Hydrogen storage based on aqueous formate-bicarbonate (bicarbonate) equilibrium

Abstract

The subject of this invention is a method for the hydrogenation of hydrocarbonates in an aqueous reaction system, wherein the method ensures that the hydrocarbonate, hydrogen, and catalyst are contacted with each other in the presence of carbon dioxide in a gas space. At this stage of the method, formate is produced. The subject of this invention is also a method for the catalytic decomposition of formate in an aqueous reaction system according to the invention, and the hydrogenation of the produced hydrocarbonate in the same reaction system, wherein a reaction system according to the invention is used, reactants and products are formed in a reversible reaction cycle, and the reaction cycle is repeated a required number of times. In the mentioned formate decomposition method, the formate is contacted with a catalyst, resulting in hydrogen and CO-free gas. X Hydrocarbonate, a byproduct, is produced as a reaction product. Another subject of the invention is a hydrogen storage system based on the method according to the invention, preferably a hydrogen storage battery. Yet another subject of the invention is a hydrogen storage system according to the invention, preferably a hydrogen storage battery used for storing hydrogen required to operate a fuel cell (or other equipment requiring H2) and, where appropriate, for releasing hydrogen as needed.

Description

[0001] The subject of this invention is a method for the hydrogenation of hydrocarbonate in an aqueous reaction system, wherein the method comprises contacting hydrocarbonate, hydrogen, and a catalyst with each other in the presence of carbon dioxide in a gaseous space. Formate is produced during this stage of the method. The subject of this invention is also a method for the catalytic decomposition of formate in an aqueous reaction system according to the invention and the hydrogenation of the hydrocarbonate produced in the same reaction system, wherein a reaction system according to the invention is used to form reactants and reaction products in a reversible reaction cycle, and the reaction cycle is repeated a desired number of times.

[0002] In the mentioned formate decomposition method, the formate is contacted with a catalyst to produce hydrogen and CO-free gas as reaction products. X Hydrocarbonate as a byproduct. The subject of this invention is also based on a hydrogen storage system according to the method of the invention, preferably a hydrogen accumulator. The subject of this invention is also the hydrogen storage system according to the invention, preferably a hydrogen accumulator, for storing hydrogen required for the operation of fuel cells (or other devices requiring H2), and optionally releasing hydrogen as needed.

[0003] Existing technology Hull In their publication (Nature Chemistry, 2012, 4(5), 383-388) [1], we disclose a reversible hydrogen storage system using CO2 and an iridium catalyst, which operates under near-ambient conditions. In the system shown, CO2 is converted to formate / formic acid at an alkaline pH. Although the authors state that dissolved CO2 is essential for the production of formate and that very small amounts of product are formed when only bicarbonate is used, they even suggest that the catalyst tested in this reversible hydrogen storage system reduces CO2 rather than bicarbonate; at the same time, they do not provide numerical data to support these findings or the experiments conducted. Table 1 in the referenced publication does not indicate the experimental conditions for the cited results obtained from the literature, although the text of the referenced publication states that the conditions (pressure, temperature) used in the cited publication are different from those in the article. Hull et al. The conditions in the reference publications used by the authors of ) are stronger.

[0004] JoóIn their publication (Chemical Communications 1999, 971-972) [2], et al. disclosed the homogeneous hydrogenation of aqueous hydrocarbonates to formate under different catalysts and studied the effect of the presence of carbon dioxide. On the one hand, they found that for [RhCl( m [tppms)3] catalyst, CO2 in the gas phase is essential for high reaction rates (although much slower reactions still occur without CO2). On the other hand, CO2 has also been found to... reduce [RuCl2( m The reaction rates proceeded under the catalysts [tppms)2]2 and [RuCl2(pta)4]. As a result, even in the presence of catalysts with remarkably similar compositions and structures (such as the two catalysts described above), the effect of CO2 on the hydrogenation rate of bicarbonate cannot be predicted in advance, and therefore can only be determined experimentally to determine whether the rate increases or decreases. In other words, for a given catalyst, it is not obvious to those skilled in the art that the presence of CO2 in the gas space will increase or decrease the hydrogenation rate of bicarbonate.

[0005] In their publications Elek et al. (Applied Catalysis A: General 2003, 255, 59-67) [3] disclosed that in constant At a NaHCO3 concentration and (equally constant) H2 pressure of 6 bar, using 5 bar of CO2 from [RuCl2( m The rate of NaHCO3 hydrogenation catalyzed by the [tppms)2]2 complex is 10% lower than that in the absence of CO2.

[0006] Generally speaking, it is difficult to compare the numerous results collected in the literature because the experimental conditions used vary significantly. This not only means differences in pressure, temperature, and reaction time, but also differences in the concentrations and concentration ratios of the substances used in the reaction. Therefore, theoretically, during the experiments described in multiple publications, the concentrations of HCO3... - Starting from the fact that both CO2 and CO2 can be hydrogenated, for example in Laurenczy In the publications of Inorg. Chem. 2000, 39, 5083-5088 [4], during certain experiments, Dissolved CO2 and HCO3 - The combined concentration (i.e., the total concentration of carbon-containing inorganic particles in the solution) remains constant. As a result, for example, to examine the effect of CO2, the amount of NaHCO3 being measured must be reduced when the CO2 pressure is increased, which leads to a decrease in pH compared to a constant HCO3 concentration. -At higher concentrations, carbon dioxide pressure increases much faster (and therefore formate concentrations increase even faster). There is also an example of the latter experimental setup (in fact, it is more common).

[0007] The authors of the aforementioned publications ([2]-[4]) clearly point out that even in the presence of CO2, the true substrate for the hydrogenation of bicarbonate is HCO3. - Anions. In this case, it is necessary to define what is considered a substrate in a chemical transformation. In our view, a substrate is a starting material on which a chemical transformation occurs and which appears in the product of the reaction in a changed form. Determining the substrate is not always straightforward if various exchange processes occur during the reaction. (Substrate and reactant are not 100% synonymous, as reactant can also be an auxiliary substrate, such as a proton-bonding base, etc.). During the hydrogenation of bicarbonate in the presence of CO2, if CO2 itself is directly hydrogenated to formate, then CO2 can (also) be a substrate. However, if its role is limited to pH adjustment (creating an acidic environment), then it is considered a simple auxiliary material. From the perspective of this invention, the measurements published in the literature to date are insufficient to determine this issue.

[0008] The following considerations are based on JN Butler "Carbon Dioxide Equilibria and TheirApplications" (Lewis Publishers, Chelsea, USA, 1991) [5] and X. Li The work of [6] (FluidPhase Equilibria 2018, 458, 253-263) uses the data available therein. The approximation mentioned refers to the fact that the activity coefficient is assumed to be 1 in the calculation and that the influence of, for example, ionic strength is not taken into account.

[0009] Henry's Law applies to the dissolution of carbon dioxide in water: [CO2] = K H × P (CO2), that is, an increase in carbon dioxide pressure linearly increases the concentration of dissolved (hydrated) CO2. If the concentration of dissolved carbon dioxide is given in moles per liter (M), and the pressure of gaseous carbon dioxide is given in atm (with a sufficient approximation in bar), then the Henry's constant for pure water at 25°C is K. H =10 –1,5 = 0.0316; and at 35°C, K H =10 –1,7= 0.0200. This value decreases with increasing temperature and also varies with ionic strength, but this does not significantly affect the following considerations. The concentration of dissolved CO2 increases with increasing CO2 pressure, and at 25°C, it is approximately 0.0316 M (1 bar), 0.316 M (10 bar), and 3.16 M (100 bar). Dissociation equilibrium: H2CO3 = HCO3 - + H + The acid dissociation constants are pK a1 = 6.35 (25°C) and 6.309 (35°C). For a given pH, the relationship between bicarbonate anion concentration and CO2 pressure can be given by the following equation: log [HCO3 – ] = pK a1 + pK H +log P (CO2) + pH Therefore, as can be read from the equation, the equilibrium bicarbonate concentration also increases due to the dissolution of a larger amount of CO2 at higher pressures. Butler The publications mentioned above[5] Measurement Data shows that in a NaHCO3 solution at 35°C with a solvent concentration of m = 1 mol / kg, the equilibrium pH (column 2) was formed under different P(CO2) pressures, as shown in the table below. The equilibrium HCO3 in column 3 can be calculated from this equilibrium pH. - concentration.

