Off-site electro-catalytic reaction method and reaction system

Abstract

Disclosed in the present invention are an off-site electro-catalytic reaction method and reaction system. The off-site electro-catalytic reaction method comprises: in a battery system, ion pairs in an electrolyte undergoing an electron exchange reaction with an electrode, so as to obtain an oxidation potential or a reduction potential; the electrolyte with the obtained oxidation potential or reduction potential entering an independent reaction system outside the battery system, and undergoing a redox reaction with a reactant in the reaction system, so as to obtain a mixture containing a reaction product; and after separation, the electrolyte, which has undergone the redox reaction, returning to the battery system, so as to obtain the oxidation potential or reduction potential again. By means of the new off-site electro-catalytic tandem reaction technique provided in the present invention, a complex reaction involving gas, liquid and solid phases, etc. can be moved out of the surface of an electrode, and a reaction process is performed outside of a battery, thereby preventing the contamination of the electrode, a catalyst, a separator, etc. by reactants and / or products; and the reaction system built by means of an off-site electro-catalytic synthesis technique operates stably, can be used for fundamental theoretical research, and has practical application significance.

Description

Off-site electrocatalytic reaction method and reaction system Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis, and in particular relates to an off-site electrocatalytic reaction method and a reaction system. Background Art

[0002] Renewable resources such as wind, solar power, water, and tidal heat can be used to generate green electricity. Using green electricity, electrocatalytic technologies can be used for organic matter conversion, alkane / olefin / aromatic activation, carbon dioxide reduction, hydrogen sulfide decomposition, and water splitting to produce hydrogen and oxygen. Electrocatalytic technology primarily involves an anode cell, a cathode cell, and a diaphragm. The anode cell undergoes oxidation, while the cathode cell undergoes reduction. The diaphragm separates the anode and cathode electrolytes, allowing protons or hydroxide ions to penetrate, thus achieving electrical conductivity for the entire system.

[0003] Current electrocatalytic synthesis involves adding reactants to the anode or cathode electrolyte, where a chemical reaction occurs on the surface of the electrode or the catalyst it supports to generate the target product. Organic reactants, especially cyclic organic compounds and aromatic hydrocarbons, are often prone to side reactions such as polymerization and deposition on the electrode surface, resulting in a decrease in the effective area of ​​the electrode and limited mass transfer. In addition, organic matter can cause harmful effects such as swelling and dissolution on the diaphragm, causing the entire electrocatalytic reaction system to fail or become less active, making it impossible to operate stably and continuously. This results in fatally low efficiency and short lifespan for industrial scale-up applications. In addition, current electrocatalytic syntheses are all half-reactions, meaning that organic reactions occur only on the anode or cathode side, while gas is produced on the other side of the electrode. Because the pressure on both sides of the diaphragm is unbalanced, penetration of substances from both sides of the diaphragm occurs during the actual production process, resulting in a short diaphragm lifespan, which also causes unstable system operation and wastes electrical resources.

[0004] Therefore, to achieve large-scale, continuous, stable, and efficient industrial application of electrocatalytic processes, it is urgent to innovate current electrocatalytic reaction methods. This means avoiding contamination, swelling, and coating of electrodes and diaphragms by reactants and / or products, while also changing traditional reaction methods. There is an urgent need to develop new electrocatalytic organic synthesis reaction technologies that can achieve stable and continuous operation of the reaction system and scale up for industrial application.

[0005] Summary of the Invention

[0006] In view of this, the present invention provides an off-site electrocatalytic reaction method and reaction system, the main purpose of which is to solve the technical problem that the reactants and / or products of the electrocatalytic organic reaction easily contaminate, swell, and cover the electrodes and diaphragms.

[0007] In one aspect, the present invention provides a method for an off-site electrocatalytic reaction, comprising the following steps:

[0008] The off-site electrocatalytic reaction method comprises the following steps:

[0009] The electrolyte ions in the battery system undergo an electron exchange reaction with the electrodes to obtain an oxidation potential or a reduction potential; the electrolyte that has obtained the oxidation potential or the reduction potential enters an independent reaction system outside the battery system, undergoes an oxidation-reduction reaction with the reactants in the reaction system, and obtains a mixture containing reaction products. After separation, the electrolyte that has undergone the oxidation-reduction reaction returns to the battery system to obtain the oxidation potential or the reduction potential again.

[0010] The battery system and the reaction system in the present invention are independent systems and can be connected by a pipeline. The pipeline is used for the electrolyte to flow between the battery system and the reaction system.

[0011] In the present invention, the electrolyte is the electrolyte that undergoes electron exchange reaction with the electrode after the battery system is energized to obtain oxidation potential or reduction potential.

[0012] The above-mentioned off-site electrocatalytic reaction method of the present invention moves the traditional chemical reaction of the reactants in the electrolytic cell to another reaction site outside the electrolytic cell for reaction. It only requires the electrolyte to be circulated and transported between the electrolytic cell and the reaction site. This can avoid the problem of contamination, swelling, and coverage of the electrodes or diaphragms caused by the chemical reaction of the reactants in the electrolytic cell in the traditional technology.

[0013] The above-mentioned off-site electrocatalytic method of the present invention is applicable to the following five reaction modes:

[0014] The first type: the anode electrolytic cell is connected to the oxidation reaction system, and the oxidation reaction is carried out separately.

[0015] The second type: the cathode electrolytic cell is connected to the reduction reaction system, and the reduction reaction is carried out separately.

[0016] The third method is that the anode electrolytic cell is connected to the oxidation reaction system and performs oxidation reaction alone. At the same time, the cathode electrolytic cell is connected to the reduction reaction system and performs reduction reaction alone. The oxidation reaction system and the reduction reaction system each independently perform chemical reactions; that is, the parallel method.

[0017] The fourth type: the anode electrolytic cell is connected to the oxidation reaction system to carry out an oxidation reaction, and the cathode electrolytic cell is connected to the reduction reaction system to carry out a reduction reaction. In particular, the product of the oxidation reaction enters the reduction reaction system as a reactant to continue to carry out a reduction reaction with the cathode electrolyte, forming a two-stage series reaction system of the oxidation reaction system-reduction reaction system.

