Partial dehydrogenation of organic liquids

Abstract

The present invention provides a method for enabling the storage and transport of hydrogen. [Solution] A method for storing and / or transporting hydrogen for generating hydrogen by partial dehydrogenation of an organic liquid, the method comprising the steps of: supplying at least one organic liquid having a degree of hydrogenation DH plus; partially dehydrogenating the liquid; first recovering gaseous hydrogen; and second recovering the organic liquid having a degree of hydrogenation DH minus, wherein the ratio DH plus / DH minus is between 1 and 25, and the endpoints are excluded.

Description

[Technical Field]

[0001] The present invention relates to hydrogen transport using liquid organic compounds, in particular liquid organic compounds having aromatic rings that can be hydrogenated to "transport" hydrogen molecules and then dehydrogenated to release the hydrogen molecules. [Background technology]

[0002] The use of aromatic molecules has already been studied in the field of hydrogen transport and storage (known as "liquid organic hydrogen carrier" technology, also abbreviated as "LOHC").

[0003] The principle is to first fix hydrogen onto a carrier molecule. This is the hydrogenation step. Preferably, the carrier molecule is liquid at room temperature. This hydrogenated carrier molecule can be easily transported and handled, and is easier and safer to handle than hydrogen in gaseous or liquid state. The principle is to release hydrogen that is advantageously located near the consumption site, preferably very close to the consumption site, on the carrier molecule. This is the dehydrogenation step.

[0004] Among the molecules considered, the use of benzyltoluene and / or dibenzyltoluene is an option of interest that has been studied and published in scientific literature and patent documents.

[0005] Accordingly, European Patent No. 2925669 describes the use of a mixture containing isomers of benzyltoluene and / or dibenzyltoluene in a catalytic method for fixing and releasing hydrogen in or from a mixture. The study by A. Bulgarin et al. (Int. Journal of Hydrogen Energy, 45(1), (2020), 712-720) refers to the dehydrogenation of perhydrodibenzyltoluene in the presence of an alumina-supported platinum catalyst at temperatures of 280°C to 300°C.

[0006] As with the immediate implementation of the hydrogenation and dehydrogenation processes, the sequencing of cycles and the maintenance of implementation levels (hydrogen fixation / release yield) are important parameters regarding the economic aspects of this technology. Furthermore, in the case of dibenzyltoluene (DBT), this cycle is based on complete hydrogenation to perhydrodibenzyltoluene (H18-DBT), but complete dehydrogenation releasing 18 hydrogen atoms is carried out under harsh operating conditions (280°C to 300°C) close to the stability limit of DBT (330°C to 350°C). This not only has the disadvantage of gradually degrading performance over several cycles, but also affects the long-term operating yield, not to mention the purity of the hydrogen produced, which degrades over several cycles due to byproducts formed by the support molecules.

[0007] The solutions proposed to date, while promising, are quite insufficient. This is because the hydrogen-containing liquids currently proposed undergo significant degradation throughout the hydrogenation / dehydrogenation cycle and therefore must be replaced relatively frequently.

[0008] Today, there is still a need for an industrially viable method for fixing and releasing hydrogen, which can be carried out under less stringent conditions than currently known, and which is economically compatible with the development of large-scale hydrogen transport, production, and use, particularly in hydrogen engines for transportation such as automobiles, trains, and boats, although only the main anticipated applications will be mentioned. [Overview of the project]

[0009] The inventors have found that by using an organic carrier liquid containing at least one aromatic ring system, it is possible to carry out numerous hydrogen fixation / release cycles (hydrogenation / dehydrogenation) by limiting the decomposition rate of the carrier liquid over several cycles, thereby enabling more economical and efficient hydrogen transport and supply, particularly with respect to the lifespan of the carrier liquid and the hydrogen purity at the end of the dehydrogenation operation of the carrier liquid.