[0010] Refer to Table 1

[0011] Since the solution placed under CO2 pressure initially contains 1 M NaHCO3 (at this temperature and concentration, the concentration of NaHCO3 solution expressed in terms of molality and molarity is almost the same), therefore, under the influence of CO2 at 9.2 bar, [HCO3] - The concentration increase was only 13%, and even under the influence of 20 bar of CO2, [HCO3] - The concentration increase was only 83%. It can also be seen that the concentration of bicarbonate ions increases with increasing CO2 pressure. nonlinear A change in CO2 pressure, more than tenfold (from 9.2 bar to 92.8 bar), resulted in only a slightly more than twofold increase in bicarbonate concentration. This phenomenon is caused by the formation of H2CO3 and HCO3- from dissolved carbon dioxide. -A buffer solution is formed. Based on these considerations, it can be concluded that if catalytic hydrogenation is first-order relative to the substrate, then the initial rate of hydrogenation should change linearly with the pressure of CO2, provided that the dissolved CO2 itself is the substrate. On the other hand, if the substrate for hydrogenation is a bicarbonate anion, then the reaction rate increases only to a small extent with increasing CO2 pressure. Some experiments have indeed shown this, but there are also different experiences. This decrease in the hydrogenation rate has been mentioned, for example, when CO2 pressure increases ([2] and [3]).

[0012] Interestingly, although the equilibrium under CO2 pressure (i.e., the HCO3 that actually exists in the reaction mixture) - The concentration may be much higher than in the absence of CO2, but according to publicly available data in the literature, this is rarely reflected in the final formate concentration achieved experimentally, which typically does not exceed [a certain value]. Measurement HCO3 - Concentration. However, in some cases, in the presence of CO2, the formed formate (especially formic acid, HCO2H) is detected more than the absorbed bicarbonate (HCO3). - The amount of formate is much greater, rarely exceeding 30%-40% of the absorbed bicarbonate. The formation of HCO2H can only be explained as the hydrogenation of dissolved (hydrated) CO2 in addition to, or in place of, bicarbonate. The logical question is whether the higher formate concentration found in acidic media over a given time, compared to the yield achieved with pure H2, is due to the higher hydrogenation of CO2 added to the gas space, or to the HCO3 already present in the solution. - In other words, the reaction mechanism favors a particular substrate, i.e., what percentage of the product comes from bicarbonate or what percentage of dissolved CO2. (Of course, the hydrogenation mechanisms of bicarbonate and hydrated carbon dioxide, especially when both substrates are present, can differ significantly depending on the catalyst used.) Under given conditions, if the dissolved CO2 (or the generated H2CO3) reacts with HCO3... - When a rapid exchange process occurs, the situation becomes complex. In this case, it is impossible to determine whether the (hydrated) CO2 dissolved in the reaction mixture, in addition to the hydrocarbonate, also reacts independently, or whether the reactants are simply HCO3 formed during the rapid exchange. -Most literature reports fail to even consider this possibility: even if the initially introduced NaHCO3 does not react 100%, they assume the process is "CO2-hydrogenation," meaning that in the absence of hydrated CO2 reacting with hydrogen, all formate formed may originate from hydrocarbonates. However, if the initially introduced HCO3 is 100% converted to formate, then any amount exceeding this formate (formic acid) must be formed from the CO2 initially present in the gas phase. Of course, the presence of a basic auxiliary material (e.g., an amine) will also reduce the CO2 in the gas phase, as it reacts with the base to form bicarbonates (potentially carbonates), which are considered hydrogenatable. However, in this case, based on experimental experience, the amount of base present determines the maximum achievable formate concentration.

[0013] The inventors of this invention believe that, in order to obtain a definitive answer, it is necessary to perform the exchange process described in the preceding paragraph, or primarily use mass spectrometry—utilizing isotope labeling—to examine the isotope ratios formed in the formate obtained as a product. However, the following observations are worth considering.

[0014] a) In the publications mentioned several times above [2]-[4], the reaction was carried out in a high-pressure NMR (nuclear magnetic resonance) tube and subsequently with NaH 13 CO3 (an isotopically labeled sodium bicarbonate starting material) is used for... 1 H or 13 NMR spectrum of C. During the reaction. 1 H and 13 The C measurement clearly shows the increase of formate concentration over time, which is obtained by measuring formate HCO2. - The formate concentration was quantitatively determined by the ratio of the proton signal intensity to the corresponding internal standard (DSS) proton signal intensity. Based on these data, the conversion rate of the starting material and the final formate concentration were calculated. Using this method, it is impossible to distinguish whether the detected formate was formed from bicarbonate or from hydrated CO2.

[0015] In other cases (such as the aforementioned publication [1]), the concentration of formate formed is determined by HPLC (High Performance Liquid Chromatography) elution using an acidic medium. This latter method also does not differentiate between formate and formic acid, as formate is also protonated in the eluent used and can be detected as formic acid.

[0016] b) HCO3 -Anions can undergo hydrogenation in aqueous solutions even in the absence of CO2. On the other hand, it is understood that hydrogenation can occur in the absence of HCO3-. - In the case where an aqueous solution containing only the catalyst is placed in an H2 / CO2 gas mixture, even under high pressure and high temperature, only a negligible amount of formic acid is formed (see, for example, [1]), so it is obvious that HCO3 - The hydrogenation rate of is much faster than that of hydrated CO2 (i.e., bicarbonate is the substrate used for hydrogenation).

[0017] c) In our earlier formulation, CO2 introduced into the gas phase in the presence of a base is also hydrogenated because it forms bicarbonate (possibly carbonate) with the base, which is a known hydrogenation process. However, in this case, based on experimental experience, the amount of base present (KOH, NaOH, dimethylamine, etc.) determines the maximum achievable formate concentration.

[0018] d) Some catalysts decompose formic acid (HCO2H) into hydrogen and CO2 at extremely high rates. Of course, this process only occurs in formic acid... No This dissociation primarily occurs in acidic media, because otherwise it would be the dehydrogenation of formate anions. The final low concentration of formic acid formed in a purely aqueous solution (i.e., in the absence of NaHCO3) during the reaction CO2 + H2 = HCO2H may also be a result of the catalyst also decomposing the products, and a strong shift in equilibrium towards the starting materials.

[0019] based on Laurenczy The data published by [4] et al. indicate that the final formate concentrations contain significant concentration data (1.53 M and 1.70 M), but within the CO2 pressure range of 1–50 bar used, the HCO2 formed in any reaction - The concentrations of none exceeded the measured NaHCO3 or KHCO3 concentrations. Assuming that formate is formed solely by the hydrogenation of the input KHCO3, the maximum bicarbonate conversion rate is 85%. These observations clearly demonstrate that CO2 present in the H2 / CO2 mixture primarily plays a role in the hydrogenation of bicarbonates. kinetic effects To date, these studies have not disclosed details in this regard, but the decrease in pH of the bicarbonate solution due to the effect of dissolved CO2 may affect the formation of catalytically active metal complex particles (almost certainly hydrogenated complexes). However, as can be seen from reference Table 1 above, the pH decrease is limited. Furthermore, the direct self-hydrogenation of dissolved CO2 does not significantly contribute to the amount of formate formed. In this sense, it is not hydrogenated. Reactants (substrate)Furthermore, the Le Chatelier-Braun principle cannot be applied, according to which increasing the concentration of one or more reactants favors product formation. While the Le Chatelier-Braun principle is a well-established law of thermodynamics, it does not specify anything about a given reaction. dynamics .