[0018] The fifth method: On the basis of the fourth method, another set of electrolytic cells and oxidation reaction systems are added to form a three-stage series reaction system of oxidation reaction system-reduction reaction system-oxidation reaction system.

[0019] In addition to the above-mentioned species connection method, the off-site electrocatalytic reaction liquid of the present invention can carry out oxidation and reduction processes in multiple stages in series or in parallel outside the electrolytic cell according to the actual reaction process.

[0020] Optionally, the anolyte M in the anolyte cell of the battery system has redox properties. x+ Oxidation reaction occurs on the anode surface, forming an oxidizing electrolyte M with an oxidation potential (x+1)+ ;

[0021] The oxidizing electrolyte M (x+1)+ Entering the oxidation reaction system, an oxidation reaction occurs with the reactant I in the oxidation reaction system, and the reactant I is oxidized to obtain a reaction product I. The oxidizing electrolyte M (x+1)+ is reduced to obtain the anolyte M x+ After separation, the anolyte M x+ Return to the anode electrolytic cell and react with the anode again to form an oxidizing electrolyte M with an oxidation potential. (x+1)+ ;

[0022] The cathode electrolyte in the battery system undergoes an oxidation-reduction reaction in the cathode electrolytic cell.

[0023] The above process of the present invention is an anode half-reaction process outside the electrolytic cell; M x+ 、M (x+1)+ The x in the equation is the valence state of the M ion.

[0024] Optionally, the cathode electrolyte N in the cathode electrolytic cell of the battery system has redox properties. y+ A reduction reaction occurs on the cathode surface, forming a reducing electrolyte N with a reduction potential. (y-1)+ ;

[0025] The reducing electrolyte N (y-1)+ Entering the reduction reaction system, a reduction reaction occurs with the reactant II in the reduction reaction system, and the reactant II is reduced to obtain a reaction product II. The reducing electrolyte N (y-1)+ is oxidized to obtain catholyte N y+ , after separation, the cathode electrolyte N y+ Return to the cathode electrolytic cell and react with the cathode again to form a reducing electrolyte N with a reduction potential. (y-1)+ ;

[0026] The anolyte in the battery system undergoes an oxidation-reduction reaction in the anolyte cell.

[0027] The above process of the present invention is a cathode half-reaction process outside the electrolytic cell; N y+ 、N(y-1)+ The y in the equation is the valence state of the N ion.

[0028] Optionally, the anolyte M in the anolyte cell of the battery system has redox properties. x+ Oxidation reaction occurs on the anode surface, forming an oxidizing electrolyte M with an oxidation potential (x+1)+ I;

[0029] The oxidizing electrolyte M (x+1)+ I enters the oxidation reaction system I, and undergoes oxidation reaction I with the reactant I in the oxidation reaction system I. The reactant I is oxidized to obtain a reaction product I. The oxidation electrolyte M (x+1)+ I is reduced to obtain the anolyte M x+ After separation, the anolyte M x+ Return to the anode electrolytic cell and react with the anode again to form an oxidizing electrolyte M with an oxidation potential. (x+1)+ ;Cyclic oxidation-reduction process;

[0030] The cathode electrolyte N in the cathode electrolytic cell of the battery system has redox properties. y+ A reduction reaction occurs on the cathode surface, forming a reducing electrolyte N with a reduction potential. (y-1)+ I;

[0031] The reducing electrolyte N (y-1)+ I enters the reduction reaction system I, and undergoes a reduction reaction I with the reactant II of the reduction reaction system I. After the reactant II is reduced, a reaction product II is obtained. The reducing electrolyte N (y-1)+ I is oxidized to give the catholyte N y+ , after separation, the cathode electrolyte N y+ Return to the cathode electrolytic cell and react with the cathode again to form a reducing electrolyte N with a reduction potential. (y-1)+ ; cyclic reduction-oxidation process.

[0032] In the above process of the present invention, the anolyte circulates between the anolyte cell and the oxidation reaction system to undergo a process of reduction-oxidation-re-reduction-reoxidation, and the reactants undergo an oxidation reaction in the oxidation reaction system; independently, the catholyte circulates between the cathode electrolytic cell and the reduction reaction system to undergo a process of oxidation-reduction-reoxidation-rereduction, and the reactants undergo a reduction reaction in the reduction reaction system.

[0033] In the above-mentioned off-site electrocatalytic technology of the present invention, an electrolytic cell system is first used to prepare a mediator with oxidation potential and a mediator with reduction potential by electrolysis; then the mediator with oxidation potential is introduced into an oxidation reactor, where an oxidation reaction occurs with the reactants under the action of a catalyst; and the mediator with reduction potential is introduced into a reduction reactor, where a reduction reaction occurs with the reactants under the action of a catalyst.

[0034] Optionally, the reaction product I of the oxidation reaction system I enters the reduction reaction system I and serves as the reactant II of the reduction reaction system I and the reducing electrolyte N in the reduction reaction system I. (y-1)+ I performs a reduction reaction I to obtain the reaction product II.

[0035] In the above process of the present invention, the oxidation reaction system and the reduction reaction system are connected in series, that is, the product of the oxidation reaction is used as the reactant of the reduction reaction system to continue the reaction.

[0036] Optionally, the reaction product II of the reduction reaction system I enters the oxidation reaction system I as the reactant III of the oxidation reaction system I and reacts with the oxidizing electrolyte M in the oxidation reaction system I. (x+1)+ I undergoes oxidation reaction II to obtain the reaction product III.

[0037] In the above process of the present invention, when the first oxidation reaction I proceeds faster, the outlet of the reduction reaction system I and the inlet of the oxidation reaction system I can be connected, and the reactant II reacts with the oxidizing electrolyte M in the oxidation reaction system I. (x+1)+ I continues to undergo a second oxidation reaction to obtain reaction product III. This process is a ring-closing reaction.

[0038] Optionally, the reaction product II of the reduction reaction system I enters the oxidation reaction system II and serves as the reactant III of the oxidation reaction system II to react with the oxidizing electrolyte M in the oxidation reaction system II. (x+1)+ II undergoes oxidation reaction II to obtain the reaction product III.