[0010] Further advantages will become apparent in light of the following description of the present invention. [Modes for carrying out the invention]

[0011] Therefore, in the first aspect, the present invention relates to a method for producing hydrogen by partial dehydrogenation of an organic liquid, wherein the method is Degree of hydrogenation DH プラス A step of supplying at least one organic liquid having, A step of partially dehydrogenating the aforementioned liquid, Firstly, gaseous hydrogen is recovered, and secondly, the degree of hydrogenation DH マイナス A step of recovering the organic liquid having the following: Includes, Ratio DH プラス / DH マイナス It is between 1 and 25, with the endpoints excluded, and preferably between 1.1 and 20, with the endpoints included.

[0012] "Degree of hydrogenation" refers to the numerical ratio of double bonds in an organic liquid that are hydrogenated, i.e., saturated with hydrogen atoms, to the total number of double bonds that can be hydrogenated. For example, the dibenzyltoluene (DBT) molecule has three aromatic rings and nine potentially hydrogenated double bonds. DBT has a degree of hydrogenation of zero (0), and a fully hydrogenated DBT molecule has a degree of hydrogenation of 1 (1).

[0013] Ratio DH プラス / DH マイナス A value of 1 (not included in the present invention) indicates that there is no hydrogen release during dehydrogenation. Specific DH プラス / DH マイナス25 (not included in the present invention) means that the residual hydrogenation degree DH of the organic liquid at the end of the dehydrogenation step マイナス corresponds to 4%.

[0014] "Partial dehydrogenation" means that not complete dehydrogenation of the organic liquid is performed, only partial dehydrogenation is performed, resulting in an organic liquid having a hydrogenation degree DH strictly greater than 0 マイナス .

[0015] The above "partial" reaction for dehydrogenation can be carried out as a conventional dehydrogenation reaction, but it can be carried out without aiming to achieve a 100% yield in said dehydrogenation reaction, that is, without aiming to supply all of the hydrogen molecules transported by the organic liquid.

[0016] Various means can be used to avoid achieving 100% yield (corresponding to 100% dehydrogenation degree of all dehydrogenable hydrogen atoms). These means are well known to those skilled in the art: stopping the reaction before 100% dehydrogenation yield is obtained, a reaction temperature lower than that generally used for dehydrogenation reactions, a reaction pressure lower than that generally used for dehydrogenation reactions, a low-selectivity dehydrogenation catalyst, and any other means for adjusting the dehydrogenation reaction rate, including, but not limited to, one or more of the above means individually or in combination of two or more thereof.

[0017] Therefore, by controlling the dehydrogenation conditions, it is possible to carry out this reaction partially, in contrast to the teachings given to those skilled in the art in the prior art. It has surprisingly been found that by operating a partial dehydrogenation step, that is, by not carrying out the reaction until all of the transported hydrogen atoms are released, the energy consumption is lower and the amount of transported hydrogen molecules is completely satisfactory.

[0018] The reason is that one of the problems associated with the hydrogenation and dehydrogenation cycles of organic liquids that can be used for hydrogen transport is their stability when heated to temperatures close to their boiling point. These organic liquids have been observed to undergo modification through phenomena such as dimerization or rearrangement / reorganization, leading to the formation of diverse chemical species. These modifications result in a loss of purity of the initial organic liquid and a loss of yield over time. This loss is primarily related to inherent modifications to the properties of the organic liquid, including, in non-limiting examples, modifications to viscosity, which can be detrimental to the handling, storage, and use of organic liquids useful for hydrogen transport.

[0019] Therefore, the method according to the present invention enables improved stability of organic liquids undergoing a hydrogenation / dehydrogenation cycle, thereby reducing the generation of decomposition products of the organic liquid, particularly light decomposition products (which are therefore volatile and prone to contaminating released hydrogen) and / or heavy decomposition products (which are therefore prone to increasing the viscosity of the organic liquid and thus impairing subsequent cycles).

[0020] Another advantage can be obtained from the system of the present invention, in particular, when the hydrogenation or dehydrogenation temperature is lower than the temperatures seen in the prior art for equivalent reactions carried out to 100% yield, the thermal decomposition of the support molecule is significantly reduced as a result, and therefore the lifespan of the support molecule is improved. The extended lifespan of the support molecule also allows for a significant increase in the number of cycles.

