A catalyst for the carbonylation of ethylene to methyl propionate and a process for its preparation and use

Abstract

The application provides a catalyst for preparing methyl propionate through ethylene alkoxy carbonylation and a preparation method and application thereof, relates to the technical field of catalysts. The catalyst for preparing methyl propionate through ethylene alkoxy carbonylation comprises an active component, a metal additive and a carrier; the corresponding metal element of the active component is Ru, the corresponding metal element of the metal additive is W and / or Mo, and the carrier is a porous material; the active component and the metal additive exist in the form of bimetallic single atoms or nanoparticles inside the pore channels and on the outer surface of the carrier. The catalyst provided by the application has the characteristics of high activity, high selectivity and high stability, can greatly improve the conversion rate of ethylene alkoxy carbonylation and exhibit good stability, and in combination with the catalyst for ethylene alkoxy carbonylation reaction provided in the application, the problem that high selectivity and high selectivity cannot be simultaneously considered in the prior art can be effectively solved.

Description

Technical Field

[0001] This application relates to the field of catalyst technology, and in particular to a catalyst for the alkyl carbonylation of ethylene to produce methyl propionate, its preparation method, and its uses. Background Technology

[0002] Alkoxycarbonylation of olefins is an important type of carbonylation synthesis reaction with broad industrial applications in the chemical industry. This reaction typically uses olefins, carbon monoxide, and alcohols as raw materials to generate corresponding ester products under the action of a catalyst. It features a wide range of raw material sources, high atom utilization, and good product selectivity. Currently, this type of reaction has achieved large-scale industrial application, producing millions of tons of ester compounds annually through this technical route. The Lucite-α process developed by Lucite is a representative industrial example in this field. This process uses ethylene, carbon monoxide, and methanol as raw materials to synthesize methyl propionate under the action of a palladium-based complex catalyst. This reaction is commonly referred to as the methoxycarbonylation of ethylene. Methyl propionate is an important organic chemical intermediate and a key raw material for the preparation of methyl methacrylate. Methyl methacrylate, as an important polymer monomer, has wide applications in coatings, plastics, and optical materials, and its market demand continues to grow. Therefore, developing efficient, stable, and environmentally friendly ethylene methoxycarbonylation catalytic technology has significant industrial importance and application prospects.

[0003] In existing technologies, the ethylene methoxy carbonylation reaction mainly employs homogeneous metal complex catalyst systems. For example, patent documents such as CN119303636A, CN118530119A, CN115957823A, and CN115819235A all introduce metal salts, phosphine ligands, and acidic auxiliaries into the reaction system to achieve the carbonylation conversion of ethylene under specific temperature and pressure conditions. Furthermore, CN115870007A discloses a multi-component composite catalytic system that achieves the ethylene carbonylation reaction through the synergistic effect of metal salts, halides, basic auxiliaries, or specific solvent systems. Meanwhile, some technical solutions attempt to use heterogeneous catalysts for the ethylene carbonylation reaction. For instance, in CN114621089A and CN114425367A, the active metal component is loaded onto an oxide support to improve catalyst stability and simplify the separation process between the catalyst and product after the reaction.

[0004] The aforementioned technical routes generally require the addition of acidic promoters to the reaction system to generate and maintain the active metal hydride species, thereby driving the reaction to proceed continuously. However, in industrial applications, the addition of acidic promoters easily leads to problems such as equipment corrosion, decreased catalyst stability, and complex product separation processes, which to some extent limits the further promotion and application of this type of technology. To reduce or avoid the use of added acidic promoters, the application of heterogeneous catalytic systems in the ethylene methoxycarbonylation reaction has attracted attention in recent years. Related technologies propose constructing metal-oxide interface structures with oxygen vacancies to activate alcohol molecules on the catalyst surface, thereby partially replacing the role of added acids. Studies have shown that oxygen vacancies can serve as important activation sites for alcohols and play a positive role in the heterogeneous ethylene methoxycarbonylation reaction.

[0005] However, existing heterogeneous catalysts are typically prepared using traditional impregnation methods combined with hydrogen reduction. This approach often results in the active metal existing in nanoparticle form, and the distribution of oxygen vacancies on the support surface lacks effective control, making it difficult to achieve precise spatial matching between metal active sites and oxygen vacancies. This not only reduces the utilization efficiency of precious metals but also limits further improvements in catalytic activity and stability. Furthermore, existing preparation methods still have limitations in controlling the number and stability of oxygen vacancies, failing to meet the demands of industrial applications for highly efficient and stable catalytic systems. Summary of the Invention

[0006] The purpose of this application is to provide a catalyst for the alkyl oxycarbonylation of ethylene to produce methyl propionate, a method for its preparation, and its uses, in order to solve the above-mentioned problems.

