals as in FIG. 11 are used for designating components which correspond to components already illustrated in FIG. 11.

The device illustrated in FIG. 12 is suitable for use with acidic ionic liquids. In the illustrated embodiment, reaction chamber 2 contains a mixture of acidic ionic liquid 8, oxygen source 7 and decomposition catalyst 9, for example pellets comprising a peroxide/catalyst mixture dispersed within the ionic liquid. Of course, the acidic ionic liquid, the oxygen source and the catalyst may be provided in any different manner, for example in the form of a dispersion of oxygen source powder in a solution of the catalyst within the ionic liquid.

The exemplary device illustrated in FIG. 12 is equipped with two injection devices 11, 11′, which are identical to the injection devices 11, 11′ of the device illustrated in FIG. 11. Injection device 11 contains an acidic compound, and injection device 11′ contains a basic compound. Injection device 11 may be omitted. An oxygen generating device 1 having only injection device 11′ allows to start the peroxide decomposition reaction by destroying receptacle 12′ and injecting the basic compound through opening 17′ into reaction chamber 2. The peroxide decomposition reaction will then proceed until all peroxide compound has been decomposed, and the oxygen generated by the composition reaction will leave reaction chamber 2 through gas permeable membrane 16.

A device for generating oxygen in a controlled manner needs at least one further injection device, for example injection device 11 containing an acidic compound, as illustrated in FIG. 12. Injecting the acidic compound contained in injection device 11 into reaction chamber 2 allows to decelerate the peroxide decomposition reaction and to reduce a too high oxygen flow rate.

In alternative embodiments, the oxygen generating device illustrated in FIG. 12 may be provided with one or more additional injection devices containing basic compounds and/or with one or more additional injection devices containing acidic compounds. Such additional injection devices allow to increase or decrease the oxygen production rate, respectively, or to stop and restart the oxygen production several times.

The oxygen produced according to this invention is pure and at a low temperature and, therefore, ideal for applications in airplanes, in self-rescuers and in rebreathers. However, the use for technical purposes such as in portable welding devices in mining and submarine applications, and in spaceflight, e.g. in control nozzles is also contemplated.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. An oxygen generator, comprising:

a composition for generating oxygen including an oxygen source, an ionic liquid, and a metal salt, and
a basic compound for starting or accelerating oxygen production;
said oxygen source comprising a peroxide compound;
said ionic liquid being in the liquid state at least in a temperature range from −10° C. to +50° C.; and
said metal salt having one single metal or two or more different metals, and an organic and/or an inorganic anion.

2. The oxygen generator according to claim 1, wherein said oxygen source is selected from the group consisting of alkali metal percarbonates, alkali metal perborates, urea hydrogen peroxide, and mixtures thereof.

3. The oxygen generator according to claim 1, wherein said ionic liquid is at least one salt having a cation and an anion, the cation is selected from the group consisting of imidazolium, pyrrolidinium, ammonium, pyridinium, pyrazolium, piperidinium, phosphonium, and sulfonium cations, and/or the anion is selected from the group consisting of dimethylphosphate, methylsulfate, ethylsulfate, trifluoromethylsulfonate, bis(trifluoromethylsulfonyl)imide, chloride, bromide, iodide, tetrafluoroborate, hexafluorophosphate, acetate, and but-3-enoate.

4. The oxygen generator according to claim 1, wherein said metal salt comprises at least one cation selected from the group consisting of vanadium, chromium, manganese, iron, cobalt, copper, molybdenum, ruthenium, iridium, and lead.

5. The oxygen generator according to claim 1, further comprising an acidic compound for decelerating or stopping oxygen production.

6. The oxygen generator according to claim 5, wherein said acidic compound is selected from the group consisting of inorganic acids, organic acids, acidic salts and ionic liquids having acidic functionality.

7. The oxygen generator according to claim 6, wherein said acidic compound is selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, acetic acid, succinic acid, citric acid, benzoic acid, sodium hydrogen sulfate, monopotassium phosphate, 1-ethyl-3-methylimidazolium hydrogen sulfate, trimethylammonium propane-sulfonic acid hydrogen sulfate, 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate, and diethylmethylammonium methanesulfonate.

8. The oxygen generator according to claim 1, wherein said basic compound is selected from the group consisting of hydroxides, basic oxides, basic salts and ionic liquids having basic properties.

