Hydrogen Carrier Compounds

Abstract

The present invention relates to siloxane hydrogen carrier compounds and methods for producing hydrogen from said siloxane hydrogen carrier compounds.

Description

[Technical Field]

[0001] The present invention relates to a siloxane hydrogen carrier compound and a method for producing hydrogen from said siloxane hydrogen carrier compound. The present invention also relates to a method for producing and regenerating said siloxane hydrogen carrier compound. [Background technology]

[0002] The ability to store, transport, and release hydrogen at sources in a safe, convenient, and environmentally friendly manner, as well as to efficiently, economically, and safely produce and store hydrogen, are major challenges that must be overcome to popularize the use of hydrogen as an energy carrier.

[0003] Currently, hydrogen is primarily delivered either by pipeline, as a compressed gas in tube trailers, or in its liquefied form in specialized tankers.

[0004] There are typically six routes for the delivery of hydrogen: hydrogen can be transported by pipeline as a gas; hydrogen can be produced on-site; hydrogen can be transported as a compressed gas in a tube trailer (e.g., as disclosed in U.S. Patent No. 6,223,999); hydrogen can be transported as a condensed liquid in a cryogenic truck (e.g., as disclosed in U.S. Patent No. 6,223,999); hydrogen can be stored in a hydrogen carrier material in the solid state and released on-site (e.g., as disclosed in U.S. Patent No. 6,223,999); and hydrogen can be stored in a hydrogen carrier material in the liquid state and released on-site.

[0005] Hydrogen can be produced on-site by two means. One method produces hydrogen on-site and the other method is defined as capturing hydrogen and consuming it directly. Another means of on-site production is by water electrolysis, which produces hydrogen from water and electricity. When powered by renewable energy, hydrogen production can be considered environmentally friendly.

[0006] In addition to the current delivery solutions of cryogenic and compressed hydrogen, alternative solutions for providing hydrogen, namely hydrogen carriers, are emerging. Hydrogen carriers are materials, either in solid or liquid state, that have the ability to store hydrogen and release it when needed. Hydrogen carriers offer advantages over current solutions for both transportation and storage. Solid-state carriers include metal hydrides, which allow hydrogen uptake by adsorbing onto metal particles to form metal hydrides. Among them, magnesium hydride is stable at low pressures and standard temperatures, making it convenient for transportation and storage. When needed, hydrogen gas is released by heating the material. Solid-state solutions have been identified as ideal for in-situ, reversible processes for energy storage from renewable energy. In practice, handling solid materials is not as convenient as handling gaseous or liquid materials.

[0007] A liquid hydrogen carrier can be any liquid-state material capable of releasing hydrogen under certain conditions. The liquid organic hydrogen carrier (LOHC) class is the most representative of liquid hydrogen carriers. Hydrogen is chemically bound to a liquid organic carrier during a process called hydrogenation, which is a catalytic reaction that requires energy in the form of heat. Typically, as described in U.S. Patent No. 5,627,297 or U.S. Patent No. 5,627,297, the carrier, an unsaturated and / or aromatic hydrocarbon such as toluene, reacts with hydrogen to produce the corresponding saturated hydrocarbon and is transported in liquid form at standard temperature and pressure. The amount of hydrogen stored in a LOHC depends on the yield of the hydrogenation process, but the maximum hydrogen content relative to the mass of the liquid carrier is 7.2% by mass. Hydrogen is then released from the saturated hydrocarbon by a process called dehydrogenation, which is a catalytic reaction that requires additional energy in the form of heat (typically above 300°C) due to the endothermic nature of the reaction. To produce hydrogen on demand, heat can be generated from grid electricity (without control over its origin and its environmental impact) or heat can be recovered by burning a portion of the organic carrier.

[0008] One of the most promising classes of hydrogen carrier compounds are silicon hydrides. In fact, silicon hydrides exhibit theoretical hydrogen weight gravimetric efficiencies of over 10% by weight, and offer the considerable advantage of releasing contained hydrogen in a spontaneous exothermic reaction when contacted with a proton source (e.g., water) and appropriate catalyst(s). Polymethylhydrosiloxane ("PHMS") is an example of a liquid, moisture-, air-, and temperature-stable silicon hydride hydrogen carrier compound. Patent applications U.S. Pat. No. 5,623,499; U.S. Pat. No. 5,623,499; U.S. Pat. No. 5,623,499; and U.S. Pat. No. 5,623,499 relate to methods for producing hydrogen from PHMS.

[0009] However, PHMS presents a major drawback in that it contains carbon fragments that ultimately lead to the emission of carbon oxides (typically CO2), thus preventing a completely carbon-free recycling process.

[0010] Poly(dihydro)siloxanes (“PHS”) represent the most promising carbon-free alternatives to PHMSs, since they may not contain any carbon atoms in their structure, and in addition, they offer a significant improvement in the mass of hydrogen relative to the mass of the liquid carrier (up to 14 wt%).

[0011] PHS can be found in two main structural forms: either linear (hence with chain ends) or cyclic. Prior to our intervention, it was known that both linear and cyclic poly(dihydro)siloxane compounds could be achieved. As an example, in patent application WO 02 / 04791, linear poly(dihydro)siloxanes with carbon-containing chain ends were obtained and used as oils exhibiting low viscosity-temperature coefficients. With the same aim, WO 02 / 04791 discloses the synthesis of linear PHS with various chain ends, while WO 02 / 04791 discloses the synthesis of poly(dihydro)siloxanes of the general formula [(H2SiO) m (Me2SiO) n ] copolymer was obtained. Academic literature also reports the structure ClSiH2O[SiH2O] 23 Examples of the synthesis and characterization of linear species are provided, such as in [1], where a SiH2Cl-centered compound is isolated.

[0012] Regarding cyclic compounds, in Patent Document 13, cyclic dihydrogenpolysiloxanes with weight-average molecular weights ranging from 1,500 to 1,000,000 were synthesized for resin applications. Patent Documents 14 and 15 disclose non-hydrolytic routes using carbonates to obtain cyclic poly(dihydro)siloxanes with structures consisting of 4 to 6 [H2SiO] repeating units. A similar product composition was achieved by the classical H2SiCl2 hydrolysis route in Patent Document 16. Finally, Non-Patent Document 2 shows that a mixture of cyclic poly(dihydro)siloxanes with repeating units ranging from 4 to 23 was obtained by the same method. The product mixture was claimed to be stable in chlorinated solvents at room temperature for several days.

[0013] Our prior invention, Patent Document 17 of Hysilabs, published on November 7, 2019, relates to a method for producing and regenerating a siloxane hydrogen carrier compound. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] International Publication No. 2013 / 109918 Brochure [Patent Document 2] International Publication No. 2011 / 141287 Brochure [Patent Document 3] International Publication No. 2009 / 080986 Brochure [Patent Document 4] International Publication No. 2014 / 082801 Brochure [Patent Document 5] International Publication No. 2015 / 146170 Brochure [Patent Document 6] International Publication No. 2010 / 070001 Brochure [Patent Document 7] European Patent Application Publication No. 2206679 [Patent Document 8] International Publication No. 2011 / 098614 Brochure [Patent Document 9] International Publication No. 2010 / 094785 Brochure [Patent Document 10] U.S. Patent No. 2,547,678 [Patent Document 11] British Patent Application Publication No. 638586 [Patent Document 12] British Patent Application Publication No. 788983 [Patent Document 13] US Patent Application Publication No. 2010188766 [Patent Document 14] International Publication No. 2007 / 118473 Brochure [Patent Document 15] US Patent Application Publication No. 2009041649 [Patent Document 16] U.S. Patent No. 2,810,628 [Patent Document 17] International Publication No. 2019 / 211301 Brochure [Non-patent literature]

[0015] [Non-Patent Document 1] Inorganic Chemistry, Vol. 23, No. 26, 1984, pp. 4412-4417 [Non-patent document 2] Inorganic Chemistry, Vol. 22, No. 15, 1983, pp. 2163-2167 Summary of the Invention [Problem to be solved by the invention]

[0016] Although several reports in the patent and academic literature have shown the achievement of obtaining poly(dihydro)siloxanes, improvements towards more energy-efficient and atom-economical routes are still needed. Furthermore, in order to popularize their unprecedented use as hydrogen carrier compounds, the stability of the isolated products needs to be significantly improved. Indeed, the isolated poly(dihydro)siloxane mixtures need to remain stable over long time ranges, meaning at least on the order of months, rather than days as per current knowledge. [Means for solving the problem]

[0017] Liquid linear siloxane hydrogen carrier compound The present invention relates to a compound of formula (I): [ka] wherein n is an integer (representing the number of repeating units) of 1 or more, preferably 2 or more, such as 3 or more, or even 4 or more, and R and R' comprise Si and hydrogen and / or oxygen and / or halogen, wherein the groups R and R' do not contain carbon and R and / or R' comprise halogen. In one embodiment of the invention, n is 500 or less, such as 50 or less. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 shows an example of the individual method steps of the production of siloxanes. [Figure 2] FIG. 1 shows an example of the individual method steps of the production of siloxanes. [Figure 3] FIG. 1 shows the H NMR spectrum of the Cl—(HSiO)—SiHCl species. [Figure 4] FIG. 1 shows the 29Si NMR spectrum of the Cl—(H2SiO)x—SiH2Cl species. [Figure 5]FIG. 1 shows H production from 1 g of a mixture of ClHSiO—(HSiO)—SiHCl species centered around the ClHSiO—(HSiO)—SiHCl species. DETAILED DESCRIPTION OF THE INVENTION

[0019] As explained and demonstrated below, applicants have discovered that halogen termination on at least one chain end of the carbon-free linear siloxane hydrogen carrier compound of formula (I) above provides numerous advantages over the prior art. In one embodiment of the present invention, both chain ends of the carbon-free linear siloxane hydrogen carrier compound of formula (I) above are halogen terminated.