[0039] In the above process of the present invention, when the first step oxidation reaction I progresses slowly and the subsequent process continues, a new oxidation reaction system II can be connected behind the reduction reaction system I, and a new battery system II can be connected at the same time. The reactant II of the reduction reaction system reacts with the new oxidized electrolyte M in the new battery system in the new oxidation reaction system II. (x+1)+ II undergoes a second oxidation reaction to obtain a reaction product III, and this process is a ring-opening reaction.

[0040] In the above process of the present invention, the oxidation reaction system, the reduction reaction system and the oxidation reaction system are connected in series in multiple stages to realize the chemical reaction process of oxidation, reduction and oxidation in a matching manner.

[0041] Optionally, the solute of the electrolyte includes a redox ion pair; the redox ion pair is selected from at least one of an inorganic metal ion pair, an organic metal ion pair, an organic pair and an inorganic pair.

[0042] Optionally, the solvent of the electrolyte includes at least one of an acid or alkali aqueous solution, an organic solution, and a composite solvent of water and organic matter;

[0043] The acid is selected from inorganic acids and / or organic acids;

[0044] The concentration of the acid is 0.01 to 6 mol / L;

[0045] Preferably, the total acid concentration is 0.01 to 3 mol / L.

[0046] The inorganic acid is selected from at least one of H2SO4, HCl, H3PO4 and HClO4;

[0047] The organic acid is selected from at least one of acetic acid, trifluoroacetic acid and benzenesulfonic acid;

[0048] The organic solvent is selected from at least one of methanol, dimethyl ether, acetonitrile, ethyl acetate, chloroform, dichloromethane and dimethyl sulfoxide.

[0049] The electrolyte may be added with alkali metals to increase the conductivity of the electrolyte and optimize the catalytic activity, but is not limited to the above-mentioned metal inorganic salts;

[0050] Optionally, the solute of the anolyte in the anolyte cell comprises a redox ion pair I, wherein the redox ion pair I is selected from I3 - / I - Br2 / Br - 、Fe(III) / Fe(II)、[Fe(CN)6] 3- / [Fe(CN)6] 4- , VO2(I) / VO(II), Ce(IV) / Ce(III) and K2MnO4 / KMnO4.

[0051] Optionally, the solute of the cathode electrolyte in the cathode electrolytic cell comprises a redox ion pair II, and the redox ion pair II is selected from at least one of an inorganic metal ion pair, an organic metal ion pair, an organic pair, and an inorganic pair;

[0052] The inorganic metal ion pair is selected from at least one of Eu(II) / Eu(III), Cr(II) / Cr(III) and V(II) / V(III);

[0053] The organometallic ion pair is selected from at least one of organically coordinated cobalt (II) / organically coordinated cobalt (III), triethanolamine iron (II) / triethanolamine iron (III), etc.;

[0054] The organic pair is selected from quinone / phenol organic pairs; preferably at least one of benzodiquinone / hydroquinone, benzophenone / benzhydrol;

[0055] The inorganic pair is selected from heteropoly acids.

[0056] Optionally, the organic-coordinated cobalt (II) / organic-coordinated cobalt (III) is selected from porphyrin cobalt (II) / porphyrin cobalt (III);

[0057] The ion pairs in the above-mentioned anolyte of the present invention are suitable for oxidation reaction with organic matter; the organic matter can be selected from at least one of oxygen-containing organic matter, nitrogen-containing organic matter, alkanes, aromatic hydrocarbons, alkenes, alkynes, H2O, CO, and H2S.

[0058] The ion pairs in the cathode electrolyte of the present invention are suitable for reduction reaction with organic matter; the organic matter can be selected from at least one of oxygen-containing organic matter, nitrogen-containing organic matter, nitrogen oxides, olefins, alkynes, aromatic hydrocarbons, protons, CO2, CO, and nitrogen.

[0059] Optionally, the reactant comprises benzene and the reaction product comprises adipic acid.

[0060] Optionally, the reactant I of the oxidation reaction system I includes benzene, and the reaction product I includes phenol; the reactant II of the reduction reaction system I includes phenol, and the reaction product II includes cyclohexanone.

[0061] Optionally, the reactant III includes cyclohexanone, and the reaction product III includes adipic acid.

[0062] In a second aspect, the present invention provides an electrocatalytic reaction device for use in the above-mentioned off-site electrocatalytic reaction method, comprising:

[0063] A battery system for providing an electrolyte having redox properties;

[0064] a reaction system for providing a reaction space for an oxidation-reduction reaction between the electrolyte delivered from the battery system and the reactants in the reaction system;

[0065] A separation system for separating the reaction products from the electrolyte after the redox reaction;

[0066] The liquid outlet of the battery system is in communication with the inlet of the reaction system;

[0067] The outlet of the reaction system is connected to the inlet of the separation system;

[0068] The electrolyte outlet of the separation system is communicated with the liquid inlet of the battery system, and the separation system has a product outlet.

[0069] The battery system of the present invention consists of three parts: an anode tank, a cathode tank, and a diaphragm. The cathode and anode chambers are separated by an ion exchange membrane to prevent cross-contamination or penetration of the cathode and anode electrolytes. The cathode and anode electrolytes are acidic water and / or organic compounds. The solute at the anode is a redox mediator M. x+ , it undergoes oxidation reaction on the anode surface, the valence state increases, and the oxidation potential M is obtained at this time (x+1)+ ; The cathode solute is a redox mediator N y+ , which undergoes a reduction reaction on the cathode surface, and the valence state decreases, and a reduction potential N is obtained. (y-1)+ .

[0070] The oxidation potential M (x+1)+ Into another reactor, it undergoes oxidation reaction with the reactant, and the mediator is reduced to generate M x+ , separating the mediator from the reactants / products, and then returning the mediator to the anode tank to complete the electrochemical / catalytic reaction on the anode side. In another spatially separated reactor, the reduced mediator N (y-1)+ Reduction reaction occurs with the reactant, and the mediator is oxidized to generate N y+ , separating the mediator and reactants / products, and then the mediator returns to the cathode tank to complete the electrochemical / catalytic reaction on the cathode side.

