Catalyst for synthesizing vinyl acetate by acetylene method, preparation method and application thereof

Abstract

The application discloses a catalyst for synthesizing vinyl acetate by an acetylene method and a preparation method and application thereof. The catalyst comprises a carrier, an active component and a metal additive. The metal additive is Rh element. The Rh element exists in the form of Rh 0 and Rh 3+ . The Rh 3+ accounts for 9% to 49% of the total amount of Rh element, and the Rh 0 accounts for 51% to 91% of the total amount of Rh element. The catalyst is used in the reaction of synthesizing vinyl acetate by the acetylene method, and has the advantages of high catalyst activity and less loss of the active component.

Description

Technical Field

[0001] This invention belongs to the field of vinyl acetate synthesis, specifically relating to a catalyst for the acetylene method of vinyl acetate synthesis, its preparation method, and its application. Background Technology

[0002] Vinyl acetate, or vinyl acetate (VAM) for short, is an important organic chemical raw material, mainly used to produce derivatives such as polyvinyl alcohol (PVOH), polyvinyl acetate (PVAc), vinyl acetate-ethylene copolymer emulsion (VAE), or copolymer resin (EVA), and has a wide range of applications.

[0003] Currently, global vinyl acetate production capacity is approximately 8.7 million tons per year, with the main production processes including the ethylene process and the acetylene process. The acetylene process is further divided into the natural gas acetylene process and the calcium carbide acetylene process. China's vinyl acetate production capacity reaches 3.4 million tons per year, still primarily using the calcium carbide acetylene process. Sinopec Chongqing Chuanwei Chemical is currently the only manufacturer in China using the natural gas acetylene process to produce vinyl acetate, with a capacity of 500,000 tons per year. This process has certain advantages over the calcium carbide acetylene process in terms of product quality and environmental friendliness.

[0004] The natural gas acetylene production process employs a fixed-bed reactor and uses zinc acetate / column activated carbon as the catalyst. This catalyst has advantages such as abundant raw material sources, simple preparation process, and low production cost. However, it also suffers from disadvantages such as low catalyst activity, easy loss of active components, and short catalyst life. CN1903435A discloses a method for preparing a catalyst for the acetylene-based vinyl acetate process, in which zinc oxide and acetic acid are used as the active components, with the addition of a small amount of bismuth carbonate, which is then impregnated in activated carbon and dried to obtain the catalyst. However, the catalysts provided by the above technologies have low activity, poor stability, excessive catalyst activity reduction rate, and short catalyst life, thus limiting the application of the acetylene-based vinyl acetate process. Summary of the Invention

[0005] One of the technical problems to be solved by this invention is that the active components of the catalysts used in the acetylene-to-vinyl acetate synthesis process are easily lost and have a short service life. This invention provides a new catalyst for the acetylene-to-vinyl acetate synthesis process, which has the advantages of high catalyst activity and low loss of active components.

[0006] The second technical problem to be solved by the present invention is to provide a method for preparing a catalyst corresponding to one of the above-mentioned technical problems.

[0007] The third technical problem to be solved by the present invention is to provide an application of the catalyst described in one of the above-mentioned technical problems in the synthesis of vinyl acetate.

[0008] To address one of the aforementioned technical problems, the first aspect of this invention provides a catalyst for the synthesis of vinyl acetate via the acetylene process. The catalyst comprises a support, an active component, and a metal auxiliary; wherein the support is activated carbon, the active component is zinc acetate, and the metal auxiliary is Rh element. The catalyst exhibits a specific valence state distribution of Rh element.

[0009] According to the present invention, the catalyst has a special valence state distribution of the Rh element. The Rh element is in the form of Rh... 0 and Rh 3+ It exists in form. Among them, based on the mass of the Rh element, Rh... 3+ It accounts for 9% to 49% of the total Rh element, preferably 20% to 30%; Rh 0 It accounts for 51% to 91% of the total Rh element, preferably 70% to 80%. Rh 3+ The percentages are, for example, but not limited to, 15%, 18%, 22%, 25%, etc. Rh 0 The percentages are, for example, but not limited to, 75%, 78%, 82%, 85%, etc.

[0010] According to the present invention, the zinc acetate content in the catalyst is 40-80 g / L, calculated as zinc. The zinc acetate content is, for example, but not limited to, 45 g / L, 50 g / L, 55 g / L, 60 g / L, 65 g / L, 70 g / L, 75 g / L, etc. The activated carbon content is 350 g / L-450 g / L. The Rh element content is 0.4 g / L-8.0 g / L. The above description refers to the mass of Zn, Rh, or activated carbon contained per liter of catalyst.