[0020] In one embodiment of the invention, the carbon-free R and R' groups are selected from -SiH, -SiHX, -SiHX, and SiX, -SiHOH, -SiH(OH), -Si(OH), where X is a halogen, preferably a halogen selected from F, Cl, Br, and I, more preferably Cl, provided that R and / or R' include a halogen.

[0021] An example of a liquid linear siloxane hydrogen carrier compound according to the present invention is HSiOH 2n Si n O n SiH2X, H3SiOH 2n Si n O n SiHX2, H3SiOH 2n Si n O n SiX3, XH2SiOH 2n Si n O n SiH2X, XH2SiOH 2n Si n O n SiHX2, XH2SiOH 2n Si n O n SiH2OH, XH2SiOH 2n Si n O n SiH(OH)2, XH2SiOH2n Si n O n Si(OH)3, X2HSiOH 2n Si n O n SiH2X, X2HSiOH 2n Si n O n SiHX2, X2HSiOH 2n Si n O n SiH2OH, X2HSiOH 2n Si n O n SiH(OH)2, X2HSiOH 2n Si n O n Si(OH)3, X3SiOH 2n Si n O n SiH2X, X3SiOH 2n Si n O n SiHX2, X3SiOH 2n Si n O n SiX3, X3SiOH 2n Si n O n SiH2OH, X3SiOH 2n Si n O n SiH(OH)2, X3SiOH 2n Si n O n Si(OH)3, or a mixture of one or more of these compounds, wherein: X is a halogen, preferably a halogen selected from F, Cl, Br, and I, more preferably Cl, and n is an integer greater than or equal to 1, preferably greater than or equal to 2, such as greater than or equal to 3, or even greater than or equal to 4. In one embodiment of the invention, n is 500 or less, such as 50 or less.

[0022] According to the present invention, the halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound of the present invention has a viscosity of 1.01325×10 at ambient temperature and pressure (NTP), e.g., 20° C. 5 It is a liquid at an absolute pressure of 10 Pa.

[0023] As will be explained and demonstrated below, the halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compounds of the present invention have many advantages, namely: - excellent gravimetric efficiency of the siloxane compounds, i.e. a high ratio of the weight of hydrogen carried by the compound compared to its overall molecular weight; - the recycling of the claimed compounds is simple compared to prior art compounds containing carbon and does not involve any carbon emissions; - A positive effect on stability when combined with other silane / siloxane hydrogen carrier compounds; - further functionalization of the chain ends is possible; Represents.

[0024] The present invention also relates to blends of the claimed liquid linear siloxane hydrogen carrier compounds with cyclic silanes and / or cyclic siloxanes. The classes of cyclic siloxanes that can be advantageously used in the claimed blends are preferably selected from the following compounds:

[0025] Liquid Cyclic Siloxane Hydrogen Carrier Compound The liquid cyclic siloxane hydrogen carrier compounds that may be used in the formulations are advantageously represented by formula (II): [ka] wherein n is an integer (representing the number of repeating units HSiO) greater than or equal to 1, preferably greater than or equal to 2, such as greater than or equal to 3, or even greater than or equal to 4. In one embodiment of the invention, n is 500 or less, such as 32 or less, for example 17 or less.

[0026] In one embodiment according to the present invention, the liquid siloxane hydrogen carrier compounds of formula (I) and formula (II) are prepared at a temperature of 20° C. and 1.01325×10 5In one embodiment according to the present invention, the liquid siloxane hydrogen carrier compounds of formula (I) and formula (II) exhibit a dynamic viscosity of between 0.1 mPa·s and 10,000 mPa·s at a temperature of 20° C. and a pressure of 1.01325×10 5 The siloxane hydrogen carrier compounds of formula (I) and formula (II) exhibit a dynamic viscosity of 0.2 mPa·s to 50 mPa·s at a temperature of 20°C and a viscosity of 1.01325×10 5 The dynamic viscosity at a pressure in Pa can be measured according to any suitable method. For example, the dynamic viscosity can be determined according to the ISO 1628-1 standard.

[0027] In one embodiment of the present invention, the molecular weight of the liquid cyclic siloxane hydrogen carrier compound of formula (II) can be in the range of 130 g / mol to 800 g / mol. The molecular weight of the siloxane hydrogen carrier compound of formula (II) can be measured according to any suitable method. For example, the molecular weight can be determined by GC-MS analysis, for example, performed on an Agilent GC / MSD 5975C instrument.

[0028] In one embodiment of the present invention, the number average molecular weight (Mn) and / or molecular weight distribution (D) of the liquid linear siloxane hydrogen carrier compound of formula (I) can be in the range of 64 g / mol to 30,000 g / mol and 1.1 to 50, respectively. The average molecular weight and molecular weight distribution of the linear siloxane hydrogen carrier compound of formula (I) can be measured according to any suitable method. For example, the average molecular weight and molecular weight distribution can be determined according to ISO 16014 standard.

[0029] In one embodiment according to the present invention, the liquid cyclic siloxane hydrogen carrier compound of formula (II) has a peak at 800 cm corresponding to a SiH unit when analyzed by FT-IR. -1 ~1000cm -1 In one embodiment according to the present invention, the cyclic siloxane hydrogen carrier compound of formula (II) exhibits a characteristic strong and sharp absorption band between 850 cm -1 ~950cm -1 It exhibits a characteristic strong and sharp absorption band between

[0030] In one embodiment according to the present invention, the liquid cyclic siloxane hydrogen carrier compound of formula (II) is prepared by the reaction of 1 When analyzed by H NMR, it exhibits characteristic resonances between 4.5 ppm and 4.9 ppm corresponding to SiHO units. 1 1 H NMR analysis can be carried out on any suitable spectrometer, for example a 400 MHz Bruker spectrometer.

[0031] In one embodiment according to the present invention, the liquid cyclic siloxane hydrogen carrier compound of formula (II) is prepared by the reaction of 29 When analyzed by Si NMR, it exhibits characteristic resonances between -45 ppm and 50 ppm corresponding to SiH2O units. 29 Si NMR analysis can be performed on any suitable spectrometer, for example a 400 MHz Bruker spectrometer.

[0032] In one embodiment according to the present invention, the compound of formula Cl-(H2SiO) x The liquid linear siloxane hydrogen carrier compound of -SiH2Cl was synthesized in CDCl3 at 25 °C as illustrated in Figure 3. 1 When analyzed by H NMR, it exhibits characteristic resonances between 4.5 ppm and 4.9 ppm and between 5.0 ppm and 5.5 ppm, corresponding to SiH2O and SiH2Cl units, respectively. 1 1 H NMR analysis can be carried out on any suitable spectrometer, for example a 400 MHz Bruker spectrometer.

[0033] In one embodiment according to the present invention, the compound of formula Cl-(H2SiO) x The liquid linear siloxane hydrogen carrier compound of -SiH2Cl was synthesized in CDCl3 at 25 °C as illustrated in Figure 4. 29 When analyzed by Si NMR, it exhibits characteristic resonances between -45 ppm and 50 ppm and between 28 ppm and 32 ppm, corresponding to SiH2O and SiH2Cl units, respectively. 29Si NMR analysis can be performed on any suitable spectrometer, for example a 400 MHz Bruker spectrometer.

[0034] In one embodiment of the present invention, the liquid siloxane hydrogen carrier compounds of formula (I) and formula (II) exhibit a refractive index between 1 and 2 at a temperature of 20°C and a wavelength of 589 nm. In one embodiment of the present invention, the liquid siloxane hydrogen carrier compounds of formula (I) and formula (II) exhibit a refractive index between 1.2 and 1.5 at a temperature of 20°C and a wavelength of 589 nm. The refractive index of the siloxane hydrogen carrier compounds of formula (I) and formula (II) can be measured according to any suitable method. For example, the refractive index can be determined according to ASTM D1218 standard.

[0035] In one embodiment according to the present invention, the liquid siloxane hydrogen carrier compounds of formula (I) and formula (II) are 1.01325 x 10 5 The boiling point of the liquid siloxane hydrogen carrier compounds of formula (I) and formula (II) can be measured according to any suitable method. For example, the boiling point can be determined according to the ISO 918 standard.

[0036] In one embodiment of the present invention, the liquid siloxane hydrogen carrier compounds of formula (I) and formula (II) exhibit a flash point between 30°C and 500°C, for example between 50°C and 500°C. The flash point of the siloxane hydrogen carrier compounds of formula (I) and formula (II) can be measured according to any suitable method. For example, the flash point can be determined according to the ISO 3679 standard.

[0037] In one embodiment according to the present invention, the liquid siloxane hydrogen carrier compound of formula (I):

[0038] In one embodiment according to the present invention, the liquid cyclic siloxane hydrogen carrier compound used in the presently claimed formulations consists of any mixture of two or more of the above liquid cyclic siloxane compounds of formula (II).

[0039] According to the present invention, the siloxane hydrogen carrier compound of formula (II) is (at ambient temperature and pressure (NTP) for example, at a temperature of 20° C. and 1.01325×10 5 It is a liquid at an absolute pressure of 10 Pa.

[0040] In one embodiment according to the present invention, the siloxane hydrogen carrier compound of formula (II) is selected from the following cyclic siloxane compounds or consists of any mixture of two or more of the following cyclic siloxane compounds:

[0041] [Table 1-A] [Table 1-B] [Table 1-C] [Table 1-D]

[0042] In one embodiment, the present invention also relates to a hydrogen carrier compound reaction mixture comprising a claimed halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound (or a claimed formulation) and water. For purposes of the hydrogen production method according to the present invention, the water is considered a reactant. The water may advantageously be selected from a variety of sources, such as, for example, fresh water, running water, tap water, salt water, deionized water, and / or distilled water.