[0021] The degree of dehydrogenation can be easily controlled by any means known to those skilled in the art, particularly by Raman spectroscopy, refractive index measurement, density measurement, or measurement of the amount of hydrogen produced, in accordance with the instructions provided by K. Muller et al. ("Experimental assessment of the degree of hydrogen loading for the dibenzyl toluene based LOHC system," International Journal of Hydrogen Energy, 41, (2016), 22097-22103).

[0022] In the method of the present invention, the organic liquid can be any type known to those skilled in the art that can transport hydrogen atoms, i.e., can be at least partially hydrogenated and / or at least partially dehydrogenated. The organic liquid that can be used in the method according to the present invention may also be a mixture of two or more organic liquids that may have the same or different degrees of hydrogenation.

[0023] The organic liquids that can be used in this invention typically and advantageously have at least one aromatic ring that may be partially dehydrogenated.

[0024] More specifically, the organic liquid that can be used in the method of the present invention is of general formula (1): (AX) n -B (1) Accordingly, in the formula, A and B are identical or different, independently of each other, and may be partially dehydrogenated, representing an aromatic ring which may be substituted with one or more saturated, partially or completely unsaturated hydrocarbon groups containing 1 to 20 carbon atoms, preferably 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, even more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, typically 1 to 3 carbon atoms. X consists of a single bond, an oxygen atom, a sulfur atom, and a divalent group -(CRR'). m - represents a spacer group selected from divalent groups >C=CRR' and divalent groups -NR'-. R and R' are either the same or different, independently selected from hydrogen and saturated, partially or completely unsaturated hydrocarbon groups containing 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. R'' represents a saturated, partially, or completely unsaturated hydrocarbon group containing 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. m represents an integer between 1 and 4 that includes the endpoint. n may be equal to 0, or an integer equal to 1, 2, or 3, preferably an integer equal to 1 or 2, provided that if n is equal to 0, B is limited to being substituted with one or more hydrocarbon groups as defined above.

[0025] "Aromatic ring" refers to monocyclic and polycyclic aromatic hydrocarbon structures containing 6 to 20 carbon atoms. "Polycyclic" refers to fused or fused ring structures.

[0026] When n is equal to 0, the organic liquid of formula (1) as defined above forms part of a class of alkylbenzenes that may be partially dehydrogenated. When n is equal to 2 or 3, the groups (AX) may be the same or different.

[0027] According to one preferred embodiment of the present invention, in an organic liquid of general formula (1), n ​​is non-zero and B is substituted with a hydrocarbon group. Preferably, the hydrocarbon group is an alkyl group containing 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, and preferably the alkyl group is a methyl group.

[0028] According to another preferred embodiment of the present invention, in the organic liquid of general formula (1), n ​​is 0, and the organic liquid of formula (1) is generally selected from linear alkylbenzenes that may be partially dehydrogenated, branched alkylbenzenes that may be partially dehydrogenated, for example, alkylbenzenes, but not limited to these, and partially dehydrogenated homologs in which the alkyl moiety contains 10 to 20 carbon atoms. Some examples of such alkylbenzenes include, but are not limited to, decylbenzene, dodecylbenzene, octadecylbenzene, and at least partially dehydrogenated homologs thereof.

[0029] As previously shown, the organic liquids according to the above general formula (1) can be used alone or as a mixture of two or more of them in any proportion. According to one preferred embodiment of the present invention, the organic liquid used in the method of the present invention may contain one compound having at least one aromatic group which may be partially dehydrogenated, or a mixture of two or more compounds having at least one aromatic group which may be partially dehydrogenated. According to one particularly preferred embodiment, the organic liquid used in the method of the present invention is a liquid at room temperature and ambient pressure.

[0030] According to yet another preferred embodiment of the present invention, the organic liquid is selected from benzyltoluene (BT), dibenzyltoluene (DBT), their partially dehydrogenated homologs, and mixtures thereof in any proportion.

[0031] In a particularly preferred embodiment, the organic liquid is selected from organic liquids sold by Arkema under the trade name Jarytherm® range.