[0011] According to the present invention, the specific surface area of ​​the activated carbon is 1000-1500 m². 2 / g. For example, but not limited to, 1050m 2 / g, 1100m 2 / g, 1150m 2 / g, 1200m 2 / g, 1250m 2 / g, 1300m 2 / g, 1350m 2 / g, 1400m 2 / g, 1450m 2 / g.

[0012] To solve the second technical problem mentioned above, a second aspect of the present invention provides a method for preparing the catalyst. The method includes:

[0013] (1) Impregnate activated carbon with active components to obtain precursor A;

[0014] (2) Precursor A was immersed in Rh salt to obtain precursor B;

[0015] (3) Mix precursor B with a reducing agent to obtain the catalyst.

[0016] According to the present invention, in step (1), the impregnation conditions are immersion at 70-90°C for 4-8 hours; after impregnation, drying can be performed. The drying can be performed using conventional parameters, such as drying at 80-120°C for 3-12 hours. The active component is zinc acetate; the active component exists in solution form. Preferably, the concentration of the zinc acetate aqueous solution is 40-80 g / L, calculated as zinc.

[0017] According to the present invention, in step (2), the Rh salt includes at least one of rhodium chloride, rhodium nitrate, and rhodium sulfate. The Rh salt exists in solution form. The concentration of the Rh salt solution, expressed as Rh, is 0.4–8.0 g / L. The impregnation conditions are immersion at 15–30°C for 2–5 hours. After impregnation, optional standing and optional drying can be performed. The standing time is 20–30 hours. The drying can be performed using conventional parameters, such as drying at 80–120°C for 3–12 hours.

[0018] According to the present invention, in step (3), the reducing agent includes at least one of sodium formate, formic acid, oxalic acid, citric acid, and hydrazine hydrate, preferably sodium formate and / or formic acid. The molar ratio of the reducing agent to Rh element is (2-30):1, preferably (4-20):1, and more preferably (5-10):1.

[0019] According to the present invention, in step (3), precursor B is mixed with reducing agent to undergo reduction reaction; the reaction conditions are 10-40°C for 2-5 hours, preferably 20-30°C for 3-4 hours.

[0020] According to the present invention, in step (3), drying can be performed after the mixing reaction. The drying can be carried out using conventional parameters, such as drying at 60-120°C for 3-12 hours.

[0021] To solve the third technical problem mentioned above, the third aspect of the present invention provides the application of the above-mentioned catalyst or the catalyst prepared by the above-mentioned preparation method in the acetylene synthesis of vinyl acetate reaction.

[0022] According to the present invention, the application includes reacting acetic acid and acetylene as raw materials in the presence of the catalyst to obtain vinyl acetate.

[0023] According to the present invention, the molar ratio of acetylene to acetic acid is 5 to 12, for example, but not limited to 6, 7, 8, 9, 10, 11, etc.

[0024] According to the present invention, the reaction pressure is 0.1 to 0.5 atm, for example, but not limited to 0.15 atm, 0.2 atm, 0.25 atm, 0.3 atm, 0.35 atm, 0.4 atm, 0.45 atm, etc. All reaction pressures are gauge pressures.

[0025] According to the present invention, the reaction temperature is 160 to 220°C, for example, but not limited to 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, etc.

[0026] According to the present invention, the volume hourly space velocity (VHSV) of the raw materials (total amount of acetic acid and acetylene) is 250–350 h⁻¹. -1 For example, but not limited to 260h -1 270h -1 280h -1 290h -1 300h -1 310h -1 320h -1 330h -1 340h -1 etc.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. In the catalyst of the present invention, the catalyst comprises a support, an active component, and a metal promoter; wherein the metal promoter is Rh element; the Rh element is in the form of Rh... 0 and Rh 3+ It exists in form; based on the mass of the Rh element, Rh 3+ It accounts for 9% to 49% of the total Rh element; Rh 0 It accounts for 51% to 91% of the total Rh element. In existing catalysts, the active component, zinc acetate, is mostly composed of Zn. 2+ It exists, and although the catalyst has high activity, Zn 2+ The catalyst is prone to loss during the reaction, leading to a rapid decline in catalyst activity and a short lifespan. The inventors surprisingly discovered that the catalyst of this invention, by adding the metal promoter Rh element and regulating the formation of a special valence state distribution, can significantly reduce the loss of active components in the catalyst and extend its lifespan. The catalyst, used in the acetylene-to-vinyl acetate synthesis reaction, has the advantages of high catalyst activity and minimal loss of active components.