[0071] In particular, for the "off-site" electrocatalytic series reaction technology, the reactant of the reduction reactor is the product of the oxidation reactor, and the product can also enter the oxidation reactor again to undergo oxidation reaction.

[0072] Optionally, the battery system comprises an H-type electrolytic cell, a liquid flow battery, or an electrolyte-free diaphragm flow electrolytic cell.

[0073] Optionally, the liquid flow battery includes an anode electrolytic cell and a cathode electrolytic cell, wherein the anode and cathode are independently selected from at least one of a carbon rod, a carbon felt, a titanium mesh and a copper mesh.

[0074] Optionally, at least one of Pt, Pd, Bi, Ag, and Pb metals is independently deposited on the surfaces of the anode and cathode.

[0075] The carbon rod, carbon felt, titanium mesh and copper mesh of the present invention can be directly used as anodes or cathodes, or the above metals can be deposited on their surfaces.

[0076] Optionally, the reaction system includes an oxidation reactor and / or a reduction reactor; the separation system includes an extractor and a distillation tower; the product outlet of the extractor is connected to the inlet of the distillation tower, and the distillation tower has a product outlet.

[0077] Optionally, the liquid outlet of the anode electrolytic cell is connected to the inlet of the oxidation reactor, reactants are set in the oxidation reactor, the outlet of the oxidation reactor is connected to the inlet of the extractor, the product outlet of the extractor is connected to the inlet of the distillation tower, the electrolyte outlet of the extractor is connected to the liquid inlet of the anode electrolytic cell, and the distillation tower has a product outlet.

[0078] Optionally, the liquid outlet of the cathode electrolytic cell is connected to the inlet of the reduction reactor, reactants are set in the reduction reactor, the outlet of the reduction reactor is connected to the inlet of the extractor, the product outlet of the extractor is connected to the inlet of the distillation tower, the electrolyte outlet of the extractor is connected to the liquid inlet of the cathode electrolytic cell, and the distillation tower has a product outlet.

[0079] Optionally, the liquid outlet of the anode electrolytic cell I is connected to the inlet of the oxidation reactor I, reactants are arranged in the oxidation reactor I, the outlet of the oxidation reactor I is connected to the inlet of the extractor I, the product outlet of the extractor I is connected to the inlet of the distillation tower I, and the electrolyte outlet of the extractor I is connected to the liquid inlet of the anode electrolytic cell I; the product I outlet of the distillation tower I is connected to the inlet of the reduction reactor, the liquid outlet of the cathode electrolytic cell is connected to the inlet of the reduction reactor, the outlet of the reduction reactor is connected to the inlet of the extractor II, the product outlet of the extractor II is connected to the inlet of the distillation tower II, the electrolyte outlet of the extractor II is connected to the liquid inlet of the cathode electrolytic cell, and the distillation tower II has a product II outlet.

[0080] Optionally, the product II outlet of the distillation tower II is connected to the inlet of the oxidation reactor I;

[0081] Alternatively, the product II outlet of the distillation tower II is connected to the inlet of the oxidation reactor II, and the liquid outlet of the anode electrolysis cell II is connected to the inlet of the oxidation reactor II; the outlet of the oxidation reactor II is connected to the inlet of the extractor III, the product outlet of the extractor III is connected to the inlet of the distillation tower III, the electrolyte outlet of the extractor III is connected to the liquid inlet of the anode electrolysis cell II, and the distillation tower III has a product III outlet.

[0082] The electrocatalytic reaction method and electrocatalytic reaction system of the present invention can be used to produce phenol from benzene, produce cyclohexanone from phenol, produce adipic acid from cyclohexanone, or produce adipic acid from benzene.

[0083] Optionally, the temperature of the battery system is 5 to 80° C., and the pressure is 1 to 30 bar.

[0084] Optionally, the oxidation reactor is selected from a fixed bed, a tank reactor, a slurry bed, a tray reactor or a fluidized bed reactor; the pressure of the oxidation reactor is 1 to 200 bar, and the temperature is 5 to 200°C.

[0085] Preferably, the pressure of the oxidation reactor is 1-20 bar and the temperature is 15-50°C.

[0086] Optionally, no catalyst may be used in the oxidation reactor or catalyst I may be selectively placed, and the active component of the catalyst I is selected from at least one of Au, Cu, Ru, Ir, Pt, Pd, Rh, Fe, Co metals and their oxides; the catalyst I may be a supported type or may be directly used as metal particles.

[0087] Alternatively, the catalyst may be directly at least one of carbide, phosphide, nitride, etc.

[0088] Optionally, the reactants in the oxidation reactor are selected from at least one of oxygen-containing organic matter, nitrogen-containing organic matter, alkanes, aromatic hydrocarbons, alkenes, alkynes, H2O, CO, and H2S.

[0089] Optionally, the reduction reactor is selected from a fixed bed reactor, a tank reactor, a slurry bed reactor or a fluidized bed reactor; the pressure of the reduction reactor is 1 to 200 bar, and the temperature is 5 to 200°C.

[0090] Preferably, the pressure of the reduction reactor is 1-20 bar and the temperature is 15-50°C.

[0091] Alternatively, no catalyst may be used in the reduction reactor, or a catalyst II may be selectively placed, wherein the active component of the catalyst II is selected from at least one of Au, Cu, Ru, Ir, Pt, Pd, Rh, Fe, Co metals, and their oxides. The catalyst I may be supported or directly used as metal particles.

[0092] Alternatively, the catalyst may be directly at least one of carbide, phosphide, nitride, etc.

[0093] Optionally, the reactants in the reduction reactor are selected from at least one of oxygen-containing organic matter, nitrogen-containing organic matter, nitrogen oxides, olefins, alkynes, aromatic hydrocarbons, protons, CO2, CO, and nitrogen.

