Methods for producing functionalized organic molecules and uses thereof

Abstract

The present invention relates to a method for producing functionalized organic molecules having 1 to 3 carbon atoms, comprising the step of contacting carbon dioxide as the sole gas or a gas mixture comprising or consisting of carbon dioxide and methane, in the presence of water, with a catalyst comprising or consisting of permanently polarized hydroxyapatite. The present invention also relates to uses of said method.

Description

[Technical Field]

[0001] The present invention relates to methods for producing functionalized organic molecules, particularly functionalized organic molecules having 1 to 3 carbon atoms, and uses thereof. [Background technology]

[0002] Carbon dioxide (CO2) is considered the primary greenhouse gas and a major cause of global warming. Therefore, its efficient utilization as a C1 feedstock for synthesizing valuable chemicals and industrial products has attracted increasing attention. For example, it is known that carbon dioxide can be utilized as a C1 feedstock for synthesizing ethanol (W. Zhang, Y. Hu, L. Ma, G. Zhu, Y. Wang, X. Xue, R. Chen, S. Yang, Z. Jin, Adv. Sci., 2018, Vol. 5, pp. 1700-275; B. An, Z. Li, Y. Song, J. Z. Zhang, L. Z. Zeng, C. Wang, W. B. Lin, Nature. Catal., 2019, Vol. 2, pp. 709-717; C Liu, BC Colon, M Ciesack, PA Silver, DGNocera, Science, 2016, 352, 1210-1213; ES Wiedner, JC Linehan, Chem.Eur.J., 2018, 24, 16964-16971; D Wang, QY Bi, GHY In, WL Zhao, FQ Huang, XMXie, MH Jiang, Chem.Commun., 2016, 52, 14226-14229).

[0003] Furthermore, transition metals and complexes capable of acting as transition metals are known to govern catalytic processes related to CO2 activation and fixation (C.S.Yeung, Angew.Chem.Int.Ed., 2019, Vol. 58, pp. 5492-5502; C.Weetman, S.Inoue, Chem Cat Chem, 2018, Vol. 10, pp. 4213-4228; PP Power, Nature, 2010, Vol. 463, pp. 171-177; D.D.Zhu, J.L.Liu, S.Z.Adv.Mater., 2016, Vol. 28, pp. 3423-3452).

[0004] Because the carbon atoms in CO2 are in their highest oxidation state, the CO2 molecule is highly inert and stable. Therefore, the conversion of CO2 to high-value chemicals with one carbon atom (C1; e.g., methanol and formic acid), two carbon atoms (C2; e.g., ethanol and acetic acid), and three carbon atoms (C3; e.g., acetone) requires highly efficient electrocatalysts to drive the kinetically slow CO2 reduction process. Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, there is a further need for methods that facilitate the conversion of CO2 to high-value chemicals, particularly those mentioned above. [Means for solving the problem]

[0006] Objectives and Solutions Therefore, in view of the foregoing, it is an underlying object of the present invention to make available a method for producing, and in particular for the selective production of, functionalized organic molecules, particularly for the selective production of functionalized organic molecules having 1 to 3 carbon atoms, which method addresses the needs described above.

[0007] This object is achieved by a method according to independent claim 1 and a use according to claims 15 and 16. Preferred embodiments of the method are defined in the dependent claims and in the present specification, the respective subject matter and wording of all claims being incorporated into this specification by express reference.

[0008] The present invention relates to a method for producing or synthesizing functionalized organic molecules, in particular a method for the selective production or synthesis, in particular a method for the selective production or synthesis of functionalized organic molecules having 1 to 3 carbon atoms, wherein the functionalized organic molecule is preferably selected from the group consisting of ethanol, methanol, formic acid, acetic acid, malonic acid, acetone, and mixtures of at least two of the aforementioned functionalized organic molecules. Preferably, the present invention relates to a method for producing or synthesizing, in particular a method for the selective production or synthesis, of ethanol or a mixture comprising or consisting of ethanol and at least one further functionalized organic molecule, preferably at least one further functionalized organic molecule selected from the group consisting of methanol, formic acid, acetic acid, malonic acid, and acetone, in particular a mixture comprising or consisting of ethanol, methanol, formic acid, acetic acid, and acetone, in particular a mixture having ethanol as the main reaction product, or a mixture comprising or consisting of ethanol, methanol, acetic acid, malonic acid, and acetone, in particular a mixture having ethanol as the main reaction product.

[0009] The method comprises: contacting carbon dioxide (CO) as the only gas (i.e. carbon dioxide and no further gases) in the presence of water, in particular liquid water (H2O), with a catalyst, in particular an electrocatalyst comprising or consisting of permanently polarized hydroxyapatite; or contacting a gas mixture comprising or consisting of carbon dioxide (CO2) and methane (CH4), in particular consisting of or exclusively of carbon dioxide (CO2) and methane (CH4), in the presence of water, in particular liquid water (H2O), with a catalyst, in particular an electrocatalyst comprising or consisting of permanently polarized hydroxyapatite; Includes:

[0010] Hereinafter, this step of the method of the present invention will be referred to as the "contacting step."

[0011] The term "functionalized organic molecule," as used in accordance with the present invention, refers to an organic molecule that bears or includes a functional group, i.e., a specific substituent or moiety that is normally involved in the characteristic chemical reactions of organic molecules. Preferably, the functional group is selected from the group consisting of a carboxy group, a formyl group, a keto group, a hydroxy group, and combinations thereof.

[0012] Furthermore, the term "functionalized organic molecule," as used in accordance with the present invention, may refer to a single type of organic molecule, such as an alcohol, e.g., ethanol, or a carboxylic acid, e.g., formic acid, or a mixture comprising or consisting of different organic molecules, which may differ, for example, in the number of carbon atoms and / or functional groups.

[0013] Preferably, the term "functionalized organic molecule" as used according to the present invention means a carboxylic acid, an aldehyde, a ketone, an alcohol or a mixture thereof. More preferably, the carboxylic acid / carboxylic acid is formic acid and / or acetic acid and / or malonic acid. The ketone / ketone is preferably acetone. The alcohol / alcohol is preferably ethanol and / or methanol.

[0014] In accordance with the preceding paragraphs, the method according to the invention is preferably a method for producing or synthesizing carboxylic acids, in particular a method for the selective production or synthesis, in particular a method for the selective production or synthesis of different carboxylic acids having 1 to 3 carbon atoms, preferably formic acid and / or acetic acid, and / or malonic acid, and / or aldehydes, in particular different aldehydes having 1 to 3 carbon atoms, and / or ketones, in particular different ketones having 1 to 3 carbon atoms, preferably acetone, and / or alcohols, in particular different alcohols having 1 to 3 carbon atoms, preferably ethanol and / or methanol.

[0015] More preferably, the method according to the invention is a method for producing or synthesizing, in particular a method for selectively producing or synthesizing, functionalized organic molecules selected from the group consisting of ethanol, methanol, formic acid, acetic acid, malonic acid, acetone and mixtures thereof, i.e., mixtures of at least two of the aforementioned functionalized organic molecules.

[0016] Particularly preferably, the process according to the invention is a process for producing or synthesizing, in particular a process for the selective production or synthesis of ethanol or a mixture comprising or consisting of ethanol, methanol, formic acid, acetic acid and acetone, in particular a mixture having ethanol as the main reaction product, or a mixture comprising or consisting of ethanol, methanol, acetic acid, malonic acid and acetone, in particular a mixture having ethanol as the main reaction product.

[0017] The term "major reaction product", as used in accordance with the present invention, particularly in the context of ethanol, means the product having the highest molar yield among a mixture of different products, particularly comprising or consisting of different functionalized organic molecules, particularly functionalized organic molecules having 1 to 3 carbon atoms.

[0018] The term "permanently polarized hydroxyapatite", as used in accordance with the present invention, means a hydroxyapatite that has undergone complete structural redistribution, in particular an almost complete structural redistribution, which hydroxyapatite has a high degree of crystallinity, i.e. a particularly low amount of amorphous calcium phosphate, and the presence of pores that can be detected by increased electrochemical activity and the accumulation of charge per unit mass and on the surface. This hydroxyapatite has electrochemical activity and ion mobility that do not disappear over time. The corresponding hydroxyapatite of permanently polarized hydroxyapatite 31 The P-NMR spectrum is as shown in Figure 1. Preferably, the spectrum is obtained using solid hydroxyapatite using phosphoric acid (H3PO4) as a standard and shows a unique peak at 2.6 ppm corresponding to the phosphate group of hydroxyapatite.