[0029] 2. In the preparation method of the catalyst of the present invention, by adding a metal promoter and a specific proportion of reducing agent, preferably sodium formate, the valence state distribution of the Rh element in the catalyst is controlled, which can significantly reduce the loss of active components in the catalyst and extend the catalyst's service life. The catalyst prepared by the method of the present invention has the advantages of high catalyst activity and low loss of active components when used in the acetylene synthesis of vinyl acetate reaction.

[0030] 3. In the application of the catalyst of the present invention, the catalyst is suitable for the synthesis of vinyl acetate by the acetylene method, and has the advantages of high catalyst activity and low loss of active components. Detailed Implementation

[0031] The present invention will now be described in detail with reference to specific embodiments. These embodiments are for illustrative purposes only and do not constitute any limitation thereof. The invention has been described with reference to exemplary embodiments, but it should be understood that the terms used are descriptive and explanatory, not limiting. Modifications and revisions can be made to the invention within the scope of the claims as specified herein, without departing from the scope and spirit of the invention. Although the invention described herein relates to specific methods, materials, and embodiments, it does not imply that the invention is limited to the specific examples disclosed herein; on the contrary, the invention can be extended to all other methods and applications with the same function.

[0032] In this invention, a Thermo iCAP 6300 inductively coupled plasma atomic emission spectrometer (ICP-AES) was used to quantitatively analyze the elements in the catalyst.

[0033] In this invention, in the examples and comparative examples, the Rh of the catalyst is... 3+ The Rh elemental distribution was characterized using an AXISUltra DLD X-ray photoelectron spectrometer (XPS) from Kratos, with calibration data at C1s 284.8 eV.

[0034] In this invention, the total specific surface area of ​​activated carbon in the examples and comparative examples was determined using a Micromeritics ASAP2460 specific surface area and porosity analyzer. A certain amount of sample was accurately weighed and pretreated under vacuum at 60°C to a density of 1×10⁻⁶. - 5 After Pa, static flow measurement was used with N2 as the adsorbate, and adsorption and desorption were determined at liquid nitrogen temperature. The specific surface area S of the sample was measured. BET The specific surface area of ​​the mesoporous structures was obtained by calculation using the BET equation and by the t-plot method.

[0035] In this invention, the space-time yield in Table 2 is the average value over the first 10 hours of the reaction; the unit is g·(L·h). -1 .

[0036] In this invention, the activity decay rate in Table 2 is calculated as follows: (average space-time yield from the first 10 hours of reaction) - (average space-time yield from the 91st to the 100th hour of reaction) / (average space-time yield from the first 10 hours of reaction) × 100%.

[0037] In this invention, Zn loss rate = (Zn content before catalyst evaluation) - (Zn content after catalyst evaluation) / (Zn content before catalyst evaluation) × 100%;

[0038] In the formula, the Zn content refers to the mass content of Zn per liter of catalyst, in g / L.

[0039] In this invention, gas chromatography is used to analyze the content of vinyl acetate in the reaction products.

[0040]

Example 1

[0041] (I) Catalyst Preparation

[0042] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (60 g / L of zinc) and immersed at 80 °C for 4 h. After drying at 110 °C for 6 h, catalyst precursor A was obtained.

[0043] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (6.0 g / L based on Rh), soak at room temperature (20 °C) for 3 h, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0044] (3) Mix 1000 mL of catalyst precursor B with a sodium formate solution Z of concentration 40.0 g / L at a molar ratio of sodium formate to Rh of 10:1. Let stand at 25 °C for 4 h, and dry at 110 °C for 3 h to obtain the catalyst.

[0045] The catalyst contains 60 g / L zinc, 6.0 g / L Rh, and 400 g / L activated carbon.

[0046] (II) Physical property characterization

[0047] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0048] (III) Catalyst Performance Evaluation

[0049] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0050] Catalyst loading volume: 40 mL;

[0051] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0052] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0053] Reaction pressure: 0.3 atm;

[0054] Reaction temperature: 180℃;

[0055] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0056]

Example 2

[0057] (I) Catalyst Preparation

[0058] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (60 g / L of zinc) and immersed at 80 °C for 4 h. After drying at 110 °C for 6 h, catalyst precursor A was obtained.