[0043] In one embodiment of the present invention, the mixture of siloxane and water is characterized in that the molar ratio of water / [SiOH2] units is greater than or equal to 0.1. In one embodiment of the present invention, the mixture of siloxane and water is characterized in that the molar ratio of water / [SiOH2] units is comprised between 2 and 10, for example between 2 and 2.5.

[0044] For example, the carbon-free liquid linear siloxane hydrogen carrier compound Cl-(H2SiO)x For -SiH2Cl, the corresponding water / [SiOH2] mixture is in the ratio H2O / [SiOH2] = (m H2O / M H2O ) / (m [SiOH2] / M [SiOH2] )=(m H2O / 18) / (m [SiOH2] / 46.11)(in the formula, m H2O is the amount of water in g, and m [SiOH2] The same calculation applies to blends of the claimed liquid linear siloxane hydrogen carrier compounds without terminal carbons and the siloxane hydrogen carrier compounds of formula (II), where m [SiOH2] is the total amount of each siloxane compound in grams.

[0045] In one embodiment, the present invention also relates to a hydrogen-carrier compound reaction mixture comprising a claimed halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound (or a claimed formulation) and at least one hydrogen-releasing initiator, and optionally and preferably water. For purposes of the hydrogen production method according to the present invention, the hydrogen-releasing initiator is considered a reagent. There is no limitation on the type of hydrogen-releasing initiator that can be used according to the present invention, so long as it favors the hydrolytic oxidation of the siloxane hydrogen carrier compound and thus results in the corresponding release of hydrogen by the siloxane reaction. For example, any compound favoring the hydrolytic oxidation of siloxanes can be advantageously used as a hydrogen-releasing initiator.

[0046] In one embodiment according to the present invention, the hydrogen releasing initiator is selected from the following list: an inorganic base, for example, the inorganic base may be an alkali metal hydroxide or an alkaline earth metal hydroxide, such as potassium hydroxide or sodium hydroxide, with sodium hydroxide being particularly preferred; - compounds capable of releasing nucleophiles capable of carrying out the hydrolytic oxidation of siloxane hydrogen carrier compounds, for example compounds of formula R R'R"R"'ZY, where Z is N or P, Y is OH, F, Cl or Br, and R, R', R" and R"' are advantageously C1-C 15 Alkyl or C6-C 10 aryl, where R, R', R", and R"' are the same or different; - protic acids, for example, the protic acids can be mineral acids or organic acids, such as hydrochloric acid, sulfuric acid, carboxylic acids (methanoic acid, ethanoic acid, etc.); - homogeneous organometallic catalysts capable of promoting the hydrolytic oxidation of siloxane hydrogen carrier compounds, such as organometallic complexes based on iron, ruthenium, rhenium, rhodium, copper, chromium, iridium, zinc, and / or tungsten; - heterogeneous catalysts capable of promoting the hydrolytic oxidation of siloxane hydrogen support compounds, such as metal nanoparticles, [M / AlO(OH), M=Pd, Au, Rh, Ru, and Cu], Pd / C, and / or any of the above metals preferably immobilized on an inorganic support; The compound is selected from one or more of the following compounds:

[0047] In one embodiment of the present invention, the hydrogen releasing initiator is selected from carbon-free hydrogen releasing initiators, such as sodium hydroxide.

[0048] In one embodiment, the present invention also relates to a hydrogen-carrier compound reaction mixture comprising a claimed halogen-terminated, carbon-free, liquid linear siloxane hydrogen-carrier compound (or a claimed formulation) and catalyst C, and optionally and preferably a hydrogen-releasing initiator as defined above, and optionally and preferably water. For purposes of the hydrogen-producing method according to the present invention, catalyst C is considered a reagent. There is no limitation on the type of catalyst C that can be used according to the present invention, so long as it enhances the kinetics of the hydrolytic oxidation of the siloxane hydrogen-carrier compound (i.e., the rate at which hydrogen is released), such that the reaction water / siloxane / hydrogen-releasing initiator / catalyst C results in a corresponding release of hydrogen. For example, any compound that significantly enhances the kinetics of the hydrolytic oxidation of siloxane can be advantageously used as catalyst C.

[0049] In one embodiment according to the present invention, catalyst C is selected from the following list: - phosphorus-based catalysts (e.g. polymer-supported catalysts with one or more phosphorus groups), - Amine-based catalysts (e.g., polymer-supported catalysts with one or more amine groups) or ammonium salts, such as R R'R"R"'NOH, where R, R', R", and R"' are C1-C 15 Alkyl or C6-C 10 aryl, and R, R', R", and R"' are the same or different; a fluoride ion source catalyst (e.g., tetrabutylammonium fluoride), and - hexamethylphosphoramide ("HMPA"), - expression [ka] a catalyst Y selected from The compound is selected from one or more of the following compounds:

[0050] In the above formula, Y is O or S, and X1 and X2 are each independently halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C12 Aryl, C6-C 12 aralkyl, 5- to 10-membered heteroaryl, OR 3 , SiR 6 R 7 R 8 wherein the alkyl and aryl groups are selected from the group consisting of 1 to 3 R 9 or substituted by a group X1 and X2 are -CR a R b together with the carbon atom to which they are attached form a 3- to 10-membered cycloalkyl, which optionally contains 1 to 3 R 9 substituted by a group and R a , R b are each independently H, halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C 12 Aryl, C6-C 12 aralkyl, 5- to 10-membered heteroaryl, OR 10 wherein the alkyl and aryl groups are selected from the group consisting of 1 to 3 R 9 or substituted by a group X1 and X2 are NR a R b where R a and R b are each independently H, halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C 12 Aryl, C6-C 12 aralkyl, 5- to 10-membered heteroaryl, OR 10 wherein the alkyl and aryl groups are selected from the group consisting of 1 to 3 R 9 or substituted by a group X1 is halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C 12 Aryl, C6-C 12 aralkyl, 5- to 10-membered heteroaryl, OR 3 , SiR6 R 7 R 8 and X2 is selected from NR a R b where R a and R b are each independently H, halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C 12 Aryl, C6-C 12 aralkyl, 5- to 10-membered heteroaryl, OR 10 wherein the alkyl and aryl groups are selected from the group consisting of 1 to 3 R 9 or substituted by a group X1 and X2 are NR c together with the carbon atom to which they are attached form a 3- to 10-membered heterocycloalkyl, which optionally contains 1 to 3 R 9 substituted by a group and R c H, halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C 12 Aryl, C6-C 12 aralkyl, 5- to 10-membered heteroaryl, OR 10 wherein the alkyl and aryl groups are selected from the group consisting of 1 to 3 R 9 or substituted by a group X1-CR a R b where R a , R b are each independently H, halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C 12 Aryl, C6-C 12 aralkyl, 5- to 10-membered heteroaryl, OR 10 and X2 is selected from NR c together with the carbon atom to which they are attached form a 3- to 10-membered heterocycloalkyl, which optionally contains 1 to 3 R 9substituted by a group, where R c H, halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C 12 Aryl, aralkyl, 5- to 10-membered heteroaryl, OR 10 wherein the alkyl and aryl groups are selected from the group consisting of 1 to 3 R 9 is substituted by a group, R 3 is H, C1-C6 alkyl, C6-C 10 Aryl, C6-C 12 is aralkyl, R 6 , R 7 , R 8 are each independently H, OR 3 , C1-C6 alkyl, C6-C 10 Aryl, C6-C 12 aralkyl, R 9 is halogen, C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C6-C 12 Aryl, C6-C 12 aralkyl, 5- to 10-membered heteroaryl, OR 10 , NO2, NR 11 R 12 , CN, C(=O)R 10 , C(=O)OR 10 , S(=O)CH3, wherein the alkyl and aryl groups are optionally selected from one or more halogen or C1-C 10 Alkyl or OR 3 is replaced by R 10 is H, C1-C6 alkyl, C6-C 10 Aryl, C6-C 12 is aralkyl, and R 11 , R 12 are each independently H or C1 to C 10 alkyl.

[0051] In one embodiment of the present invention, the mixture of siloxane, water, and hydrogen-releasing initiator and catalyst C is characterized in that the molar ratio of hydrogen-releasing initiator / [SiOH2] units is 0.01 or more. In one embodiment of the present invention, the mixture of siloxane, water, and hydrogen-releasing initiator is characterized in that the molar ratio of hydrogen-releasing initiator / [SiOH2] units is between 0.05 and 3, for example between 0.05 and 0.35.

[0052] In one embodiment of the present invention, the mixture of siloxane, water, hydrogen-releasing initiator, and catalyst C is characterized in that the molar ratio of catalyst to [SiOH] monomer units in compound (I) is in the range of 0.01 to 0.5. Preferably, the molar ratio of catalyst C to [SiOH] monomer units in compound (I) is in the range of 0.02 to 0.1. More preferably, the molar ratio of catalyst C to [SiOH] monomer units in compound (I) is less than 0.05, for example equal to 0.04.

[0053] For the above calculation of the molar ratio of initiator and catalyst C to [SiOH2] units, if a selected compound simultaneously meets the definition of a hydrogen-releasing initiator and the definition of catalyst C, it is its total amount that is used for both ratios.

[0054] In another embodiment of the present invention, it has also been found that the claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compounds (and also cyclic siloxane compounds of formula (II)) can be produced from silica and / or silicate compounds without the need for carbon-containing reactants and / or without substantial carbon emissions, preferably without carbon emissions.

