Efficient synthesis of ethylene oxide and its preparation method and application

Abstract

The present application relates to the field of electrochemical synthesis, discloses a kind of efficient synthesis material of ethylene oxide and its preparation method and application, efficient synthesis material of ethylene oxide is composed of TiV@TiO2 alloy as first active center and RuO nanoparticle as second active site, the RuO nanoparticle is uniformly distributed on the surface of the TiV@TiO2 alloy, the TiV@TiO2 alloy is obtained by surface oxidation from TiV alloy with three-dimensional porous structure.The RuO / TiV@TiO2 catalyst of the present application can catalyze ethanol molecules to be dehydrated in the process of catalytic reaction, and the formed ethylene is transferred to the second active center ruthenium oxide to be selectively oxidized, so that ethylene oxide can be efficiently synthesized, and the selectivity of ethylene oxide is improved.The TiO2 oxide layer formed on the surface of the carrier has outstanding acid corrosion resistance, so that the RuO / TiV@TiO2 catalyst exhibits excellent stability.

Description

Technical Field

[0001] This invention relates to the field of electrochemical synthesis, specifically to a highly efficient synthetic material for ethylene oxide, its preparation method, and its applications. Background Technology

[0002] As a broad-spectrum sterilizing agent, ethylene oxide is widely used to disinfect various microorganisms such as vegetative bacteria, fungal spores, viruses, and endospores. It is one of the two mainstream sterilization methods for medical devices, especially disposable medical devices, and is widely used in the sterilization of sterile medical device products both domestically and internationally.

[0003] The current main method for preparing ethylene oxide is the ethylene epoxidation process. This method uses fossil fuels as raw materials, producing ethylene through cracking and separation, followed by selective catalytic oxidation to produce ethylene oxide. This process is complex, requires sophisticated reaction equipment, and releases large amounts of carbon dioxide, a greenhouse gas. Furthermore, the ethylene-to-ethylene oxide reaction is a typical exothermic reaction, and the released heat significantly affects the performance and lifespan of the catalyst. Therefore, developing novel ethylene oxide preparation processes for a green and efficient synthesis of ethylene oxide is of great significance. Summary of the Invention

[0004] The purpose of this invention is to provide a catalyst material for the efficient synthesis of ethylene oxide, composed of ruthenium oxide nanoparticles and a surface-oxidized TiV alloy (TiV@TiO2). TiV@TiO2 serves as the first active center for the dehydration of ethanol, while the ruthenium oxide (RuO) nanoparticles act as the second active site for the selective oxidation of ethylene formed from the dehydration of ethanol. This enables the efficient and highly selective synthesis of ethylene oxide. Furthermore, the TiO2 oxide layer formed on the support surface exhibits outstanding acid corrosion resistance, endowing the catalyst with high stability, thereby achieving a green and efficient synthesis of ethylene oxide from ethanol.

[0005] To achieve the above objectives, on the one hand, the present invention provides an efficient ethylene oxide synthesis material, which is composed of a TiV@TiO2 alloy as a first active center and RuO nanoparticles as a second active site. The RuO nanoparticles are uniformly distributed on the surface of the TiV@TiO2 alloy, which is obtained by surface oxidation of a TiV alloy with a three-dimensional porous structure.

[0006] As a further preferred embodiment of the present invention, the diameter of the RuO nanoparticles is 1-1000 nm.

[0007] As a further preferred embodiment of the present invention, the loading of RuO nanoparticles in the high-efficiency ethylene oxide synthesis material is 0.5-20 wt%.

[0008] According to another aspect of the present invention, the present invention also provides a method for preparing a RuO / TiV@TiO2 catalyst, comprising the following steps:

[0009] S1. Place the three-dimensional porous TiV alloy in an alkaline solution first, and then in an acidic solution to remove the oxides formed on the surface of the TiV alloy.

[0010] S2. The TiV alloy after surface treatment in step S1 is immersed in an aqueous solution of ruthenium metal precursor, and then electroplated and dried to obtain a Ru / TiV intermediate.

[0011] S3. Place the Ru / TiV intermediate prepared in step S2 in an oxygen-containing atmosphere to oxidize the Ru and TiV surfaces, thereby obtaining the RuO / TiV@TiO2 catalyst, which is a high-efficiency material for the synthesis of ethylene oxide.