9. The oxygen generator according to claim 1, wherein said basic compound is selected from the group consisting of sodium hydroxide, potassium hydroxide, potassium phosphate, sodium acetate, sodium percarbonate, potassium carbonate, calcium hydroxide, calcium oxide, 1-ethyl-3-methylimidazolium acetate, tetrabutylammonium arginine, and tetraethylammonium but-3-enoate.

10. The oxygen generator according to claim 1, wherein a pKb-value of said basic compound is below 10, and/or wherein the oxygen generator further comprises an amount of said basic compound sufficient for allowing complete oxidation of said metal ion of said metal salt by at least one oxidation state.

11. The oxygen generator according to claim 10, wherein the pKb-value of said basic compound is below 9.5 and said basic compound is present in an amount sufficient for allowing the complete oxidation of said metal ion by two oxidation states.

12. The oxygen generator according to claim 5, wherein said acidic compound is provided in solid form or in a solution or dispersion or as a pure liquid substance, and/or wherein said basic compound is provided in solid form or in a solution or dispersion or as a pure liquid substance.

13. The oxygen generator according to claim 12, wherein said acidic compound is a tuner compact.

14. A composition for generating oxygen, comprising:

an oxygen source, an ionic liquid, a metal salt, and a basic compound; or
if the ionic liquid is a basic ionic liquid or the oxygen source is basic, an oxygen source, an ionic liquid and a metal salt;
wherein:
the oxygen source comprises a peroxide compound;
the ionic liquid is in a liquid state in a temperature range from −10° C. to +50° C.; and
the metal salt comprises one single metal or two or more different metals, and an organic and/or an inorganic anion.

15. A method of starting or accelerating an oxygen production of an oxygen generating composition, the method comprising:

providing an oxygen source comprising a peroxide compound;
providing an ionic liquid, which in a liquid state in a temperature range from −10° C. to +50° C.;
providing a metal salt, the metal salt having one single metal or two or more different metals, and an organic and/or an inorganic anion;
contacting the oxygen source, the ionic liquid and the metal salt; and
starting or accelerating the oxygen production by adding a basic compound to the oxygen source, the ionic liquid, and/or the metal salt.

16. The method according to claim 15, which comprises decelerating or stopping the oxygen production after a desired time interval by adding an acidic compound, once or multiple times.

17. The method according to claim 15, wherein a pKb-value of the basic compound and/or a further basic compound is below 10.

18. The method according to claim 15, which comprises setting an amount of the basic compound to be sufficient for allowing complete oxidation of the metal ion of the metal salt by at least one oxidation state.

19. The method according to claim 18, wherein a pKb-value of the basic compound and/or a further basic compound is below 9.5 and an amount of the basic compound is sufficient to completely oxidize the metal ion of the metal salt by at least two oxidation states.

20. A device for generating oxygen in a controlled manner, the device comprising:

a reaction chamber for housing a composition for generating oxygen, the composition being a combination of constituents including of an oxygen source, an ionic liquid, and a metal salt;
at least one dosing device housing a basic compound and being configured for introducing the basic compound into said reaction chamber, and,
optionally, at least one dosing device housing an acidic compound and being configured for introducing the acidic compound into said reaction chamber;
a separator device for maintaining at least one of the oxygen source, the ionic liquid, and the metal salt physically separated from remaining constituents of the composition for generating oxygen;
a device for establishing physical contact between the oxygen source, the ionic liquid, and the metal salt; and
a device for allowing oxygen to exit the reaction chamber;
or
a reaction chamber housing a composition for generating oxygen, the composition comprising a combination of constituents including of an oxygen source, an ionic liquid, and a metal salt;
a device for allowing oxygen to exit the reaction chamber;
at least one dosing device housing a basic compound and being configured for introducing the basic compound into said reaction chamber, and, optionally, at least one dosing device housing an acidic compound and being configured for introducing the acidic compound into said reaction chamber;
wherein:
the metal salt comprises a single metal or two or more different metals, and an organic and/or an inorganic anion;
the oxygen source comprises a peroxide compound, the ionic liquid is in the liquid state at least in the temperature range from −10° C. to +50° C.; and
a control device for controlling an oxygen production rate by selectively adding the basic compound or, optionally, the acidic compound to the composition for generating oxygen.
Patent History
Publication number: 20210147232
Type: Application
Filed: Jan 28, 2021
Publication Date: May 20, 2021
Inventors: CHRISTOPH KALLFASS (SCHWAEBISCH HALL), ANDREAS HINTERBERGER (MUENCHEN), FRITZ KUEHN (GARCHING)
Application Number: 17/160,454
Classifications
International Classification: C01B 13/02 (20060101); B01J 31/02 (20060101);