[0055] The silica compound according to the present invention may be defined as a silica-containing compound and / or a mixture of two or more of the above silica-containing compounds.

[0056] In one embodiment according to the present invention, the silica compound is Silica compounds of the general formula SiO2,xH2O, [SiO2] n (where n is 2 or greater), or - a mixture of two or more of the above silica compounds; is selected from.

[0057] A silicate compound according to the present invention may be defined as a silicate-containing compound and / or a mixture of two or more of the above silicate-containing compounds.

[0058] In one embodiment according to the present invention, the silicate compound is · General formula Na 2x SiO 2+x Or K 2x SiO 2+x (wherein x is an integer between 0 and 2), or · General formula [SiO x (OH) 4-x ] x- (wherein x is an integer between 0 and 4) or a compound represented by the general formula [SiO x (OH) 4-2x ] n (wherein, when n=1, x=0 or 1, and when n=2, x=1 / 2 or 3 / 2), or Structure (Si2O7) 6- disilicate ion, or the general structure [SiO3 2- ] n , [SiO 11 6- ] n or [Si2O5 2- ] n (where n is 2 or more), or a silicate compound having a polymeric structure such as a macroanion of - a mixture of two or more of the above silicate compounds, is selected from.

[0059] It has also been found that the claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compounds (and also the cyclic siloxane compounds of formula (II)) can be regenerated without the need for carbon-containing reactants and / or without substantial carbon emissions, preferably without carbon emissions.

[0060] The most important advantage of the production / regeneration process of the present invention is that it can be applied continuously, and such a continuous process can also be operated without the need for raw material inputs and / or without the discharge of by-products, as will be explained below.

[0061] Also, by using the claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compounds (and also the claimed formulations): - Hydrogen can be produced in large quantities, in high yield, in a very short time, at a very low production cost, and without any energy input to release the hydrogen; and - by storing energy and recycling the by-products from hydrogen production, it was possible to make the siloxane hydrogen carrier compounds without substantial carbon emissions, preferably without carbon emissions; and - the siloxane hydrogen carrier compounds could be stored at room temperature for several weeks, preferably several months, without loss of their hydrogen content or significant deterioration of their physical and chemical properties; was also found.

[0062] The term "hydrogen carrier compound" can be understood as a chemical compound that can store hydrogen, transport hydrogen, and release hydrogen on demand. A feature of the hydrogen carrier compounds according to the present invention is that they can store / transport / release hydrogen without requiring any energy input (e.g., heat, electricity, etc.).

[0063] Method for producing liquid siloxane hydrogen carrier compounds The present invention relates to a method for producing the claimed liquid siloxane hydrogen carrier compounds from silica and / or silicate compounds without the need for carbon-containing reactants and / or without substantial carbon emissions, preferably without carbon emissions.

[0064] Although silica and / or silicate compounds (B), as defined below, are the preferred source of starting material for the process of producing liquid siloxane hydrogen carrier compounds according to the present invention, silica and / or other silicate-containing minerals, such as zircon, jade, mica, quartz, cristobalite, sand, etc., can be advantageously used as the source of starting material for the process of producing liquid siloxane hydrogen carrier compounds. For purposes of this invention and the appended claims, silica and / or silicate compounds (B) are preferably silica and / or silicate compounds produced from the hydrolytic oxidation of siloxane hydrogen carrier compound(s).

[0065] Method for regenerating siloxane hydrogen carrier compounds The present invention also relates to a method for regenerating a liquid siloxane hydrogen carrier compound as claimed in the claims, comprising the steps of hydrolytically oxidizing the siloxane hydrogen carrier compound to produce hydrogen and a silica and / or silicate compound (B), and converting the silica and / or silicate compound (B) to a liquid siloxane hydrogen carrier compound, wherein the method does not require any carbon-containing reactants and / or does not involve substantial carbon emissions, preferably does not involve carbon emissions.

[0066] The production and regeneration of the claimed liquid siloxane hydrogen carrier compounds according to the present invention will be explained in more detail in the detailed description below. The achievement of developing a corresponding process that does not require carbon-containing reactants and / or does not involve substantial carbon emissions, preferably no carbon emissions, represents a breakthrough in the fields of hydrogen energy, hydrogen transportation, and hydrogen for the automotive industry.

[0067] Hydrogen generation The present invention also relates to a method for producing hydrogen by hydrolytic oxidation of siloxanes in the presence of water, wherein the siloxane is a liquid siloxane hydrogen carrier compound selected from among the liquid siloxanes already claimed hereinbefore, preferably a blend of the siloxanes claimed hereinbefore.

[0068] In one embodiment of the hydrogen generation method according to the present invention, the formulation preferably comprises a mixture in which the molar ratio of the cyclic siloxane of formula (II) to the claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound is in the range of 0.001 to 1, preferably 0.01 to 0.25, more preferably 0.01 to 0.1, e.g., less than 0.05.

[0069] In one embodiment of the hydrogen generation method according to the present invention, the formulation preferably comprises a mixture in which the molar ratio of the claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound to the cyclic siloxane of formula (II) is in the range of 0.001 to 1, preferably 0.01 to 0.25, more preferably 0.01 to 0.1, e.g., lower than 0.05.

[0070] In one embodiment of the method for producing hydrogen according to the present invention, the formulation allows for the presence of a solvent. Any solvent can be used, such as diethyl ether, tetrahydrofuran, methyltetrahydrofuran, cyclohexane, methylcyclohexane, dichloromethane, pentane, heptane, toluene, decahydronaphthalene, with pentane and dichloromethane being particularly preferred.

[0071] In one embodiment of the hydrogen production method according to the present invention, when the cyclic siloxane hydrogen carrier compound of formula (II) represents the predominant species in the amount of substance (in moles) in the formulation (i.e., the molar percentage of the cyclic siloxane of formula (II) relative to the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound of formula (I) is greater than 50 mol %), and the weight percentage of solvent in the formulation is less than 45 wt %, it is advantageous to maintain the molar percentage of the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound of formula (I) relative to the cyclic siloxane of formula (II) greater than 0.005 mol %, preferably greater than 1.0 mol %, more preferably greater than 2.0 mol %.

[0072] In one embodiment of the hydrogen production method according to the present invention, when the cyclic siloxane hydrogen carrier compound of formula (II) represents the predominant species in the amount of substance (in moles) in the formulation (i.e., the molar percentage of the cyclic siloxane of formula (II) relative to the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound of formula (I) is greater than 50 mol %), and the weight percentage of solvent in the formulation is less than 25 wt %, it is advantageous to maintain the molar ratio of the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound of formula (I) to the cyclic siloxane of formula (II) greater than 0.005 mol %, preferably greater than 2.0 mol %, more preferably greater than 5.0 mol %.

[0073] In one embodiment of the hydrogen production method according to the invention, when the linear siloxane hydrogen carrier compound of formula (I) represents the predominant species in the amount of substance (in moles) in the formulation (i.e., the molar percentage of halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound as claimed in formula (I) relative to the cyclic siloxane hydrogen carrier compound of formula (II) is greater than 50 mol %), it is advantageous to limit the weight percentage of solvent in the formulation to less than 20 wt %, preferably less than 10 wt %, and in one embodiment less than 5 wt %, or even less than 2 wt %.

[0074] In one embodiment of the present invention, the liquid siloxane hydrogen carrier compound claimed in formula (I) comprises a mixture of two or more of the above liquid linear siloxane compounds of formula (I), preferably comprising at least 50 mol %, e.g., more than 80 mol %, of compounds of formula (I) where n is between 10 and 30 (i.e., having between 10 and 30 repeating HSiO units), based on the total number of moles of siloxane hydrogen carrier compounds of formula (I) in the mixture.

[0075] In one embodiment of the invention, the method for producing hydrogen is characterized in that the molar ratio of water / [SiOH2] units is greater than or equal to 0.1. In one embodiment of the invention, said mixture of siloxane and water is characterized in that the molar ratio of water / [SiOH2] units is comprised between 2 and 10, for example between 2 and 2.5.

[0076] In one embodiment of the present invention, the method for producing hydrogen is characterized in that at least one hydrogen-releasing initiator is present during the hydrolytic oxidation of siloxane in the presence of water. There are no limitations on the type of hydrogen-releasing initiator that can be used according to the present invention, as long as it is beneficial for the hydrolytic oxidation of the siloxane hydrogen carrier compound of formula (I) and thus results in the corresponding release of hydrogen upon the water / siloxane reaction. For example, any compound beneficial for the hydrolytic oxidation of siloxane can be advantageously used as a hydrogen-releasing initiator. Useful hydrogen-releasing initiators have already been defined herein above. In one embodiment of the present invention, the mixture of siloxane, water, hydrogen-releasing initiator, and optional catalyst C is characterized in that the molar ratio of hydrogen-releasing initiator / [SiOH] units is 0.01 or greater. In one embodiment of the present invention, the mixture of siloxane, water, and hydrogen-releasing initiator is characterized in that the molar ratio of hydrogen-releasing initiator / [SiOH] units is between 0.05 and 3, for example, between 0.05 and 0.35.

[0077] In one embodiment of the present invention, a method for producing hydrogen is characterized in that a mixture of a siloxane hydrogen carrier compound of formula (I), water, a hydrogen-releasing initiator as defined above, and catalyst C is present. There are no limitations on the type of catalyst C that can be used according to the present invention, as long as it enhances the kinetics of the hydrolytic oxidation of the siloxane hydrogen carrier compound of formula (I) (i.e., the rate at which hydrogen is released), and thus the reaction water / siloxane / hydrogen-releasing initiator / catalyst C results in a corresponding release of hydrogen. For example, any compound that significantly enhances the kinetics of the hydrolytic oxidation of siloxane can be advantageously used as catalyst C. Useful catalysts C have already been defined herein above. In one embodiment of the present invention, the mixture of siloxane, water, hydrogen-releasing initiator, and catalyst C is characterized in that the molar ratio of catalyst to [SiOH] monomer units in compound (I) is in the range of 0.01 to 0.5. Preferably, the molar ratio of catalyst C to [SiOH] monomer units in compound (I) is in the range of 0.02 to 0.1. More preferably, the molar ratio of catalyst C to [SiOH2] monomer units in compound (I) is lower than 0.05, for example equal to 0.04.