[0019] The term "thermally polarized hydroxyapatite", as used in accordance with the present invention, preferably means permanently polarized hydroxyapatite obtained or obtainable by a method (thermal polarization process) comprising the following steps (a) and (b): (a) sintering a sample of hydroxyapatite, in particular at a temperature between 700°C and 1200°C; (b) applying a constant or variable DC voltage between 250V and 2500V, in particular for at least 1 minute, and / or at a temperature between 900°C and 1200°C, in particular between 1000°C and 1200°C; or (b) applying an equivalent electric field between 1.49 kV / cm and 15 kV / cm, in particular for at least 1 minute, and / or at a temperature between 900°C and 1200°C, in particular between 1000°C and 1200°C; or Step (b) of applying an electrostatic discharge between 2500V and 1500000V, in particular for a period of >0 minutes to 24 hours, for example for less than 10 minutes, and / or at a temperature between 900°C and 1200°C, in particular between 1000°C and 1200°C, or Step (b) applying an equivalent electric field between 148.9 kV / cm and 8928 kV / cm, in particular for a period of >0 minutes to 24 hours, for example less than 10 minutes, and / or at a temperature between 900°C and 1200°C, in particular 1000°C and 1200°C.

[0020] The hydroxyapatite sample in step (a) may be a natural, i.e. naturally occurring, hydroxyapatite sample or a synthetic hydroxyapatite sample.

[0021] Furthermore, the hydroxyapatite sample of step (a) may in particular be selected from the group consisting of a crystalline hydroxyapatite sample, an amorphous hydroxyapatite sample, a mixed sample of crystalline hydroxyapatite and amorphous calcium phosphate, and mixtures thereof.

[0022] Therefore, the permanently polarized hydroxyapatite of the composition or material according to the invention is preferably obtained or obtainable by the above-mentioned method (thermal polarization process).

[0023] The term "room temperature", as used in accordance with the present invention, means a temperature of 15°C to 35°C, in particular 18°C ​​to 30°C, preferably 20°C to 30°C, more preferably 20°C to 28°C, in particular 20°C to 25°C.

[0024] The present invention is based on the surprising discovery that the production or synthesis, particularly the selective production or synthesis, of functionalized organic molecules having one carbon atom (e.g., methanol and / or formic acid), two carbon atoms (e.g., ethanol and / or acetic acid), and three carbon atoms (e.g., acetone) from carbon dioxide alone or from carbon dioxide and methane in the presence of permanently polarized hydroxyapatite as a catalyst can be achieved under mild conditions (e.g., pressures <10 bar and temperatures ≦250°C, especially <250°C), with reduced levels of environmental pollution and cost. Without wishing to be bound by theory, the production or synthesis of functionalized organic molecules having 1 to 3 carbon atoms according to the present invention involves hydrogenation of reduced carbon dioxide and the construction of a C-C bond. Thus, the method according to the invention may also be viewed as a method for the electrolytic reduction of carbon dioxide to carboxylic acids (e.g., formic acid and / or acetic acid) and / or aldehydes and / or ketones (e.g., acetone) and / or alcohols (e.g., methanol and / or ethanol), and the permanently polarized hydroxyapatite may also be viewed as an electrocatalyst.

[0025] In one embodiment of the present invention, the permanently polarized hydroxyapatite is a crystallinity of >65%, in particular >70%, preferably >75%, more preferably 65% ​​to 99.9%; and / or amorphous calcium phosphate in a proportion of <18% by weight, in particular 0.1% to 17% by weight or <9% by weight, preferably <5% by weight, in particular <0.1% by weight, based on the total weight of the permanently polarized hydroxyapatite, and / or β-tricalcium phosphate in a proportion of <36% by weight, in particular 0.1% to 35% by weight or <12% by weight, preferably <5% by weight, in particular <0.5% by weight, relative to the total weight of the permanently polarized hydroxyapatite, and / or Bulk resistance, 10 7Ωcm 2 ~10 4 Ωcm 2 , especially 10 7 Ωcm 2 ~10 5 Ωcm 2 , especially 10 6 Ωcm 2 ~10 5 Ωcm 2 , preferably 10 5 Ωcm 2 the bulk resistance of and / or It comprises or has a surface capacitance which after 3 months reduces to less than 8%, in particular to between 8% and 0.1%, preferably to between 5% and 3%.

[0026] The term "bulk resistance", as used in accordance with the present invention, means the resistance to electron transfer and can be determined by electrochemical impedance spectroscopy.

[0027] Preferably, the bulk resistance increases by 0.1% to 33%, in particular by 4% to 63%, preferably by 4% after 3 months.

[0028] The term "surface capacitance", as used in accordance with the present invention, means the capacitance resulting from the surface changes of hydroxyapatite induced by the thermal polarization process, and can be determined by means of electrochemical impedance spectroscopy.

[0029] For further features and advantages of the permanently polarized hydroxyapatite used in accordance with the present invention, see PCT application WO2018 / 024727A1, the contents of which are incorporated herein by express reference.

[0030] In a further embodiment of the present invention, the permanently polarized hydroxyapatite is obtained or obtainable by a method comprising the following steps (a), (b), (c) and (d): (a) providing a sample of hydroxyapatite, in particular crystalline hydroxyapatite; Step (b) of sintering the sample prepared in step (a), in particular at a temperature between 700 ° C and 1200 ° C; Step (c) of applying a constant or variable DC voltage between 250 V and 2500 V to the sample or compact obtained in step (b), in particular for at least 1 minute and / or at a temperature between 900 ° C and 1200 ° C, in particular between 1000 ° C and 1200 ° C, or Step (c) of applying an electric field equivalent to between 1.49 kV / cm and 15 kV / cm to the sample obtained in step (b) or to a compact thereof, in particular for at least 1 minute and / or at a temperature between 900°C and 1200°C, in particular at 1000°C to 1200°C; or Step (c) of applying an electrostatic discharge between 2500V and 1500000V to the sample obtained in step (b) or to a compact thereof, in particular for a period of >0 minutes to 24 hours, for example for less than 10 minutes, and / or at a temperature between 900°C and 1200°C, in particular between 1000°C and 1200°C; or Step (c) of applying an equivalent electric field between 148.9 kV / cm and 8928 kV / cm to the sample obtained in step (b) or to a compact thereof, in particular for a period of >0 minutes to 24 hours, for example for less than 10 minutes, and / or at a temperature between 900°C and 1200°C, in particular between 1000°C and 1200°C; and (d) cooling the sample obtained in step (c) while maintaining the DC voltage or equivalent electric field; or (d) cooling the sample obtained in step (c) while maintaining the electrostatic discharge or equivalent electric field; or Step (d) cooling the sample obtained in step (c) without maintaining a DC voltage, electrostatic discharge or equivalent electric field.

[0031] The term "sample", when used in accordance with the present invention, may in particular mean one sample, i.e., only one sample (singular), or multiple samples, i.e., two or more samples. Thus, the term "shaped body", when used in accordance with the present invention, may in particular mean one shaped body, i.e., only one shaped body (singular), or multiple shaped bodies, i.e., two or more shaped bodies.

[0032] The above step (a) can be carried out by using dibasic ammonium phosphate (diammonium hydrogen phosphate, (NH4)2HPO4) and calcium nitrate (Ca(NO3)2) as reactants or starting materials. In particular, step (a) can be carried out by the following steps (a1) to (a6): (a1) providing a mixture, in particular an aqueous mixture, preferably an aqueous-alcoholic mixture of dibasic ammonium phosphate and calcium nitrate; Step (a2) of stirring the mixture prepared in step (a1), in particular at room temperature, Step (a3) ​​of hydrothermally treating the mixture stirred in step (a2); Step (a4) of cooling the hydrothermally treated mixture of step (a3); Step (a5) of cooling the mixture of step (a4) and then separating the resulting precipitate; and Step (a6) freeze-drying the precipitate separated in step (a5) to produce hydroxyapatite, in particular crystalline hydroxyapatite.

[0033] Step (a1) may be carried out using a mixture comprising or consisting of dibasic ammonium phosphate, calcium nitrate, water, especially deionized water, ethanol, and optionally a chelated calcium solution. Advantageously, the pH of the mixture and / or the pH of the aqueous calcium nitrate solution used to prepare the mixture may be adjusted to 10-12, preferably 10.5. Thus, the shape and size of the hydroxyapatite, especially the nanoparticle morphology, can be controlled. Furthermore, step (a2) may be carried out under stirring, especially gentle stirring, for example, at 150 rpm to 400 rpm. Furthermore, step (a2) may be carried out for 1 minute to 12 hours, especially 1 hour. Step (a2) may also be referred to as an aging step according to the present invention. Furthermore, step (a3) ​​may be carried out at a temperature of 60°C to 240°C, preferably at 150°C. Furthermore, step (a3) ​​may be carried out at a pressure of 1 bar to 250 bar, preferably at 20 bar. Furthermore, step (a3) ​​may be carried out for 0.1 to 72 hours, preferably 24 hours. Furthermore, step (a4) may be carried out by cooling the mixture hydrothermally treated in step (a3) ​​to a temperature of 0 to 90°C, particularly 25°C. Furthermore, step (a5) may be carried out by centrifugation and / or filtration. Furthermore, the precipitate separated in step (a5) may be washed, particularly with water and / or a mixture of ethanol and water, before step (a6) is carried out. Furthermore, step (a6) may be carried out for 1 to 4 days, particularly 2 to 3 days, preferably 3 days.