[0007] To achieve the above objectives, this application adopts the following technical solution: A catalyst for the alkyl carbonylation of ethylene to produce methyl propionate, the catalyst comprising an active component, a metal promoter, and a support; The active component corresponds to the metal element Ru, the metal auxiliary corresponds to the metal element W and / or Mo, and the support is a porous material; The active component and the metal additive exist in the form of bimetallic single atoms or nanoparticles inside the pores and on the outer surface of the carrier.

[0008] Preferably, the catalyst for the alkylation of ethylene to methyl propionate satisfies one or more of the following conditions: (1) The mass ratio of the active component, the metal auxiliary agent and the carrier is (0.01-0.5):(0.01-1.0):100; (2) The average size of the active component is less than 0.2 nm; (3) The carrier is selected from one or more of amorphous silica, Silicalite-1 molecular sieve and Silicalite-2 molecular sieve.

[0009] This application also provides a method for preparing the catalyst described above for the alkyloxycarbonylation of ethylene to methyl propionate, comprising: A water-soluble Ru salt precursor, a metal auxiliary salt precursor, water and isobutanol were mixed, the pH was adjusted to strongly acidic with hydrochloric acid, and then photodeposition reaction was carried out by ultraviolet light irradiation to obtain a complex solution of Ru and metal auxiliary. The carrier is mixed with the complex solution of Ru and metal additive, stirred and impregnated, and then dried to obtain a solid powder loaded with active components and metal additives; The solid powder was washed with a mixture of water and ethanol to obtain the catalyst.

[0010] Preferably, the water-soluble Ru salt precursor is selected from one or more of hexaammonium trichloride, ruthenium trichloride, and ruthenium nitrate.

[0011] Preferably, the metal auxiliary salt precursor is selected from one or more of sodium molybdate, ammonium molybdate, and potassium molybdate.

[0012] Preferably, the method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate satisfies one or more of the following conditions: (1) The pH corresponding to the strong acidity is 1-2; (2) The stirring and impregnation time is 0.5-5h, and the stirring speed is 300-1000r / min; (3) The drying is carried out by rotary evaporation at a temperature of 30-60℃ and a vacuum of 20-50mbar.

[0013] Preferably, the method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate satisfies one or more of the following conditions: (1) The washing endpoint is when the conductivity of the washing liquid is less than 20 μS / cm; (2) The washing process also includes drying at 50-80℃ for 5-15 hours.

[0014] Preferably, the ultraviolet light irradiation time is 5-100 minutes, and the power is 50-100 mW / cm². 2 .

[0015] This application also provides the use of the catalyst described above for the alkyl oxocarbonylation of ethylene to methyl propionate, for use as a catalyst for the alkyl oxocarbonylation of ethylene to methyl propionate.

[0016] Preferably, the use of the catalyst for the alkylation of ethylene to methyl propionate satisfies one or more of the following conditions: (1) The reaction temperature of the alkoxycarbonylation is 140-180℃ and the reaction pressure is 1.0-3.0 MPa; (2) In the alkoxycarbonylation reaction, the molar ratio of ethylene to CO is 0.5-2.0:1; (3) The solvent for alkoxycarbonylation is selected from one or more of methanol, ethanol, and toluene; (4) The equipment for alkoxycarbonylation is selected from one or more of fixed bed, fluidized bed and moving bed.

[0017] Compared with the prior art, the beneficial effects of this application include: The catalyst provided in this application features high activity, high selectivity, and high stability, significantly improving the conversion rate of ethylene alkoxycarbonylation while exhibiting excellent stability. Combined with the catalyst for the ethylene alkoxycarbonylation reaction provided in this application, it effectively solves the problem in existing technologies where it is difficult to simultaneously achieve both high selectivity and high efficiency. Furthermore, this method is characterized by its simplicity, ease of operation, and economic viability.