[0032] Other organic liquids suitable for the requirements of the present invention, and at least partially dehydrogenated homologs, are, for example, those sold by Eastman under the trade name Marlotherm®.

[0033] As yet another example of organic liquids suitable for the requirements of the present invention, the following are some of the main organic liquids known and usable in the context of the present invention: Diphenylethane (DPE) and its isomers, particularly 1,1-DPE (CAS 612-00-0), 1,2-DPE (CAS 103-29-7), and mixtures thereof (particularly CAS 38888-98-1), such organic liquids are commercially available or described in literature, for example, European Patent No. 0098677. Ditrill ether (DT) and its isomers, particularly those corresponding to CAS numbers 4731-34-4 and 28299-41-4, and mixtures thereof, which are commercially available from Lanxess under the trade name DiphylDT. Phenylxylethane (PXE) and its isomers, particularly those corresponding to CAS numbers 6196-95-8 and 76090-67-0, and mixtures thereof, which are commercially available from Changzhou Winschem under the trade name PXE Oil. This product is 1,2,3,4-tetrahydro-(1-phenylethyl)naphthalene (CAS 63674-30-6), and is particularly marketed by Dow under the designation Dowtherm® RP. In particular, diisopropylnaphthalene (CAS 38640-62-9), available from Indus Chemie Ltd under the trade name KMC 113, Monoisopropyl biphenyl and its isomers (CAS 25640-78-2), in particular, are available under the trade name Wemcol. Phenylethylphenylethane (PEPE) and its isomers (CAS 6196-94-7) are available, particularly from Changzhou Winschem or Yantai Jinzheng. and their homologs, at least partially dehydrogenated and mixtures of two or more of them in any proportion, One could list these:

[0034] Organic liquids that can be used in the context of the present invention are well known to those skilled in the art and may further contain, for example, one or more additives selected from antioxidants, passivators, pour point depressants, degradation inhibitors, and mixtures thereof. Organic liquids particularly preferred for the method of the present invention contain at least one antioxidant.

[0035] Antioxidants that can be advantageously used in organic liquids include, without limitation, phenolic antioxidants such as dibutylhydroxytoluene, butylhydroxyanisole, tocopherol, and acetates of these phenolic antioxidants. Further examples include amine-type antioxidants such as phenyl-α-naphthylamine, diamine-type antioxidants such as N,N'-di(2-naphthyl)-para-phenylenediamine, as well as ascorbic acid and its salts and esters of ascorbic acid, which can be used alone, in mixtures of two or more of them, or in combination with other components such as green tea extract and coffee extract.

[0036] In principle, the organic liquid used in the partial dehydrogenation method according to the present invention is a fully hydrogenated or at least partially dehydrogenated organic liquid. According to one embodiment of the present invention, the organic liquid used in the partial dehydrogenation step is a hydrogenation degree DH of 1 or less. プラス It has a degree of hydrogenation DH. プラス Strictly speaking, it is greater than 0, preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.4 or more, particularly preferably 0.6 or more, and advantageously greater than 0.8.

[0037] In one particularly preferred embodiment of the method according to the present invention, the organic liquid used in the dehydrogenation step is given by the following inequality: 0.6 ≤ DH プラス <1 Hydrogenation degree DH according to プラス It holds.

[0038] Therefore, at the end of the partial dehydrogenation step of the organic liquid, the organic liquid is partially dehydrogenated, advantageously substantially dehydrogenated but not completely dehydrogenated. According to one embodiment of the present invention, at the end of the partial dehydrogenation reaction, the organic liquid has a degree of hydrogenation DH of strictly less than 1, preferably 0.8 or less, more preferably 0.6 or less, and more preferably 0.4 or less. マイナス It holds.

[0039] In one particularly preferred embodiment of the method according to the present invention, the organic liquid at the end of the partial dehydrogenation step satisfies the following inequality: 0 <DH マイナス ≤0.6 Hydrogenation degree DH according to マイナス It holds.

[0040] As shown earlier, relative DH プラス / DH マイナス The result is anything other than 1 (no dehydrogenation reaction), therefore DH プラス DH マイナス It cannot be equal to that.