[0094] The entire electrocatalytic system of the present invention includes a battery system, an oxidation reactor, a reduction reactor, an extractor and a distillation column. The products and redox media of the oxidation reactor and the reduction reactor are separated by extraction with an organic solvent. The redox media returned to the anode tank and the cathode tank does not contain reactants and products, thereby avoiding contamination of the electrodes, diaphragms, etc. This operating method of separating the reactants and products from the electrodes and diaphragms and connecting the oxidation reactor and the reduction reactor in series is the new electrocatalytic reaction technology proposed by the present invention, which is called "off-site" electrocatalytic series reaction technology. This "off-site" electrocatalytic reaction system can not only conduct basic theoretical research in the laboratory of basic research, but also the battery amplification does not require adjustments to the flow channel and internal structure process due to the amplification effect. The oxidation and reduction reactors are very mature in industry and easy to amplify. Therefore, industrial tests at the scale of electrochemical demonstration, pilot test, and application can also be carried out.

[0095] Preferably, taking benzene to adipic acid as an example, the step-by-step reaction process is as follows:

[0096] Anode tank: M x+ -e - →M (x+1)+ (1)

[0097] Cathode tank: N y+ +e - →N (y-1)+ (2)

[0098] Oxidation reactor: benzene + M (x+1)+ +H2O→phenol+M x+ +2H + (3)

[0099] Reduction reactor: phenol + 4N (y-1)+ +4H + →Cyclohexanone+4N y+ (4)

[0100] Oxidation reactor: cyclohexanone + M (x+1)+ +2H2O→Adipic acid+M x+ +2H + (5)

[0101] Overall reaction: Benzene + 4H2O → Adipic acid + 2H2 (6)

[0102] In addition to being applicable to the series reaction of benzene to adipic acid, the off-site electrocatalytic technology of the present invention can also be used separately in the oxidation reactor and the reduction reactor. For example, the oxidation reactor performs an oxidation reaction, and the reduction reactor performs a hydrogen release experiment; conversely, the reduction reactor performs a reduction reaction, and the oxidation reactor performs an oxygen release experiment. The reactants of the oxidation reactor can be selected from at least one of oxygen-containing organic matter, nitrogen-containing organic matter, alkanes, aromatic hydrocarbons, alkenes, alkynes, H2O, CO, H2S, etc., but are not limited to these substances; the reactants in the reduction reactor can be selected from at least one of oxygen-containing organic matter, nitrogen-containing organic matter, nitrogen oxides, alkenes, alkynes, aromatic hydrocarbons, protons, CO2, CO, nitrogen, etc., but are not limited to these substances. In addition, when the oxidation reactor uses H2O and the reduction reactor uses protons, the oxidation reactor produces oxygen and the reduction reactor produces hydrogen, which is a double-off-site water decomposition process.

[0103] Compared with the prior art, the present invention has the following beneficial effects:

[0104] The present invention provides an "off-site" electrocatalytic series reaction system and operation method, which transfers complex catalytic reactions from traditional electrochemical reaction cells to reactors outside the battery, avoiding the contamination of electrodes, diaphragms, catalysts, etc. by reactants or products, ensuring the stable operation of the entire system, and having practical application value. At the same time, since the deactivation caused by contamination of electrodes, diaphragms, catalysts, etc. is avoided, the "off-site" electrocatalytic reaction technology can also be used in basic theoretical research to obtain the correlation between intrinsic catalytic activity and catalyst structure. The innovation of the battery reaction operating system of the present invention not only promotes the development of basic research, but also has practical application value, which can ensure the stable operation and long-term operation of the battery reaction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] FIG1 is a schematic diagram of an off-site electrocatalytic reaction method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0106] The present application will be further described below in conjunction with specific embodiments. The following description is merely a few embodiments of the present application and does not limit the present application in any form. Although the present application discloses the preferred embodiments below, it is not intended to limit the present application. Any person skilled in the art who, without departing from the scope of the technical solution of the present application, makes slight changes or modifications using the above disclosed technical content is equivalent to an equivalent implementation case and falls within the scope of the technical solution.

[0107] Unless otherwise specified, the raw materials in the examples of this application were purchased from commercial channels and used directly without any special treatment.

[0108] Example 1 (Off-site electrocatalytic series method: benzene to adipic acid)

[0109] The specific experimental steps are as follows: a liquid flow electrolysis cell was used, the anode and cathode electrodes were solid graphite rods, and the anode and cathode used H2SO4 solution of water and ethyl acetate mixed solvent (volume ratio 8:2) as electrolyte (c H2SO4 =3mol / L), the ion pair at the anode is Ce(IV) / Ce(III), the molar concentration of Ce is 0.5mol / L, the ion pair at the cathode is tetrahydrosilicotungstic acid / hexahydrosilicotungstic acid, the molar concentration of silicotungstic acid is 0.5mol / L, and Nafion 117 (DuPont commercial membrane) is used as the diaphragm.

[0110] S1: The reactant of the oxidation reactor is benzene, and a tank reactor is used. The temperature is 25 ° C, and Ce (IV) solution and benzene (n 苯 :n Ce =3:7) are introduced into the reactor at the same time, and the catalyst is RuO x After 4 hours of reaction, the water and ethyl acetate solvents were separated by standing. Benzene and phenol were now dissolved in ethyl acetate. Gas chromatography analysis revealed a benzene conversion of 99% and a phenol selectivity of 98%. The benzene feedstock and phenol product were separated using a laboratory micro-rectifier. The corresponding Ce(III) was further introduced into the anode tank for oxidative regeneration.

[0111] S2: Phenol product and hexahydrosilicotungstic acid are introduced into the reduction reactor, using a kettle reactor, the temperature is 25 ° C, the molar ratio of hexahydrosilicotungstic acid solution to phenol is n 苯酚 :n 六氢型硅 钨酸 =1:3, with a Pd / C catalyst. After 1 hour of reaction, the water and ethyl acetate solvents were separated by standing. Phenol and cyclohexanone were now dissolved in ethyl acetate. Gas chromatography analysis revealed a phenol conversion of 60% and a cyclohexanone selectivity of 92%. Phenol and cyclohexanone were then separated using a laboratory micro-rectifier. The corresponding tetrahydrosilicotungstic acid was then transferred to the cathode tank for reduction regeneration.