[0059] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (6.0 g / L based on Rh), soak at room temperature (20 °C) for 3 h, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0060] (3) Mix 1000 mL of catalyst precursor B with sodium formate solution Z with a concentration of 20.0 g / L according to the molar ratio of sodium formate to Rh = 5:1, let stand at 25 °C for 4 h, and dry at 110 °C for 3 h to obtain the catalyst.

[0061] The catalyst contains 60 g / L zinc, 6.0 g / L Rh, and 400 g / L activated carbon.

[0062] (II) Physical property characterization

[0063] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0064] (III) Catalyst Performance Evaluation

[0065] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0066] Catalyst loading volume: 40 mL;

[0067] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0068] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0069] Reaction pressure: 0.3 atm;

[0070] Reaction temperature: 180°C;

[0071] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0072]

Example 3

[0073] (I) Catalyst Preparation

[0074] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (60 g / L of zinc) and immersed at 80 °C for 4 h. After drying at 110 °C for 6 h, catalyst precursor A was obtained.

[0075] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (6.0 g / L based on Rh), soak at room temperature (20 °C) for 3 h, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0076] (3) Mix 1000 mL of catalyst precursor B with sodium formate solution Z with a concentration of 4.0 g / L according to the molar ratio of sodium formate to Rh = 1:1, let stand at 25 °C for 4 h, and dry at 110 °C for 3 h to obtain the catalyst.

[0077] The catalyst contains 60 g / L zinc, 6.0 g / L Rh, and 400 g / L activated carbon.

[0078] (II) Physical property characterization

[0079] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0080] (III) Catalyst Performance Evaluation

[0081] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0082] Catalyst loading volume: 40 mL;

[0083] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0084] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0085] Reaction pressure: 0.3 atm;

[0086] Reaction temperature: 180℃;

[0087] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0088]

Example 4

[0089] (I) Catalyst Preparation

[0090] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (60 g / L of zinc) and immersed at 80 °C for 4 h. After drying at 110 °C for 6 h, catalyst precursor A was obtained.

[0091] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (6.0 g / L based on Rh), soak at room temperature (20 °C) for 3 h, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0092] (3) Mix 1000 mL of catalyst precursor B with hydrazine hydrate solution Z with a concentration of 29.0 g / L according to the molar ratio of hydrazine hydrate to Rh = 10:1, let stand at 25 °C for 4 h, and dry at 110 °C for 3 h to obtain the catalyst.

[0093] The catalyst contains 60 g / L zinc, 6.0 g / L Rh, and 400 g / L activated carbon.

[0094] (II) Physical property characterization

[0095] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0096] (III) Catalyst Performance Evaluation

[0097] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0098] Catalyst loading volume: 40 mL;

[0099] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0100] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0101] Reaction pressure: 0.3 atm;

[0102] Reaction temperature: 180℃;

[0103] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0104]

Example 5

[0105] (I) Catalyst Preparation

[0106] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (60 g / L of zinc) and immersed at 80 °C for 4 h. After drying at 110 °C for 6 h, catalyst precursor A was obtained.

[0107] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (6.0 g / L based on Rh), soak at room temperature (20 °C) for 3 h, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0108] (3) Mix 1000 mL of catalyst precursor B with a formic acid solution Z with a concentration of 27.0 g / L according to the molar ratio of formic acid to Rh = 10:1, let stand at 25 °C for 4 h, and dry at 110 °C for 3 h to obtain the catalyst.

[0109] The catalyst contains 60 g / L zinc, 6.0 g / L Rh, and 400 g / L activated carbon.

[0110] (II) Physical property characterization

[0111] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0112] (III) Catalyst Performance Evaluation

[0113] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0114] Catalyst loading volume: 40 mL;

[0115] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0116] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0117] Reaction pressure: 0.3 atm;

[0118] Reaction temperature: 180℃;

[0119] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0120]

Example 6

[0121] (I) Catalyst Preparation

[0122] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (40 g / L based on zinc) and immersed at 80 °C for 4 h. After drying at 110 °C for 6 h, catalyst precursor A was obtained.

[0123] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (0.4 g / L based on Rh), soak at room temperature (20 °C) for 3 h, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0124] (3) Mix 1000 mL of catalyst precursor B with sodium formate solution Z with a concentration of 2.6 g / L according to the molar ratio of sodium formate to Rh = 10:1, let stand at 25 °C for 4 h, and dry at 110 °C for 3 h to obtain the catalyst.