[0018] The catalyst preparation method provided in this application constructs an oxygen-vacancy-rich metal-oxide interface structure in the catalyst via photosynthesis, enabling effective activation of alcohol molecules on the catalyst surface. This replaces the reliance on externally added acidic promoters and organic ligands in traditional homogeneous and heterogeneous systems. The catalytic cycle can be maintained without the introduction of additional strong acids or ligands during the reaction, significantly simplifying the reaction system composition, reducing the risk of equipment corrosion, and facilitating the separation of post-reaction products and the reuse of the catalyst.

[0019] This invention employs a photosynthesis method to anchor Ru and auxiliary metals in an atomically dispersed form on the support surface, forming a stable double single-atom structure. This effectively avoids the problem of metal agglomeration and nanoparticle formation in traditional preparation methods. This structure maximizes the exposure of metal active sites, increasing the catalytic activity per unit amount of precious metal. Therefore, while ensuring high reaction performance, it reduces the amount of precious metal used, which is beneficial for reducing catalyst costs and improving the feasibility of industrial applications.

[0020] This invention employs a photosynthesis method to prepare catalysts. By adjusting the light conditions, precursor composition, and reaction parameters, the dispersion state of single-atom metals and the number of oxygen vacancies can be effectively controlled, offering a high degree of freedom in structural design. This method facilitates precise spatial matching between active metal sites and functional oxygen vacancies, thereby improving the structural stability and lifespan of the catalyst during the reaction process, and providing a new technical route for achieving sustainable carbonylation reactions.

[0021] Under acid-free and ligand-free conditions, the catalyst of this invention exhibits high catalytic activity and product selectivity in the methoxycarbonylation reaction of ethylene. This technical effect demonstrates that the single-atom metal-oxide interface structure constructed in this invention can effectively promote the key steps of the reaction, thereby significantly improving the overall reaction efficiency. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0023] Figure 1 This is a TEM image of the heterogeneous catalyst of Example 1 of this application; Figure 2 This is an AC-STEM image of the heterogeneous catalyst in Example 1 of this application. Detailed Implementation

[0024] To better illustrate the technical solution provided in this application, the technical solution will be described in its entirety before the embodiments, as follows: A catalyst for the alkyl carbonylation of ethylene to produce methyl propionate, the catalyst comprising an active component, a metal promoter, and a support; The active component corresponds to the metal element Ru, the metal auxiliary corresponds to the metal element W and / or Mo, and the support is a porous material; The active component and the metal additive exist in the form of bimetallic single atoms or nanoparticles inside the pores and on the outer surface of the carrier.

[0025] In an optional embodiment, the catalyst for the alkylation of ethylene to methyl propionate satisfies one or more of the following conditions: (1) The mass ratio of the active component, the metal auxiliary agent and the carrier is (0.01-0.5):(0.01-1.0):100; Optionally, the mass ratio of the active component, the metal auxiliary agent, and the carrier can be 0.01:0.01:100, 0.01:0.1:100, 0.01:0.5:100, 0.01:1:100, 0.05:0.01:100, 0.05:0.05:100, 0.05:0.1:100, 0.05:0.5:100, 0.05:1:100, 0.1:0.01:100, 0.1:0.05:100, or 0.1:0. Any value between 1:100, 0.1:0.5:100, 0.1:1:100, 0.5:0.01:100, 0.5:0.05:100, 0.5:0.1:100, 0.5:0.5:100, 0.5:1:100, or (0.01-0.5):(0.01-1.0):100; (2) The average size of the active component is less than 0.2 nm; (3) The carrier is selected from one or more of amorphous silica, Silicalite-1 molecular sieve and Silicalite-2 molecular sieve.

[0026] This application also provides a method for preparing the catalyst described above for the alkyloxycarbonylation of ethylene to methyl propionate, comprising: A water-soluble Ru salt precursor, a metal auxiliary salt precursor, water and isobutanol were mixed, the pH was adjusted to strongly acidic with hydrochloric acid, and then photodeposition reaction was carried out by ultraviolet light irradiation to obtain a complex solution of Ru and metal auxiliary. The carrier is mixed with the complex solution of Ru and metal additive, stirred and impregnated, and then dried to obtain a solid powder loaded with active components and metal additives; The solid powder was washed with a mixture of water and ethanol to obtain the catalyst.

[0027] In an optional embodiment, the water-soluble Ru salt precursor is selected from one or more of hexaammonium trichloride, ruthenium trichloride, and ruthenium nitrate.

[0028] In an optional embodiment, the metal auxiliary salt precursor is selected from one or more of sodium molybdate, ammonium molybdate, and potassium molybdate.