[0034] Furthermore, the above step (b) may be carried out at a temperature between 700°C and 1150°C, in particular at a temperature between 800°C and 1100°C, in particular at a temperature of 1000°C.

[0035] Furthermore, the method preferably further comprises step (bc) between step (b) and step (c), in which the sample obtained in step (b) is pressed or formed into a compact, i.e., a compact of the sample obtained in step (b) is formed.

[0036] In particular, step (bc) may be carried out at a pressure of 1 MPa to 1000 MPa, in particular at a pressure of 100 MPa to 800 MPa, preferably at a pressure of 600 MPa to 700 MPa, and further, step (bc) may be carried out for 1 minute to 90 minutes, in particular at a pressure of 5 minutes to 50 minutes, preferably at a pressure of 10 minutes to 30 minutes.

[0037] The shaped body may have a polygonal, for example triangular, square or rectangular, pentagonal, hexagonal, heptagonal, octagonal or nonagonal, or cornerless, in particular circular, oval or elliptical, cross section. Furthermore, the shaped body may have a thickness of >0 cm to 10 cm, in particular >0 cm to 5 cm, preferably >0 cm to 2 cm. In particular, the shaped body may have a thickness of 0.1 cm to 10 cm, in particular 0.1 cm to 5 cm, preferably 0.5 cm to 2 cm.

[0038] Preferably, the shape of the molded body is a disk, a plate, a cone or a cylinder.

[0039] Advantageously, step (c) can be carried out to achieve catalytic activation of the sample or its shaped body obtained in step (b). Preferably, step (c) is carried out by placing the sample or its shaped body obtained in step (b) between an anode and a cathode, with the sample or its shaped body obtained in step (b) in contact with both electrodes. The electrodes can be, for example, in the form of stainless steel plates, in particular stainless steel AISI 304 plates. Furthermore, the electrodes can have a mutual distance of 0.01 mm to 10 cm, in particular 0.01 mm to 5 cm, preferably 0.01 mm to 1 mm.

[0040] The electrodes can have different shapes. They can have a polygonal cross section, for example a square or rectangular, or a cornerless, particularly a circular, oval or elliptical, cross section. In particular, the electrodes can have a thickness of >0 cm to 10 cm, in particular >0 cm to 5 cm, preferably >0 cm to 1 mm. For example, the electrodes can be in the form of a disk, a plate or a cylinder.

[0041] Furthermore, in the above step (c), a constant or variable DC voltage or equivalent electric field may be applied for 1 hour to 24 hours, particularly 0.1 hour to 10 hours, and particularly 1 hour.

[0042] Furthermore, the DC voltage applied in the above step (c) is preferably 500V, which is equivalent to a constant electric field of 3 kV / cm.

[0043] Furthermore, the equivalent electric field applied in the above step (c) is preferably 3 kV / cm.

[0044] Furthermore, the temperature in the above step (c) is preferably at least 900° C., more preferably at least 1000° C. Preferably, the temperature in step (c) is between 900° C. and 1200° C., particularly between 1000° C. and 1200° C., especially 1000° C.

[0045] Preferably, step (c) is carried out by applying a constant or variable DC voltage of 500 V at 1000° C. for 1 hour to the sample or compact obtained in step (b), in particular to the disk-shaped compact thereof.

[0046] Furthermore, the above step (d) may be carried out by cooling the sample obtained in step (c) to room temperature.

[0047] Furthermore, the above step (d) may be carried out for 1 minute to 72 hours, particularly 15 minutes to 5 hours, and preferably 15 minutes to 2 hours.

[0048] In a further embodiment of the present invention, the permanently polarized hydroxyapatite is obtained or obtainable by a method comprising the following steps (a), (b), (c) and (d): (a) preparing a sample of hydroxyapatite, in particular crystalline hydroxyapatite, in particular using dibasic ammonium phosphate (diammonium hydrogen phosphate, (NH4)2HPO4) and calcium nitrate (Ca(NO3)2) as reactants or starting materials; Step (b) of sintering the sample prepared in step (a), in particular at a temperature of 1000°C, in particular for 2 hours; Step (c) of applying an equivalent electric field of 3 kV / cm to the sample or compact obtained in step (b), in particular at a temperature of 1000 ° C, in particular for 1 hour; Step (d) of cooling the sample obtained in step (c) while maintaining the equivalent electric field, in particular for 30 minutes.

[0049] For further features and advantages of steps (a)-(d), please see the entire above description.

[0050] In a further embodiment of the present invention, the contacting step is carried out in the presence of liquid water and / or water vapor, in other words, according to a further embodiment of the present invention, the water for carrying out the contacting step is in liquid and / or vapor form.

[0051] In a further embodiment of the invention, the contacting step is carried out under conditions where the volume ratio of permanently polarized hydroxyapatite to water, in particular liquid water and / or water vapor, is between 1000:1 and 0.01:1, in particular between 500:1 and 100:1, preferably between 300:1 and 350:1.

[0052] In a further embodiment of the present invention, the contacting step is carried out with carbon dioxide alone.

[0053] In a further embodiment of the invention, the contacting step is carried out under conditions where the volume ratio of carbon dioxide to methane is 200:1, in particular 3:1, preferably 1:1.

[0054] In a further embodiment of the invention, the contacting step is carried out under a total pressure of from 0.1 bar to 100 bar, in particular from 0.1 bar to 10 bar, in particular from 1 bar to 10 bar, in particular from 1 bar to 8 bar, in particular from 1 bar to 6 bar, preferably 6 bar.

[0055] The term "total pressure", as used in accordance with the present invention, refers to the carbon dioxide pressure (if this gas is used alone) or the sum of the partial pressures of each gas in a gas mixture, preferably at room temperature.

[0056] In a further embodiment of the invention, the contacting step is carried out under conditions in which the carbon dioxide pressure is between 0.035 bar and 90 bar, in particular between 0.1 bar and 10 bar, in particular between 1 bar and 8 bar, preferably 6 bar.

[0057] In a further embodiment of the invention, the contacting step is carried out under a carbon dioxide partial pressure of from 0.035 bar to 90 bar, in particular from 0.1 bar to 3 bar, in particular from 1 bar to 3 bar, preferably 3 bar, and / or under a methane partial pressure of from 0.00017 bar to 5 bar, in particular from 1 bar to 3 bar, preferably 3 bar.

[0058] Furthermore, the contacting step may be carried out under conditions where the total pressure of the gas mixture is between 0.0001 bar and 250 bar, and where the catalyst and water, particularly liquid water, are present.

[0059] Additionally, the contacting step may be carried out in the presence of the catalyst at a pressure ratio of carbon dioxide to methane (CO2:CH4) of 0.0001 bar:250 bar to 250 bar:0.0001 bar.

[0060] Furthermore, the gas mixture may specifically be free of nitrogen (N2), in other words, the contacting step may be carried out in the absence of nitrogen.

[0061] In a further embodiment of the invention, the contacting step is carried out under conditions in which the molar ratio of carbon dioxide to permanently polarized hydroxyapatite is between 0.1 and 0.5, in particular between 0.2 and 0.5, preferably between 0.3 and 0.5.

[0062] In a further embodiment of the invention, the contacting step is carried out under conditions in which the molar ratio of methane to permanently polarized hydroxyapatite is between 0.1 and 0.5, in particular between 0.2 and 0.5, preferably between 0.3 and 0.5.

[0063] Preferably, the contacting step is carried out using uncoated permanently polarized hydroxyapatite, i.e., by using permanently polarized hydroxyapatite without a coating. Surprisingly, the application of uncoated permanently polarized hydroxyapatite advantageously significantly increases the conversion of carbon dioxide to functionalized organic molecules having two and / or three carbon atoms (e.g., ethanol and / or acetic acid and / or acetone), and in particular, further maximizes the selective synthesis of ethanol as the primary reaction product. Similarly, the application of uncoated permanently polarized hydroxyapatite advantageously significantly increases the conversion of carbon dioxide and methane to ethanol, and in particular, further maximizes the selective synthesis of ethanol as the primary reaction product.

