Electrosynthesis hydrogen peroxide mediated series synthesis method for chemicals

Abstract

The invention discloses an electrosynthesis hydrogen peroxide (H2O2) mediated chemical series synthesis method which comprises the following steps: S1, carrying out first catalytic reaction on oxygen (O2) and an electrocatalyst to obtain H2O2; and S2, carrying out a second catalytic reaction on the H2O2, a chemical catalyst and a reactant to obtain an oxidation product. The method is safe, sustainable and energy-saving, in-situ hydrogen peroxide synthesis and utilization and organic matter conversion can be realized in the same system, the purification and transportation cost of hydrogen peroxide is reduced, and development and innovation of a high-added-value chemical production process are facilitated.

Description

Technical Field

[0001] The invention relates to the field of electrochemical synthesis, and in particular to a chemical series synthesis method mediated by electrosynthetic hydrogen peroxide. Background Art

[0002] Hydrogen peroxide (H2O2) plays an important role in green chemical synthesis due to its mild and environmentally friendly oxidation properties. Promoting technological innovation and application of H2O2 in chemical synthesis is expected to accelerate the sustainable green transformation of industrial production and is an important technology to help achieve the goals of carbon peak and carbon neutrality.

[0003] The H2O2 industrial production technology based on anthraquinone is suitable for large-scale centralized production of high-concentration H2O2, but it has the disadvantages of complex steps, high organic waste, and high energy consumption, which makes it difficult to meet the growing demand for distributed synthesis. – ORR), used for tandem oxidation of organic matter, provides a safe, sustainable and energy-saving on-site synthesis method, which can realize in situ H2O2 synthesis and utilization and organic matter conversion in the same system, which not only reduces the purification and transportation costs of H2O2, but also is conducive to the development and innovation of high value-added chemical production processes.

[0004] In situ electrochemical H2O2-mediated tandem systems for chemical synthesis involve multi-step catalytic processes of electrochemical and chemical reactions. The combined catalysis of titanium silicalite (TS-1) and H2O2 can significantly improve the efficiency and selectivity of organic matter conversion, overcoming the limitations of poor H2O2 oxidation selectivity and low efficiency, but unreacted residual H2O2 is still observed in the electrolyte after the reaction, which theoretically leads to a decrease in the electronic efficiency of the tandem reaction.

[0005] Therefore, considering the uniqueness and correlation of the two reactions in the tandem system, optimizing the synergistic matching between multi-step catalysis and enhancing the effective oxidation between H2O2 and organic substrates are the keys to improving the electronic efficiency and yield of the tandem reaction. Currently, relevant research is relatively scarce. Summary of the invention

[0006] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, one object of the present invention is to provide a chemical tandem synthesis method mediated by electrosynthesis of hydrogen peroxide, wherein the tandem system comprises an electrocatalytic step of electrochemically reducing O2 to H2O2, and a chemical catalytic step of oxidizing organic matter using H2O2 in combination with a chemical catalyst to obtain an oxidation product, wherein the oxidation product comprises one of an epoxide and a sulfone compound.

[0007] In one aspect of the present invention, the present invention discloses a method for electrosynthesizing hydrogen peroxide. According to an embodiment of the present invention, the present invention performs a first catalytic reaction between oxygen (O2) and an electrocatalyst to obtain H2O2. The H2O2 can be used to oxidize organic matter, providing a safe, sustainable, and energy-saving on-site synthesis method, which can realize in-situ hydrogen peroxide synthesis and utilization in the same system, effectively reducing the purification and transportation costs of hydrogen peroxide.

[0008] According to an embodiment of the present invention, the first catalytic reaction is carried out in an electrochemical reactor.

[0009] According to an embodiment of the present invention, the cathode in the first catalytic reaction is a gas diffusion electrode.

[0010] According to an embodiment of the present invention, in the first catalytic reaction, O2 is continuously introduced into the cathode gas diffusion layer, and the gas flow rate is 20 to 200 mL / min.

[0011] According to an embodiment of the present invention, the first catalytic reaction is carried out by reducing O2 through constant current electrolysis or constant voltage electrolysis.

[0012] According to an embodiment of the present invention, the current density of the first catalytic reaction is 0-100 mA / cm 2 , the electrode potential is 0~-0.8V vs.RHE.

[0013] According to an embodiment of the present invention, the concentration of H2O2 generated is 100 mg / L to 5000 mg / L.

[0014] In another aspect of the present invention, the present invention also provides a green chemical oxidation synthesis method. According to an embodiment of the present invention, the H2O2, chemical catalyst and reactant are subjected to a second catalytic reaction to obtain an oxidation product. The method is conducive to the development and innovation of high value-added chemical production processes.