[0029] In an optional embodiment, the method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate satisfies one or more of the following conditions: (1) The pH corresponding to the strong acidity is 1-2; Optionally, the pH corresponding to the strong acidity can be any value between 1, 1.5, 2, or 1-2; (2) The stirring and impregnation time is 0.5-5h, and the stirring speed is 300-1000r / min; Optionally, the stirring and impregnation time can be any value between 0.5h, 1h, 2h, 3h, 4h, 5h or 0.5-5h, and the stirring speed can be any value between 300r / min, 400r / min, 500r / min, 600r / min, 700r / min, 800r / min, 900r / min, 1000r / min or 300-1000r / min; (3) The drying is carried out by rotary evaporation at a temperature of 30-60℃ and a vacuum of 20-50mbar.

[0030] Optionally, the temperature can be any value between 30℃, 40℃, 50℃, 60℃ or 30-60℃, and the vacuum degree can be any value between 20mbar, 30mbar, 40mbar, 50mbar or 20-50mbar.

[0031] In an optional embodiment, the method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate satisfies one or more of the following conditions: (1) The washing endpoint is when the conductivity of the washing liquid is less than 20 μS / cm; (2) The washing process further includes drying at 50-80℃ (which can be any value between 50℃, 60℃, 70℃, 80℃ or 50-80℃) for 5-15 hours (which can be any value between 5h, 10h, 15h or 5-15h).

[0032] In one optional embodiment, the ultraviolet light irradiation time is 5-100 minutes, and the power is 50-100 mW / cm². 2 .

[0033] Optionally, the ultraviolet irradiation time can be any value between 5 min, 10 min, 20 min, 50 min, 100 min, or 5 min - 100 min, and the power can be 50 mW / cm². 2 60 mW / cm 2 70 mW / cm 2 80 mW / cm 2 90 mW / cm 2 100 mW / cm 2 Or 50-100mW / cm 2 Any value between.

[0034] This application also provides the use of the catalyst described above for the alkyl oxocarbonylation of ethylene to methyl propionate, for use as a catalyst for the alkyl oxocarbonylation of ethylene to methyl propionate.

[0035] In an optional embodiment, the use of the catalyst for the alkylation of ethylene to methyl propionate satisfies one or more of the following conditions: (1) The reaction temperature of the alkoxycarbonylation is 140-180℃ and the reaction pressure is 1.0-3.0 MPa; Optionally, the reaction temperature of the alkoxycarbonylation can be any value between 140°C, 150°C, 160°C, 170°C, 180°C or 140-180°C, and the reaction pressure can be any value between 1 MPa, 2 MPa, 3 MPa or 1.0-3.0 MPa. (2) In the alkoxycarbonylation reaction, the molar ratio of ethylene to CO is 0.5-2.0:1; Optionally, the molar ratio of ethylene to CO can be any value between 0.5:1, 1:1, 1.5:1, 2:1, or 0.5-2.0:1; (3) The solvent for alkoxycarbonylation is selected from one or more of methanol, ethanol, and toluene; (4) The equipment for alkoxycarbonylation is selected from one or more of fixed bed, fluidized bed and moving bed.

[0036] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0037] In this embodiment, the product analysis method used was Agilent chromatography. The specific detection methods for ethylene, methyl propionate, and other products were as follows: The chromatographic column used was an HP-5, 60m × 320μm × 0.5μm, connected to a FID detector. The detector temperature was 350℃, the air flow rate was 400mL / min, and the hydrogen flow rate was 30mL / min. The column oven temperature program was: initial temperature 40℃, retention time 3min, temperature ramp rate 10℃ / min, final temperature 250℃, retention time 5min.

[0038] Example 1 The catalyst in this embodiment consists of 0.1 wt% Ru, 0.15 wt% W, and 99.75 wt% amorphous silica, denoted as Cat1#, and is prepared as follows: (1) Weigh 0.0023 g of hexaammonium trichloride and 0.0027 g of sodium tungstate, dissolve them in 150 g of deionized water, mix them, add 1 µL of isopropanol, and adjust the pH of the solution to 1~2 with hydrochloric acid. Then, irradiate with ultraviolet light for 15 min to carry out photodeposition reaction to obtain a complex solution of Ru and W.

[0039] (2) Add 5 g of SiO2 carrier to the above step (1), impregnate it, stir it thoroughly for 1 h, and then dry it by rotary evaporation at 40 °C and 30 mbar to obtain a solid powder loaded with active components and additives.