[0020] patent US4067958 A method for producing hydrogen from a fuel gas containing carbon monoxide (CNO) and other components is disclosed. The fuel gas is passed through an aqueous solution containing sodium carbonate and potassium carbonate, and / or sodium bicarbonate and potassium bicarbonate, in the presence of corresponding formates. The formate solution is then catalytically decomposed to produce hydrogen and carbonates and / or bicarbonates. The cited patent document also shows an apparatus for carrying out this process. The catalyst used can be a transition metal, its oxide, or its sulfide on an alkali-resistant support.

[0021] Laurenczy Inorg. Chem. Comm. 2007, 10, 558-562, et al. (Inorg. Chem. Comm. 2007, 10, 558-562) disclosed a Ru(II) complex, namely, [RuCl2(PTA)([9]aneS3)] complex (wherein PTA is 1,3,5-triaza-7-phosphaadamantane and [9]aneS3 is 1,4,7-trithiocyclononane), which can catalyze the hydrogenation of carbon dioxide and bicarbonate in an aqueous medium. The publication states that, although the catalytic activity is moderate, the presence of intermediate products that occur during the reaction is undoubtedly confirmed by previous theoretical and practical results.

[0022] In patents US20120321550 In the file, Fukuzumi et al. have disclosed in great detail mononuclear transition metal complexes (including stereoisomers) that can be used in hydrogen storage methods (from... Y.Himeda (This follows previous work). In their case, hydrogen was produced from the alcohol, and the initial alcohol was subsequently recovered from the formed aldehyde by hydrogenation using a similar catalyst. Furthermore, HCOOH / HCOO was successfully used in these systems. - / CO2 / HCO3 - Balance. In their case, the pH of the given system is also a critical issue, and is also related to the pH sensitivity of the ligands. Although the formate / hydrocarbonate cycle works in the system described in the reference patent document, the catalyst family used has a different structure than that disclosed in this invention and does not contain N-heterocyclic (hereinafter sometimes: NHC(N-heterocyclic)) carbene or phosphine.

[0023] Mahajan In patents US6596423 The document summarizes his experiments on the catalytic decomposition of formates (sodium formate, potassium formate, lithium formate, and cesium formate) using transition metal complexes. The reactions were carried out according to the described procedure (at temperatures ranging from 80 to 150°C), and the reaction products also contained trace amounts of carbon monoxide (less than 50 ppm). The patent document mentions several possible complexing metals, including iridium. Possible catalysts could be transition metal carbonyl complexes or ligand coordination complexes containing an N-donor group (e.g., a 2,2'-bipyridine group). It also provides several options for the reaction medium, such as water or methanol.

[0024] In patent application number DE102006030449 This paper discloses a device suitable for reversible hydrogen storage. The device operates based on the combination and release of hydrogen. In the presence of hydrogen gas and a ZnO or ZnO / TiO2 catalyst, hydrogen is used to reduce potassium carbonate and / or potassium bicarbonate in an aqueous solution to potassium formate using an electric current. Hydrogen is then released from the aqueous solution of potassium formate, formic acid, or mixtures thereof using a platinum or palladium catalyst. Notably, the catalysts used for hydrogen storage and hydrogen release are different.

[0025] Patent application number US7939461 Metal complexes catalyzing the decomposition of formic acid accompanied by hydrogen formation are disclosed. This application also discloses the theoretical possibility of devices capable of storing and recovering hydrogen generated during formic acid decomposition. The disclosed metal complexes comprise two transition metal ions (dinuclear complexes), which may be the same or different. In the description of the invention, iridium is included among the possible metal atoms. Possible ligands in substituted or unsubstituted forms are cyclopentadiene, nitrogen-containing heterocyclic aromatic compounds such as bipyridine, phenanthroline, and pyrimidine. In the examples given, the generation of a water-soluble iridium-ruthenium complex and the decomposition of formic acid accompanied by the formation of hydrogen and carbon dioxide under different conditions (different temperatures and pH) are shown. The specification also illustrates complexes catalyzing the formation of formic acid from hydrogen and carbon dioxide (e.g., containing iridium). Catalysts disclosed in the reference patent documents have different structures from the complex catalysts disclosed in this invention, and therefore, for example, they do not contain phosphine ligands.

[0026] exist BellerIn his research group's publication (Tetrahedron Lett. 2009, 50, 1603-1606), he described how the addition of organic bases and inorganic salts to the catalyst system affects the production of hydrogen from formic acid using a Ru-containing catalyst. It has been demonstrated that the presence of amidine compounds increases hydrogen production, and that formic acid / amine mixtures can efficiently produce hydrogen under optimal conditions. In the case of [RuCl2(benzene)]2 as a precursor, the catalyst system has proven to be most efficient in the presence of 1,2-bis(diphenylphosphino)ethane (dppe) and N,N-dimethyl-n-hexylamine.

[0027] Patent document number WO2012143372 A method for producing hydrogen from formic acid by selective dehydration is disclosed using a catalyst system comprising a transition metal complex with at least one tetradentate ligand. While iridium is mentioned among possible transition metals, ruthenium, cobalt, and iron are included in the preferred embodiments disclosed in this invention. Phosphine ligands are mentioned, but carbene complexes of transition metals as precursors are not mentioned.

[0028] Joó [Angew. Chem. Int. Ed. 2011, 50, 10433-10435 (hereinafter: their own findings)] also investigated the possibility of using a formate / hydrocarbonate cycle. The catalyst described here is Ru(II)- m The tppms-complex forms a Ru-formate dihydrogenate during the reaction, which is specifically designed for decomposition. The chemical storage of H2 in the formate is achieved within a single system because, at the applied temperature, the formate decomposes (without CO2 emissions) in the presence of the Ru(II)-mtppms catalyst, and after decomposition, the initial formate solution can be filled with H2 at a relatively high pressure to form HCO3. - Recovery is performed using a catalyst solution. Several cycles can be completed consecutively. Although the formate / hydrocarbonate cycle works in the system described in the publication, the catalyst is a Ru(II) complex, and there is no mention of iridium or other transition metal complexes, nor is there any mention of the use of NHC carbene as a ligand.

[0029] Himeda(Green Chem. 2009, 11, 2018-2022) The decomposition of formic acid in an aqueous medium in the presence of an iridium catalyst was investigated. The generated hydrogen contained no carbon monoxide. 4,4'-dihydroxy-2,2'-bipyridine was present as the ligand. Based on the results, the Ir-bipyridine complex was demonstrated to be a highly active catalyst. At 90°C, the catalytic activity was TOF = 14000 h⁻¹. -1 The author also investigated the effect of formate on the decomposition of formic acid. He found that this catalyst had an effect on the HCOOH / HCOO... - The decomposition of the mixture is also reactive. Furthermore, at the theoretical-principle level, he predicted the formation of an aqueous solution (HCO3-) from CO2. - The solution can be hydrogenated again and formic acid is re-formed by lowering the pH. He also proposed the mechanism of the reaction, in which he identified the catalytically active intermediate as the Ir-hydride.

[0030] Using a similar Ir catalyst Himeda Other researchers have also addressed the rehydrogenation of CO2 formed from the decomposition of formic acid by altering the pH of a single system (Nature Chem. 2012, 4, 383-388). The catalyst they used (through the pH sensitivity of the ligand) catalyzes the decomposition of formic acid in an acidic pH range, while highlighting the reduction of CO2 in alkaline solutions. According to their proposal, H2 can be reversibly stored in formate solutions.