[0078] There are no limitations as to the methods that can be used for the hydrogen production method according to the present invention, as long as the release of hydrogen from the claimed hydrogen carrier compounds may not require additional energy and meets the requirements of the hydrogen industry.

[0079] In one embodiment of the present invention, the temperature of the claimed method for producing hydrogen from siloxane hydrogen carrier compounds can vary over a wide range, particularly from 0° C. to 200° C. More preferably, the temperature is in the range of 15° C. to 30° C.

[0080] In one embodiment of the present invention, the pressure of the claimed method for producing hydrogen from siloxane hydrogen carrier compounds can range over a wide range, particularly from 1×10 5 Pa~500×10 5 The range can be Pa.

[0081] In one embodiment of the present invention, the method for producing hydrogen from the claimed siloxane hydrogen carrier compound can tolerate the presence of a solvent. There is no limitation on the type of solvent that can be used in the hydrogen production method of the present invention, as long as the hydrogen release from the claimed hydrogen carrier compound meets the requirements of the hydrogen industry. In one embodiment of the present invention, the solvent is selected from alcohol (e.g., methanol), an aqueous solvent, an organic solvent, and / or a mixture of two or more of the above solvents. For the purposes of the hydrogen production method of the present invention, the solvent is considered a reagent.

[0082] In one embodiment according to the present invention, a method for producing hydrogen from a claimed siloxane hydrogen carrier compound comprises the steps of: a) contacting a cyclic siloxane hydrogen carrier compound of formula (II) and optional catalyst C with a claimed halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound (or mixtures thereof) to form a siloxane / catalyst mixture; and b) combining the siloxane with an aqueous solution of a hydrogen-releasing initiator in the presence of the optional catalyst C to produce hydrogen. Steps a) and b) can be performed sequentially or simultaneously.

[0083] In one embodiment according to the present invention, the reaction mixture used in the method for producing hydrogen from a siloxane hydrogen carrier compound comprises: - a halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound according to claim 1, - a cyclic siloxane hydrogen carrier compound of formula (II), - the corresponding silicate-type by-products, - hydrogen, - water, - hydrogen-releasing initiator(s), and an optional catalyst C, and - any solvent, It is characterized in that it represents at least 90% by weight of said reaction mixture, preferably at least 95% by weight, for example at least 99% by weight.

[0084] In one embodiment, the present invention also provides a device for producing hydrogen according to the method described hereinabove, comprising: - an inlet for a reaction mixture comprising a siloxane hydrogen carrier compound of formula (I) and an optional solvent; - a hydrogen outlet; optionally a by-product collector; - a surface intended to come into contact with said mixture, optionally coated with a polymer-supported catalyst as described herein above, The present invention relates to a device comprising a reaction chamber comprising:

[0085] Production of liquid siloxane and regeneration of liquid siloxane As explained hereinabove, it is also an object of the present invention to produce and regenerate the claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compounds in an environmentally friendly manner and / or without substantial carbon emissions, preferably without carbon emissions, by recycling the by-products from hydrogen production.

[0086] The present invention therefore relates to a method for producing the claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compounds from silica and / or silicate compounds, preferably from silica and / or silicate compounds (B), without the need for carbon-containing reactants and / or without substantial carbon emissions, preferably without carbon emissions.

[0087] The present invention also relates to a method for regenerating a claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound, comprising the steps of hydrolytically oxidizing a claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound to produce hydrogen and silica and / or silicate compound(s) (B), and converting the silica and / or silicate compound(s) (B) to a claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound, preferably a claimed halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound, wherein the method does not require any carbon-containing reactants and / or does not involve substantial carbon emissions, preferably does not involve carbon emissions.

[0088] In one embodiment according to the present invention, there is provided a method for producing halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s), comprising the following sequential steps: providing a silica compound and / or a silicate compound; ○ For reaction path Y, subjecting silica and / or silicate compounds to a reduction step to produce silicon; ○ In the case of reaction path Z, subjecting a silica compound and / or silicate compound to a halogenation step to produce silicon tetrahalides; and subjecting the silicon tetrahalide to a reduction step to produce silicon; For reaction paths Y and Z, subjecting silicon to a hydrohalogenation process to produce a halosilane; and subjecting the halosilane to a hydrolysis step to produce halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s); The method comprises reaction pathway Y or reaction pathway Z comprising:

[0089] Silicates / Silica In one embodiment of the present invention, i.e., when silicates are selected as starting materials for the siloxane production / regeneration process, additional processing of the silicates (e.g., solvent evaporation, chemical treatment with acids, pyrolysis, etc.) can be advantageously used to obtain silica (SiO2), which is used as raw material for the siloxane process.

[0090] In one embodiment of the present invention, the silica and / or silicate compounds may be subjected to additional mechanical treatment, such as grinding and / or sieving, before being subjected to the reduction step of reaction pathway Y and / or the halogenation step of reaction pathway Z.

[0091] In one embodiment of the present invention for reaction pathway Y, the initial step of subjecting silica and / or silicate compounds to a reduction step to form silicon can be carried out in one or two steps, for example in a one-step reduction process or a two-step reduction process with intermediate formation of SiO.

[0092] For purposes of this specification and the appended claims, the following numbering has been used for the individual reaction steps: - For reaction path Z, The halogenation of silica and / or silicate compounds to form silicon tetrahalides corresponds to step 2(a). Any suitable halide source can be used in step 2(a) as long as it favors the formation of silicon tetrahalides; Step 3(a') and / or step 3(b) correspond to the reduction of silicon tetrahalide to form silicon; - For reaction path Y, step 2(c) corresponds to the reduction of silica and / or silicate compounds to form silicon in one step; Steps 2(b) and 3(c) correspond to the two-step reduction of silica and / or silicate compounds to produce silicon; - in the case of reaction paths Y and Z, Step 4 corresponds to the hydrohalogenation of silicon to produce halosilanes; Step 5 corresponds to the hydrolysis of the halosilane to produce halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s).

[0093] For illustrative and non-limiting purposes, FIG. 1 details one example of a method for producing siloxanes, and FIG. 2 shows example individual method steps. In step 3(b) of FIG. 2, when Na is used as the reducing agent (step 3(b)), the 4 equivalents of NaF formed are recycled to regenerate 4Na and 4HF in a manner not disclosed here. In step 3(c) of Figure 2, when the route of hydrogen gas reduction of SiO is used (step 3(c)), two equivalents of Si are formed. One equivalent of Si may advantageously be reinjected into step 2(b) to avoid introducing Si into the process, and the other equivalent (the "excess" content) is advantageously consumed in the subsequent step 4 of the process. In FIG. 2, step 4 of the production method is a multi-step process not fully disclosed here.

[0094] In one embodiment according to the present invention, there is provided a method for regenerating halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s), comprising hydrolytically oxidizing the halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s) to produce hydrogen and silica and / or silicate compound (B), followed by the following successive steps: ○ For reaction path Y, subjecting the silica compound and / or silicate compound (B) to a reduction step to produce silicon, subjecting silicon to a hydrohalogenation process to produce a halosilane; and subjecting the halosilane to a hydrolysis step to regenerate halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s), preferably the same halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s); ○ In the case of reaction path Z, subjecting the silica and / or silicate compound (B) to a halogenation step to produce silicon tetrahalides; subjecting the silicon tetrahalide to a reduction step to produce silicon; subjecting silicon to a hydrohalogenation process to produce a halosilane; and subjecting the halosilane to a hydrolysis step to regenerate the halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s), preferably the same halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s); The method includes carrying out reaction pathway Y or reaction pathway Z, wherein the reaction pathway Y comprises:

[0095] The regenerated halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s) can be advantageously used in the hydrogen production method of the present invention, thereby allowing the cycle to begin again.

[0096] A major advantage offered by the polydihydrosiloxane compounds according to the invention as hydrogen-based energy carriers is that their complete hydrolysis during the hydrogen liberation process inherently yields silica / silicate compound(s) (B), which are direct starting materials for environmentally friendly and / or carbon-emission-free processes, allowing the recovery of the exact starting fuel oil by the exhaustively exemplified atom-economical regeneration methods.

[0097] Step 2(a)—Halogenation of Silica / Silicate-Type Products (Pathway Z) In one embodiment of the present invention, a method is provided for halogenating a silica / silicate compound (B) with a halide source to produce a silicon tetrahalide compound. Any halide source can be advantageously used. Hydrogen halide is a preferred halide source. The hydrogen halide can advantageously be an aqueous solution or a gas, such as hydrogen fluoride (HF). For example, when hydrogen fluoride is used in the halogenation step, silicon tetrafluoride and water as a by-product are formed. The water can be collected and reused in further process steps, or it can be electrolyzed to form hydrogen gas and oxygen gas, where the hydrogen gas is consumed, for example, directly by the next process step.

[0098] Step 2(b)—Formation of SiO by Reduction of Silica / Silicate-Type Product (First Step of Reduction in Reaction Pathway Y-2) In one embodiment of the present invention, a method is provided for reducing a silica / silicate compound (B) in the presence of elemental silicon to produce SiO. Any source of elemental silicon can be advantageously used. Metallurgical grade silicon is a preferred source of elemental silicon. Because elemental silicon is used in the reduction step, two equivalents of SiO are formed per converted silicate. The formed SiO is directly consumed, for example, by step 3(c) of the method.