[0125] The catalyst contains 40 g / L zinc, 0.4 g / L Rh, and 400 g / L activated carbon.

[0126] (II) Physical property characterization

[0127] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0128] (III) Catalyst Performance Evaluation

[0129] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0130] Catalyst loading volume: 40 mL;

[0131] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 5:1;

[0132] Reactant volume hourly space velocity: 250 h⁻¹ -1 ;

[0133] Reaction pressure: 0.1 atm;

[0134] Reaction temperature: 160℃;

[0135] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0136]

Example 7

[0137] (I) Catalyst Preparation

[0138] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (80 g / L based on zinc) and immersed at 80 °C for 4 h. After drying at 110 °C for 6 h, catalyst precursor A was obtained.

[0139] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (8.0 g / L based on Rh), soak at room temperature (20 °C) for 3 h, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0140] (3) Mix 1000 mL of catalyst precursor B with sodium formate solution Z with a concentration of 53.00 g / L according to the molar ratio of sodium formate to Rh = 10:1, let stand at 25 °C for 4 h, and dry at 110 °C for 3 h to obtain the catalyst.

[0141] The catalyst contains 80 g / L zinc, 8.0 g / L Rh, and 400 g / L activated carbon.

[0142] (II) Physical property characterization

[0143] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0144] (III) Catalyst Performance Evaluation

[0145] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0146] Catalyst loading volume: 40 mL;

[0147] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 12:1;

[0148] Reactant volume hourly space velocity: 350 h⁻¹ -1 ;

[0149] Reaction pressure: 0.5 atm;

[0150] Reaction temperature: 220℃;

[0151] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0152]

Comparative Example 1

[0153] (I) Catalyst Preparation

[0154] (1) Same as step (1) in Example 1, the activated carbon is impregnated in a zinc acetate solution X and dried to obtain catalyst C, the zinc content in the catalyst is 60 g / L.

[0155] (II) Physical property characterization

[0156] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0157] (III) Catalyst Performance Evaluation

[0158] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0159] Catalyst loading volume: 40 mL;

[0160] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0161] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0162] Reaction pressure: 0.3 atm;

[0163] Reaction temperature: 180℃;

[0164] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0165] [Comparative Example 2]

[0166] (I) Catalyst Preparation

[0167] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (60 g / L based on zinc) and immersed at 80 °C for 4 h. After drying, catalyst precursor A was obtained.

[0168] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (6.0 g / L based on Rh), soak for 3 h at room temperature, let stand for 24 h, and dry at 110 °C for 6 h to obtain the finished catalyst product.

[0169] The catalyst contains 60 g / L zinc, 6.0 g / L Rh, and 400 g / L activated carbon.

[0170] (II) Physical property characterization

[0171] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0172] (III) Catalyst Performance Evaluation

[0173] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0174] Catalyst loading volume: 40 mL;

[0175] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0176] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0177] Reaction pressure: 0.3 atm;

[0178] Reaction temperature: 180℃;

[0179] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0180] Comparative Example 3

[0181] (I) Catalyst Preparation

[0182] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (60 g / L based on zinc) and immersed at 80 °C for 4 h. After drying, catalyst precursor A was obtained.

[0183] (2) Place 1000 mL of catalyst precursor A in 1000 mL of RhCl3 aqueous solution Y (6.0 g / L based on Rh), soak for 3 h at room temperature, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0184] (3) Place 1000 mL of catalyst precursor B in a tube furnace and reduce it at 500 °C for 5 h in a mixed atmosphere of H2 and N2 with a volume ratio of 1:9. After cooling, the catalyst product C is obtained.

[0185] The catalyst contains 60 g / L zinc, 6.0 g / L Rh, and 400 g / L activated carbon.

[0186] (II) Physical property characterization

[0187] The preparation conditions and characterization of the catalyst are listed in Table 1.

[0188] (III) Catalyst Performance Evaluation

[0189] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0190] Catalyst loading volume: 40 mL;

[0191] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0192] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0193] Reaction pressure: 0.3 atm;

[0194] Reaction temperature: 180℃;

[0195] The reaction was carried out for 100 hours, and the evaluation results of the catalyst are shown in Figure 2.

[0196] [Comparative Example 4]

[0197] (I) Catalyst Preparation

[0198] (1) 1000 mL of activated carbon was immersed in 1000 mL of zinc acetate solution X (60 g / L of zinc) and immersed at 80 °C for 4 h. After drying at 110 °C for 6 h, catalyst precursor A was obtained.