[0112] S3: Cyclohexanone is then introduced into an oxidation reactor (returning to the system in S1), using a tank reactor at a temperature of 40°C, Ce(IV) solution and cyclohexanone (n 环己酮 :n Ce =1:7) were simultaneously introduced into a reactor and stirred for 2 hours. The water and ethyl acetate solvents were then separated by standing. Cyclohexanone and adipic acid were now dissolved in ethyl acetate. Liquid chromatography analysis revealed a cyclohexanone conversion of >99% and adipic acid selectivity of 100%. Because adipic acid is slightly soluble in water but soluble in ethyl acetate, the ethyl acetate was removed by distillation to yield adipic acid with a purity of 99%. The resulting Ce(III) was then oxidized and regenerated in the anode tank.

[0113] Example 2 (Benzene Oxidation to Phenol in an Off-site Electrocatalytic Series Method)

[0114] The steps of Example 2 are the same as those of Example 1. This example is an activity optimization process for preparing phenol from benzene. The specific process is as follows: the reactant in the oxidation reactor is benzene, a kettle reactor is used, the temperature is 25°C, different redox media solutions and benzene (n 苯 :n 媒介体 =2:8) and simultaneously introduced into the oxidation reactor, 10% trifluoroacetic acid organic acid was added to promote the formation of phenol, and the catalyst was RuO x After 1 hour of reaction, the water and ethyl acetate solvents were separated by standing. Benzene and phenol were dissolved in ethyl acetate. Gas chromatography was used to determine the benzene conversion and phenol selectivity. The benzene feedstock and phenol product were then separated using a laboratory micro-rectifier. The corresponding redox mediators were then introduced into the anode tank for oxidative regeneration. The benzene conversion and phenol selectivity for different redox mediators are shown in Table 1 below.

[0115] Table 1. Benzene conversion and phenol selectivity under different redox mediators

[0116] Note: The electron mediator utilization rate is the percentage of electrons transferred to the product.

[0117] Example 3 (Phenol reduction to cyclohexanone in an off-site electrocatalytic series method)

[0118] The steps of Example 3 are the same as those of Example 1. This example is an activity optimization process for the reduction of phenol to cyclohexanone. The specific process is as follows: the phenol product and the redox mediator are introduced into a reduction reactor. A tank reactor is used. The temperature is 25°C. The molar ratio of phenol to the redox mediator solution is n 苯酚 :n 媒介体 =1:3 or 1:5, the catalyst is Pd / C, and n-octanol is grafted onto the catalyst surface to modulate the surface hydrophilicity and, therefore, the catalytic activity. After 1 hour of reaction, the water and ethyl acetate solvents are separated by a static method. Phenol and cyclohexanone are now dissolved in ethyl acetate. Gas chromatography is used to determine the phenol conversion and cyclohexanone selectivity. Phenol and cyclohexanone are then separated using a laboratory micro-rectifier. The corresponding oxidized redox mediators are then fed into the cathode tank for reduction regeneration. The phenol conversion and cyclohexanone selectivity for different redox mediators are shown in Table 2 below.

[0119] Table 2. Phenol conversion and cyclohexanone selectivity under different redox mediators

[0120] Note: The electron mediator utilization rate is the percentage of electrons transferred to the product.

[0121] Example 4 (Oxidation of cyclohexanone to adipic acid in an off-site electrocatalytic series process)

[0122] The steps of Example 4 are the same as those of Example 1. This example is an activity optimization process for the oxidation of cyclohexanone to adipic acid. The specific process is as follows: cyclohexanone and a redox mediator are introduced into an oxidation reactor. A tank reactor is used. The temperature is 40°C. The molar ratio of cyclohexanone to the redox mediator solution is n: 环己酮 :n 媒介体 =1:7. After stirring for 2 hours, the mixture was allowed to stand for separation of water and the organic solvent. Cyclohexanone and adipic acid were dissolved in the organic solvent. Liquid chromatography analysis was used to determine the cyclohexanone conversion and adipic acid selectivity. Because adipic acid is slightly soluble in water but soluble in solvents such as ethyl acetate, ethyl acetate was used as the extractant. Adipic acid was then removed by distillation to yield a product with a purity of at least 99%. The resulting reduced redox electron mediator was then fed to the anode tank for oxidative regeneration. The cyclohexanone conversion and adipic acid selectivity for different redox mediators are shown in Table 3 below.

[0123] Table 3. Cyclohexanone conversion and adipic acid selectivity under different redox mediators

[0124] Note: The electron mediator utilization rate is the percentage of electrons transferred to the product.

[0125] As shown in Figure 1, the reaction systems of Examples 1-4 of the present invention can successfully produce adipic acid from benzene, with the yields and conversion rates of intermediate and final products meeting practical application requirements. The electrocatalytic systems of Examples 1-4 of the present invention comprise a battery system, an oxidation reactor, a reduction reactor, an extractor, and a distillation column. The products and redox mediators from the oxidation and reduction reactors are separated by organic solvent extraction. The redox mediators returned to the anode and cathode tanks are free of reactants and products, thus preventing contamination of the electrodes, diaphragms, and other components. This method of separating reactants and products from the electrodes and diaphragms and connecting the oxidation and reduction reactors in series represents the novel electrocatalytic reaction technology proposed in this invention, referred to as "off-site" electrocatalytic series reaction technology. This "off-site" electrocatalytic reaction system not only enables fundamental theoretical research in basic research laboratories, but also eliminates the need for adjustments to the flow path, internal structure, and process due to the scale-up effect. The oxidation and reduction reactors are highly mature and easily scaled up in industry, thus allowing for industrial testing at scales such as electrochemical demonstration, pilot, and application.

[0126] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An off-site electrocatalytic reaction method, characterized in that: The off-site electrocatalytic reaction method comprises the following steps: The electrolyte ions in the battery system undergo an electron exchange reaction with the electrodes to obtain an oxidation potential or a reduction potential; the electrolyte having obtained the oxidation potential or the reduction potential enters an independent reaction system outside the battery system, undergoes an oxidation-reduction reaction with the reactants in the reaction system to obtain a mixture containing reaction products, and after separation, the electrolyte after the oxidation-reduction reaction returns to the battery system to obtain the oxidation potential or the reduction potential again.