[0041] The dehydrogenation reaction may be carried out by any method known to those skilled in the art, with the limitation that it is not carried out in such a way that the entire organic liquid used is dehydrogenated.

[0042] The following are some non-exclusive examples of operating conditions that may be used: The reaction temperature is generally 150°C to 350°C, preferably 180°C to 350°C, advantageously 200°C to 350°C, more preferably 250°C to 350°C, preferably 250°C to 330°C, more preferably 280°C to 330°C, and overall preferably 280°C to 320°C. The reaction pressure is generally 0.01 Pa to 3 Pa, preferably 0.1 Pa to 2 Pa, and atmospheric pressure is preferred.

[0043] The reaction is typically, and advantageously, carried out in the presence of at least one dehydrogenation catalyst well known to those skilled in the art. Non-limiting examples of catalysts that can be used in the partial dehydrogenation reaction include heterogeneous catalysts containing at least one metal on a support. The metal is selected from metals of groups 3 to 12 of the IUPAC periodic table of elements, i.e., transition metals of the periodic table. In one preferred embodiment, the metal is selected from metals of groups 5 to 11, more preferably groups 5 to 10, of the IUPAC periodic table of elements.

[0044] The metals used in these catalysts are typically selected from iron, cobalt, copper, titanium, molybdenum, manganese, nickel, platinum, and palladium, as well as mixtures thereof. Preferably, the metals are selected from copper, molybdenum, platinum, and palladium, as well as mixtures of two or more of these in any proportion.

[0045] The catalyst support may be of any type well known to those skilled in the art, and is advantageously selected from porous supports, and more advantageously from porous refractory supports. Non-limiting examples of supports include alumina, silica, zirconia, magnesia, beryllium oxide, chromium oxide, titanium oxide, thorium oxide, ceramics, carbon such as carbon black, graphite and activated carbon, and combinations thereof. Specific and preferred examples of supports that can be used in the method of the present invention include amorphous aluminosilicates, crystalline aluminosilicates (zeolites) and silica-titanium oxide-based supports.

[0046] The method according to the present invention, which includes a partial dehydrogenation step of an organic liquid, is advantageously achieved in one or more hydrogenation / dehydrogenation cycles, more advantageously in multiple cycles, thereby enabling the storage and transport of hydrogen in the hydrogenated organic liquid.

[0047] The hydrogenation reaction can be carried out with the organic liquid defined above, preferably an organic liquid containing at least one aromatic ring, and more preferably an organic liquid conforming to the general formula (1) defined above, by any method well known to those skilled in the art.

[0048] The hydrogenation reaction is generally carried out at a temperature of 120°C to 200°C, preferably 130°C to 180°C, and more preferably 140°C to 160°C. The pressure used in this reaction is generally 0.1 MPa to 5 MPa, preferably 0.5 MPa to 4 MPa, and more preferably 1 MPa to 3 MPa.

[0049] The hydrogenation reaction is typically carried out in the presence of a catalyst, more specifically in the presence of a hydrogenation catalyst well known to those skilled in the art, and advantageously, in non-limiting examples, is selected from heterogeneous catalysts containing a metal on a support. The metal is selected from metals of Groups 3 to 12 of the IUPAC periodic table of elements, i.e., transition metals of the periodic table. In one preferred embodiment, the metal is selected from metals of Groups 5 to 11 of the IUPAC periodic table of elements, more preferably from Groups 5 to 10.

[0050] The metals used in these hydrogenation catalysts are typically selected from iron, cobalt, copper, titanium, molybdenum, manganese, nickel, platinum, and palladium, as well as mixtures thereof. Preferably, the metals are selected from copper, molybdenum, platinum, and palladium, as well as mixtures of two or more of these in any proportion.

[0051] The catalyst support may be of any type well known to those skilled in the art, and is advantageously selected from porous supports, and more advantageously from porous refractory supports. Non-limiting examples of supports include alumina, silica, zirconia, magnesia, beryllium oxide, chromium oxide, titanium oxide, thorium oxide, ceramics, carbon such as carbon black, graphite and activated carbon, and combinations thereof. Specific and preferred examples of supports that can be used in the method of the present invention include amorphous aluminosilicates, crystalline aluminosilicates (zeolites) and silica-titanium oxide-based supports.