[0040] (3) The solid powder obtained in step (2) is filtered and washed several times with a mixed solution of deionized water and ethanol until the conductivity of the filtrate is less than 20 μS / cm, to obtain a heterogeneous catalyst that can be used for the reaction. It is denoted as catalyst Cat1#.

[0041] Electron microscopy analysis revealed that Ru exists in the catalyst Cat1# in the form of single atoms.

[0042] Figure 1 This is a TEM image of the heterogeneous catalyst in Example 1. Figure 2 This is an AC-STEM image of the heterogeneous catalyst in Example 1.

[0043] Using Cat1# as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat1# and 4 mL of methanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, and then successively purged with 0.75 MPa ethylene and 0.9 MPa CO. The reaction was stirred at 165 °C and 1000 rpm for 6 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0044] Example 2 The catalyst in this embodiment consists of 0.2 wt% Ru, 0.3 wt% W, and 99.5 wt% Silicalite-1 (Tianjin Nanhua Catalyst Co., Ltd.), denoted as Cat2#, and was prepared as follows: (1) Weigh 0.0041 g of ruthenium trichloride and 0.0044 g of ammonium tungstate, dissolve them in 150 g of deionized water, mix them, add 2 µL of isopropanol, and adjust the pH of the solution to 1~2 with hydrochloric acid. Then, irradiate with ultraviolet light for 30 min to carry out photodeposition reaction to obtain a complex solution of Ru and W.

[0045] (2) Add 5 g of Silicalite-1 to the above step (1), impregnate, stir thoroughly for 2 hours, and then dry by rotary evaporation at 50 °C and 40 mbar to obtain a solid powder loaded with active components and additives.

[0046] (3) The solid powder obtained in step (2) is filtered and washed several times with a mixed solution of deionized water and ethanol until the conductivity of the filtrate is less than 20 μS / cm, to obtain a heterogeneous catalyst that can be used for the reaction. It is denoted as catalyst Cat2#.

[0047] Electron microscopy analysis revealed that the average size of Ru clusters in catalyst Cat2# was less than 0.2 nm.

[0048] Using Cat2# as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat2# and 6 mL of toluene were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, and then 0.8 MPa of ethylene and 1.5 MPa of CO were sequentially introduced. The reaction was stirred at 170 °C and 800 rpm for 10 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0049] Example 3 The catalyst in this embodiment consists of 0.15 wt% Ru, 0.25 wt% Mo, and 99.6 wt% Silicalite-2 (Tianjin Nanhua Catalyst Co., Ltd.), denoted as Cat3#, and was prepared according to the following method: (1) Weigh 0.0031 g of ruthenium trichloride and 0.0051 g of ammonium molybdate, dissolve them in 150 g of deionized water, mix them, add 1.5 µL of isopropanol, and adjust the pH of the solution to 1~2 with hydrochloric acid. Then, irradiate with ultraviolet light for 40 min to carry out photodeposition reaction to obtain a complex solution of Ru and Mo.

[0050] (2) Add 5g of Silicalite-2 to the above step (1), impregnate, stir thoroughly for 1.5h, and then dry by rotary evaporation at 60℃ and 30mbar to obtain a solid powder loaded with active components and additives.

[0051] (3) The solid powder obtained in step (2) is filtered and washed several times with a mixed solution of deionized water and ethanol until the conductivity of the filtrate is less than 20 μS / cm, to obtain a heterogeneous catalyst that can be used for the reaction. It is denoted as catalyst Cat3#.

[0052] Electron microscopy analysis showed that the average size of Ru clusters in catalyst Cat3# was less than 0.2 nm.

[0053] Using Cat3# as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat3# and 10 mL of ethanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, and then 0.6 MPa of ethylene and 1.0 MPa of CO were sequentially introduced. The reaction was stirred at 180 °C and 800 rpm for 8 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0054] Example 4 The catalyst in this embodiment has a composition of 0.2 wt% Ru, 0.4 wt% Mo and 99.4 wt% SiO2, denoted as Cat4#, and is prepared as follows: (1) Weigh 0.0046 g of hexaammonium trichloride and 0.0082 g of ammonium molybdate, dissolve them in 150 g of deionized water, mix them, add 1.5 µL of isopropanol, and adjust the pH of the solution to 1~2 with hydrochloric acid. Then, irradiate with ultraviolet light for 20 min to carry out photodeposition reaction to obtain a complex solution of Ru and Mo.