[0031] Although the formate / hydrocarbonate cycle also appears in the two publications mentioned above, the catalysts used do not contain NHC carbene or phosphine, and the pH is in the acidic range during decomposition, i.e., formic acid decomposes (also forming CO2), and the pH must be raised to start the reduction process. In contrast, in our system, the pH does not change significantly.

[0032] NolanIn US patent document 6774274, [Authors] disclosed a complex of formula [Ir(cod)(N)(L)]X, which is prepared by reacting [Ir(cod)(py)2]PF6 (where cod is 1,5-cyclooctadiene and py means pyridine) with an L ligand, or with an N ligand and an L ligand. The use of the catalyst in the hydrogenation of olefins is also disclosed. The preparation and key characteristics of the complex according to formula [Ir(cod)(py)(SIMes)]PF6 (where SIMes is 1,3-dimethyl-4,5-dihydro-imidazolium-2-ylene or related N-heterocyclic carbene) are demonstrated. The referenced patent document mentions nucleophilic N-heterocyclic carbenes as alternatives to phosphine ligands widely used in homogeneous catalysis, emphasizing the general experimental experience that using N-heterocyclic carbene ligands with more favorable steric and / or electronic properties to replace phosphine ligands can achieve significant improvements in catalytic performance in the case of olefins. The patent document does not disclose a catalyst containing a mixture of NHC carbene and phosphine ligands, and furthermore, it provides a solution to a fundamentally different technical problem.

[0033] In their paper (Angew. Chem. Int. Ed. 2008, 47, 3966-3968), Laurenczy Others demonstrated a highly efficient and selective system suitable for releasing hydrogen from an aqueous solution of formic acid in the presence of a water-soluble, in-situ produced catalyst. The system uses a [Ru(II)(H₂O)₆](tos)₂]- complex (where tos refers to toluyl-4-sulfonate and RuCl₃) as a precursor, and meta-trisulfonated triphenylphosphine... ，m (tppts) are used as ligands. Sodium formate is added to the solution to activate the catalyst.

[0034] In another publication (Chem Cat Chem 2013), Laurenczy Others investigated the HCOOH / HCOO reaction in the presence of a water-soluble catalyst containing Ru ions. - The catalytic decomposition of mixtures was performed, wherein the ligands forming the complexes were cationic triarylphosphine derivatives substituted with one or more trimethylammonium groups. Optimization experiments were also conducted on the most promising precursors during the optimization process. The effects of pH, temperature, catalyst concentration, and ligand / Ru ratio were investigated among other factors. The catalyst cycle number achieved under optimal conditions was TOF = 1950 h. -1 .

[0035] In the publications listed above, the catalyst systems are ruthenium-based, and although various phosphine ligands are included, NHC carbene is not mentioned as a possible ligand.

[0036] Laurenczy Patent document WO2008047312 by [Author Name] relates to a method for producing hydrogen and carbon dioxide from formic acid in an aqueous medium via a catalytic process without generating carbon monoxide. The catalytic process is carried out over a wide temperature range and at room temperature (T = 25°C). The patent document also mentions iridium as a transition metal, and its complexes may be suitable as catalysts in the studied method, but does not disclose relevant experimental results. In a preferred embodiment of the invention, iridium is not included. Among the possible ligands for the transition metal complex catalyst, it mentions phosphine and carbene, preferably aromatic phosphine, particularly... m tppts and m tppms ligands. However, the document does not provide a specific example of the latter. The patent document does not describe the carbon dioxide or HCO3 formed during decomposition. - The solution will be converted back into formic acid or formate solution.

[0037] Laurenczy The US patent document 8133464 by [Authors' Name] also relates to the decomposition of various formic acid / formate mixtures into hydrogen and carbon dioxide. The range of catalysts used is expanded compared to their previous patent (WO2008047312). The patent document discloses complexes having the composition M(L)n, wherein M is preferably Ru and Rh, but can also be Ir. Several variations of L as a ligand are claimed, wherein L can be sulfonated phosphine and / or carbene and / or hydrophilic groups and combinations thereof. However, the patent document does not provide a clear range of possible carbenes as ligands.

[0038] US Patent US10944119B2 Methods for storing and releasing hydrogen are disclosed. Although the document mentions the bicarbonate-formate cycle related to hydrogen storage and release, during hydrogen release, a transition metal catalyst (a ruthenium-containing complex) is dissolved in an organic solvent or solvent mixture, and the resulting bicarbonate is formed in the aqueous phase separated from the catalyst-containing organic solution. Much has been disclosed regarding the hydrogenation of bicarbonates, a step that can also be facilitated by the same catalyst system as formate decomposition.

[0039] Chinese patent document number CN105283436B A method for producing formic acid from hydrogen and carbon dioxide in the presence of a catalyst is disclosed. The method is carried out in an acidic medium containing a polar solvent (e.g., water or DMSO) and without the addition of a base, carbonate, bicarbonate, or formate.

[0040] US Patent Documents US20150105571A1 A method for converting carbon dioxide or bicarbonate into formic acid derivatives (e.g., formate, formate esters, and formamides) using a catalyst system containing molecular hydrogen and cobalt complexes is disclosed.

[0041] Based on existing technology, it can be determined that the effect of CO2 on the hydrogenation of bicarbonates using various catalysts may be accelerating or decelerating, and the extent of this effect cannot be determined based on prior knowledge. Based on the research results and experience summarized above, the inventors of this invention believe that the actual substrate for CO2 hydrogenation is... HCO 3 - anions Its concentration increases naturally with CO2 pressure, but not linearly as required by Henry's law (even over very small pressure ranges). Summary of the Invention

[0042] 1. A method for reacting hydrocarbonate (HCO3) in aqueous reaction systems - A method for hydrogenating and using the hydrogen carbonate to produce a formate, wherein the hydrogen carbonate is preferably selected from sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3), and potassium bicarbonate (KHCO3), and the formate is preferably a formate selected from the group consisting of sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), and potassium formate (HCOOK). The method includes: bringing the hydrocarbonate and the catalyst into contact with each other at a pressure of 1-1200 bar, preferably 10-100 bar, and at an elevated temperature, preferably 60-100°C, more preferably 80°C; The catalyst is [Ir(cod)(NHC)P] a ]+nP b general formula catalyst, Wherein, in the formula Ir stands for iridium; COD is 1,5-cyclooctadiene; NHC is an N-heterocyclic carbene, preferably 1-R-3-methylimidazol-2-ylidene, wherein R is a C1-C6 alkyl or benzyl group; n is an integer from 1 to 4; and P a and P b Independently, it is 1,3,5-triaza-7-phosphadamantane (pta) and monosulfonated triphenylphosphine.m tppms) or trisulfonated triphenylphosphine, m tppts); in The hydrogenation of hydrocarbonates is carried out in the presence of carbon dioxide in a gaseous space.

[0043] 2. According to the method described in point 1, in The catalyst used is selected from the following: a) According to the formula [Ir(emim)(cod)( m tppms)]+ m The catalyst of TPPTS, wherein emim is 1-ethyl-3-methylimidazolium-2-ylene, and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; b) According to the formula [Ir(bmim)(cod)( m tppms)]+ m The catalyst in TPPTS, where BMIM is 1-butyl-3-methylimidazolium-2-ylene and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; c) According to the formula [Ir(hexmim)(cod)( m tppms)]+ m The catalyst in TPPTS, where hexmim is 1-hexyl-3-methylimidazolium-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; d) According to the formula [Ir(2mim)(cod)( m tppms)]+ m The catalyst of TPPTS, wherein 2MIM is 1,3-dimethyl-imidazolium-2-ylene and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; e) According to the formula [Ir(Bnmim)(cod)( m tppms)]+ mThe catalyst for tppts, wherein Bnmim is 1-benzyl-3-methylimidazolium-2-ylene, and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; f) According to the formula [Ir(emim)(cod)( m The catalyst is tppms)]+pta, where emim is 1-ethyl-3-methylimidazol-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and pta is 1,3,5-triaza-7-phosphadamane; and g) According to the formula [Ir(emim)(cod)( m tppms)]+ m The catalyst for tppms, where emim is 1-ethyl-3-methylimidazolium-2-ylene and cod is 1,5-cyclooctadiene. m tppms represents monosulfonated triphenylphosphine.