[0012] As a further preferred technical solution of the present invention, Ti and V metals are used as raw materials, with a layer thickness of 0.01-0.1 mm and a scanning interval of 0.01-0.1 mm, and the three-dimensional porous TiV alloy in step S1 is obtained by laser melting 3D printing. Further, the optimal 3D printing parameters are set with a layer thickness of 0.03 mm and a scanning interval of 0.065 mm.

[0013] As a further preferred technical solution of the present invention, in step S1, the alkaline solution is a potassium hydroxide solution and / or sodium hydroxide solution with a concentration of 1 mol / L-6 mol / L, and the TiV alloy is treated in the alkaline solution for 1 h-24 h; the acidic solution is a hydrochloric acid solution or sulfuric acid solution with a concentration of 0.2 mol / L-3 mol / L, and the TiV alloy is treated in the acidic solution for 3 h-24 h.

[0014] As a further preferred technical solution of the present invention, in step S2, the concentration of the ruthenium metal precursor aqueous solution is 0.02-1 mol / L, wherein the ruthenium metal precursor is at least one of ruthenium trichloride, ruthenium tripyridine chloride hexahydrate, and ruthenium acetylacetone.

[0015] As a further preferred technical solution of the present invention, in step S2, the electroplating method is cyclic voltammetry or constant potential deposition method, wherein the potential range of the cyclic voltammetry method is -0.2 to 0.5V vs. RHE, and the potential of the constant potential deposition method is -0.1V vs. RHE.

[0016] As a further preferred technical solution of the present invention, in step S2, the oxygen-containing atmosphere is air, or a mixture of oxygen and an inert gas, wherein the volume fraction of oxygen in the mixture is 10%-50%.

[0017] As a further preferred technical solution of the present invention, in step S3, the Ru / TiV intermediate is heated in an oxygen-containing atmosphere at a temperature of 120-240°C for 0.2-6 hours.

[0018] According to another aspect of the present invention, the present invention also provides the application of an efficient ethylene oxide synthesis material in the catalytic preparation of ethylene oxide from ethanol.

[0019] By adopting the above technical solution, the present invention can achieve the following beneficial effects:

[0020] (1) The preparation method of the RuO / TiV@TiO2 catalyst of the present invention is simple, the materials are readily available, the cost is low, and it is easy to industrialize.

[0021] (2) The TiV alloy (TiV@TiO2) oxidized on the surface of the RuO / TiV@TiO2 catalyst of the present invention serves as the first active center, and the uniformly distributed nano-ruthenium oxide nanoparticles serve as the second active center. During the catalytic reaction, the TiO2 formed on the surface of the TiV alloy can catalyze the dehydration of ethanol molecules, and the ethylene formed is transferred to the second active center ruthenium oxide for selective oxidation, which can efficiently synthesize ethylene oxide and improve the selectivity of ethylene oxide.

[0022] (3) In the RuO / TiV@TiO2 catalyst of the present invention, the TiO2 oxide layer formed on the surface of the support has outstanding acid corrosion resistance, which makes the RuO / TiV@TiO2 catalyst exhibit excellent stability.

[0023] (4) The RuO / TiV@TiO2 catalyst of this invention does not use precious metals, and has the advantages of low cost and easy operation, and can be produced on a large scale. It exhibits excellent catalytic activity and stability in the electrochemical synthesis of ethylene oxide from ethanol. Attached Figure Description

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] Figure 1 This is a scanning electron microscope image of the RuO / TiV@TiO2 catalyst obtained in Example 1, magnified 50,000 times.

[0026] Figure 2 The image shows the electrochemical mass spectrometry (DEMS) spectrum of RuO / TiV@TiO2 obtained in Example 1 during the catalytic preparation of ethylene oxide.

[0027] Figure 3 The graph shows the catalytic activity and selectivity of RuO / TiV@TiO2 obtained in Example 1 in the catalytic preparation of ethylene oxide.

[0028] Figure 4This is a schematic diagram illustrating the principle of catalytic ethanol-to-ethylene oxide production using RuO / TiV@TiO2 obtained in Example 1.

[0029] Figure 5 The image shows the catalytic stability curve of RuO / TiV@TiO2 obtained in Example 1.

[0030] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0031] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0032] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods.