2. The off-site electrocatalytic reaction method according to claim 1, characterized in that: The anolyte M having redox properties in the anolyte cell of the battery system x+ Oxidation reaction occurs on the anode surface, forming an oxidizing electrolyte M with an oxidation potential (x+1)+ ; The oxidizing electrolyte M (x+1)+ Entering into the oxidation reaction system, an oxidation reaction occurs with the reactant I in the oxidation reaction system, and the reactant I is oxidized to obtain a reaction product I. The oxidation electrolyte M (x+1)+ is reduced to obtain the anolyte M x+ After separation, the anolyte M x+ Return to the anode electrolytic cell and react with the anode again to form an oxidizing electrolyte M with an oxidation potential. (x+1)+ ; The cathode electrolyte in the battery system undergoes a redox reaction in the cathode electrolytic cell.

3. A method for off-site electrocatalytic reaction according to claim 1 or 2, characterized in that: The cathode electrolyte N in the cathode electrolytic cell of the battery system has redox properties. y+ A reduction reaction occurs on the cathode surface to form a reducing electrolyte N with a reduction potential. (y-1)+ ; The reducing electrolyte N (y-1)+ Entering the reduction reaction system, a reduction reaction occurs with the reactant II in the reduction reaction system, and the reactant II is reduced to obtain a reaction product II. The reducing electrolyte N (y-1)+ is oxidized to obtain the cathode electrolyte N y+ , after separation, the cathode electrolyte N y+ Return to the cathode electrolytic cell and react with the cathode again to form a reducing electrolyte N with a reducing potential. (y-1)+ ; The anolyte in the battery system undergoes a redox reaction in the anolyte cell. answer.

4. A method for off-site electrocatalytic reaction according to any one of claims 1 to 3, characterized in that: The anolyte M having redox properties in the anolyte cell of the battery system x+ Oxidation reaction occurs on the anode surface, forming an oxidizing electrolyte M with an oxidation potential (x+1)+ I; The oxidizing electrolyte M (x+1)+ I enters the oxidation reaction system I, and undergoes oxidation reaction I with the reactant I in the oxidation reaction system I. After the reactant I is oxidized, a reaction product I is obtained. The oxidation electrolyte M (x+1)+ I is reduced to obtain the anolyte M x+ After separation, the anolyte M x+ Return to the anode electrolytic cell and react with the anode again to form an oxidizing electrolyte M with an oxidation potential. (x+1)+ ; The cathode electrolyte N in the cathode electrolytic cell of the battery system has redox properties. y+ A reduction reaction occurs on the cathode surface to form a reducing electrolyte N with a reduction potential. (y-1)+ I; The reducing electrolyte N (y-1)+ I enters the reduction reaction system I, and undergoes a reduction reaction I with the reactant II of the reduction reaction system I. After the reactant II is reduced, a reaction product II is obtained. The reducing electrolyte N (y-1)+ I is oxidized to obtain catholyte N y+ , after separation, the cathode electrolyte N y+ Return to the cathode electrolytic cell and react with the cathode again to form a reducing electrolyte N with a reducing potential. (y-1)+ .

5. A method for off-site electrocatalytic reaction according to any one of claims 1 to 4, characterized in that: The reaction product I of the oxidation reaction system I enters the reduction reaction system I, serving as the reactant II of the reduction reaction system I and the reducing electrolyte N in the reduction reaction system I. (y-1)+ I undergoes a reduction reaction I to obtain the reaction product II.

6. A method for off-site electrocatalytic reaction according to any one of claims 1 to 5, characterized in that: The reaction product II of the reduction reaction system I enters the oxidation reaction system I as the reactant III of the oxidation reaction system I and reacts with the oxidizing electrolyte M in the oxidation reaction system I. (x+1)+ I performs oxidation reaction II to obtain the reaction product III; Alternatively, the reaction product II of the reduction reaction system I enters the oxidation reaction system II as the reactant III of the oxidation reaction system II and reacts with the oxidizing electrolyte M in the oxidation reaction system II. (x+1)+ II undergoes oxidation reaction II to obtain the reaction product III.

7. A method for off-site electrocatalytic reaction according to any one of claims 1 to 6, characterized in that: The solute of the electrolyte includes a redox ion pair; the redox ion pair is selected from at least one of an inorganic metal ion pair, an organic metal ion pair, an organic pair and an inorganic pair.

8. An off-site electrocatalytic reaction method according to any one of claims 1 to 7, characterized in that: The solvent of the electrolyte includes at least one of an acid or alkali aqueous solution, an organic solution, and a composite solvent of water and organic matter; The acid is selected from inorganic acids and / or organic acids; The concentration of the acid is 0.01 to 6 mol / L; The inorganic acid is selected from at least one of H2SO4, HCl, H3PO4 and HClO4; The organic acid is selected from at least one of acetic acid, trifluoroacetic acid and benzenesulfonic acid; The organic solvent is selected from at least one of methanol, dimethyl ether, acetonitrile, ethyl acetate, chloroform, dichloromethane and dimethyl sulfoxide.

9. A method for off-site electrocatalytic reaction according to any one of claims 1 to 8, characterized in that: The solute of the anolyte in the anolyte cell comprises a redox ion pair I, wherein the redox ion pair I is selected from I3 - / I - Br2 / Br - 、Fe(III) / Fe(II)、[Fe(CN)6] 3- / [Fe(CN)6] 4- , VO2(I) / VO(II), Ce(IV) / Ce(III) and K2MnO4 / KMnO4.

10. An off-site electrocatalytic reaction method according to any one of claims 1 to 9, characterized in that: The solute of the cathode electrolyte in the cathode electrolytic cell comprises a redox ion pair II, wherein the redox ion pair II is selected from at least one of an inorganic metal ion pair, an organic metal ion pair, an organic pair and an inorganic pair; The inorganic metal ion pair is selected from Eu(II) / Eu(III), Cr(II) / Cr(III) and At least one of V(II) / V(III); The organic metal ion pair is selected from at least one of organic-coordinated cobalt (II) / organic-coordinated cobalt (III), triethanolamine iron (II) / triethanolamine iron (III); The organic compound is selected from at least one of benzoquinone / hydroquinone, benzophenone / benzhydrol; The inorganic pair is selected from heteropoly acids.