[0044] 3. A method for: decomposing formate in an aqueous reaction system and for producing CO-free products. X The byproduct hydrogen gas (H2), preferably a formate selected from sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), and potassium formate (HCOOK); and, in the same reaction system, the hydrocarbonate (HCO3) obtained by hydrogenation in an aqueous reaction system. - The formate is thus produced, wherein the hydrocarbonate is preferably a hydrocarbonate selected from the group consisting of sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3), and potassium bicarbonate (KHCO3), and the formate is preferably a formate selected from the group consisting of sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), and potassium formate (HCOOK). The reaction system, which uses a formate decomposition step and a bicarbonate hydrogenation step, and selects the values ​​of temperature, pressure and pH within the range specified below, forms reactants and reaction products in a reversible reaction cycle, and the reaction cycle is repeated as required. The formate decomposition step includes contacting the formate with a catalyst in an aqueous reaction system under an Ar atmosphere, at an elevated temperature, preferably 60-100°C, preferably 80°C, preferably at a pH greater than 8, preferably at a pH of 8.3 ± 0.2. The hydrogenation step of the hydrocarbonate includes bringing the hydrocarbonate and the catalyst into contact with each other at a pressure of 1-1200 bar, preferably 10-100 bar, and at an elevated temperature, preferably 60-100°C, more preferably 80°C. The catalyst is [Ir(cod)(NHC)P] a ]+nP b general formula catalyst, Wherein, in the formula Ir stands for iridium; COD is 1,5-cyclooctadiene; NHC is an N-heterocyclic carbene, preferably 1-R-3-methylimidazol-2-ylidene, wherein R is a C1-C6 alkyl or benzyl group; n is an integer from 1 to 4; and P a and P b Independently 1,3,5-triaza-7-phosphadamane (PTA), monosulfonated triphenylphosphine ( m tppms) or trisulfonated triphenylphosphine ( m tppts); According to this method, the hydrogenation of hydrocarbonates is carried out in the presence of carbon dioxide in a gaseous space.

[0045] 4. According to the method in point 3, According to this method The catalyst used is selected from the following: a) According to the general formula [Ir(emim)(cod)( m tppms)]+ m The catalyst of TPPTS, wherein emim is 1-ethyl-3-methylimidazolium-2-ylene, and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; b) According to the general formula [Ir(bmim)(cod)( m tppms)]+ m The catalyst in TPPTS, where BMIM is 1-butyl-3-methylimidazolium-2-ylene and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; c) According to the general formula [Ir(hexmim)(cod)( m tppms)]+ mThe catalyst in TPPTS, where hexmim is 1-hexyl-3-methylimidazolium-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; d) According to the general formula [Ir(2mim)(cod)( m tppms)]+ m The catalyst of TPPTS, wherein 2MIM is 1,3-dimethyl-imidazolium-2-ylene and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; e) According to the general formula [Ir(Bnmim)(cod)( m tppms)]+ m The catalyst for tppts, wherein Bnmim is 1-benzyl-3-methylimidazolium-2-ylene, and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; f) According to the general formula [Ir(emim)(cod)( m The catalyst is tppms)]+pta, where emim is 1-ethyl-3-methylimidazol-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and pta is 1,3,5-triaza-7-phosphadamane; and g) According to the general formula [Ir(emim)(cod)( m tppms)]+ m The catalyst for tppms, wherein emim is 1-ethyl-3-methylimidazolium-2-ylene and cod is 1,5-cyclooctadiene. m tppms represents monosulfonated triphenylphosphine.

[0046] 5. The method described in point 3 is used in hydrogen storage systems.

[0047] 6. According to point 4, the hydrogen storage system is a hydrogen battery.

[0048] 7. The hydrogen storage system according to point 5 or 6 is used for storing hydrogen required to operate fuel cells or other equipment that requires H2, and optionally releasing it to the extent necessary. Attached Figure Description

[0049] Figure 1 A catalyst cycle suitable for storing and releasing hydrogen, wherein hydrocarbonate (HCO3) - The hydrogenation of ) is carried out in a gaseous space in the presence of carbon dioxide (CO2).

[0050] Figure 2 In a 0.1 M NaHCO3 solution at 80°C, the pH changes with increasing CO2 pressure.

[0051] Figure 3 In a batch reactor with a total volume of 100 ml, using [Ir(emim)(cod)( m tppms)] + m The catalyst cycle number (hereinafter referred to as Turnover Number: TON) of TPPTS catalysts depends on the variation of the applied CO2 pressure.

[0052] Figure 4 In a batch reactor with a total volume of 100 ml, using [Ir(emim)(cod)( m tppms)] + m The catalyst cycle number (TON) of tppts catalyst varies with pH.

[0053] Figure 5 In a batch reactor with a total volume of 600 ml, using [Ir(emim)(cod)( m tppms)] + m The catalyst cycle number (TON) of tppts catalyst varies with the applied CO2 pressure.

[0054] Figure 6 In a batch reactor with a total volume of 600 ml, using [Ir(emim)(cod)( m tppms)] + m The catalyst cycle number (TON) of tppts catalyst varies with pH.

[0055] Figure 7 Comparison of catalyst cycle number (TON) values ​​obtained in Examples 4-7.

[0056] The problem to be solved by the present invention The technical problem to be solved by this invention is to provide a reaction system suitable for the reversible storage of hydrogen in fuel cells or other devices requiring H2, which can produce CO-free hydrogen by decomposing formate in an aqueous reaction system. XThe byproduct hydrogen (H2) and the resulting hydrocarbonate are hydrogenated in the same reaction system using the same catalyst in such a manner that the activity of the catalyst in the hydrogenation step of the hydrocarbonate is greater than that of the catalyst in the previously known hydrogenation process of hydrocarbonate.

[0057] According to the discovery of the present invention Our invention achieves the above objectives with a solution based on the following surprising discovery: if the hydrogenation of hydrocarbonates is carried out in an aqueous reaction system with carbon dioxide present in a gaseous space, the activity of the catalyst according to the invention will be up to six times greater – depending on the conditions used (appropriate selection of pressure and temperature) – such as the hydrogenation of hydrocarbonates with pure hydrogen in an aqueous reaction system. Detailed Implementation

[0058] In our work, we developed a method for reacting hydrocarbonate (HCO3) in an aqueous reaction system in the presence of a catalyst. - A method for hydrogenation, wherein the method comprises contacting the aforementioned hydrocarbonate, hydrogen, and catalyst in the presence of carbon dioxide in a gaseous space to generate formate (HCOO). - ).

[0059] In our work, we made the following surprising discovery: if the hydrogenation of hydrocarbonates is carried out in an aqueous reaction system with carbon dioxide in the gas space, the activity of the catalyst according to the invention will be six times higher than that of the hydrogenation of hydrocarbonates in an aqueous reaction system with pure hydrogen – depending on the applied pressure and temperature.

[0060] Based on the above description, a first aspect of the present invention is to provide a method for reacting hydrocarbonate (HCO3) in an aqueous reaction system in the presence of carbon dioxide in a gaseous space. - A method for hydrogenating and producing formate, wherein the hydrocarbonate is preferably sodium hydroxide (NaHCO3), lithium hydroxide (LiHCO3), cesium hydroxide (CsHCO3), or potassium hydroxide (KHCO3), and the formate is preferably sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), or potassium formate (HCOOK), wherein the hydrocarbonate and the catalyst are brought into contact with each other at a pressure of 1-1200 bar, preferably 10-100 bar, at an elevated temperature, preferably 60-100°C, more preferably 80°C.