[0033] Example 1:

[0034] A method for preparing a high-efficiency synthetic material of ethylene oxide, specifically comprising the following steps:

[0035] (1) Synthesis and Surface Treatment of TiV Alloy

[0036] Selective laser melting 3D printing was performed on an SLM DiMetal-100H machine with the following parameters: layer thickness, scanning spacing, scanning speed, and laser power were 0.03 mm, 0.065 mm, and 1100 mm / s, respectively. -1 The feed ratio (mass ratio) of Ti and V metals was 1:1. The three-dimensional porous TiV alloy obtained by 3D printing was first placed in a 2 mol / L potassium hydroxide solution and stirred for 12 hours. Then it was quickly transferred to a 2 mol / L hydrochloric acid solution and treated for another 6 hours to remove the oxides formed on the surface of the TiV alloy.

[0037] (2) Preparation of Ru / TiV intermediate

[0038] With a ruthenium oxide loading of 6%, 0.1 g of ruthenium trichloride was weighed and added to ultrapure water to prepare a ruthenium metal precursor solution with a concentration of 0.1 mol / L. The surface-treated TiV alloy was completely immersed in the ruthenium trichloride aqueous solution. Using Ag / AgCl as the reference electrode, Pt wire as the counter electrode, and TiV alloy as the working electrode, electrochemical deposition was performed by cyclic voltammetry within a potential range of -0.2 to 0.5 V vs. RHE, with a scan rate of 10 mV / s and 2000 scan cycles. The electroplated sample was dried to obtain the Ru / TiV intermediate.

[0039] (3) Preparation of RuO / TiV@TiO2 catalyst

[0040] The Ru / TiV intermediate was placed in an oxygen / nitrogen mixture with an oxygen volume fraction of 20% and heated to 250°C for 2 hours to form a surface oxide layer on the TiV alloy, thereby oxidizing the metallic ruthenium to ruthenium oxide and obtaining the RuO / TiV@TiO2 catalyst.

[0041] The RuO / TiV@TiO2 catalyst prepared in Example 1 was tested as follows:

[0042] 1) SEM (Scanning Electron Microscopy) testing of the catalyst

[0043] The results were obtained by testing with a scanning electron microscope at 50,000x magnification. Figure 1 As shown. From Figure 1 The scanning electron microscope images show that ruthenium oxide particles with a diameter of about 20-500 nanometers are uniformly distributed on the TiV@TiO2 surface, which is very beneficial to the adsorption and oxidation of reaction intermediates.

[0044] 2) Performance testing of the RuO / TiV@TiO2 catalyst prepared in Example 1 for the catalytic production of ethylene oxide from ethanol:

[0045] The working electrode was placed in a mixed electrolyte of 0.1 mol / L HClO4 and 2 mol / L ethanol, using a three-electrode system. The electrode prepared in step (3) was used as the working electrode, the Ag / AgCl electrode as the reference electrode, and the Pt wire as the auxiliary electrode. Cyclic voltammetry was performed on an electrochemical workstation (CHI660d, Shanghai Chenhua Instrument Co., Ltd.) at a scanning potential of 1.0–2.5 vs·RHE and a scanning rate of 10 mV / s. The reaction products were recorded using a mass spectrometer, and the results are as follows: Figure 2 Then, the reaction was carried out at 2.0V vs. RHE, and the product composition and content were analyzed by mass spectrometry after 1 hour. The results... Figure 3 As shown. From Figure 2 and Figure 3It can be seen that the catalyst prepared in Example 1 produces only ethylene oxide in the catalytic process of ethanol to ethylene oxide, with a selectivity of 100%. Furthermore, the catalyst can completely convert ethanol to ethylene oxide within 1 hour, achieving a conversion rate of 100%, demonstrating the excellent dehydration effect of TiV@TiO2 on ethanol and the superior performance of RuO in catalyzing the epoxidation of ethylene to ethylene oxide.

[0046] The mechanism of RuO / TiV@TiO2 catalyst in catalyzing the production of ethylene oxide from ethanol is as follows: Figure 4 As shown, ethanol first dehydrates on the Lewis acid TiO2 surface formed on the TiV support to generate ethylene. The ethylene then transfers to the RuO surface for ring-opening oxidation to generate ethylene oxide. Because the activation energy for breaking the first carbon-carbon bond in the ethylene double bond is relatively small, while the activation energy for breaking the second carbon-carbon bond is relatively large, ethylene on the ruthenium oxide surface undergoes ring-opening oxidation to ethylene oxide, rather than being completely oxidized to carbon dioxide.