[0064] Alternatively, the contacting step may be carried out using coated, permanently polarized hydroxyapatite. In principle, the contacting step may be carried out using permanently polarized hydroxyapatite coated with an inorganic photocatalyst, such as TiO2, MgO2, MnO2, or a combination thereof. More specifically, the contacting step may be carried out using permanently polarized hydroxyapatite having a three-layer coating, particularly, this three-layer coating may be composed of two layers of aminotris(methylene phosphonic acid) and one layer of zirconium oxychloride (ZrOCl2) or zirconia (ZrO2), with the zirconium oxychloride layer being disposed between or sandwiched between the two layers of aminotris(methylene phosphonic acid). The use of coated, permanently polarized hydroxyapatite can advantageously increase the efficiency of the reaction.

[0065] In a further embodiment of the present invention, the contacting step is carried out under UV (ultraviolet) or UV-Vis (ultraviolet-visible) irradiation. In particular, the contacting step may be carried out under conditions where the UV or UV-Vis irradiation has a wavelength of 200 nm to 850 nm, particularly 240 nm to 400 nm, preferably 250 nm to 260 nm, and more preferably 253.7 nm. Furthermore, the contacting step may be carried out under conditions where the UV irradiation has a wavelength of 200 nm to 280 nm, particularly 240 nm to 270 nm, preferably 250 nm to 260 nm, and more preferably 253.7 nm. Preferably, the permanently polarized hydroxyapatite is directly exposed to UV or UV-Vis irradiation or is irradiated with UV or UV-Vis irradiation. Advantageously, the UV or UV-Vis irradiation is provided by a suitable UV and / or Vis source, such as a UV lamp and / or a Vis lamp.

[0066] In a further embodiment of the invention, the contacting step is carried out with UV (ultraviolet) radiation or UV-Vis (ultraviolet-visible) radiation at a dose of 0.1 W / m 2 ~200W / m 2 , especially 1 W / m2 ~50W / m 2 、 Preferably 2W / m 2 ~10W / m 2 , more preferably 3 W / m 2 Regarding the advantages of this embodiment, see the preceding paragraph.

[0067] In a further embodiment of the invention, the contacting step is carried out at a temperature of between 25°C and 250°C, in particular between 95°C and 140°C, preferably 95°C.

[0068] More preferably, the contacting step is carried out at a temperature of 95° C. and under UV irradiation. These reaction conditions are particularly useful for synthesizing, in high yield, functionalized organic molecules, particularly those having two carbon atoms (e.g., ethanol and / or acetic acid), selectively.

[0069] Furthermore, the contacting step may be preferably carried out without UV irradiation and at a temperature between 25° C. and 250° C., particularly between 95° C. and 140° C., preferably 140° C. Furthermore, the reaction conditions according to this embodiment result in high yields of synthesis, particularly the selective synthesis of functionalized organic molecules having two carbon atoms (e.g., ethanol and / or acetic acid).

[0070] Furthermore, the contacting step may be carried out for 0.0001 hours to 120 hours, particularly 24 hours to 72 hours, and preferably 48 hours to 72 hours.

[0071] Furthermore, the method, particularly the contacting step, may be carried out continuously or discontinuously, particularly as a batch process.

[0072] Furthermore, the contacting step may be carried out using air, in particular traffic-polluted air, as the gas mixture, thus allowing the synthesis of functionalized organic molecules having 1 to 3 carbon atoms, in particular ethanol and / or acetic acid and / or methanol and / or formic acid and / or acetone, as valuable compounds, and in parallel the removal of carbon dioxide from air, in particular traffic-polluted air.

[0073] Preferably, the method further comprises the step of isolating and / or separating and / or purifying the functionalized organic molecule obtained during or after the contacting step.

[0074] Said further steps are preferably carried out by dissolving and extracting the catalyst and / or by extracting the supernatant liquid formed during or in the contacting step.

[0075] In a further embodiment of the invention, the method is used to produce or synthesize, in particular to selectively produce or synthesize, ethanol.

[0076] In a further embodiment of the invention, the method is used to produce or synthesize a mixture comprising or consisting of ethanol and finally, preferably one further functionalized organic molecule selected from the group consisting of methanol, formic acid, acetic acid, malonic acid and acetone.

[0077] More preferably, the method is used to produce or synthesize a mixture comprising or consisting of ethanol and at least one further functionalized organic molecule selected from the group consisting of methanol, formic acid, acetic acid and acetone.

[0078] Instead, the method is preferably used to produce or synthesize a mixture comprising or consisting of ethanol and at least one additional functionalized organic molecule selected from the group consisting of methanol, acetic acid, malonic acid and acetone.

[0079] In a further embodiment of the invention, the method is used to produce or synthesize a mixture comprising or consisting of ethanol, methanol, formic acid, acetic acid and acetone.

[0080] In a further embodiment of the invention, the method is used to produce or synthesize a mixture comprising or consisting of ethanol, methanol, acetic acid, malonic acid and acetone.

[0081] Furthermore, the present invention relates to the use of the method according to the invention for removing carbon dioxide from the atmosphere, in particular from air, i.e. from the Earth's atmosphere. In particular, the present invention relates to the use of the method according to the invention for removing carbon dioxide from dirty or polluted air, for example traffic-polluted air.

[0082] The term "air" or "Earth's atmosphere", as used in accordance with the present invention, means the layer of gases held in place by the Earth's gravity, surrounding the Earth, and forming the planet's atmosphere.

[0083] For further features and advantages of use, please see the entire above description.

[0084] Finally, the present invention provides contacting carbon dioxide (CO2) as the only gas (i.e., carbon dioxide but no further gases) in the presence of water, especially liquid water, (H2O), with a catalyst, especially an electrocatalyst comprising or consisting of permanently polarized hydroxyapatite; or contacting a gas mixture comprising or consisting of carbon dioxide (CO2) and methane (CH4), in particular comprising or consisting only of carbon dioxide (CO2) and methane (CH4), in the presence of water, in particular liquid water (H2O), with a catalyst, in particular an electrocatalyst comprising or consisting of permanently polarized hydroxyapatite; The present invention relates to the use of a process for the production or synthesis, in particular for the particularly selective production or synthesis of organic molecules having 1 to 3 carbon atoms, comprising the steps of:

[0085] Preferably, the use of the method is for the production or synthesis, in particular for the selective production or synthesis of ethanol or a mixture comprising or consisting of ethanol and at least one further functionalized organic molecule selected from the group consisting of methanol, formic acid, acetic acid, malonic acid and acetone, in particular for a mixture comprising or consisting of ethanol, methanol, formic acid, acetic acid and acetone, in particular a mixture having ethanol as the main reaction product, or for a mixture comprising or consisting of ethanol, methanol, acetic acid, malonic acid and acetone, in particular a mixture having ethanol as the main reaction product. For further features and advantages of the use, in particular with respect to the method and the functionalized organic molecule, reference is made to the above description.

[0086] Further features and advantages of the present invention will become apparent from the following examples in conjunction with the subject matter of the dependent claims. The individual features can be realized alone or in separate combinations in one embodiment of the present invention. The preferred embodiments serve only for the illustration and better understanding of the present invention and should not be understood as limiting the present invention in any way.

[0087] For a better understanding of what is disclosed, several figures are appended which show, diagrammatically or graphically and purely by way of non-limiting example, practical cases of embodiments of the invention. [Brief explanation of the drawings]