[0061] In one embodiment of the invention, during the contact between the hydrocarbonate and the catalyst, the amount of CO2 present in the gas space is: p(CO2) > 0 bar and p(CO2) ≤ 50 bar.

[0062] The catalyst mentioned is of the general formula [Ir(cod)(NHC)P] a ]+nP b A catalyst suitable for decomposing formate in aqueous reaction systems and producing CO-free products. X The byproduct hydrogen gas (H2) can be used for hydrocarbonation (HCO3). - The hydrogenation of ), wherein Ir is iridium, cod is 1,5-cyclooctadiene, and NHC is N-heterocyclic carbene, preferably 1-R-3-methylimidazol-2-ylene, wherein R is C1-C6 alkyl or benzyl, P a and P b Independently, they are 1,3,5-triaza-7-phosphadamane (PTA) and monosulfonated triphenylphosphine (PTA). m tppms) or trisulfonated triphenylphosphine ( m tppts), and n is an integer from 1 to 4.

[0063] If the catalytic hydrogenation of bicarbonate to formate and the catalytic decomposition of formate to bicarbonate according to the invention are combined in such a way that the steps mentioned are carried out in the same reaction system, in an aqueous medium, in the presence of a water-soluble catalyst, i.e., the reactants and products are formed in a reversible reaction cycle, then we can create a hydrogen storage system.

[0064] Based on the above, another aspect of the present invention is to provide a method for: decomposing formate in an aqueous reaction system and for producing CO-free products. X The byproduct hydrogen gas (H2), preferably sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), or potassium formate (HCOOK); and, in the same reaction system, hydrocarbonate (HCO3) produced by hydrogenation in an aqueous reaction system in the presence of carbon dioxide in the gas space. - The method for producing formate, preferably sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3), or potassium bicarbonate (KHCO3), and preferably sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), or potassium formate (HCOOK), is used, wherein the reaction system for decomposing formate and for hydrogenating hydrocarbonate according to the invention is used, and reactants and products are formed in a reversible reaction cycle by selecting reaction conditions (such as temperature, pressure, and pH) within the range given below, and the reaction cycle is repeated the required number of times.

[0065] In the mentioned method, the formate decomposition step is carried out by contacting the formate (preferably sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), or potassium formate (HCOOK)) with a catalyst in an aqueous reaction system under an Ar atmosphere, at an elevated temperature, preferably 60-100°C, preferably 80°C, preferably at a pH greater than 8, preferably at a pH of 8.3 ± 0.2.

[0066] Another aspect of the present invention is a hydrogen storage system including the components described above. The hydrogen storage system according to the present invention is preferably a hydrogen storage battery.

[0067] Another aspect of the invention is the use of the hydrogen storage system according to the invention to store hydrogen required for operating fuel cells (or other devices that require H2) and, where applicable, to release it as needed.

[0068] In the following text, our invention is illustrated with examples for better understanding; however, it is not intended to be construed as a limitation of the invention.

[0069] Example Example 1: Detection of pH change in NaHCO3 solution with CO2 pressure.

[0070] We investigated the change in pH of a 0.1 M NaHCO3 solution at 80°C with the applied CO2 pressure. Xiaolu Li, Cheng Peng, John P. Crawshaw, Geoffrey C. Maitland, JP Martin Trusler , Fluid Phase Equilibria, 2018, 458, 253 -263).

[0071] exist Figure 2 The change in pH with CO2 pressure can be seen from... Figure 2 It is clear that the pH of the solution shifts towards acidity with increasing CO2 pressure; however, this change is not linear – even small amounts of carbon dioxide result in a noticeable degree of acidification. It can be concluded that by using the highest CO2 pressure we employed (50 bar), the pH actually decreased from 8.2 to 5.7.

[0072] Example 2: The effect of CO2 on [Ir(emim)(cod)( m tppms)]+ m The effect of TPPTS catalyst activity.

[0073] The general formula of the tested catalyst is [Ir(emim)(cod)( m tppms)]+ mtppts, where emim is 1-ethyl-3-methylimidazol-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine.

[0074] Reaction mixture: In a 100.0 mL isothermal batch reactor (a 100 mL series 5500 HP compact reactor manufactured by Parr Instruments): 20.0 ml solution volume, 80°C [Ir] = 0.0005 mol / dm 3 , [ m tppms] = [Ir], [ m tppts] = 0.001 mol / dm 3 , [HCO3Na] = 0.1 mol / dm 3 , p(H2) = 50 bar p(CO2) varies in the range of 0-50 bar. Reaction time = 1 hour.

[0075] In summary, we found that by varying the CO2 pressure between 0 and 50 bar (under the reaction conditions used), the achieved TON value increased from 121 to 213, which means the reaction rate almost doubled. The formate concentration in the solution obtained after 1 hour of reaction was [HCO2] in the absence of CO2. - ]0 = 60.5 mM, and in a 50 bar CO2 atmosphere, [HCO2] - ] 50 = 106.5 mM. Therefore, a total of 2.13 mmol of HCO2 was formed in a CO2 atmosphere of 50 bar. - This is only 6.5% more than the initially measured amount of bicarbonate (2 mmol). The obtained measurement results are as follows: Figure 3 As shown.

[0076] according to Figure 3 The data in the example is obtained by using the example shown in Example 1. Figure 2 The data (pH variation with increasing CO2 pressure) were used to determine the change in catalyst cycle number with pH. The results obtained are as follows: Figure 4 As shown.

[0077] Example 3: The effect of CO2 on [Ir(emim)(cod)( m tppms)]+ m The effect of tppts catalyst activity.

[0078] Reaction mixture: in a 600.0 ml isothermal batch reactor (600.0 ml series 5500HP compact reactor manufactured by Parsons Instruments): 200.0 ml solution volume, 80°C [Ir] = 0.00005 mol / dm 3 , [ m tppms] = [Ir], [ m tppts] = 0.0001 mol / dm 3 , [HCO3Na] = 0.1 mol / dm 3 p(H2) = 50 bar p(CO2) varies within the range of 0-50 bar. Reaction time = 1 hour.

[0079] In summary, we found that by varying the CO2 pressure between 0 and 50 bar (under the reaction conditions used), the achieved TON value increased from 260 to 576, which means the rate was increased more than twofold. The formate concentration in the solution obtained after 1 hour of reaction was [HCO2] without the use of CO2. - ]0 = 13.0 mM, and in a 50 bar CO2 atmosphere, [HCO2] - ] 50 = 28.8 mM. In other words, the obtained formate concentration is never close to the measured bicarbonate concentration (100.0 mM) under any circumstances, and the maximum extent of bicarbonate conversion (conversion rate) is 28.8%. The obtained measurement results are as follows: Figure 5 As shown.

[0080] according to Figure 5 The data in the example is obtained by using the method mentioned in Example 1. Figure 2 The data (pH changes with increasing CO2 pressure) determined the variation of catalyst cycle number with pH. The results obtained are as follows: Figure 6 As shown.

[0081] Example 4: The effect of CO2 on the catalyst [Ir(bmim)(cod)( m tppms)]+m The effect of tppts activity.

[0082] The general formula of the tested catalyst is [[Ir(bmim)(cod)( m tppms)]+ m tppts, where bmim is 1-butyl-3-methylimidazolium-2-ylene, and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine.

[0083] Reaction mixture: in 100.0 ml and 600.0 ml isothermal batch reactors (100 ml and 600 ml series 5500 HP compact reactors manufactured by Parsons Instruments): Solution volumes of 20.0 ml and 200.0 ml 80°C [Ir] = 0.0005 mol / dm 3 and 0.00005 mol / dm 3 , [mtppms] = [Ir], [mtppts] = 0.001 mol / dm 3 and 0.0001 mol / dm 3 , [HCO3Na] = 0.1 mol / dm 3 p(H2) = 50 bar p(CO2) = 0 or 50 bar Reaction time = 1 hour.