[0199] (2) Place 1000 mL of catalyst precursor A in 1000 mL of H2PdCl4 aqueous solution Y (6.0 g / L based on Pd), soak at room temperature (20 °C) for 3 h, let stand for 24 h, and dry at 110 °C for 6 h to obtain catalyst precursor B.

[0200] (3) 1000 mL of catalyst precursor B was mixed with a sodium formate solution Z with a concentration of 38.0 g / L, according to a sodium formate to Pd molar ratio of 10:1. The mixture was allowed to stand at 25°C for 4 h and then dried at 110°C for 3 h to obtain the catalyst. The catalyst contained 60 g / L zinc, 6.0 g / L Pd, and 400 g / L activated carbon.

[0201] (II) Physical property characterization

[0202] The preparation conditions for the catalyst are listed in Table 1.

[0203] (III) Catalyst Performance Evaluation

[0204] The evaluation was conducted using a fixed-bed reactor, under the following conditions:

[0205] Catalyst loading volume: 40 mL;

[0206] Composition of reactants (in molar ratio): Acetylene: Acetic acid = 6:1;

[0207] Reactant volume hourly space velocity: 300 h⁻¹ -1 ;

[0208] Reaction pressure: 0.3 atm;

[0209] Reaction temperature: 180℃;

[0210] The reaction was carried out for 100 h, and the evaluation results of the catalyst are shown in Table 2.

[0211] Table 1. Catalyst preparation and characterization for each example.

[0212]

[0213] Table 2 Catalyst Evaluation Results

[0214]

[0215] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A catalyst for the synthesis of vinyl acetate via the acetylene process, comprising a support, an active component, and a metal auxiliary agent; wherein, The metallic additive is Rh element; Rh element with Rh 0 and Rh 3+ It exists in form; based on the mass of the Rh element, Rh 3+ It accounts for 9% to 49% of the total Rh element; Rh 0 It accounts for 51% to 91% of the total Rh element; The carrier is activated carbon; the active component is zinc acetate; The catalyst contains 40-80 g / L zinc acetate (calculated as zinc); 350-450 g / L activated carbon; and 0.4-8.0 g / L Rh.

2. The catalyst according to claim 1, characterized in that, Rh element with Rh 0 and Rh 3+ It exists in form; based on the mass of the Rh element, Rh 3+ It accounts for 20% to 30% of the total Rh element; Rh 0 It accounts for 70% to 80% of the total Rh element.

3. A method for preparing the catalyst according to any one of claims 1 to 2, the method comprising: (1) The carrier is impregnated in the active component to obtain precursor A; (2) Precursor A was immersed in Rh salt to obtain precursor B; (3) Mix precursor B with a reducing agent to obtain the catalyst.

4. The preparation method according to claim 3, characterized in that, In step (3), the reducing agent includes at least one of sodium formate, formic acid, oxalic acid, citric acid, and hydrazine hydrate.

5. The preparation method according to claim 4, characterized in that, In step (3), the reducing agent is sodium formate and / or formic acid.

6. The preparation method according to any one of claims 3 to 5, characterized in that, In step (3), the molar ratio of reducing agent to Rh element is (2~30):

1.

7. The preparation method according to claim 6, characterized in that, In step (3), the molar ratio of reducing agent to Rh element is (4~20):

1.

8. The preparation method according to claim 6, characterized in that, In step (3), the molar ratio of reducing agent to Rh element is (5~10):

1.

9. The preparation method according to claim 3, characterized in that, In step (3), precursor B is mixed with a reducing agent to undergo a reduction reaction; the reaction conditions are 10~40. o React at C for 2-5 hours.

10. The preparation method according to claim 9, characterized in that, In step (3), precursor B is mixed with reducing agent to undergo reduction reaction; the reaction conditions are 20~30℃ for 3~4 h.

11. The application of the catalyst according to any one of claims 1 to 2 or the catalyst prepared by any one of claims 3 to 10 in the acetylene synthesis of vinyl acetate reaction.

12. The application according to claim 11, characterized in that, The application includes a contact reaction of acetic acid and acetylene as raw materials in the presence of the catalyst to obtain vinyl acetate; the reaction conditions are as follows: The molar ratio of acetylene to acetic acid is 5–12; and / or, the reaction pressure is 0.1–0.5 atm; and / or, the reaction temperature is 160–220 °C; and / or, the feed volume hourly space velocity is 250–350 h⁻¹. -1 .

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