[0055] (2) Add 5g of SiO2 to the above step (1), impregnate, stir thoroughly for 1h, and then dry by rotary evaporation at 60℃ and 30mbar to obtain a solid powder loaded with active components and additives.

[0056] (3) The solid powder obtained in step (2) is filtered and washed several times with a mixed solution of deionized water and ethanol until the conductivity of the filtrate is less than 20 μS / cm, to obtain a heterogeneous catalyst that can be used for the reaction. It is denoted as catalyst Cat4#.

[0057] Electron microscopy analysis revealed that the average size of Ru clusters in catalyst Cat4# was less than 0.2 nm.

[0058] Using Cat4# as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat4# and 10 mL of methanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, and then 1.0 MPa of ethylene and 1.5 MPa of CO were sequentially introduced. The reaction was stirred at 170 °C and 800 rpm for 12 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0059] Comparative Example 1 The comparative catalyst, composed of 0.35 wt% Ru, 0.4 wt% W, and 99.25 wt% amorphous silica, denoted as Cat1# - impregnation method, was prepared as follows: (1) Weigh 0.008g of hexaammonium trichloride and 0.0072g of sodium tungstate, and dissolve them in 20g of deionized water to obtain a mixed solution.

[0060] (2) Weigh 5g of silica support and add it to the above step (1), stir for 1h, impregnate and adsorb, and wash. Then dry at 60℃ for 8h to obtain a heterogeneous catalyst. It is denoted as Cat1#-impregnation method.

[0061] Electron microscopy analysis showed that the average size of Ru clusters in the Cat1#-impregnation catalyst was approximately 3.5 nm.

[0062] Using Cat1# impregnation as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat1#-impregnation method and 4 mL of methanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, and then 0.75 MPa of ethylene and 0.9 MPa of CO were sequentially introduced. The reaction was stirred at 165 °C and 1000 rpm for 6 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0063] Comparative Example 2 The comparative catalyst, composed of 0.15 wt% Ru, 0.25 wt% Mo, and 99.6 wt% Silicalite-2, denoted as Cat2# - impregnation method, was prepared as follows: (1) Weigh 0.0031g of ruthenium trichloride and 0.0051g of ammonium molybdate, and dissolve them in 20g of deionized water to obtain a mixed solution.

[0064] (2) Weigh 5g of Silicalite-2 support and add it to the above step (1). Stir for 1h, impregnate and adsorb, and wash. Dry at 60℃ for 8h to obtain a heterogeneous catalyst. It is denoted as Cat2#-impregnation method.

[0065] Electron microscopy analysis showed that the average size of Ru clusters in the Cat2#-impregnation catalyst was approximately 3.5 nm.

[0066] Using Cat2# impregnation as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: Using Cat2# impregnation as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat2#-impregnation method and 10 mL of ethanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, and then 0.6 MPa of ethylene and 1.0 MPa of CO were sequentially introduced. The reaction was stirred at 180 °C and 800 rpm for 8 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0067] Comparative Example 3 This comparative catalyst, composed of 0.15 wt% W and 99.85 wt% amorphous silica, denoted as Cat3# - photo-irradiation method, was prepared as follows: (1) Weigh 0.0027 g sodium tungstate, dissolve it in 150 g deionized water, mix them, add 1 µL isopropanol, and adjust the pH of the solution to 1~2 with hydrochloric acid. Then, irradiate it with ultraviolet light for 15 min to carry out photodeposition reaction and obtain a solution of W.

[0068] (2) Add 5 g of SiO2 carrier to the above step (1), impregnate it, stir it thoroughly for 1 h, and then dry it by rotary evaporation at 40 °C and 30 mbar to obtain a solid powder loaded with active components and additives.

[0069] (3) The solid powder obtained in step (2) is filtered and washed several times with a mixed solution of deionized water and ethanol until the conductivity of the filtrate is less than 20 μS / cm, thus obtaining a heterogeneous catalyst that can be used for the reaction. It is denoted as catalyst Cat3#-light irradiation method.

[0070] Using Cat3#-photocatalysis as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat3#-photocatalyst and 10 mL of ethanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, followed by sequential introduction of 1 MPa ethylene and 1.0 MPa CO. The reaction was stirred at 170 °C and 1000 rpm for 10 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0071] Comparative Example 4 This comparative catalyst, composed of 0.2 wt% Ru and 99.8 wt% Silicalite-1 (Tianjin Nanhua Catalyst Co., Ltd.), denoted as Cat4# - photoluminescence method, was prepared as follows: (1) Weigh 0.0046 g of hexaammonium trichloride ruthenium, dissolve it in 150 g of deionized water, mix them, add 2 µL of isopropanol, and adjust the pH of the solution to 1~2 with hydrochloric acid. Then, irradiate with ultraviolet light for 30 min to carry out photodeposition reaction to obtain Ru solution.