[0084] Table 1: Number of Catalyst Cycles (TON) Received

[0085] In summary, we found that by changing the CO2 pressure from 0 bar to 50 bar (under the reaction conditions used), the TON values ​​increased from 144 to 212 and from 368 to 808, respectively, which is also due to the fact that the effect of CO2 in this case means a significant increase in the reaction rate.

[0086] Example 5: The effect of CO2 on [Ir(hexmim)(cod)( m tppms)]+ m The effect of tppts catalyst activity.

[0087] The general formula of the catalyst studied is [Ir(hexmim)(cod)( m tppms)]+ m tppts, where hexmim is 1-hexyl-3-methylimidazolium-2-ylene, and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine.

[0088] Reaction mixture: in 100.0 ml and 600.0 ml isothermal batch reactors (100 ml and 600 ml series 5500 HP compact reactors manufactured by Parsons Instruments). 20.0 ml and 200.0 ml solution volumes 80°C [Ir] = 0.0005 mol / dm 3 and 0.00005 mol / dm 3 , [ m tppms] = [Ir], [ m tppts] = 0.001 mol / dm 3 and 0.0001 mol / dm 3 , [HCO3Na] = 0.1 mol / dm 3 p(H2) = 50 bar p(CO2) = 0 or 50 bar Reaction time = 1 hour.

[0089] Table 2: Number of Catalyst Cycles (TON) Values ​​Obtained

[0090] In summary, we found that by changing the CO2 pressure from 0 bar to 50 bar (under the reaction conditions used), the TON values ​​increased from 134 to 204 and from 285 to 522, respectively, which is also due to the fact that the effect of CO2 in this case means a significant increase in the reaction rate.

[0091] Example 6: The effect of CO2 on the catalyst [Ir(2mim)(cod)( m tppms)]+ m The effect of tppts activity.

[0092] The general formula of the tested catalyst is [Ir(2mim)(cod)(m tppms)]+ m tppts, where 2mim is 1,3-dimethylimidazol-2-ylene, and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine.

[0093] Reaction mixture: in 100.0 ml and 600.0 ml isothermal batch reactors (100 ml and 600 ml series 5500 HP compact reactors manufactured by Parsons Instruments): 20.0 ml and 200.0 ml solution volumes 80°C [Ir] = 0.0005 mol / dm 3 and 0.00005 mol / dm 3 , [ m tppms] = [Ir], [ m tppts] = 0.001 mol / dm 3 and 0.0001 mol / dm 3 , [HCO3Na] = 0.1 mol / dm 3 p(H2) = 50 bar p(CO2) = 0 or 50 bar Reaction time = 1 hour.

[0094] Table 3: Number of Catalyst Cycles (TON) Received

[0095] In summary, we found that by changing the CO2 pressure from 0 bar to 50 bar (under the reaction conditions used), the TON values ​​increased from 158 to 256 and from 228 to 786, respectively, which is also due to the fact that the effect of CO2 in this case means a significant increase in the reaction rate.

[0096] Example 7: The effect of CO2 on the catalyst [Ir(Bnmim)(cod)( m tppms)]+ m The effect of tppts activity.

[0097] The general formula of the tested catalyst is [Ir(Bnmim)(cod)( m tppms)]+ mtppts, where Bnmim is 1-benzyl-3-methylimidazolium-2-ylene, and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine.

[0098] Reaction mixture: in 100.0 ml and 600.0 ml isothermal batch reactors (100 ml and 600 ml series 5500 HP compact reactors manufactured by Parsons Instruments): 20.0 ml and 200.0 ml solution volumes 80°C [Ir] = 0.0005 mol / dm 3 and 0.00005 mol / dm 3 , [ m tppms] = [Ir], [ m tppts] = 0.001 mol / dm 3 and 0.0001 mol / dm 3 , [HCO3Na] = 0.1 mol / dm 3 p(H2) = 50 bar p(CO2) = 0 or 50 bar Reaction time = 1 hour.

[0099] Table 4: Number of Catalyst Cycles (TON) Received

[0100] In summary, we found that by changing the CO2 pressure from 0 bar to 50 bar (under the reaction conditions used), the TON values ​​increased from 121 to 262 and from 361 to 1119, respectively, which is also due to the fact that the effect of CO2 in this case means a significant increase in the reaction rate.

[0101] Example 8: Study on the effect of CO2 on [Ir(emim)(cod)( m The effect of tppms)]+pta catalyst activity.

[0102] The general formula of the tested catalyst is [Ir(emim)(cod)( m tppms)]+pta, where emim is 1-ethyl-3-methylimidazol-2-ylene and cod is 1,5-cyclooctadiene. mtppms is monosulfonated triphenylphosphine, and pta is 1,3,5-triaza-7-phosphaadamantane.

[0103] Reaction mixture: in 100.0 ml and 600.0 ml isothermal batch reactors (100 ml and 600 ml series 5500 HP compact reactors manufactured by Parsons Instruments): 20.0 ml and 200.0 ml solution volumes 80°C [Ir] = 0.0005 mol / dm 3 and 0.00005 mol / dm 3 , [ m tppms] = [Ir], [pta] = 0.001 mol / dm 3 and 0.0001 mol / dm 3 , [HCO3Na] = 0.1 mol / dm 3 p(H2) = 50 bar p(CO2) = 0 or 50 bar Reaction time = 1 hour.

[0104] Table 5: Number of Catalyst Cycles (TON) Received

[0105] In summary, we found that by changing the CO2 pressure from 0 bar to 50 bar (under the reaction conditions used), the TON values ​​increased from 67 to 108 and from 260 to 1084, respectively, which is also due to the fact that the effect of CO2 in this case means a significant increase in the reaction rate.

[0106] Example 9: Study on the effect of CO2 on [Ir(emim)(cod)( m tppms)]+ m The effect of tppms on catalyst activity.

[0107] The general formula of the tested catalyst is [Ir(emim)(cod)( m tppms)]+ m tppms, where emim is 1-ethyl-3-methylimidazol-2-ylene and cod is 1,5-cyclooctadiene. m tppms represents monosulfonated triphenylphosphine.

[0108] Reaction mixture: in 100.0 ml and 600.0 ml isothermal batch reactors (100 ml and 600 ml series 5500 HP compact reactors manufactured by Parsons Instruments). 20.0 ml and 200.0 ml solution volumes 80°C [Ir] = 0.0005 mol / dm 3 and 0.00005 mol / dm 3 , [ m [tppms] = 0.0015 mol / dm 3 and 0.00015 mol / dm 3 , [HCO3Na] = 0.1 mol / dm 3 p(H2) = 50 bar p(CO2) = 0 or 50 bar Reaction time = 1 hour.

[0109] Table 6: Number of Catalyst Cycles (TON) Received

[0110] In summary, we found that by changing the CO2 pressure from 0 bar to 50 bar (under the reaction conditions used), the achieved TON values ​​increased from 263 to 320 and from 325 to 2050, respectively, which is also due to the fact that the effect of CO2 in this case means a significant increase in rate.

[0111] Figure 7 Visual representations of the results shown in Examples 4-9 are provided. The results clearly demonstrate that, by changing both the carbene and phosphine ligands, the hydrogenation rate of bicarbonate can be increased several times (2-6 times) in the presence of CO2 (under given conditions).

[0112] Industrial applicability Our invention's method for the hydrogenation of hydrocarbonates offers an opportunity to provide renewable energy, based on the catalytic decomposition of formate in an aqueous reaction system to produce CO2-free products. X A method for the catalytic hydrogenation of hydrocarbonates produced in the same reaction system in the presence of carbon dioxide in a gaseous space, thereby producing the corresponding formate.