[0099] An example of a method for producing Si from a silica / silicate compound (B), in this case represented as silica (SiO2), which is a combination of steps 2(b) and 3(c), can be found in Figure 1.

[0100] Step 2(c)—Reduction of Silica / Silicate-Type Products to Form Si (Reduction Pathway Y-1) In one embodiment of the present invention, a method is provided for producing elemental silicon by reducing a silica / silicate compound (B) in the presence of hydrogen gas. The produced elemental silicon can be either metallurgical or photovoltaic grade. In addition to hydrogen, other gas(es), such as inert gases such as argon or nitrogen, can optionally be used. Since the reduction reaction of silica / silicate compounds with hydrogen is an endothermic reaction, a heat source is required. Any heat source can be selected, such as electric arc technology, induction heating, microwaves, hot filaments, or plasma technology. Plasma is particularly preferred. For example, the corresponding plasma technology can advantageously include a plasma torch capable of generating a plasma jet. The plasma jet is preferably produced from hydrogen gas with or without additional gas(es) (e.g., argon) passing through an electrode. After introducing silica into the hydrogen plasma jet under vacuum, it can react with hydrogen in the gas phase at temperatures between 2000 K and 20,000 K to form silicon and water. The silicon is then condensed and recovered as a solid.

[0101] The reduction reaction of silica / silicate compounds with hydrogen gas produces water as a by-product. The water formed can be advantageously used as a chemical reactant and / or as a heat source for other uses, and / or it can be converted in an electrolyzer to reform hydrogen gas, and / or it can be used to power a steam turbine to generate electricity.

[0102] Step 3(a') - Reduction of silicon tetrahalides In one embodiment according to the present invention, a method is provided for producing elemental silicon by reducing a silicon tetrahalide compound with hydrogen gas (e.g., hydrogen formed by electrolysis of water collected from a previous step, or hydrogen recovered from another process step, or unavoidable hydrogen collected from an external process) [Step 3(a')]. When silicon tetrafluoride (SiF) is used as the silicon tetrahalide source, the reduction step using hydrogen gas can provide elemental silicon and release hydrogen fluoride (HF) as a by-product [Step 3(a')]. The HF formed can be advantageously reinjected into the halogenation step [Step 2(a)] to balance the mass balance across steps (2) and (3) of the production / regeneration method.

[0103] Step 3(b) - Reduction of the tetrahalogenated silicon compound In one embodiment of the present invention, a method is provided for producing elemental silicon by reducing a silicon tetrahalide compound with a metal reducing agent.The metal reducing agent can be advantageously selected as an alkali metal, such as sodium.The reduction step using an alkali metal, such as sodium, produces elemental silicon and may release sodium fluoride (NaF), where the sodium fluoride (NaF) is advantageously recycled in a multi-step process to regenerate Na and HF.The regenerated Na is advantageously reused as a reducing agent in step 3(b) described herein, thereby achieving a balanced mass balance.The regenerated HF is advantageously reused, for example, in step 2(a) of the method, thereby achieving a balanced mass balance.

[0104] Step 3(c)—Reduction of SiO with hydrogen gas In one embodiment according to the present invention, a method is provided for reducing SiO with hydrogen gas to produce elemental silicon, where a portion of the produced elemental silicon is advantageously reinjected in step 2(b) to avoid input of elemental silicon in the method, and another portion of the produced elemental silicon ("excess") is directly consumed in the subsequent hydrohalogenation step 4 of the method.

[0105] Step 4 - Hydrohalogenation of elemental silicon In one embodiment according to the present invention, a method is provided for hydrohalogenating elemental silicon to produce halosilanes, such as monohalosilanes (HSiX), dihalosilanes (HSiX), trihalosilanes (HSiX), and / or tetrahalosilanes (SiX), or mixtures of these compounds (where X is a halide). The elemental silicon used in the hydrohalogenation step preferably originates from a previous step in the process. Hydrogen chloride (HCl) is the preferred hydrogen halide source for the hydrohalogenation of elemental silicon to dichlorosilanes (HSiCl) and / or trichlorosilanes (HSiCl) and / or tetrachlorosilanes (SiCl). The hydrogen chloride can advantageously be an aqueous solution or a gas. When hydrogen chloride is used, the method can be designed to redistribute HSiCl, the primary product of the silicon hydrochlorination reaction, into a mixture of HSiCl, HSiCl, HSiCl, and SiCl by catalytic disproportionation. SiCl4 can be recycled, advantageously via reduction, by reducing it with hydrogen gas in the presence of elemental silicon to a mixture of HSiCl2, HSiCl3, and SiCl4. The elemental silicon used in the SiCl4 reduction step preferably comes from a previous step in the process. The hydrogen gas used in the SiCl4 reduction step can advantageously be a by-product of another step in the process, such as the above-mentioned elemental silicon hydrohalogenation step. Several subsequent separation and purification steps make it possible to isolate pure HSiCl2 (or generally HSiX2, where X is a halogen) which can be consumed directly in the next step (5) of the process.

[0106] In one embodiment of the present invention, the halosilane (H2SiX2 reactant) is subjected to a condensation step prior to the addition of water, during which the temperature of the reaction medium is maintained between -50°C and 0°C, preferably between -45°C and 25°C.

[0107] Step 5 - Controlled Hydrolysis of Halosilane In one embodiment of the present invention, a method for the controlled hydrolysis of halosilanes with water to produce / regenerate siloxane hydrogen carrier compounds is provided. When H2SiCl2 is used as the halosilane source for the controlled hydrolysis, HCl is formed as a by-product. The HCl formed can be advantageously reinjected in step 4 of the method. When H2SiF2 is used as the halosilane source for the controlled hydrolysis, HF is formed as a by-product. The HF formed can be advantageously reinjected in step 2(a) of the method. The hydrolysis can advantageously be carried out under operating conditions characterized by a [H2O / H2SiX2] molar ratio of less than 0.99, preferably less than 0.98. In one embodiment of the present invention, this ratio is greater than 0.2, preferably greater than 0.25, for example greater than 0.3. The hydrolysis can advantageously be carried out under a controlled atmosphere, such as argon, nitrogen, or the like. The hydrolysis can advantageously be carried out in the presence of a solvent. Any solvent can be used, such as diethyl ether, tetrahydrofuran, methyltetrahydrofuran, cyclohexane, methylcyclohexane, dichloromethane, pentane, heptane, toluene, decahydronaphthalene, with pentane and dichloromethane being particularly preferred. The hydrolysis can be advantageously carried out under operating conditions characterized by a volume of solvent per weight of H2SiX2 of less than 10, preferably less than 8. The hydrolysis can be advantageously carried out under operating conditions characterized by a rate of addition of water to the reaction medium of preferably more than 0.05 mL / min.

[0108] In one embodiment according to the invention, the rate of addition of water to the reaction medium is greater than 0.05 mL of water per 20 g of HSiX per minute, e.g., greater than 0.075 mL of water per 20 g of HSiX per minute, and more preferably greater than or equal to 0.25 mL of water per 20 g of HSiX per minute. For example, if the reaction medium contains 1 kg of HSiX, the rate of addition of water to the reaction medium is greater than 2.5 mL of water per minute, preferably greater than 3.75 mL of water per minute, and most preferably greater than 12.5 mL of water per minute.

[0109] In one embodiment according to the invention, the rate of addition of water to the reaction medium is less than 5.00 mL of water per 20 g of HSiX per minute, such as less than 4.00 mL of water per 20 g of HSiX per minute, more preferably less than 3.50 mL of water per 20 g of HSiX per minute.

[0110] Said hydrolysis can advantageously be carried out under operating conditions characterized by a volume of solvent per weight of water of less than 50 mL / g, preferably less than 45 mL / g.

[0111] The hydrolysis is exothermic, and therefore the temperature of the reaction medium is preferably maintained between -50°C and +100°C, for example between -50°C and +50°C, more preferably between -40°C and 30°C, throughout the reaction period.

[0112] During the step of adding water, the temperature of the reaction medium is preferably maintained between -50°C and 0°C, more preferably between -45°C and 25°C.

[0113] Once the addition of water is complete, the reaction is continued and the reaction medium is warmed to a temperature not exceeding 30° C. For example, the temperature of the reaction medium is warmed from −30° C. to 20° C. over a certain period of time, for example 1 hour 30 minutes.

[0114] The hydrolysis may advantageously be carried out in the presence of a chain terminator, preferably a carbon-free chain terminator, such as H3SiCl, HSiCl3, and the like.

[0115] An illustrative example of an equation showing the chemical equilibrium that occurs during step 5 of the present invention is shown below: nH2SiCl2+(ny)H2O→yCl-(H2SiO) x -SiH2Cl+2(ny)HCl where n, y, z, and x are integers, n is the number of H2SiCl2 molecules in the reaction medium, and y is the composition Cl-(H2SiO) x-SiH2Cl polymer chain number, where x is the number of (H2SiO) repeat units.

[0116] Final processing steps such as washing with water with or without inorganic bases, gas stripping, drying steps, quenching, distillation under reduced pressure, etc. may be advantageously carried out.

[0117] In one embodiment according to the present invention, the liquid linear siloxane hydrogen carrier compound(s) are obtained by distillation of the crude reaction mixture under reduced pressure, the liquid linear siloxane hydrogen carrier compound(s) representing the heavy fraction.

[0118] In one embodiment according to the present invention, the energy consumption required by the entire method for producing the siloxane hydrogen carrier of formula (I) can be between 1 kWh and 200 kWh per kg of siloxane produced, for example, between 1 kWh and 35 kWh per kg of siloxane produced.