[0072] (2) Add 5 g of Silicalite-1 carrier to step (1) above, impregnate, stir thoroughly for 1 h, and then dry by rotary evaporation at 60 °C and 50 mbar to obtain a solid powder loaded with active components and additives.

[0073] (3) The solid powder obtained in step (2) is filtered and washed several times using a mixed solution of deionized water and ethanol until the conductivity of the filtrate is less than 20 μS / cm, thus obtaining a heterogeneous catalyst that can be used for the reaction. It is denoted as catalyst Cat4#-light irradiation method.

[0074] Electron microscopy analysis showed that the average size of Ru clusters in the Cat4# catalyst obtained by photoluminescence method was less than 0.2 nm.

[0075] Using Cat4#-photocatalysis as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat4# (photocatalysis method) and 6 mL of ethanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, followed by sequential introduction of 0.65 MPa ethylene and 0.8 MPa CO. The reaction was stirred at 160 °C and 1000 rpm for 6 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0076] Comparative Example 5 The catalyst in this embodiment consists of 0.1 wt% Ru, 0.2 wt% Mo, and 99.4 wt% Silicalite-1 (Tianjin Nanhua Catalyst Co., Ltd.), denoted as Cat5# - photocatalytic method, and was prepared according to the following method: (1) Weigh 0.0023g of hexaammonium trichloride and 0.0041g of ammonium molybdate, dissolve them in 150g of deionized water, mix them, and adjust the pH of the solution to 1~2 with hydrochloric acid. Then, irradiate with ultraviolet light for 30min to carry out photodeposition reaction to obtain a complex solution of Ru and Mo.

[0077] (2) Add 5g of Silicalite-1 to the above step (1), impregnate, stir thoroughly for 1 hour, and then dry by rotary evaporation at 30°C and 30mbar to obtain a solid powder loaded with active components and additives.

[0078] (3) The solid powder obtained in step (2) is filtered and washed several times using a mixed solution of deionized water and ethanol until the conductivity of the filtrate is less than 20 μS / cm, thus obtaining a heterogeneous catalyst that can be used for the reaction. It is denoted as catalyst Cat5#-light irradiation method.

[0079] Electron microscopy analysis showed that the average size of Ru clusters in the Cat5# catalyst, obtained by photoluminescence method, was less than 0.2 nm.

[0080] Using Cat5#-photocatalysis as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat5# (photocatalysis method) and 4 mL of methanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, followed by sequential introduction of 0.75 MPa ethylene and 1.5 MPa CO. The reaction was stirred at 160 °C and 800 rpm for 8 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0081] Comparative Example 6 The catalyst in this embodiment consists of 0.15 wt% Ru, 0.25 wt% Mo, and 99.6 wt% Silicalite-2 (Tianjin Nanhua Catalyst Co., Ltd.), denoted as Cat6# - photocatalytic method, and was prepared as follows: (1) Weigh 0.0031 g of ruthenium trichloride and 0.0051 g of ammonium molybdate, dissolve them in 150 g of deionized water, mix them, add 2 µL of isopropanol, pH 6~7, and then irradiate with ultraviolet light for 20 min to carry out photodeposition reaction to obtain a complex solution of Ru and Mo.

[0082] (2) Add 5g of Silicalite-2 to the above step (1), impregnate, stir thoroughly for 1h, and then dry by rotary evaporation at 60℃ and 30mbar to obtain a solid powder loaded with active components and additives.

[0083] (3) The solid powder obtained in step (2) is filtered and washed several times using a mixed solution of deionized water and ethanol until the conductivity of the filtrate is less than 20 μS / cm, thus obtaining a heterogeneous catalyst that can be used for the reaction. It is denoted as catalyst Cat6#-light irradiation method.

[0084] Electron microscopy analysis showed that the average size of Ru clusters in the Cat6# catalyst, obtained by photoluminescence method, was less than 0.2 nm.