Claims

1. A method for reacting hydrocarbonate (HCO3) in an aqueous reaction system - A method for hydrogenating and using the hydrogen carbonate to produce formate, wherein the hydrogen carbonate is selected from sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3), and potassium bicarbonate (KHCO3), and the formate is a formate selected from the group consisting of sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), and potassium formate (HCOOK). The method includes: The hydrocarbonate and the catalyst are brought into contact with each other at a pressure of 1-1200 bar and at an elevated temperature; The catalyst is a catalyst with the following structure: [Ir(cod)(NHC)P] a ]+nP b general formula catalyst, Wherein, in the formula Ir stands for iridium; COD is 1,5-cyclooctadiene; NHC is an N-heterocyclic carbene; n is an integer from 1 to 4; and P a and P b Independently 1,3,5-triaza-7-phosphadamane (PTA), monosulfonated triphenylphosphine ( m tppms) or trisulfonated triphenylphosphine ( m tppts); Its features The hydrogenation of hydrocarbonates is carried out in the presence of carbon dioxide in a gaseous space.

2. The method according to claim 1, wherein the temperature is in the range of 60°C to 100°C.

3. The method according to claim 1, wherein the temperature is 80°C.

4. The method of claim 1, wherein the pressure is in the range of 10 bar to 100 bar.

5. The method according to claim 1, wherein the N-heterocyclic carbene is 1-R-3-methylimidazol-2-ylene, wherein R is C1-C6 alkyl or benzyl.

6. The method according to claim 1, Its features The catalyst used is selected from the following: a) According to the formula [Ir(emim)(cod)( m tppms)]+ m The catalyst of TPPTS, wherein emim is 1-ethyl-3-methylimidazolium-2-ylene, and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; b) According to the formula [Ir(bmim)(cod)( m tppms)]+ m The catalyst in TPPTS, where BMIM is 1-butyl-3-methylimidazolium-2-ylene and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; c) According to the formula [Ir(hexmim)(cod)( m tppms)]+ m The catalyst in TPPTS, where hexmim is 1-hexyl-3-methylimidazolium-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; d) According to the formula [Ir(2mim)(cod)( m tppms)]+ m The catalyst of TPPTS, wherein 2MIM is 1,3-dimethyl-imidazolium-2-ylene and COD is 1,5-cyclooctadiene. m tppms represents monosulfonated triphenylphosphine, and mtppts represents trisulfonated triphenylphosphine; e) According to the formula [Ir(Bnmim)(cod)( m tppms)]+ m The catalyst for tppts, wherein Bnmim is 1-benzyl-3-methylimidazolium-2-ylene, and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; f) According to the formula [Ir(emim)(cod)( m The catalyst is tppms)]+pta, where emim is 1-ethyl-3-methylimidazol-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and pta is 1,3,5-triaza-7-phosphadamane; and g) According to the formula [Ir(emim)(cod)( m tppms)]+ m The catalyst for tppms, wherein emim is 1-ethyl-3-methylimidazolium-2-ylene and cod is 1,5-cyclooctadiene. m tppms represents monosulfonated triphenylphosphine.

7. A method for: decomposing formate in an aqueous reaction system and for producing CO-free products. X The byproduct hydrogen gas (H2), wherein the formate is selected from the following formates: sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs), and potassium formate (HCOOK); and, in the same reaction system, the hydrocarbonate (HCO3) obtained by hydrogenation in the aqueous reaction system. - The formate is produced thereby, wherein the hydrocarbonate is a hydrocarbonate selected from the group consisting of sodium bicarbonate (NaHCO3), lithium bicarbonate (LiHCO3), cesium bicarbonate (CsHCO3) and potassium bicarbonate (KHCO3), and the formate is a formate selected from the group consisting of sodium formate (HCOONa), lithium formate (HCOOLi), cesium formate (HCOOCs) and potassium formate (HCOOK); in, The reaction system, through the formate decomposition step and the bicarbonate hydrogenation step, and by selecting the values ​​of temperature, pressure and pH within the range specified below, forms reactants and reaction products in a reversible reaction cycle, and the reaction cycle is repeated the required number of times. The formate decomposition step includes contacting the formate with the catalyst in an aqueous reaction system under an Ar atmosphere, at an elevated temperature, and at a pH greater than 8. The hydrogenation step of the hydrocarbonate includes bringing the hydrocarbonate and the catalyst into contact with each other at an elevated temperature under a pressure of 1-1200 bar. The catalyst is of the general formula [Ir(cod)(NHC)P]. a ]+nP b catalyst, Wherein, in the formula Ir stands for iridium; COD is 1,5-cyclooctadiene; NHC is an N-heterocyclic carbene; n is an integer from 1 to 4; and P a and P b Independently 1,3,5-triaza-7-phosphadamane (PTA), monosulfonated triphenylphosphine ( m tppms) or trisulfonated triphenylphosphine ( m tppts); Its features The hydrogenation of hydrocarbonates is carried out in the presence of carbon dioxide in a gaseous space.

8. The method of claim 7, wherein during the formate decomposition step, the temperature is in the range of 60°C to 100°C.

9. The method of claim 7, wherein the temperature is 80°C during the formate decomposition step.

10. The method of claim 7, wherein during the formate decomposition step, the pH is 8.3 ± 0.

2.

11. The method of claim 7, wherein during the hydrogenation step, the temperature is in the range of 60°C to 100°C.

12. The method of claim 7, wherein the temperature is 80°C during the hydrogenation step.

13. The method of claim 7, wherein during the hydrogenation step, the pressure is in the range of 10 bar to 100 bar.

14. The method of claim 7, wherein the N-heterocyclic carbene is 1-R-3-methylimidazol-2-ylene, wherein R is a C1-C6 alkyl or benzyl.

15. The method according to claim 7, Its features The catalyst used is selected from the following: a) According to the general formula [Ir(emim)(cod)( m tppms)]+ m The catalyst of TPPTS, wherein emim is 1-ethyl-3-methylimidazolium-2-ylene, and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; b) According to the general formula [Ir(bmim)(cod)( m tppms)] + m The catalyst in TPPTS, where BMIM is 1-butyl-3-methylimidazolium-2-ylene and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; c) According to the general formula [Ir(hexmim)(cod)( m tppms)]+ m The catalyst in TPPTS, where hexmim is 1-hexyl-3-methylimidazolium-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; d) According to the general formula [Ir(2mim)(cod)( m tppms)]+ m The catalyst of TPPTS, wherein 2MIM is 1,3-dimethyl-imidazolium-2-ylene and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; e) According to the general formula [Ir(Bnmim)(cod)( m tppms)]+ m The catalyst for tppts, wherein Bnmim is 1-benzyl-3-methylimidazolium-2-ylene, and COD is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and m tppts is trisulfonated triphenylphosphine; f) According to the general formula [Ir(emim)(cod)( m The catalyst is tppms)]+pta, where emim is 1-ethyl-3-methylimidazol-2-ylene and cod is 1,5-cyclooctadiene. m tppms is monosulfonated triphenylphosphine, and pta is 1,3,5-triaza-7-phosphadamane; and g) According to the general formula [Ir(emim)(cod)( m tppms)]+ m The catalyst for tppms, wherein emim is 1-ethyl-3-methylimidazolium-2-ylene and cod is 1,5-cyclooctadiene. m tppms represents monosulfonated triphenylphosphine.

16. The method of claim 7 for use in a hydrogen storage system.

17. The use according to claim 16, wherein the hydrogen storage system is a hydrogen battery.

18. The use according to claim 16 or 17, wherein the hydrogen storage system is a hydrogen storage system for storing hydrogen required to operate a fuel cell or other equipment that requires H2, and for releasing the hydrogen.

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