[0052] According to one preferred embodiment, the hydrogenation reaction is carried out on a completely or partially dehydrogenated, preferably partially dehydrogenated, organic liquid, more specifically, when the organic liquid is obtained from a partially dehydrogenated method as defined above.

[0053] The hydrogenation reaction may be partial or complete, preferably complete, meaning that the entire double bond in the support liquid to be hydrogenated is completely hydrogenated.

[0054] In another aspect, the present invention relates to a hydrogenation / dehydrogenation cycle comprising at least the method defined above for producing hydrogen by partial dehydrogenation of an organic liquid and at least one hydrogenation reaction of the organic liquid.

[0055] It should be understood that in the cycle of the present invention, the hydrogenation reaction of the organic liquid (a carrier molecule that stores hydrogen) can be operated in a single step or repeated two or more times. Therefore, partial or complete hydrogenation can be performed first, and then one or more further partial or complete hydrogenation can be performed directly on the organic liquid from the immediately preceding step.

[0056] Similarly, in the cycle of the present invention, the method of partial dehydrogenation of the organic liquid (the carrier molecule that will release hydrogen) may be performed in one step or repeated two or more times, however, it should be understood that at least one, preferably two, more preferably more, and more preferably all of the dehydrogenation methods are performed partially, i.e., without completely dehydrogenating the organic liquid, as previously described.

[0057] Therefore, in a cycle according to the present invention, it may be considered to operate one or more dehydrogenation methods, including at least one of the partial dehydrogenation methods according to the present invention, before and / or after one or more hydrogenation steps for an organic liquid that can store, transport and release hydrogen.

[0058] One or more dehydrogenation and hydrogenation reactions may be carried out with the same or different dehydrogenation and hydrogenation yields. Therefore, it is possible to carry out at least one dehydrogenation reaction partially (including at least one part) and then another dehydrogenation reaction at a higher or lower or the same degree of dehydrogenation. Similarly, it is possible to carry out at least one hydrogenation reaction partially or completely and then another hydrogenation reaction at a higher or lower or the same degree of dehydrogenation.

[0059] The cycle of the present invention allows for storage in liquid form at room temperature and pressure, transport in liquid form at room temperature and pressure, and release of hydrogen in a safe and fully acceptable economic yield. More specifically, the partial dehydrogenation step in the method according to the present invention allows for observation of limited and controlled aging (decomposition) of the organic liquid, i.e., aging (decomposition) into a more stable organic liquid.

[0060] By increasing the stability of organic liquids, the formation of light decomposition products (which are therefore volatile and may contaminate released hydrogen) and heavy decomposition products (which may increase the viscosity of the products and impair subsequent cycles) is reduced.

[0061] Therefore, the cycle of the present invention represents an efficient and beneficial hydrogen transport system that is also safe because it avoids the transport of hydrogen in gaseous form. The cycle of the present invention allows for the "transport" of hydrogen molecules, i.e., the fixation of hydrogen into an organic liquid, and then the release of the fixed hydrogen onto the organic liquid, as has already been proposed in the prior art, but differs in that at least one dehydrogenation step in the cycle is performed only partially, rather than entirely, as described above.

[0062] The present invention will now be described by the following embodiments, which are provided as embodiments of the present invention and do not in any way limit the scope of protection as defined in the appended claims. [Examples]

[0063] Example 1 The following examples correspond to partial dehydrogenation tests performed on an organic liquid, namely Arkema's dibenzyltoluene (DBT).

[0064] A 100 mL three-necked flask equipped with a condenser is packed with 0.1 mol of H18-DBT and 0.15 mol% of alumina-supported platinum (0.5 wt%) catalyst. The assembly is purged by nitrogen flushing to remove trace amounts of ambient air from the reactor. After calibration of a thermal conductivity analyzer (FTC200, version 1.05, Wagner) at room temperature, the mixture is heated to 300°C using a heating jacket. The released hydrogen is collected by a constant nitrogen stream, and the amount of hydrogen produced is continuously monitored using a thermal conductivity analyzer (FTC200, version 1.05, Wagner).