[0047] 3) Stability test of catalyst RuO / TiV@TiO2

[0048] The test conditions for the catalytic production of ethylene oxide from ethanol were the same, i.e., in a three-electrode system, using the potentiostatic method, and the current-time curve of the catalyst was measured at 2.0 V vs. RHE. The results are as follows. Figure 5 As shown. From Figure 5 The stability test results show that after 100 hours of reaction, the reaction performance did not change significantly, indicating that the catalyst RuO / TiV@TiO2 has excellent stability. This is due to the outstanding acid corrosion resistance of the TiO2 oxide layer formed on the support surface, which greatly improves the overall stability of the catalyst.

[0049] Example 2:

[0050] (1) Surface treatment of TiV alloy

[0051] The three-dimensional porous TiV alloy was first placed in a mixed solution of 1 mol / L potassium hydroxide and sodium hydroxide and stirred for 8 hours. Then it was quickly transferred to a 1 mol / L sulfuric acid solution and treated for another 5 hours to remove the oxides formed on the surface of the TiV alloy.

[0052] (2) Preparation of Ru / TiV intermediate

[0053] With a ruthenium oxide loading of 10 wt%, 0.18 g of a mixture of ruthenium trichloride and ruthenium acetylacetonate was weighed and placed in ultrapure water to prepare a ruthenium metal precursor solution with a concentration of 0.08 mol / L. The surface-treated TiV alloy was completely immersed in the ruthenium trichloride and ruthenium acetylacetonate aqueous solution. Using Ag / AgCl as the reference electrode, Pt wire as the counter electrode, and TiV alloy as the working electrode, electrochemical deposition was performed at a constant potential of -0.1 V vs. RHE for 30 minutes. The electroplated sample was dried to obtain the Ru / TiV intermediate.

[0054] (3) Preparation of RuO / TiV@TiO2 catalyst

[0055] The Ru / TiV intermediate was heated in air at 220°C for 4 hours to form a surface oxide layer on the TiV alloy, where ruthenium metal was oxidized to ruthenium oxide, thus obtaining the RuO / TiV@TiO2 catalyst.

[0056] Example 3

[0057] (1) Surface treatment of TiV alloy

[0058] The three-dimensional porous TiV alloy was first placed in a 2 mol / L sodium hydroxide solution and stirred for 8 hours. Then it was quickly transferred to a 2 mol / L hydrochloric acid solution and treated for another 8 hours to remove the oxides formed on the surface of the TiV alloy.

[0059] (2) Preparation of Ru / TiV intermediate

[0060] With a ruthenium oxide loading of 12 wt%, 0.18 g of ruthenium trichloride and ruthenium tripyridine chloride hexahydrate were weighed and placed in ultrapure water to prepare a ruthenium metal precursor solution with a concentration of 0.12 mol / L. The surface-treated TiV alloy was completely immersed in the aqueous solution of ruthenium trichloride and ruthenium tripyridine chloride hexahydrate. Using Ag / AgCl as the reference electrode, Pt wire as the counter electrode, and TiV alloy as the working electrode, electrochemical deposition was performed by cyclic voltammetry within a potential range of -0.2 to 0.5 V vs. RHE, with a scan rate of 10 mV / s and 2000 scan cycles. The electroplated sample was dried to obtain the Ru / TiV intermediate.

[0061] (3) Preparation of RuO / TiV@TiO2 catalyst

[0062] The Ru / TiV intermediate was placed in an oxygen / argon mixture with an oxygen volume fraction of 15% and heated to 220°C for 3 hours to form a surface oxide layer on the TiV alloy, thereby oxidizing the metallic ruthenium to ruthenium oxide and obtaining the RuO / TiV@TiO2 catalyst.

[0063] Following the test method of Example 1, the catalysts prepared in Examples 2 and 3 were subjected to catalytic ethanol-to-ethylene oxide conversion tests and stability tests under the same conditions. The test results showed that the catalytic performance and stability of the catalysts prepared in Examples 2 and 3 were similar to those of the catalyst prepared in Example 1. The catalyst prepared in Example 2 had a selectivity of 100%, a conversion rate of 99%, and no significant performance degradation after 100 hours of continuous reaction; the catalyst prepared in Example 3 also had a selectivity of 100%, a conversion rate of 98.6%, and no significant performance degradation after 100 hours of continuous reaction.