[0015] According to an embodiment of the present invention, the chemical catalyst is titanium silicon molecular sieve, Fe 2+ ,I - Br - ,TEMPO,Cu 2+ WO4 2- , Os 6+ One or more of the .

[0016] According to an embodiment of the present invention, the solid loading amount of the chemical catalyst is 1 to 30 g / L (cm 2 ).

[0017] According to an embodiment of the present invention, the content of the soluble chemical catalyst is 1-100 mmol / L.

[0018] According to an embodiment of the present invention, the oxidation product includes one selected from alcohols, acids, epoxides and sulfone compounds.

[0019] According to an embodiment of the present invention, the concentration of the liquid reactant is 0.01-0.5 mol / L, and the flow rate of the gas reactant is 10-50 mL / min.

[0020] According to an embodiment of the present invention, the temperature of the chemical catalytic reaction is 25-50°C.

[0021] In another aspect of the present invention, the present invention discloses a chemical tandem synthesis method mediated by electrosynthetic hydrogen peroxide. According to an embodiment of the present invention, the method is carried out in a tandem reaction device, and the tandem system can simultaneously realize in-situ hydrogen peroxide synthesis and utilization and organic matter conversion.

[0022] According to an embodiment of the present invention, the above method may further include at least one of the following additional technical features:

[0023] According to an embodiment of the present invention, the reaction device is an H-type reactor or a flow reactor.

[0024] According to an embodiment of the present invention, the reaction device adopts the inside-outside tank method, the first catalytic reaction is separated from the second catalytic reaction process, and the multi-step processes do not interfere with each other, which is conducive to the independent optimization of the two.

[0025] According to an embodiment of the present invention, the reaction device adopts an in-tank method, the first catalytic reaction and the second catalytic reaction are integrated into the same reactor, multiple steps occur simultaneously, the in-situ H2O2 activity is high, and the reactor integration is strong.

[0026] According to an embodiment of the present invention, the first catalytic reaction and the second catalytic reaction are carried out in a catalytic solution, and the catalytic solution is adapted to the two-step catalytic reaction without causing other side reactions.

[0027] According to an embodiment of the present invention, the catalytic solution is an acidic solution or a neutral solution.

[0028] According to an embodiment of the present invention, the catalytic solution is a potassium perchlorate solution or a potassium sulfate solution.

[0029] According to an embodiment of the present invention, the concentration of the catalytic solution is 0.1-1 mol / L.

[0030] According to an embodiment of the present invention, the chemical catalyst is placed inside the electrochemical reactor, fixed outside the electrochemical reactor or in the electrolyte.

[0031] According to an embodiment of the present invention, the chemical catalytic reactants flow through the series reaction device once or cyclically.

[0032] In another aspect of the present invention, the present invention also provides a chemical tandem synthesis method mediated by electrosynthesis of hydrogen peroxide (H2O2). According to an embodiment of the present invention, the method comprises:

[0033] S1: subjecting oxygen (O2) and an electrocatalyst to a first catalytic reaction to obtain H2O2;

[0034] S2: subjecting the H2O2, chemical catalyst and reactants to a second catalytic reaction to obtain an oxidation product.

[0035] According to an embodiment of the present invention, the above method may further include at least one of the following additional technical features:

[0036] According to an embodiment of the present invention, the first catalytic reaction is performed by an in-tank method or an out-tank method.

[0037] According to an embodiment of the present invention, the first catalytic reaction and the second catalytic reaction are performed in a catalytic solution.

[0038] According to an embodiment of the present invention, the catalytic solution is an acidic solution or a neutral solution.

[0039] According to an embodiment of the present invention, the catalytic solution is a potassium perchlorate solution or a potassium sulfate solution.

[0040] According to an embodiment of the present invention, the concentration of the catalytic solution is 0.1-1 mol / L.

[0041] According to an embodiment of the present invention, the first catalytic reaction is carried out in an electrochemical reactor.

[0042] According to an embodiment of the present invention, the electrochemical reactor is an H-type reactor or a flow reactor.

[0043] According to an embodiment of the present invention, the cathode in the first catalytic reaction is a gas diffusion electrode.

[0044] According to an embodiment of the present invention, in the first catalytic reaction, O2 is continuously introduced into the cathode gas diffusion layer, and the gas flow rate is 20 to 200 mL / min.

[0045] According to an embodiment of the present invention, the first catalytic reaction is carried out by reducing O2 through constant current electrolysis or constant voltage electrolysis.