[0088] [Figure 1] 1 is a graph showing the 31P-NMR spectrum of permanently polarized hydroxyapatite (p-HAp) according to the present invention. [Figure 2] Figure 2a schematically represents the Raman spectrum of a hydroxyapatite (HAp) sample with deconvolution of the ν1 peak in the 930-990 cm-1 interval. The counts (AU) are plotted on the vertical axis. The Raman shift (cm-1) is plotted on the horizontal axis. Figure 2b schematically represents the Raman spectrum of a permanently polarized hydroxyapatite (p-HAp) sample with deconvolution of the ν1 peak in the 930-990 cm-1 interval. The counts (AU) are plotted on the vertical axis. The Raman shift (cm-1) is plotted on the horizontal axis. Figure 2(a)-(b) compare the Raman ν1 peak in the 930-990 cm-1 interval before and after polarization of HAp, proving the success of the polarization process. The regions of HAp, amorphous calcium phosphate (ACP), and β-tricalcium phosphate (β-TCP) suggest the contents of each phase. The content of coexisting phases decreased in the poled samples (i.e., 4.3% and 9.8% for ACP and β-TCP, respectively), accompanied by a reduction in the full width at half maximum (FWHM) from 9 cm for HAp to 5 cm for p-HAp. This result suggests an increase in the HAp phase due to a reduction in the distortion of crystalline defects, e.g., PO 3-tetrahedra. [Figure 3a] Scanning electron microscopy image of permanently polarized hydroxyapatite. Permanently polarized hydroxyapatite can therefore be described as particles of (approximately) 100 nm to 300 nm that aggregate to form aggregates up to 1 μm in size. [Figure 3b] The graph shows the H-NMR spectrum of the solution obtained after extraction of the reaction product from a reaction carried out under UV light at 95 °C for 72 hours in the presence of conventional (i.e., non-polarized) hydroxyapatite as catalyst using CO (3 bar), CH (3 bar), and HO (1 mL). The reacted catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. [Figure 3c]The graph shows the 1H-NMR spectrum of the solution obtained after extraction of the reaction product from a reaction carried out at 95 °C under UV light for 72 hours using CO2 (3 bar), CH4 (3 bar), HO (1 mL) and (uncoated) permanently polarized hydroxyapatite as catalyst. The reacted catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. [Figure 3d] This graph shows the H-NMR spectrum of the solution obtained after extraction of the reaction product from a 72-hour reaction in the presence of coated p-HAp using CO2 (3 bar), CH4 (3 bar), and HO (1 mL). p-HAp was coated with aminotris(methylenephosphonic acid) (hereafter referred to as ATMP) and zirconium oxychloride (ZrOCl2) (hereafter referred to as ZC) at 95 °C under UV light. The reacted catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. As shown in Figures 3(b)–(d), the chemical shifts observed after dissolution of the coated p-HAp are slightly deshielded with respect to the product peaks derived from the uncoated catalyst. This effect is attributed to aminotris(methylenephosphonic acid) (ATMP), which increases the acidity of the medium, causing a downfield shift that is not detected for p-HAp and HAp, regardless of the conditions. On the other hand, Figure 3(b)-(c) suggests that removing the coating from the catalyst not only increases the conversion to ethanol by 20%, but also maximizes the selective synthesis of ethanol as the major reaction product. [Figure 4]Figure 4a graphically shows a further H-NMR spectrum of the solution obtained after extraction of the reaction product obtained after 72 hours from CO2 (3 bar), CH4 (3 bar), and HO (1 mL) using permanently polarized hydroxyapatite (uncoated) as a catalyst and reaction conditions of 95 °C and UV light. The catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. Figure 4b graphically shows a H-NMR spectrum of the solution obtained after extraction of the reaction product obtained after 72 hours from CO2 (3 bar), CH4 (3 bar), and HO (1 mL) using permanently polarized hydroxyapatite (uncoated) as a catalyst and reaction conditions of 95 °C and no UV light. The catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. Figure 4c shows a graph of the H-NMR spectrum of the solution obtained after extraction of the reaction product obtained after 72 h from CO2 (3 bar), CH4 (3 bar), and HO (1 mL) using permanently polarized hydroxyapatite as the catalyst and reaction conditions of 140 °C and no UV light. The catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. Figure 4d shows a graph of an additional H-NMR spectrum of liquid water from CO2 (3 bar), CH4 (3 bar), and HO (1 mL) after 72 h of reaction using permanently polarized hydroxyapatite (uncoated) as the catalyst and reaction conditions of 95 °C and UV light. The spectrum has been cropped to avoid the very sharp water peak at 4.7 ppm. Figure 4e graphically shows an additional H-NMR spectrum of the solution obtained after extraction of the reaction product from CO (3 bar), CH (3 bar), and HO (1 mL) after 72 hours using permanently polarized hydroxyapatite (uncoated) as catalyst and reaction conditions of 95 °C and UV light. The catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. The spectrum has been cropped to avoid the very sharp water peak at 4.7 ppm.The spectra reveal the sudden appearance of methanol and formic acid as reaction products in the liquid water used for the reaction. Ethanol and acetic acid appear in both the catalyst and the liquid water, while acetone is only detected in the former. [Figure 5] The graph shows the representation of CO2 adsorbed molecules in three protonated forms on the OH-vacancies of permanently polarized hydroxyapatite. The values ​​(unit: eV) represent the calculated adsorption energies. To support the p-HAp immobilization mechanism based on the formation of carboxylates, DFT calculations were performed at the PBE-D3 level. The calculations were carried out considering the (0001) plane, the most stable HAp surface, and the isodesmic model, in which H2 was used as the proton source. By inserting the molecule into the hydroxyl vacancies of the mineral, the adsorption energies of the three different protonation products of CO2 were calculated. The results demonstrated that the protonation of CO2 to formic acid is exothermic by -3.1 kcal / mol in the gas phase, but is exothermic by -32.7 kcal / mol when adsorbed on the p-HAp substrate. However, all protonated species exhibit endothermic adsorption energies, with the energy for protonated formic acid being minimal (0.2 kcal / mol) but 5.1 kcal / mol for CO (other sites were checked with p-HAp, which exhibited higher energies, as shown for some representative cases in Figure 5), making this pathway impossible to fully follow and shifting the site of catalysis to other nearby sites. [Figure 6] The graph shows an additional H-NMR spectrum of the solution obtained after extraction of the reaction product from CO (3 bar), CH (3 bar), and HO (1 mL) in the presence of aminotris(methylenephosphonic acid) and permanently polarized hydroxyapatite coated with zirconium oxychloride at 95 °C under UV light for 72 hours. The reacted catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. The spectrum contains an OH band at 4.65 ppm. [Figure 7]This graph shows the H-NMR spectra of liquid water from CO (3 bar), CH (3 bar), and HO (1 mL) after 72 hours at 95 °C with (Control 1) and without UV light (Control 2). No catalyst was used for this reaction. [Figure 8] Figure 8a shows a further H-NMR spectrum of the reaction product obtained after 72 h at 95 °C from CO (3 bar), CH (3 bar), and HO (1 mL) using UV light and permanently polarized hydroxyapatite (uncoated) as catalyst. Analysis of the solution obtained after product extraction was performed by dissolving the catalyst with 100 mM HCl and 50 mM NaCl. Figure 8b shows a further H-NMR spectrum of the reaction product obtained after 72 h at 95 °C from CO (3 bar), CH (3 bar), and HO (1 mL) using UV light and permanently polarized hydroxyapatite (uncoated) as catalyst. Liquid water incorporated in the reaction chamber was analyzed. [Figure 9] Figure 9a graphically shows the 1H-NMR spectrum of the reaction product obtained after 72 hours at 95°C from CO2 (3 bar) and CH4 (3 bar) in the absence of water using UV light and permanently polarized hydroxyapatite (uncoated) as catalyst. Figure 9b graphically shows the 1H-NMR spectrum of the reaction product obtained after 72 hours at 95°C from CO2 (3 bar) and CH4 (3 bar) in the presence of excess water using UV light and permanently polarized hydroxyapatite (uncoated) as catalyst. [Figure 10] Graphical representation of the H-NMR spectrum of the solution obtained after extraction of the reaction product from contaminated air (atmospheric pressure) and HO (1 mL) after 72 hours at 95°C under UV light using permanently polarized hydroxyapatite (uncoated) as catalyst. The reacted catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. [Figure 11a]Figure 1 shows an additional H-NMR spectrum of liquid water after 48 hours of reaction from CO (6 bar) and HO (1 mL) using permanently polarized hydroxyapatite (uncoated) as catalyst and 140 °C as reaction conditions (no UV light). The spectrum has been truncated to avoid the very sharp water peak at 4.7 ppm. [Figure 11b] This graph shows an additional H-NMR spectrum of the solution obtained after extraction of the reaction product from CO (6 bar) and HO (1 mL) after 48 h using permanently polarized hydroxyapatite (uncoated) as catalyst and 140 °C as reaction conditions (without UV light). The catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. The spectrum has been omitted to avoid the very sharp water peak at 4.7 ppm. The spectrum shows the appearance of methanol, formic acid, ethanol, acetic acid, and acetone as reaction products in both liquid water and with the catalyst and liquid water. The yields (μmol / g of catalyst) in liquid water were: 0.21 ± 0.07 (methanol), 2.44 ± 0.97 (formic acid), 4.50 ± 0.91 (ethanol), 2.22 ± 0.88 (acetic acid), and 0.74 ± 0.15 (acetone). The yields in catalyst (μmol / g of catalyst) were: 0.56 ± 0.19 (methanol), 3.22 ± 0.54 (formic acid), 6.60 ± 2.32 (ethanol), 0.49 ± 0.12 (acetic acid), and 0.62 ± 0.27 (acetone). [Figure 12]Figure 12a shows the variation of the yields of ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) (expressed as μmol of product / g of catalyst) versus CO pressure (units: bar), as measured by H NMR spectroscopy from solutions obtained after extraction of the reaction products after 48 h using CO (1, 2, 4, or 6 bar) and HO (1 mL) at 140 °C (without UV light). The catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. Figure 12b shows the variation of yields (expressed as μmol of product / g of catalyst) of ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) versus CO pressure (in bar) as measured by 1H NMR spectroscopy from liquid water using permanently polarized hydroxyapatite (uncoated) as catalyst. In all cases, reactions were carried out using CO (1, 2, 4, or 6 bar) and HO (1 mL) at 140 °C (without UV light) for 48 h. Figure 12c shows the variation of the total yield (expressed as μmol of product / g of catalyst) for ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) obtained from the solutions obtained after extraction of the reaction products from the catalyst (Figure 12a) and supernatant (Figure 12b) versus CO2 pressure (units: bar). In all cases, the reactions were carried out using CO2 (1, 2, 4, or 6 bar) and H2O (1 mL) at 140 °C (without UV light) for 48 h. Figure 12d shows the variation of the total yield (expressed as μmol of product / g of catalyst) for C1 (methanol and formic acid; MeOH + HCOOH), C2 (ethanol and acetic acid; EtOH + AcOH), and C3 (acetone; Ace) versus CO2 pressure (units: bar) obtained from the solutions obtained after extraction of the reaction products from the catalyst (Figure 12a) and supernatant (Figure 12b). In all cases, the reactions were carried out for 48 h using CO2 (1, 2, 4, or 6 bar) and H2O (1 mL) at 140 °C (without UV light). [Figure 13] Figure 13a shows the variation of the yields of ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) (expressed as μmol of product / g of catalyst) versus temperature (°C) as measured by H NMR spectroscopy from solutions obtained after extraction of the reaction products after 48 h using CO (6 bar) and HO (1 mL) at 95, 120, or 140 °C (without UV light). The catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. Figure 13b shows the variation of the yields (expressed as μmol of product / g of catalyst) of ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) versus temperature (°C) as measured by 1H NMR spectroscopy from liquid water using permanently polarized hydroxyapatite (uncoated) as catalyst. In all cases, the reactions were carried out using CO2 (6 bar) and HO (1 mL) at 95, 120, or 140 °C (without UV light) for 48 h. Figure 13c shows the variation of the total yield (expressed as μmol of product / g of catalyst) obtained from the solutions obtained after extraction of the reaction products from the catalyst (Figure 13a) and supernatant (Figure 13b) for ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) versus temperature (units: °C). In all cases, the reactions were carried out using CO2 (6 bar) and HO (1 mL) at 95, 120, or 140 °C (without UV light) for 48 h. Figure 13d shows the variation of the total yield (expressed as μmol of product / g of catalyst) obtained from the solutions obtained after extraction of the reaction products from the catalyst (Figure 13a) and supernatant (Figure 13b) for C1 (methanol and formic acid; MeOH + HCOOH), C2 (ethanol and acetic acid; EtOH + AcOH), and C3 (acetone; Ace) versus temperature (units: °C). In all cases, the reactions were carried out using CO2 (6 bar) and HO (1 mL) at 95, 120, or 140 °C (without UV light) for 48 h. [Figure 14]Figure 14a shows the variation of the yields of ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) (expressed as μmol of product / g of catalyst) versus reaction time (in hours), as measured by H NMR spectroscopy from solutions obtained after extraction of the reaction products obtained after 24, 48, and 72 hours using CO (6 bar) and HO (1 mL) at 140 °C (without UV light). The catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. Figure 14b shows the variation of the yields (expressed as μmol of product / g of catalyst) of ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) versus time (in hours) as measured by 1H NMR spectroscopy from liquid water using permanently polarized hydroxyapatite (uncoated) as catalyst. In all cases, the reactions were carried out using CO2 (6 bar) and HO (1 mL) at 140 °C (without UV light) for 24, 48, or 72 hours. Figure 14c shows the variation of the total yield (expressed as μmol of product / g of catalyst) obtained from the solution obtained after extraction of the reaction products from the catalyst (Figure 14a) and the supernatant (Figure 14b) for ethanol (EtOH), acetic acid (AcOH), methanol (MeOH), formic acid (HCOOH), and acetone (Ace) versus time (in hours). In all cases, the reactions were carried out using CO2 (6 bar) and HO (1 mL) at 140 °C (without UV light) for 24, 48, or 72 hours. Figure 14d shows the variation of the total yield (expressed as μmol of product / g of catalyst) versus time (in hours) obtained from the solutions obtained after extraction of the reaction products from the catalyst (Figure 14a) and the supernatant (Figure 14b) for C1 (methanol and formic acid; MeOH + HCOOH), C2 (ethanol and acetic acid; EtOH + AcOH), and C3 (acetone; Ace). In all cases, the reactions were carried out for 24, 48, or 72 hours using CO2 (6 bar) and HO (1 mL) at 140 °C (without UV light). [Figure 15]The graph shows the 1H-NMR spectrum of the solution obtained after extraction of the reaction product obtained after 72 hours at 95°C from contaminated air (atmospheric pressure) and HO (1 mL) using permanently polarized hydroxyapatite (uncoated) as catalyst at 95°C and under UV light. The reacted catalyst was dissolved in an aqueous solution containing 100 mM HCl and 50 mM NaCl. DETAILED DESCRIPTION OF THE INVENTION