[0119] In one embodiment according to the present invention, the energy consumption required by the entire method for regenerating the siloxane hydrogen carrier of formula (I) can be between 1 kWh and 2000 kWh per kg of H released, for example, between 1 kWh and 400 kWh per kg of H released.

[0120] In one embodiment according to the present invention, the energy consumption required by step 2(a) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) may be comprised between 1 kWh and 50 kWh per kg of SiF produced.

[0121] In one embodiment of the present invention, the temperature of the process for producing SiF4 in step 2(a) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can vary over a wide range, particularly from 0°C to 1000°C.

[0122] In one embodiment of the present invention, the pressure of the process for producing SiF in step 2(a) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, in particular from 1 Pa to 1×10 7 The range can be Pa.

[0123] In one embodiment of the present invention, step 2(a) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) is characterized in that the molar ratio of the mixture of hydrogen fluoride (HF) / silicate compound (B) is greater than or equal to 1. In one embodiment of the present invention, said mixture of HF and silicate compound (B) is characterized in that the molar ratio of HF / (B) is comprised between 4 and 100.

[0124] In one embodiment according to the present invention, the number of unit operations (e.g., reaction, separation, purification, etc.) required by step 2(a) of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can be comprised between 1 and 10.

[0125] In one embodiment according to the present invention, the energy consumption required by step 2(b) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) may be comprised between 1 kWh and 50 kWh per kg of SiO produced.

[0126] In one embodiment according to the present invention, the temperature of the process for producing SiO in step 2(b) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can vary over a wide range, in particular in the range of 1000°C to 2000°C.

[0127] In one embodiment of the present invention, the pressure of the process for producing SiO in step 2(b) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, in particular from 1 Pa to 1×10 7 The pressure may be in the range of 100 Pa to 10,000 Pa. More preferably, the pressure is in the range of 100 Pa to 10,000 Pa.

[0128] In one embodiment of the present invention, step 2(b) of the method for producing a siloxane hydrogen carrier of formula (I) is characterized in that the mixture of silicate compound (B) / Si has a molar ratio of 0.1 or more. In one embodiment of the present invention, the mixture of silicate compound (B) and Si has a molar ratio of compound (B) / Si comprised between 0.5 and 1.5. Preferably, the molar ratio of silicate compound (B) / Si is 1.

[0129] In one embodiment according to the present invention, the number of unit operations (e.g., reaction, separation, purification, etc.) required by step 2(b) of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can be comprised between 1 and 10.

[0130] In one embodiment according to the present invention, the energy consumption required by step 2(c) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) may be comprised between 1 kWh and 50 kWh per kg of Si produced.

[0131] In one embodiment of the present invention, the temperature of the process for producing Si in step 2(c) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, particularly from 30°C to 6000°C.

[0132] In one embodiment of the present invention, the pressure of the process for producing Si in step 2(c) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, in particular from 1 Pa to 1×10 7 The pressure may be in the range of 10 Pa to 10,000 Pa. More preferably, the pressure is in the range of 10 Pa to 10,000 Pa.

[0133] In one embodiment of the present invention, step 2(c) of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) is characterized in that the molar ratio of the mixture of H gas / silicate compound (B) is 0.1 or more. In one embodiment of the present invention, the mixture of H gas and silicate compound (B) is characterized in that the molar ratio of H gas / compound (B) is comprised between 2 and 100, preferably between 2 and 20.

[0134] In one embodiment according to the present invention, the number of unit operations (e.g., reaction, separation, purification, etc.) required by step 2(c) of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can be comprised between 1 and 10.

[0135] In one embodiment according to the present invention, the energy consumption required by step 3(a') of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) may be comprised between 1 kWh and 50 kWh per kg of Si produced.

[0136] In one embodiment of the present invention, the temperature of the process for producing Si in step 3(a') of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, particularly from 30°C to 6000°C.

[0137] In one embodiment of the present invention, the pressure of the process for producing Si in step 3(a') of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, in particular from 1 Pa to 1 x 10 7 The range can be Pa.

[0138] In one embodiment of the present invention, step 3(a') of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) is characterized in that the molar ratio of the mixture of hydrogen gas (H2) / SiF4 is equal to or greater than 2. In one embodiment of the present invention, the mixture of H2 and SiF4 is characterized in that the molar ratio of H2 / SiF4 is comprised between 2 and 100.

[0139] In one embodiment according to the present invention, the energy consumption required by step 3(b) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) may be comprised between 1 kWh and 50 kWh per kg of Si produced.

[0140] In one embodiment of the present invention, the temperature of the process for producing Si in step 3(b) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, particularly from 100°C to 1000°C.

[0141] In one embodiment of the present invention, the pressure of the process for producing Si in step 3(b) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, in particular from 1 Pa to 1×10 7 The range can be Pa.

[0142] In one embodiment of the present invention, step 3(b) of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) is characterized in that the molar ratio of the mixture of sodium (Na) / SiF4 is greater than or equal to 1. In one embodiment of the present invention, the mixture of Na and SiF4 is characterized in that the molar ratio of Na / SiF4 is comprised between 4 and 100.

[0143] In one embodiment according to the present invention, the number of unit operations (e.g., reaction, separation, purification, etc.) required by step 3(b) of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can be comprised between 1 and 10.

[0144] In one embodiment according to the present invention, the energy consumption required by step 3(c) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) may be comprised between 1 kWh and 50 kWh per kg of Si produced.

[0145] In one embodiment of the present invention, the temperature of the process for producing Si in step 3(c) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, particularly from 500°C to 2000°C.

[0146] In one embodiment of the present invention, the pressure of the process for producing Si in step 3(c) of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can range over a wide range, in particular from 1 Pa to 1×10 7The range can be Pa.

[0147] In one embodiment of the present invention, step 3(c) of the method for producing / regenerating a siloxane hydrogen carrier of formula (I) is characterized in that the mixture of hydrogen gas (H2) / SiO has a molar ratio of at least 1. In one embodiment of the present invention, said mixture of H2 and SiO has a molar ratio of H2 / SiO comprised between 5 and 10. In one embodiment of the present invention, said mixture of H2 and SiO has a molar ratio of H2 / SiO of 6.

[0148] In one embodiment according to the present invention, the number of unit operations (e.g., reaction, separation, purification, etc.) required by step 3(c) of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) may be comprised between 1 and 10.

[0149] In one embodiment according to the present invention, the energy consumption required by step 4 of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can be comprised between 1 kWh and 50 kWh per kg of [H2SiX2, preferably H2SiCl2] produced.

[0150] In one embodiment according to the present invention, the number of unit operations (e.g., reaction, separation, purification, etc.) required by step 4 of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can be comprised between 1 and 20.

[0151] The controlled hydrolysis of the halosilane of step 5 according to the present invention can be advantageously illustrated as shown in FIG.

[0152] In one embodiment according to the present invention, the energy consumption required by step 5 of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can be comprised between 1 kWh and 50 kWh per kg of [H2SiO] produced, where [H2SiO] is the repeating unit in the siloxane hydrogen carrier of formula (I).

[0153] In one embodiment according to the present invention, the process temperature in step 5 of the process for producing / regenerating the siloxane hydrogen carrier of formula (I) can vary over a wide range, in particular from -50°C to 100°C.

[0154] In one embodiment of the present invention, the pressure in the method for producing the siloxane hydrogen carrier of formula (I) in step 5 of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can range in a wide range, particularly from 1 Pa to 1 × 10 7 The range can be Pa.

[0155] In one embodiment according to the present invention, the number of unit operations (e.g., reaction, separation, purification, etc.) required by step 5 of the method for producing / regenerating the siloxane hydrogen carrier of formula (I) can be comprised between 1 and 10.

[0156] The following terms and expressions contained herein are defined as follows: - Hydrogen carriers are materials, either in solid or liquid state, that contain hydrogen atoms and can be readily released as molecular dihydrogen (H2) when required.

[0157] It should be apparent to those skilled in the art that the present invention allows for embodiments under many other specific forms without departing from the field of application of the invention as defined by the claims. Therefore, the present embodiments should be considered as examples and may be modified to the extent defined by the appended claims, and the invention should not be limited to the details given above. [Example]

[0158] Example 1: ClHSiO—(HSiO) x Example of synthesis of a mixture of -SiH2Cl species [ka]

[0159] A 250 mL double-jacketed glass reactor was charged with diethyl ether (70 mL, 3.5 volumes of solvent per weight of dichlorosilane) under an inert atmosphere and then cooled to −40° C. Dichlorosilane (20 g) was introduced into the reactor by bubbling in diethyl ether with stirring at −40° C. Distilled water (3.3 mL, 0.25 mL / min) was added dropwise, while the reaction medium was maintained below −30° C. by controlled reactor cooling along with this controlled water addition. By controlling the reactor temperature (e.g., by reducing or stopping reactor cooling, or even by heating the reactor), the reaction could be allowed to warm to 20° C. over 1 hour and 30 minutes.

[0160] The crude mixture was purified by distillation, resulting in the isolation of two fractions: - 43.8 g of a volatile fraction containing diethyl ether and a cyclic siloxane hydrogen carrier of formula (II). These compounds accounted for 4% ( 1 1 H NMR) in diethyl ether solution, corresponding to 1.7 g of the cyclic compound. - 5.97 g of non-volatile fraction was obtained as a colorless liquid. This fraction consisted of ClH2SiO-(H2SiO) centered on the average structure x=14 (hence, average molar mass of 793 g / mol). x -SiH2Cl species mixture ( 1 (Isolated yield = 51%, ClHSiO-(HSiO) in the mixture) x -SiH2Cl species mole fraction = 83%).