[0046] According to an embodiment of the present invention, the chemical catalyst is titanium silicon molecular sieve, Fe 2+ ,I - Br - ,TEMPO,Cu 2+ WO4 2- , Os6+ One or more of the .

[0047] According to an embodiment of the present invention, the second catalytic reaction is carried out inside the electrochemical reactor, outside the electrochemical reactor or in an electrolyte.

[0048] According to an embodiment of the present invention, the chemical catalyst is placed inside the electrochemical reactor, fixed outside the electrochemical reactor or in the electrolyte.

[0049] According to an embodiment of the present invention, the oxidation product includes one selected from alcohols, acids, epoxides and sulfone compounds.

[0050] According to an embodiment of the present invention, the oxidation product is ethylene glycol, formic acid, propylene oxide, cyclohexanone oxime or dimethyl sulfone.

[0051] According to an embodiment of the present invention, the reactant is selected from olefins, aldehydes, alcohols, ketones or sulfides.

[0052] According to an embodiment of the present invention, the reactant exists in liquid form, and the concentration of the reactant is 0.01-0.5 mol / L.

[0053] According to an embodiment of the present invention, the reactant exists in the form of gas, and the flow rate of the reactant is 5 to 50 mL / min.

[0054] According to an embodiment of the present invention, the temperature of the second catalytic reaction is 0-80°C.

[0055] According to the embodiments of the present invention, the present invention has at least one of the following beneficial effects:

[0056] 1) The in-situ electrochemical H2O2-mediated tandem system for chemical synthesis provided in the present invention specifically comprises an electrocatalytic step of electrochemically reducing O2 to H2O2 and a chemical catalytic step of oxidizing organic matter with H2O2 in combination with a chemical catalyst to obtain an oxidation product. The electrochemical technology is used to reduce O2 to H2O2 and is applied to the tandem oxidation reaction of organic matter, opening up a new on-site synthesis route that is safe, environmentally friendly and energy-saving.

[0057] 2) The method of the present invention allows the immediate generation and application of H2O2 and the effective conversion of organic matter in the same reaction system. It not only significantly reduces the demand for H2O2 purification and transportation and reduces the related costs, but also brings the possibility of innovation and improvement to the production process of high value-added chemicals. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0059] Figure 1 Schematic diagram of the in situ electrochemical H2O2-mediated tandem system. DETAILED DESCRIPTION

[0060] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0061] The present invention is described below with reference to specific embodiments. It should be noted that these embodiments are merely illustrative and do not limit the present invention in any way.

[0062] Embodiment 1:

[0063] Using a flow electrochemical reactor, with a gas diffusion electrode as the cathode, O2 is continuously introduced into the cathode gas diffusion layer, the gas flow rate is 40mL / min, constant potential electrolysis is performed at -0.5V vs. RHE, the electrolysis time is 2h, and the electrolysis Faraday efficiency is ≥80%. Titanium silicon molecular sieve combined with H2O2 is used as a chemical catalyst to catalyze the oxidation of propylene to propylene oxide. The titanium silicon molecular sieve is fixed inside the cathode chamber of the flow electrochemical reactor to form an in-tank electrochemical reaction system. The titanium silicon molecular sieve loading is 10g / m 2 , the propylene flow rate is 20mL / min, the electrolyte is 0.1M K2OS4, the reaction temperature is 30℃, the reaction time is 2h, the H2O2 utilization rate of the organic matter conversion reaction is ≥60%, the propylene oxide selectivity is ≥70%, and the product yield is ≥60%.

[0064] Embodiment 2:

[0065] An H-type reactor was used, with a gas diffusion electrode as the cathode, and O2 was continuously introduced into the cathode gas diffusion layer, with a gas flow rate of 10 mL / min, and constant potential electrolysis was performed at -0.5 V vs. RHE, the electrolysis time was 2 h, and the electrolysis Faraday efficiency was ≥80%. Titanium silicate molecular sieve combined with H2O2 was used as a chemical catalyst to catalyze the oxidation of propylene to propylene oxide, and the titanium silicate molecular sieve was placed in the cathode chamber to keep the cathode liquid stirred, the titanium silicate molecular sieve loading was 10 g / L, the propylene flow rate was 20 mL / min, the electrolyte was 0.1MK2OS4, the reaction temperature was 30 ° C, the reaction time was 2 h, the H2O2 utilization rate of the organic matter conversion reaction was ≥50%, the propylene oxide selectivity was ≥80%, and the product yield was ≥55%.