[0089] (Experimental Section) 1.Material Calcium nitrate (Ca(NO3)2), diammonium hydrogen phosphate ((NH4)2HPO4; purity >99.0%), and ammonium hydroxide solution 30% (NH4OH; purity: 28–30% w / w) were purchased from Sigma-Aldrich. Ethanol (purity >99.5%) was purchased from Scharlab. All experiments were performed using milli-Q water.

[0090] 2. Hydrothermal synthesis of hydroxyapatite (HAp) 15 mL of 0.5 M NH4)2HPO4 in deionized water was added at a rate of 2 mL / min to 25 mL of 0.5 M Ca(NO3)2 in ethanol (pH previously adjusted to 10.5 using ammonium hydroxide solution) and aged for 1 h. The entire process was carried out under gentle stirring (150 rpm) and at room temperature. A hydrothermal treatment at 150 °C was applied using a Digestec DAB-2 autoclave for 24 h. The autoclave was cooled before opening. The precipitate was separated by centrifugation and washed (twice) with water and a 60 / 40 v / v mixture of ethanol and water. After freeze-drying for 3 days, the resulting white powder was sintered in air at 1000 °C for 2 h using a Carbolite ELF11 / 6W / 301 furnace.

[0091] 3. Thermally stimulated polarization process (TSP) Mechanically uniform disks approximately 1.5 mm thick were obtained by pressing 150 mg of pre-sintered HAp powder at 620 MPa for 10 min. Thermal polarization was performed by placing the HAp disk between two stainless steel (AISI 304) plates and applying 3 kV / cm at 1000 °C for 1 h using a GAMMA power supply in the same laboratory furnace as described above. The applied potential was maintained for 30 min to allow the disk to cool, and finally, all systems were turned off and the disk was left to cool overnight.

[0092] 4. Characterization Vibrational spectra for structural fingerprints were obtained on an inVia Qontor confocal Raman microscope (Renishaw) equipped with a Renishaw Centrus 2957T2 detector and a 785 nm laser.

[0093] SEM images were obtained using a Zeiss Neon 40 microscope equipped with a SEM GEMINI column. HRTEM was performed on a JEOL 2010F microscope equipped with a field emission electron source and operated at an accelerating voltage of 200 kV. The point resolution was 0.19 nm, and the line-to-line resolution was 0.14 nm. Samples were dispersed in an alcohol suspension in an ultrasonic bath, and a drop of the suspension was placed on a grid with a holey carbon film. Images were not digitally filtered or processed and correspond to the raw data. All 1 H-NMR spectra were acquired on a Bruker Avance III-400 spectrometer operating at 400.1 MHz and accumulating 64 scans. Chemical shift calibration was performed using tetramethylsilane as an internal standard. Samples were dissolved in milli-Q water containing 100 mM HCl and 50 mM NaCl with a final addition of deuterated water.

[0094] 5. Calculation details A 2 × 1 × 2 HAp supercell was chosen to create the (0001) plane for p-HAp. -The (0001) plane for p-HAp was constructed by removing the α-axis from the HAp supercell (previously optimized at the selected DFT level). Consequently, an overall charge of +1 was applied to all calculations, except those involving formates, and unpaired spins were considered when necessary. The initial coordinates of HAp were optimized to accommodate surface tension, according to the computational details provided below. The plane wave method implemented in the Quantum Espresso 4.6 suite of open-source computer codes was used. Calculations were performed at the PBE level of theory, corrected for Grimme three-body dispersion potentials (PBE-D3), applying the default C6 software coefficients. A kinetic energy cutoff for the wave function 40 Ry was utilized. A 3 × 3 × 1 k-point mesh was automatically generated. Alternatively, a Gamma-centered 1 × 1 × 1 k-mesh was used for the calculations of individual molecules, and a 7 × 7 × 7 k-mesh was used for the calculations of bulk HAp. Both the energy and force fluctuations between successive steps were 10, respectively. -3 au and 10 -4 Shape optimization was performed using the conjugate gradient algorithm until the deviation from self-consistency was less than 10 -5 The energy of each step was optimized until it was less than Ry. The adsorption energy was calculated according to the following method: A + S → AS* (where A is the adsorbate, S is the surface, and AS* is the adsorbed state). The adsorption energy (E ads ) to E ads =E AS* -(E A +E s ) was expressed as follows.