11. A method for off-site electrocatalytic reaction according to any one of claims 1 to 10, characterized in that: The reactant includes benzene, and the reaction product includes adipic acid.

12. An off-site electrocatalytic reaction method according to any one of claims 1 to 11, characterized in that: The reactant I of the oxidation reaction system I includes benzene, and the reaction product I includes phenol; the reactant II of the reduction reaction system I includes the phenol, and the reaction product II includes cyclohexanone.

13. An off-site electrocatalytic reaction method according to any one of claims 1 to 12, characterized in that: The reactant III includes cyclohexanone, and the reaction product III includes adipic acid.

14. An electrocatalytic reaction device used in the off-site electrocatalytic reaction method according to any one of claims 1 to 13, characterized in that: The electrocatalytic reaction device comprises: A battery system for providing an electrolyte having redox properties; A reaction system, which is used to provide a reaction space for the electrolyte delivered by the battery system and the reactants in the reaction system to undergo a redox reaction; A separation system, which is used to separate the reaction product from the electrolyte after the redox reaction; The liquid outlet of the battery system is in communication with the inlet of the reaction system; The outlet of the reaction system is connected to the inlet of the separation system; The electrolyte outlet of the separation system is communicated with the liquid inlet of the battery system, and the separation system has a product outlet.

15. The electrocatalytic reaction device according to claim 14, characterized in that: The battery system comprises an H-type electrolytic cell, a liquid flow battery or an electrolyte-free diaphragm flow electrolytic cell.

16. The electrocatalytic reaction device according to claim 14 or 15, characterized in that: The liquid flow battery comprises an anode electrolytic cell and a cathode electrolytic cell, wherein the anode and the cathode are independently selected from at least one of a carbon rod, a carbon felt, a titanium mesh and a copper mesh; Preferably, at least one of Pt, Pd, Bi, Ag and Pb metals is deposited independently on the surfaces of the anode and cathode.

17. The electrocatalytic reaction device according to any one of claims 14 to 16, characterized in that: The reaction system comprises an oxidation reactor and / or a reduction reactor; the separation system comprises an extractor and a distillation tower; the product outlet of the extractor is connected to the inlet of the distillation tower, and the distillation tower has a product outlet.

18. The electrocatalytic reaction device according to any one of claims 14 to 17, characterized in that: The liquid outlet of the anode electrolytic cell is connected to the inlet of the oxidation reactor, reactants are arranged in the oxidation reactor, the outlet of the oxidation reactor is connected to the inlet of the extractor, the product outlet of the extractor is connected to the inlet of the distillation tower, the electrolyte outlet of the extractor is connected to the liquid inlet of the anode electrolytic cell, and the distillation tower has a product outlet.

19. The electrocatalytic reaction device according to any one of claims 14 to 18, characterized in that: The liquid outlet of the cathode electrolytic cell is connected to the inlet of the reduction reactor, reactants are arranged in the reduction reactor, the outlet of the reduction reactor is connected to the inlet of the extractor, the product outlet of the extractor is connected to the inlet of the distillation tower, the electrolyte outlet of the extractor is connected to the liquid inlet of the cathode electrolytic cell, and the distillation tower has a product outlet.

20. The electrocatalytic reaction device according to any one of claims 14 to 19, characterized in that: The liquid outlet of the anode electrolytic cell I is communicated with the inlet of the oxidation reactor I, reactants are arranged in the oxidation reactor I, the outlet of the oxidation reactor I is communicated with the inlet of the extractor I, the product outlet of the extractor I is communicated with the inlet of the distillation tower I, and the electrolyte outlet of the extractor I is communicated with the liquid inlet of the anode electrolytic cell I; the product I outlet of the distillation tower I is communicated with the inlet of the reduction reactor, the liquid outlet of the cathode electrolytic cell is communicated with the inlet of the reduction reactor, the outlet of the reduction reactor is communicated with the inlet of the extractor II, the product outlet of the extractor II is communicated with the inlet of the distillation tower II, the electrolyte outlet of the extractor II is communicated with the liquid inlet of the cathode electrolytic cell, and the distillation tower II has a product II outlet.

21. The electrocatalytic reaction device according to any one of claims 14 to 20, characterized in that: The product II outlet of the distillation tower II is connected to the inlet of the oxidation reactor I; Alternatively, the product II outlet of the distillation tower II is connected to the inlet of the oxidation reactor II, and the liquid outlet of the anode electrolysis cell II is connected to the inlet of the oxidation reactor II; the outlet of the oxidation reactor II is connected to the inlet of the extractor III, the product outlet of the extractor III is connected to the inlet of the distillation tower III, the electrolyte outlet of the extractor III is connected to the liquid inlet of the anode electrolysis cell II, and the distillation tower III has a product III outlet.

22. The electrocatalytic reaction device according to any one of claims 14 to 21, characterized in that: The oxidation reactor is selected from a fixed bed, a tank reactor, a slurry bed, a tray reactor or a fluidized bed reactor; the pressure of the oxidation reactor is 1 to 200 bar, and the temperature is 5 to 200° C.; A catalyst I is placed in the oxidation reactor, wherein the active component of the catalyst I is selected from at least one of Au, Cu, Ru, Ir, Pt, Pd, Rh, Fe, Co metals and oxides thereof; The reactants in the oxidation reactor are selected from at least one of oxygen-containing organic matter, nitrogen-containing organic matter, alkanes, aromatic hydrocarbons, olefins, alkynes, H2O, CO, and H2S.

23. The electrocatalytic reaction device according to any one of claims 14 to 22, characterized in that: The reduction reactor is selected from a fixed bed, a tank reactor, a slurry bed reactor or a fluidized bed reactor; the pressure of the reduction reactor is 1 to 200 bar, and the temperature is 5 to 200° C.; A catalyst II is placed in the reduction reactor, wherein the active component of the catalyst II is selected from at least one of Au, Cu, Ru, Ir, Pt, Pd, Rh, Fe, Co metals and oxides thereof; The reactant in the reduction reactor is selected from at least one of oxygen-containing organic matter, nitrogen-containing organic matter, nitrogen oxides, olefins, alkynes, aromatic hydrocarbons, protons, CO2, CO, and nitrogen.

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