[0161] Example 2: (HSiO) x / ClH2SiO-(H2SiO) x -SiH2Cl mixture synthesis example In a 250 mL Schlenk flask, itself connected to a -25 °C refrigerant and connected to a NaOH trap, dry dichloromethane (160 mL) was introduced under an inert atmosphere. After the reaction medium was cooled to -25 °C via a liquid nitrogen bath, dichlorosilane (20.0 g, 0.198 mol) was introduced. The liquid nitrogen bath was replaced with an ice bath. The reaction was warmed to 0 °C, and water (0.186 mol, 0.94 eq) was introduced via a syringe pump (4.45 mL / h). The reaction was left under stirring for 1 hour. The reaction was warmed to 25 °C over 1 hour. The reaction was then degassed for 1 hour via nitrogen stripping. The crude mixture was distilled under reduced pressure to obtain 10.5 g of a colorless liquid. The product was obtained by distilling in CDCl3. 1 H NMR and 29 Analyzed by Si NMR: 1 H NMR(CDCl3,273K),400MHz:δ 4.71(s,2H,SiH2); 29 Si NMR(CDCl3,273K),400MHz:δ -47.04(s,(H2SiO)4),δ -48.77(s,(H2SiO)5),δ -49.09(s,(H2SiO)6),δ -49.17(s,(H2SiO)7),δ -49.24(s,(H2SiO) 8+ ),δ -22.0(s,OSiCl),δ -28.47(s,OSiCl),δ -29.98(s,OSiCl),δ -30.30(s,OSiCl),δ -30.41(s,OSiCl),δ -46.78(s,OSiCl),δ -47.75(s,OSiCl),δ -47.92(s,OSiCl),δ -47.96(s,OSiCl),δ -48.87(s,OSiCl),δ -48.91(s,OSiCl).

[0162] Example 3: ClHSiO—(HSiO) 14 -SiH2Cl-based ClH2SiO-(H2SiO) x Example of H2 production from a mixture of -SiH2Cl species Description of the experimental equipment A 60 mL PET preform was connected (by screwing) to a pressure-resistant ball-lock coupler featuring an outlet nozzle for hydrogen gas discharge and a female thread onto which a stainless steel needle with a stainless steel stopcock was crimped for reactant injection. The hydrogen gas outlet nozzle was connected to a flow meter to monitor the kinetics of hydrogen release. Hydrogen gas was collected in an inverted 2 L graduated measuring cylinder filled with water, which served as an additional volumetric measuring device. The hydrogen gas flow released into the measuring cylinder was controlled by a needle valve.

[0163] In a 60 mL PET preform, 1.000 g (1.26 mmol, 1.0 equiv.) of ClH2SiO-(H2SiO) 14 -SiH2Cl, and 5 mL of NaOH (20 wt% in water, 30.5 mmol, 1.5 equivalents relative to [H2Si]) was rapidly added to the reaction medium via an injection needle using a 5 mL syringe under vigorous stirring. The stopcock was closed, and 970 mL (>99% yield) of hydrogen gas was collected in the measuring cylinder over 70 seconds (see Figure 5).

Claims

1. Formula (I) 【Chemical 1】 wherein n is an integer between 1 and 50, inclusive (excluding n being an integer of 23); R and R' contain Si and hydrogen and / or oxygen and / or halogen, and wherein the groups R and R' are carbon-free and R and / or R' contain halogen.

2. Compound H n , n , 2 , n , 2 , n , 2n , 2 , 2n , 2 , 2n , 2n , n , 2n , n , n , 2 , n , 2 , 2 , 2 , 2 , n , 2 , n , 2 , n , 2n , n , 2n , 2 , 3 , n , n , 2 , 2n , 2 , 2n , 2 , n , 2 , n , 2 SiOH 2n Si n O n SiH 2 X, H 3 SiOH 2n Si n O n SiHX 2 , H 3 SiOH 2n Si n O n SiX 3 , XH 2 SiOH 2n Si n O n SiH 2 X, XH 2 SiOH 2n Si n O n SiHX 2 , XH 2 SiOH 2n Si n O n SiH 2 OH, XH 2 SiOH 2n Si n O n SiH(OH) 2 , XH 2 SiOH 2n Si n O n Si(OH) 3 , X 2 HSiOH 2n Si n O n SiH 2 X, X<000004​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​ n O n Si(OH) 3 , X 3 SiOH 2n Si n O n SiH 2 X, X 3 SiOH 2n Si n O n SiHX 2 , X 3 SiOH 2n Si n O n Six 3 , X 3 SiOH 2n Si n O n SiH 2 OH, X 3 SiOH 2n Si n O n SiH(OH) 2 , X 3 SiOH 2n Si n O n Si(OH) 3 10. The siloxane hydrogen carrier compound of claim 1, wherein X is a halogen and n is an integer between 1 and 50, inclusive, excluding n being an integer of 23, or a mixture of one or more of these compounds.

3. 3. The siloxane hydrogen carrier compound of claim 1, wherein the halogen is Cl.

4. compound ClH 2 SiOH 2n Si n O n SiH 2 4. The siloxane hydrogen carrier compound according to claim 1, wherein the siloxane hydrogen carrier compound is selected from the group consisting of siloxane, siloxane hydrogen carrier ...

5. A siloxane hydrogen carrier compound according to any one of claims 1 to 4 and a compound represented by formula (II) 【Chemistry 2】 wherein n is an integer of 1 to 32.

6. A method for producing hydrogen by hydrolytically oxidizing a siloxane hydrogen carrier compound according to any one of claims 1 to 4 or a formulation according to claim 5 in the presence of water.

7. Water / [SiOH 2 7. The method for producing hydrogen according to claim 6, wherein the molar ratio of units is 0.1 or more.

8. The following successive steps: providing a silica compound and / or a silicate compound; For reaction path Y, subjecting the silica compound and / or silicate compound to a reduction step to produce silicon; ○ In the case of reaction path Z, subjecting said silica and / or silicate compounds to a halogenation step to produce silicon tetrahalides; and subjecting the silicon tetrahalide to a reduction step to produce silicon; For reaction paths Y and Z, subjecting silicon to a hydrohalogenation process to produce a halosilane; and subjecting the halosilane to a hydrolysis step to produce halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s); wherein the hydrolysis is carried out by reaction pathway Y or reaction pathway Z comprising H 2 O and H 2 Six 2 and [H 2 O / H 2 Six 2 5. The method for producing the siloxane hydrogen carrier compound of claim 1, wherein the method is carried out under operating conditions characterized in that the molar ratio of [(a)-(b)-(c)-(d)] is lower than 0.99 and higher than 0.

2.

9. 10. A method for regenerating the siloxane hydrogen carrier compound of any one of claims 1 to 4, comprising subjecting the liquid siloxane hydrogen carrier compound of any one of claims 1 to 4 to hydrolytic oxidation to produce hydrogen and silica and / or silicate compounds, followed by producing the liquid siloxane hydrogen carrier compound of any one of claims 1 to 4 via Reaction Pathway Y or Reaction Pathway Z of claim 8.

10. 10. The method of claim 9, wherein the regenerated siloxane hydrogen carrier compound is chemically identical to the siloxane hydrogen carrier compound that was subjected to hydrolytic oxidation.

11. 11. A method for producing and / or regenerating the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s) according to any one of claims 8 to 10, wherein the hydrolysis comprises the step of: 2 O and H 2 Six 2 and [H 2 O / H 2 Six 2 The process is carried out under operating conditions characterized in that the molar ratio of [C₁₈] to [C₁₈] is lower than 0.

98.

12. The [H 2 O / H 2 Six 2 12. The method of claim 11, wherein the molar ratio of [(a)-(b)-(c)-(d)] is greater than 0.

25.

13. The rate of addition of water to the reaction medium was 20 g H O per minute. 2 Six 2 13. A method for producing and / or regenerating the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s) of any one of claims 8 to 12, wherein the amount of water is greater than 0.05 mL per 120 ml of the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s).

14. The rate of addition of water to the reaction medium was 20 g H O per minute. 2 Six 2 14. A method for producing and / or regenerating the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s) of any one of claims 8 to 13, wherein the amount of water is less than 5.00 mL per 100 ml of the halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s).

15. 15. The method for producing and / or regenerating halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s) according to claim 13 or 14, wherein the hydrolysis is carried out under operating conditions in which the temperature of the reaction medium is maintained between −50° C. and +100° C. throughout the duration of the hydrolysis reaction.

16. 16. The method of producing and / or regenerating halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s) of claim 15, wherein the hydrolysis comprises adding water while maintaining a temperature between -50°C and 0°C.

17. 16. The method of producing and / or regenerating halogen-terminated, carbon-free, liquid linear siloxane hydrogen carrier compound(s) of claim 15, wherein the hydrolysis comprises the step of adding water followed by the step of continuing the reaction and warming the reaction medium to a temperature not exceeding 30°C.

18. 18. The method for producing and / or regenerating halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s) according to any one of claims 8 to 17, wherein the hydrolysis is followed by distillation to isolate the halogen-terminated, carbon-free liquid linear siloxane hydrogen carrier compound(s).

19. Use of a siloxane hydrogen carrier compound according to any one of claims 1 to 4 or a formulation according to claim 5 for storing and transporting hydrogen and / or energy.

20. 20. The use of the siloxane hydrogen carrier compound of claim 19, wherein the hydrogen is derived from renewable energy production and / or the energy is derived from renewable energy production, off-peak electricity production, and / or waste heat recovery.

21. Carbon-free use of a siloxane hydrogen carrier compound according to any one of claims 1 to 4 or a formulation according to claim 5 in a carbon-free method according to claim 6 or 7 for the on-demand release of hydrogen.

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