[0065] The number of moles of hydrogen released is the degree of hydrogenation DH at the end of the dehydrogenation process. マイナス This can be correlated with the results. For each test, the molar percentage of the decomposed DBT (number of remaining moles / number of introduced moles) is determined.

[0066] The results are shown in Table 1 below: TIFF2026139653000001.tif50170

[0067] The above results indicate complete dehydrogenation (DH). マイナス This clearly shows that (=0) results in 5% decomposition of DBT. Partial dehydrogenation process (DH) マイナス >0) significantly reduces the decomposition of DBT, and DH exceeds 0.15. マイナス In such cases, it can be ignored or effectively ignored.

[0068] Therefore, for example, it is possible to assume a series of partial dehydrogenation reactions, where each reaction involves the release of hydrogen, a low percentage of DBT (undegraded DBT) remaining, and even 0.33 DH. マイナス (residual percentage of DBT is 0.99%). After n partial dehydrogenation reactions, and therefore n hydrogen release reactions, the decomposition of DBT is 0.99% at the end of the nth dehydrogenation reaction. n This decomposition is equivalent to keeping it within a perfectly reasonable range.

[0069] Example 2 This example is carried out starting from H12-BT, a hydrogenated form of benzyltoluene (BT) prepared by Arkema.

[0070] A 100 mL three-necked flask equipped with a condenser contains DH プラス The assembly is packed with 0.1 moles of H12-BT characterized by =0.95 and 0.15 mol% of alumina-supported platinum (0.5 wt%) catalyst. The assembly is purged by nitrogen flushing to remove trace amounts of ambient air from the reactor. The mixture is heated to various temperatures using a heating jacket. The released hydrogen is collected by a constant stream of nitrogen, and the amount of hydrogen produced is continuously monitored using a thermal conductivity analyzer (FTC200, version 1.05, Wagner).

[0071] The number of moles of hydrogen released is the degree of hydrogenation DH at the end of the dehydrogenation process. マイナス This can be correlated with the results. For each test, the molar percentage of decomposed BT (number of remaining moles / number of moles introduced in the form of H12-BT) is determined.

[0072] The results are shown in Table 2 below: TIFF2026139653000002.tif38170

[0073] Example 3 This example is carried out starting with H12-BT, a hydrogenated form of benzyltoluene (BT) prepared by Arkema, and describes the changes in the support molecule (referred to as LOHC) over 200 consecutive hydrogenation / dehydrogenation cycles. Each dehydrogenation step is carried out according to the procedure described in Example 2, and each hydrogenation step is carried out in a 300 mL stainless steel batch autoclave. The hydrogenated or partially hydrogenated form of the LOHC molecule is introduced simultaneously with the Ru / Al2O3 catalyst in a molar ratio of 400:1. The reaction is carried out at 150°C with a hydrogen pressure of 50 bar (5 MPa) and a reaction time of 1 hour.

[0074] For each test, the molar percentage of residual BT at the end of 200 cycles (number of residual moles / number of moles introduced in the form of H12-BT) is determined. "Residual BT" means any molecule that is neither BT nor partially or completely hydrogenated BT. Residual BT can be readily analyzed and quantified (in moles) by any suitable analytical means, particularly by GC-MS analysis. More specifically, in the context of this invention, decomposition is measured by fluid analysis at the end of the cycle by coupled gas chromatography / mass spectrometry (GC / MS) in electron ionization and quadrupole analyzer modes.

[0075] Test 3.01 corresponds to a series of complete hydrogenation and dehydrogenation reactions performed at 280°C. Test 3.02 corresponds to a series of partial hydrogenation and dehydrogenation reactions performed at 250°C.