[0095] 6. Reaction Chamber All reactions were carried out using an ad hoc designed, high-pressure stainless steel reactor. Briefly, the reactor was equipped with a manometer, an electric heater with a thermocouple, and an external temperature controller. The reactor also featured an inert reaction chamber coated with a perfluorinated polymer (Teflon®, 120 mL), in which both the catalyst and water were incorporated. The reactor was equipped with three independent inlet valves for the incorporation of gases and an outlet valve for the recovery of gaseous reaction products. A UV lamp (GPH265T5L / 4, 253.7 nm) for direct irradiation of the catalyst was also located in the center of the reactor, protected by a UV-transparent quartz tube. All surfaces were coated with a thin film of perfluorinated polymer (Teflon®) to prevent any contact between the reaction medium and the reactor surface, thus eliminating any other catalytic effects.

[0096] 7. Synthesis of Coated p-HAp A three-layer system consisting of successive depositions of aminotris(methylenephosphonic acid) (ATMP) and zirconium oxychloride (ZC) on p-HAp was obtained by immersion in the corresponding aqueous solutions at room temperature for 5 hours. To deposit the first ATMP layer, p-HAp was immersed in a 5 mM ATMP solution for 5 hours. Subsequently, ZC was deposited on the ATMP-layered p-HAp by immersing the ATMP-layered p-HAp in a 5 mM ZrOCl2 solution for 5 hours. Finally, a second layer of ATMP was deposited on the ZC- and ATMP-layered p-HAp by immersing the ZC- and ATMP-layered p-HAp in a 1.25 mM ATMP solution for 5 hours.

[0097] 8. Synthesis of functionalized organic molecules with 1–3 carbon atoms using uncoated p-HAp as a catalyst Functionalized organic molecules with 1–3 carbon atoms were synthesized from CO gas alone (1, 2, 4, or 6 bar) and from CO and CH gas mixtures (3 bar each) in the presence of uncoated p-HAp as a catalyst and in the presence of liquid HO (1 mL). The reactions were carried out for 24, 48, or 72 h at 95, 120, or 140 °C, with or without UV irradiation from a UV lamp (GPH265T5L / 4, 253.7 nm) irradiating the uncoated p-HAp directly.

[0098] As a representative example of the reaction, the following yields (expressed as μmol of product per gram of catalyst) were obtained: The reaction was carried out using CO2 (3 bar), CH4 (3 bar) and H2O (1 mL) at 95 °C under UV light for 72 h.

[0099] The yields obtained from the solution obtained after extraction by dissolving the catalyst were: ethanol (19.4 ± 3.8 μmol / g), acetone (0.9 ± 0.1 μmol / g) and acetic acid (0.6 ± 0.1 μmol / g). Methanol and formic acid were not detected.

[0100] Yields obtained from liquid water (supernatant): ethanol (0.7 ± 0.14 μmol / g), acetic acid (2.0 ± 0.5 μmol / g), methanol (1.5 ± 0.3 μmol / g), and formic acid (1.9 ± 0.6 μmol / g). No acetone was detected.

[0101] The reaction was carried out using CO2 (6 bar) and H2O (1 mL) at 140 °C without UV light for 48 h.

[0102] The yields obtained from the solution obtained after extraction by dissolving the catalyst were: ethanol (6.6 ± 2.3 μmol / g), formic acid (3.2 ± 0.5 μmol / g), acetone (0.6 ± 0.3 μmol / g), methanol (0.6 ± 0.2 μmol / g) and acetic acid (0.5 ± 0.1 μmol / g).

[0103] Yields obtained from liquid water (supernatant): ethanol (4.5 ± 0.9 μmol / g), formic acid (2.4 ± 1.0 μmol / g), acetic acid (2.2 ± 0.9 μmol / g), acetone (0.7 ± 0.1 μmol / g) and methanol (0.2 ± 0.1 μmol / g).

[0104] The reaction was carried out using CO2 (1 bar) and H2O (1 mL) at 140 °C without UV light for 48 h.

[0105] The yields obtained from the solution obtained after extraction by dissolving the catalyst were: acetone (1.6 ± 0.6 μmol / g), formic acid (1.1 ± 0.3 μmol / g), ethanol (0.8 ± 0.2 μmol / g), acetic acid (0.8 ± 0.2 μmol / g) and methanol (0.5 ± 0.2 μmol / g).

[0106] The yields obtained from liquid water (supernatant) were: acetic acid (2.4 ± 1.0 μmol / g), formic acid (1.3 ± 0.3 μmol / g), formic acid (1.1 ± 0.3 μmol / g), acetone (0.8 ± 0.3 μmol / g), ethanol (0.8 ± 0.1 μmol / g), and methanol (0.1 ± 0.03 μmol / g).

[0107] The reaction was carried out for 48 h at 95 °C without UV light using CO2 (6 bar) and H2O (1 mL).

[0108] The yields obtained from the solution obtained after extraction by dissolution of the catalyst were: formic acid (1.1 ± 0.3 μmol / g), ethanol (0.7 ± 0.3 μmol / g), acetone (0.6 ± 0.2 μmol / g), acetic acid (0.5 ± 0.1 μmol / g) and methanol (0.3 ± 0.1 μmol / g).

[0109] The yields obtained from the liquid water (supernatant) were: acetic acid (4.6 ± 0.6 μmol / g), acetone (2.3 ± 0.3 μmol / g), formic acid (1.1 ± 0.1 μmol / g), and ethanol (0.4 ± 0.1 μmol / g). No methanol was detected.

[0110] The reaction was carried out using CO2 (6 bar) and H2O (1 mL) at 140 °C without UV light for 72 h.

[0111] The yields obtained from the solution obtained after extraction by dissolving the catalyst were: ethanol (10.2 ± 3.0 μmol / g), formic acid (2.4 ± 0.5 μmol / g), acetone (0.9 ± 0.2 μmol / g), acetic acid (0.7 ± 0.2 μmol / g) and methanol (0.6 ± 0.2 μmol / g).

[0112] Yields obtained from liquid water (supernatant): ethanol (7.0 ± 1.1 μmol / g), acetic acid (3.0 ± 1.2 μmol / g), formic acid (1.9 ± 0.8 μmol / g), acetone (1.1 ± 0.4 μmol / g) and methanol (0.2 ± 0.1 μmol / g).

[0113] 9. Synthesis of functionalized organic molecules with 1–3 carbon atoms using coated p-HAp as a catalyst Functionalized organic molecules with 1–3 carbon atoms were synthesized from a CO2 and CH4 gas mixture (3 bar each) in the presence of coated p-HAp as a catalyst and liquid HO (1 mL). The reaction was carried out at 95 °C for 72 h under irradiation with a UV lamp (GPH265T5L / 4, 253.7 nm) directly on the coated p-HAp. p-HA was coated with two layers of aminotris(methylenephosphonic acid) and one layer of zirconium oxychloride (ZrOCl2), with the zirconium oxychloride layer either sandwiched between the two layers of aminotris(methylenephosphonic acid). The yields (expressed as μmol of product per gram of coated p-HAp) obtained from the solution obtained after extraction by dissolving the catalyst were: ethanol (16.1 ± 3.2 μmol / g), methanol (4.9 ± 1.0 μmol / g), acetone (0.8 ± 0.2 μmol / g), and acetic acid (0.6 ± 0.1 μmol / g).

[0114] 10. Synthesis of ethanol using coated p-HAp as a catalyst Ethanol was synthesized from a CO2 and CH4 gas mixture (3 bar each) in the presence of coated p-HAp as a catalyst and liquid HO (1 mL). The reaction was carried out at 95 °C for 72 hours under irradiation with a UV lamp (GPH265T5L / 4, 253.7 nm) directly irradiating the coated p-HAp. p-HA was coated with two layers of aminotris(methylenephosphonic acid) and one layer of zirconium oxychloride (ZrOCl2), with the zirconium oxychloride layer either sandwiched between the two layers of aminotris(methylenephosphonic acid). The reaction resulted in the following yields (expressed as μmol of product per gram of coated p-HAp): ethanol (16.1 ± 3.2 μmol / g), methanol (4.9 ± 1.0 μmol / g), malonic acid (1.6 ± 0.2 μmol / g), acetone (0.8 ± 0.2 μmol / g), and acetic acid (0.6 ± 0.1 μmol / g). The major product, ethanol, was 1 It was identified by H-NMR spectroscopy by a sharp OH peak at 4.65 ppm as well as a quartet (CH2) and a triplet (CH3) at 3.53 ppm and 1.06 ppm, respectively.