[0066] Embodiment 3:

[0067] A flow electrochemical reactor was used, with a gas diffusion electrode as the cathode, O2 was continuously introduced into the cathode gas diffusion layer, the gas flow rate was 40 mL / min, constant potential electrolysis was performed at -0.8 V vs. RHE, the electrolysis time was 2 h, and the electrolysis Faraday efficiency was ≥90%. A titanium silicalite molecular sieve combined with H2O2 was used as a chemical catalyst to catalyze the oxidation of cyclohexanone to cyclohexanone oxime, and the titanium silicalite molecular sieve was fixed outside the flow electrochemical reactor to form an out-of-tank electrochemical reaction system, the titanium silicalite molecular sieve loading was 5 g / L, the cyclohexanone concentration was 0.2 mol / L, the electrolyte was 0.1 M K2OS4, NH3 was introduced into the out-of-tank device, the reaction temperature was 30 ° C, the reaction time was 2 h, the H2O2 utilization rate of the organic matter conversion reaction was ≥80%, the cyclohexanone oxime selectivity was ≥90%, and the product yield was ≥55%.

[0068] Embodiment 4:

[0069] Using a flow electrochemical reactor, with a gas diffusion electrode as the cathode, O2 is continuously introduced into the cathode gas diffusion layer, the gas flow rate is 40mL / min, constant potential electrolysis is performed at -0.8V vs. RHE, the electrolysis time is 2h, and the electrolysis Faraday efficiency is ≥90%. Using titanium silicon molecular sieve combined with H2O2 as a chemical catalyst to catalyze the oxidation of cyclohexanone to cyclohexanone oxime, the titanium silicon molecular sieve is fixed to the outside of the flow electrochemical reactor to form an out-of-tank electrochemical reaction system, the cyclohexanone concentration is 0.2mol / L, the electrolyte is 0.1MK2OS4, NH3 is introduced into the out-of-tank device, the reaction temperature is 30℃, the reaction time is 2h, the H2O2 utilization rate of the organic matter conversion reaction is ≤15%, the cyclohexanone oxime selectivity is ≤30%, and the product yield is ≤10%.

[0070] Embodiment 5:

[0071] A flow electrochemical reactor was used, with a gas diffusion electrode as the cathode, air was continuously introduced into the cathode gas diffusion layer, the gas flow rate was 40 mL / min, constant potential electrolysis was performed at -0.8 V vs. RHE, the electrolysis time was 2 h, and the electrolysis Faraday efficiency was ≥50%. A titanium silicon molecular sieve combined with H2O2 was used as a chemical catalyst to catalyze the oxidation of cyclohexanone to cyclohexanone oxime, and the titanium silicon molecular sieve was fixed to the outside of the flow electrochemical reactor to form an out-of-tank electrochemical reaction system, the cyclohexanone concentration was 0.2 mol / L, the electrolyte was 0.1 M K2OS4, NH3 was introduced into the out-of-tank device, the reaction temperature was 30 ° C, the reaction time was 2 h, the H2O2 utilization rate of the organic matter conversion reaction was ≥70%, the cyclohexanone oxime selectivity was ≥80%, and the product yield was ≥20%.

[0072] Embodiment 6:

[0073] Using a flow electrochemical reactor, with a gas diffusion electrode as the cathode, O2 is continuously introduced into the cathode gas diffusion layer, the gas flow rate is 20mL / min, constant potential electrolysis is performed at -0.8V vs. RHE, the electrolysis time is 2h, and the electrolysis Faraday efficiency is ≥90%. Using titanium silicon molecular sieve combined with H2O2 as a chemical catalyst to catalyze the oxidation of cyclohexanone to cyclohexanone oxime, the titanium silicon molecular sieve is fixed inside the flow electrochemical reactor to form an in-tank electrochemical reaction system, the cyclohexanone concentration is 0.2mol / L, the electrolyte is 0.1MK2OS4, NH3 is introduced into the cathode liquid, the reaction temperature is 30℃, the reaction time is 2h, the H2O2 utilization rate of the organic matter conversion reaction is ≥80%, the cyclohexanone oxime selectivity is ≥50%, and the product yield is ≥40%.

[0074] Embodiment 7:

[0075] A flow electrochemical reactor was used, with a gas diffusion electrode as the cathode, and O2 was continuously introduced into the cathode gas diffusion layer at a gas flow rate of 20 mL / min. The electrolysis was performed at a constant potential of -0.2 V vs. RHE for 4 h, and the electrolysis Faraday efficiency was ≥90%. 2+ Combined with H2O2 as a chemical catalyst, formaldehyde is oxidized to formic acid, Fe 2+ With the circulation of electrolyte, the content is 10mmol / L, the formaldehyde concentration is 0.1mol / L, the electrolyte is 0.1M H2SO4, the reaction temperature is 25℃, the reaction time is 4h, the H2O2 utilization rate of the organic matter conversion reaction is ≥70%, the formic acid selectivity is ≥80%, and the product yield is ≥75%.