[0085] Using Cat6#-photocatalysis as a catalyst, and propylene and CO as raw materials, an alkoxycarbonylation reaction was carried out, as detailed below: 0.1 g of heterogeneous catalyst Cat6# (photocatalysis method) and 8 mL of ethanol were sequentially added to a 50 mL stainless steel autoclave equipped with a magnetic stirrer. The reactor was purged three times with hydrogen, followed by sequential introduction of 0.6 MPa ethylene and 1.0 MPa CO. The reaction was stirred at 180 °C and 1000 rpm for 6 h to obtain the reaction product, which was analyzed online by gas chromatography.

[0086] The results of the catalytic oxycarbonylation of ethylene alkane with the catalysts obtained in the examples and comparative examples are shown in Table 1: Table 1. Results of ethylene alkoxycarbonylation catalyzed by various catalysts in the reactor. As shown in Table 1 above, the heterogeneous catalyst provided by this invention is suitable for the ethylene alkoxycarbonylation reaction, and has the characteristics of high catalytic activity, high selectivity and high stability, and has important industrial application value.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A catalyst for the alkylation of ethylene to produce methyl propionate, characterized in that, The catalyst includes an active component, a metal promoter, and a support; The active component corresponds to the metal element Ru, the metal auxiliary corresponds to the metal element W and / or Mo, and the support is a porous material; The active component and the metal additive exist in the form of bimetallic single atoms or nanoparticles inside the pores and on the outer surface of the carrier.

2. The catalyst for the alkyloxycarbonylation of ethylene to methyl propionate according to claim 1, characterized in that, One or more of the following conditions must be met: (1) The mass ratio of the active component, the metal auxiliary agent and the carrier is (0.01-0.5):(0.01-1.0):100; (2) The average size of the active component is less than 0.2 nm; (3) The carrier is selected from one or more of amorphous silica, Silicalite-1 molecular sieve and Silicalite-2 molecular sieve.

3. A method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate as described in claim 1 or 2, characterized in that, include: A water-soluble Ru salt precursor, a metal auxiliary salt precursor, water and isobutanol were mixed, the pH was adjusted to strongly acidic with hydrochloric acid, and then photodeposition reaction was carried out by ultraviolet light irradiation to obtain a complex solution of Ru and metal auxiliary. The carrier is mixed with the complex solution of Ru and metal additive, stirred and impregnated, and then dried to obtain a solid powder loaded with active components and metal additives; The solid powder was washed with a mixture of water and ethanol to obtain the catalyst.

4. The method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate according to claim 3, characterized in that, The water-soluble Ru salt precursor is selected from one or more of hexaammonium trichloride, ruthenium trichloride, and ruthenium nitrate.

5. The method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate according to claim 3, characterized in that, The metal auxiliary salt precursor is selected from one or more of sodium molybdate, ammonium molybdate, and potassium molybdate.

6. The method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate according to claim 3, characterized in that, One or more of the following conditions must be met: (1) The pH corresponding to the strong acidity is 1-2; (2) The stirring and impregnation time is 0.5-5h, and the stirring speed is 300-1000r / min; (3) The drying is carried out by rotary evaporation at a temperature of 30-60℃ and a vacuum of 20-50mbar.

7. The method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate according to claim 3, characterized in that, One or more of the following conditions must be met: (1) The washing endpoint is when the conductivity of the washing liquid is less than 20 μS / cm; (2) The washing process also includes drying at 50-80℃ for 5-15 hours.

8. The method for preparing the catalyst for the alkyloxycarbonylation of ethylene to methyl propionate according to any one of claims 3-7, characterized in that, The ultraviolet light irradiation time is 5-100 minutes, and the power is 50-100 mW / cm². 2 .

9. Use of the catalyst according to claim 1 or 2 for the alkyloxycarbonylation of ethylene to methyl propionate, characterized in that, It is used as a catalyst for the alkyloxycarbonylation of ethylene to produce methyl propionate.

10. The use of the catalyst according to claim 9 for the alkyloxycarbonylation of ethylene to methyl propionate, characterized in that, One or more of the following conditions must be met: (1) The reaction temperature of the alkoxycarbonylation is 140-180℃ and the reaction pressure is 1.0-3.0 MPa; (2) In the alkoxycarbonylation reaction, the molar ratio of ethylene to CO is 0.5-2.0:1; (3) The solvent for alkoxycarbonylation is selected from one or more of methanol, ethanol, and toluene; (4) The equipment for alkoxycarbonylation is selected from one or more of fixed bed, fluidized bed and moving bed.

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