[0115] 11. Synthesis of ethanol using HAp (uncoated) as a catalyst Ethanol was synthesized from a CO and CH gas mixture (3 bar each) in the presence of uncoated HAp as a catalyst and liquid HO (1 mL). The reaction was carried out at 95 °C for 72 h under irradiation with a UV lamp (GPH265T5L / 4, 253.7 nm) directly irradiating the p-HAp. The reaction resulted in a very low yield of ethanol (1.9 ± 0.5 μmol / g catalyst). Furthermore, the yields of acetone and acetic acid were <0.1 μmol / g catalyst.

[0116] 12. Synthesis of ethanol without a solid support acting as a catalyst Ethanol was synthesized from a CO and CH gas mixture (3 bar each) in the presence of uncoated HAp as a catalyst and liquid HO (1 mL). The reaction was carried out at 95 °C for 72 h under irradiation with a UV lamp (GPH265T5L / 4, 253.7 nm). In the absence of any solid support acting as a catalyst (see Figure 7(a)), the yield of ethanol is essentially zero (0.1 ± 0.05 μmol / g). This small amount, due to incidental photoinduced CO reduction and water decomposition, completely disappears without UV light (see Figure 7(b)).

[0117] 13. Synthesis of functionalized organic molecules with 1-3 carbon atoms, especially ethanol, using traffic-polluted air. As a proof of concept, a reaction to synthesize ethanol was carried out at atmospheric pressure using polluted air collected from the area surrounding the East Campus of the Universitat Politecnica de Catalunya (UPC) Barcelona, ​​an area heavily polluted by vehicular traffic due to its proximity to one of the city's major roads. The air, polluted by the combustion of fossil fuels (carburants), contains significantly higher levels of CO2 and CH4 than the average ambient air. The reaction was carried out using p-HAp as a catalyst, in the presence of 1 mL of water, and at 95 °C under UV light. Analysis of the reaction products after 72 h showed ethanol among other products, some of which had not been identified in previous reactions with controlled gas mixtures. Despite the fact that the amounts of ethanol (1.1 ± 0.2 μmol / g), acetic acid (0.03 ± 0.01 μmol / g), acetone (0.09 ± 0.02 μmol / g), formic acid (0.13 ± 0.05 μmol / g) and methanol (0.16 ± 0.04 μmol / g) were minimal, while functionalized organic molecules with 1–3 carbon atoms were obtained as valuable products, the formation of high-value chemical products confirmed the potential applicability of p-HAp as a catalyst for the regeneration of polluted air.

[0118] 14. Further studies on mechanistic pathways The formation of functionalized organic molecules with 1–3 carbon atoms can be related to the pressure of the feed gas, temperature, and reaction time. To explore the role of reaction conditions, the method was repeated without UV irradiation using CO gas and uncoated p-HAp as the catalyst. As shown in Figure 12(a)–(d), the yield of functionalized organic molecules with 1–3 carbon atoms increases with pressure. Increasing the pressure from 1 to 6 bar increased the total yield (the sum of the yields obtained for each product by dissolving the catalyst + the sum of the yields obtained for each product from the supernatant) from 11.9 ± 1.6 to 23.1 ± 2.3 μmol / g.

[0119] In summary, we have confirmed the catalytic activity of permanently polarized hydroxyapatite in converting gaseous CO2 into high-value organic chemicals, i.e., functionalized organic molecules with 1-3 carbon atoms, according to an electroreduction mechanism. Experiments under different reaction conditions reflect the formation of functionalized organic molecules with 1-3 carbon atoms, which are formed via the electroreduction of CO2 induced by permanently polarized hydroxyapatite. As a proof of concept, the proposed reaction successfully obtains high-value chemical products from road traffic-polluted air, opening up an interesting new avenue for converting greenhouse gas emissions into valuable chemical products using simple catalysts based on Earth-abundant minerals.

Claims

1. 1. A method for producing functionalized organic molecules selected from the group consisting of ethanol, methanol, formic acid, acetic acid, malonic acid, acetone, and a mixture of at least two of the foregoing functionalized organic molecules, comprising: Carbon dioxide as the only gas or a gas mixture comprising or consisting of carbon dioxide and methane, In the presence of water, contacting the catalyst with a catalyst comprising or consisting of permanently polarized hydroxyapatite; The contacting step is carried out under conditions where the temperature is 95°C to 140°C; The gas mixture is free of nitrogen. method.

2. The permanently polarized hydroxyapatite is a crystallinity of 65% to 99%; and / or Amorphous calcium phosphate in a proportion of 0.1% to 17% by weight relative to the total weight of the permanently polarized hydroxyapatite, and / or β-tricalcium phosphate in a proportion of 0.1% to 35% by weight relative to the total weight of the permanently polarized hydroxyapatite, and / or 10 ７ Ω cm ２ ~10 ５ Ω cm ２ wherein the bulk resistance increases by between 4% and 73% after 3 months; and / or After 3 months, the surface capacitance decreased by 8% to 0.1%.

2. The method of claim 1, comprising:

3. (a) providing a sample of hydroxyapatite; (b) sintering the sample prepared in step (a) at a temperature between 700°C and 1200°C; (c) applying a constant or variable DC voltage between 250V and 2500V to the sample or its compact obtained in step (b); or (c) applying an equivalent electric field between 1.49 kV / cm and 15 kV / cm to the sample obtained in step (b) or a compact thereof; or (c) applying an electrostatic discharge between 2500V and 1500000V to the sample obtained in step (b) or to a compact thereof; or Step (c) of applying an equivalent electric field between 148.9 kV / cm and 8928 kV / cm to the sample obtained in step (b) or a molded body thereof; (d) cooling the sample obtained in step (c) while maintaining the DC voltage or the equivalent electric field applied in step (c); or Step (d) of cooling the sample obtained in step (c) with or without maintaining the electrostatic discharge or the equivalent electric field; 3. The method according to claim 1, wherein the permanently polarized hydroxyapatite is obtained by a process comprising the steps of:

4. (a) providing a sample of hydroxyapatite; (b) sintering the sample prepared in step (a) at a temperature of 1000°C; (c) applying an equivalent electric field of 3 kV / cm to the sample or compact obtained in step (b) at a temperature of 1000°C; (d) cooling the sample obtained in step (c) while maintaining the equivalent electric field; 4. The method according to claim 1, wherein the permanently polarized hydroxyapatite is obtained by a process comprising:

5. 5. The method according to claim 1, wherein the contacting step is carried out in the presence of liquid water.

6. 6. The method according to claim 1, wherein the contacting step is carried out under conditions where the volume ratio of the permanently polarized hydroxyapatite to water is 1000:1 to 0.01:

1.

7. 7. The method of claim 1, wherein the contacting step is carried out under conditions where the volume ratio of carbon dioxide to methane is 200:

1.

8. 8. The method according to any one of claims 1 to 7, wherein the contacting step is carried out under a total pressure of between 0.1 bar and 100 bar.

9. 9. The method according to claim 1, wherein the contacting step is carried out under conditions in which the carbon dioxide pressure is between 0.035 bar and 100 bar.

10. The contacting step comprises: a partial pressure of carbon dioxide between 0.035 bar and 90 bar; and / or The partial pressure of methane is 0.00017 bar to 5 bar.

10. The method according to any one of claims 1 to 9.

11. The contacting step comprises: The molar ratio of carbon dioxide to permanently polarized hydroxyapatite is between 0.1 and 0.5, and / or The method is characterized in that the molar ratio of methane to permanently polarized hydroxyapatite is 0.1 to 0.

5.

11. The method according to any one of claims 1 to 10.

12. 12. The method according to any one of claims 1 to 11, wherein the contacting step is carried out under conditions where the UV or UV-Vis radiation has a wavelength of 200 nm to 850 nm.

13. 13. The method according to any one of claims 1 to 12, characterized in that the contacting step is carried out under UV irradiation and / or visible light irradiation.

14. 14. Use of the method according to any one of claims 1 to 13 for producing ethanol or a mixture comprising or consisting of ethanol and at least one further functionalised organic molecule selected from the group consisting of methanol, formic acid, acetic acid, malonic acid and acetone, or a mixture comprising or consisting of ethanol, methanol, formic acid, acetic acid and acetone, or a mixture comprising or consisting of ethanol, methanol, acetic acid, malonic acid and acetone.

15. 14. Use of the method according to any one of claims 1 to 13 for removing carbon dioxide from the atmosphere.

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