[0076] Embodiment 8:

[0077] An H-type electrochemical reactor was used, with a gas diffusion electrode as the cathode, and O2 was continuously introduced into the cathode gas diffusion layer at a gas flow rate of 20 mL / min. The electrolysis was performed at a constant potential of -0.2 V vs. RHE for 4 h, and the electrolysis Faraday efficiency was ≥90%. 2+ Combined with H2O2 as a chemical catalyst, formaldehyde is oxidized to formic acid, Fe 2+ The cathode liquid is placed in the cathode chamber to keep stirring, the content is 10mmol / L, the formaldehyde concentration is 0.5mol / L, the electrolyte is 0.1M HClO4, the reaction temperature is 25°C, the reaction time is 4h, the H2O2 utilization rate of the organic matter conversion reaction is ≥80%, the formic acid selectivity is ≥90%, and the product yield is ≥80%.

[0078] Embodiment 9:

[0079] An H-type electrochemical reactor was used, with a gas diffusion electrode as the cathode, and N2 was continuously introduced into the cathode gas diffusion layer at a gas flow rate of 20 mL / min. The electrolysis was performed at a constant potential of -0.2 V vs. RHE for 2 h. 2+ Combined with H2O2 as a chemical catalyst, formaldehyde is oxidized to formic acid, Fe 2+ Place it in the cathode chamber to keep the cathode liquid stirring, the formaldehyde concentration is 0.5 mol / L, the electrolyte is 0.1M HClO4, the reaction temperature is 25°C, the reaction time is 4h, the formic acid selectivity is ≤5%, and the product yield is ≤5%.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0081] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for tandem synthesis of chemicals mediated by electrosynthetic hydrogen peroxide (H2O2), characterized in that: include: S1: subjecting oxygen (O2) and an electrocatalyst to a first catalytic reaction to obtain H2O2; S2: subjecting the H2O2, chemical catalyst and reactants to a second catalytic reaction to obtain an oxidation product.

2. The method according to claim 1, characterized in that The first catalytic reaction is carried out by an in-tank method or an out-tank method.

3. The method according to claim 1, characterized in that The first catalytic reaction and the second catalytic reaction are carried out in a catalytic solution; Optionally, the catalytic solution is an acidic solution or a neutral solution; Optionally, the catalytic solution is a potassium perchlorate solution or a potassium sulfate solution; Optionally, the concentration of the catalytic solution is 0.1 to 1 mol / L.

4. The method according to claim 1, characterized in that The first catalytic reaction is carried out in an electrochemical reactor; Optionally, the electrochemical reactor is an H-type reactor or a flow reactor; Optionally, the cathode in the first catalytic reaction is a gas diffusion electrode; Optionally, during the first catalytic reaction, O2 is continuously introduced into the cathode gas diffusion layer at a gas flow rate of 20 to 200 mL / min.

5. The method according to claim 1, characterized in that The first catalytic reaction is carried out by reducing O2 by constant current electrolysis or constant voltage electrolysis.

6. The method according to claim 1, characterized in that The chemical catalyst is titanium silicon molecular sieve, Fe 2+ ,I - Br - ,TEMPO,Cu 2+ WO4 2- , Os 6+ One or more of the .

7. The method according to claim 1, characterized in that The second catalytic reaction is carried out inside the electrochemical reactor, outside the electrochemical reactor or in the electrolyte; Optionally, the chemical catalyst is placed inside the electrochemical reactor, fixed outside the electrochemical reactor or in the electrolyte.

8. The method according to claim 1, characterized in that The oxidation product comprises one selected from alcohols, acids, epoxides and sulfone compounds; Optionally, the oxidation product is ethylene glycol, formic acid, propylene oxide, cyclohexanone oxime or dimethyl sulfone.

9. The method according to claim 1, characterized in that: The reactant is selected from olefins, aldehydes, alcohols, ketones or sulfides; Optionally, the reactant is in liquid form, and the concentration of the reactant is 0.01 to 0.5 mol / L; Optionally, the reactant is in the form of gas, and the flow rate of the reactant is 5 to 50 mL / min.

10. The method according to claim 1, characterized in that The temperature of the second catalytic reaction is 0-80°C.

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