[0076] The results are shown in Table 3 below: DH shown in Table 3 プラス and DH マイナス The value of DH in each cycle プラス and DH マイナス This is the average value calculated from the values ​​of [the specified value]. TIFF2026139653000003.tif29170

[0077] These results indicate that when the cycle is carried out under conditions where the hydrogenation and dehydrogenation reactions are completed, the proportion of residual BT is low, thus representing substantial degradation of the LOHC compound. Conversely, when the hydrogenation and dehydrogenation reactions are only partial, the LOHC compound is significantly less degraded.

Claims

1. A method for producing hydrogen by partial dehydrogenation of an organic liquid, wherein the method is Hydrogenation DH プラス A step of supplying at least one organic liquid having, A step of partially dehydrogenating the aforementioned liquid, Firstly, gaseous hydrogen is recovered, and secondly, the degree of hydrogenation DH マイナス A step of recovering the organic liquid having the following: Includes, Ratio DH プラス / DH マイナス A method in which the endpoint is between 1 and 25, and the endpoint is excluded, preferably between 1.1 and 20, and the endpoint is included.

2. The partial dehydrogenation process, Blocking the reaction before a 100% dehydrogenation yield is obtained. A reaction temperature lower than the temperature commonly used for dehydrogenation reactions, A reaction pressure lower than the pressure commonly used in dehydrogenation reactions, Low-selectivity dehydrogenation catalysts, and Any other means for adjusting the rate of the dehydrogenation reaction, The method according to claim 1, which is carried out by implementing one or more of the means individually or in combination of two or more of them.

3. The method according to claim 1 or 2, wherein the organic liquid is a liquid at room temperature and ambient pressure.

4. The method according to any one of claims 1 to 3, wherein the organic liquid is a mixture of two or more organic liquids that may have the same or different degrees of hydrogenation.

5. The method according to any one of claims 1 to 4, wherein the organic liquid has at least one aromatic ring that may be partially dehydrogenated.

6. Organic liquids are given by general formula (1): (A-X) ｎ -B (1) (In the formula, A and B are the same or different, and independently of each other, represent partially dehydrogenated aromatic rings which may be substituted with one or more saturated, partially or completely unsaturated hydrocarbon groups, and which contain 1 to 20 carbon atoms, preferably 1 to 18 carbon atoms, more preferably 1 to 12 carbon atoms, even more preferably 1 to 10 carbon atoms, even more preferably 1 to 6 carbon atoms, typically 1 to 3 carbon atoms.) X consists of a single bond, an oxygen atom, a sulfur atom, and a divalent group - (CRR'). ｍ - represents a spacer group selected from divalent group > C = CRR' and divalent group -NR'-. R and R' are either the same or different, independently selected from hydrogen and saturated, partially or completely unsaturated hydrocarbon groups containing 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. R'' represents a saturated, partially, or completely unsaturated hydrocarbon group containing 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms. m represents an integer from 1 to 4 that includes the endpoint. n may be equal to 0, or an integer equal to 1, 2, or 3, preferably an integer equal to 1 or 2. However, if n is equal to 0, B is restricted to being substituted with one or more hydrocarbon groups, as defined above. The method according to any one of claims 1 to 5, corresponding to the present invention.

7. The method according to any one of claims 1 to 6, wherein the organic liquid is selected from benzyltoluene (BT), dibenzyltoluene (DBT), partially dehydrogenated homologs thereof, and mixtures thereof in any proportion.

8. Organic liquids satisfy the inequality 0.6 ≤ DH プラス <Hydrogenation degree DH that conforms to 1 プラス The method according to any one of claims 1 to 7, comprising:

9. The organic liquid has a degree of hydrogenation DH satisfying the inequality 0 < DH マイナス ≦ 0.6 マイナス The method according to any one of claims 1 to 8.

10. A hydrogenation / dehydrogenation cycle comprising at least the method according to any one of claims 1 to 9 for producing hydrogen by partial dehydrogenation of a liquid and at least one hydrogenation reaction of an organic liquid.

11. The cycle according to claim 10, comprising one or more dehydrogenation methods, which include at least one of the partial dehydrogenation methods described in any one of claims 1 to 9, before and / or after one or more hydrogenation reactions in an organic liquid capable of storing, transporting and releasing hydrogen.

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