[0064] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. An efficient synthesis material of ethylene oxide, characterized in that, The TiV@TiO2 alloy as a first active center and RuO nanoparticles as a second active site are composed, the RuO nanoparticles are uniformly distributed on the surface of the TiV@TiO2 alloy, and the TiV@TiO2 alloy is obtained by surface oxidation of a TiV alloy with a three-dimensional porous structure; The preparation method of the efficient ethylene oxide synthesis material comprises the following steps: S1, the three-dimensional porous TiV alloy is first placed in an alkaline solution and then in an acidic solution to remove the oxides formed on the surface of the TiV alloy; S2, the TiV alloy after surface treatment in step S1 is immersed in a ruthenium metal precursor aqueous solution, and then electroplated and dried to obtain a Ru / TiV intermediate; S3, the Ru / TiV intermediate prepared in step S2 is placed in an oxygen-containing atmosphere and heated to form a surface oxidation layer on the TiV alloy, and the metal ruthenium is oxidized to ruthenium oxide to obtain a RuO / TiV@TiO2 catalyst, which is the efficient ethylene oxide synthesis material.

2. The efficient ethylene oxide synthesis material according to claim 1, characterized by, The diameter of the RuO nanoparticles is 1-1000 nm.

3. The efficient ethylene oxide synthesis material according to claim 1, characterized by, The loading amount of the RuO nanoparticles in the efficient ethylene oxide synthesis material is 0.5-20 wt%.

4. A process for the preparation of an efficient ethylene oxide synthesis material according to any one of claims 1 to 3, characterized in that, The preparation method comprises the following steps: S1, the three-dimensional porous TiV alloy is first placed in an alkaline solution and then in an acidic solution to remove the oxides formed on the surface of the TiV alloy; S2, the TiV alloy after surface treatment in step S1 is immersed in a ruthenium metal precursor aqueous solution, and then electroplated and dried to obtain a Ru / TiV intermediate; S3, the Ru / TiV intermediate prepared in step S2 is placed in an oxygen-containing atmosphere and heated to form a surface oxidation layer on the TiV alloy, and the metal ruthenium is oxidized to ruthenium oxide to obtain a RuO / TiV@TiO2 catalyst, which is the efficient ethylene oxide synthesis material.

5. The process for the production of an ethylene oxide high efficiency synthesis material according to claim 4, characterized by, In step S1, the alkaline solution is a potassium hydroxide solution and / or a sodium hydroxide solution with a concentration of 1 mol / L-6 mol / L, and the TiV alloy is treated in the alkaline solution for 1h-24h; the acidic solution is a hydrochloric acid solution or a sulfuric acid solution with a concentration of 0.2 mol / L-3 mol / L, and the TiV alloy is treated in the acidic solution for 3h-24h.

6. The process for the production of an ethylene oxide high efficiency synthesis material according to claim 4, characterized by, In step S2, the concentration of the ruthenium metal precursor aqueous solution is 0.02-1 mol / L, and the ruthenium metal precursor is at least one of ruthenium trichloride, trispyridine ruthenium chloride hexahydrate, and acetylacetone ruthenium.

7. The process for the production of an ethylene oxide high efficiency synthesis material according to claim 4, characterized by, In step S2, the electroplating method is cyclic voltammetry with a potential range of -0.2~0.5 V vs. RHE, or constant potential deposition with a potential of -0.1 V vs. RHE.

8. The process for the production of an ethylene oxide high efficiency synthesis material according to claim 4, characterized by, In step S2, the oxygen-containing atmosphere is air or a mixture of oxygen and inert gas, and the volume fraction of oxygen in the mixture is 10%-50%.

9. The process for the production of an ethylene oxide high efficiency synthesis material according to claim 4, characterized by, In step S3, the Ru / TiV intermediate is heated in the oxygen-containing atmosphere at a temperature of 120-240℃ for 0.2-6 hours.

10. The efficient ethylene oxide synthesis material according to any one of claims 1-3 is used for catalyzing the preparation of ethylene oxide from ethanol.

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