A catalyst for preparing vinyl acetate, a method for preparing the same, and an application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- RUNHE CATALYST (SHANDONG) CO LTD
- Filing Date
- 2025-04-23
- Publication Date
- 2026-06-23
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This invention relates to a catalyst for the preparation of vinyl acetate, its preparation method and application, and particularly to a carbon-based composite support catalyst for the preparation of vinyl acetate using the acetylene method, including its preparation method and application process, belonging to the field of chemical technology. Background Technology
[0002] Vinyl acetate is one of the world's 50 most produced chemical products. As a raw material for vinyl acetate resin and polyvinyl alcohol, and as a copolymer monomer with ethylene, styrene, acrylate, methacrylate, etc., it is widely used in adhesives, paints, coatings, films, laminates, fiber treatment agents and other fields. It is an important industrial material with high economic value.
[0003] In 1922, the German company Wacker first used a gas-phase synthesis method with acetylene as a raw material, which was later improved by Hochst and put into industrial production. The catalyst in this synthesis method uses zinc acetate as the active component and activated carbon as the support, and this method is still in use today, as shown in CN1903435A. Although products using ethylene as a raw material currently have better quality, and newly built foreign plants primarily use ethylene as a raw material, China still mainly uses the acetylene method to produce vinyl acetate. Several such plants were imported in China as early as the 1960s. Therefore, research on the acetylene method for synthesizing vinyl acetate continues in China, with particular attention paid to the combination and adjustment of the active components of the catalyst.
[0004] In the domestic gas-phase synthesis of vinyl acetate from acetylene, whether in a fixed-bed or fluidized-bed process, the catalyst used is a zinc acetate / activated carbon catalyst. However, different manufacturers choose different types of activated carbon as the support, the zinc acetate loading, and especially the co-catalyst. Commonly used activated carbon supports include coconut shell carbon, apricot kernel carbon, pecan carbon, olive kernel carbon, and coal-derived carbon, etc. Currently, coconut shell activated carbon is the most common support, with only a few manufacturers using coal-derived activated carbon as the catalyst support in fixed-bed processes.
[0005] Currently, the catalysts used in China for the gas-phase synthesis of vinyl acetate using acetylene have many drawbacks, including low activity, low yield per unit volume, poor mechanical strength, easy shedding of active components, and short deactivation cycle.
[0006] Existing technologies have conducted extensive research on active components, additives, and supports to address the existing problems. For example, in the earlier patent document CN86107833A, two zinc active components, zinc nitrate and zinc chloride, were used and supported on a high-strength activated carbon support. The catalyst prepared by calcination improved the space-time yield. CN112517064A also disclosed a catalyst with two zinc salt active components. In addition to zinc acetate, a dicarboxylic acid zinc salt was used as the second zinc salt active component, which reduced the acetone content in the product.
[0007] Research on additives is also very active. For example, in the catalyst and its preparation method disclosed in CN1903435A, activated carbon is used as a support, zinc acetate is used as an active component, and basic bismuth carbonate is used as a co-catalyst to inhibit the formation of acetylene polymer in the product, reduce the poisoning effect on the catalyst, and thus improve the activity and lifespan. In CN102039180A, rare earth element modification is used to improve the single-pass conversion rate of the process.
[0008] Some organic compounds have also been used as additives. For example, CN103934024A uses aromatic esters as additives, CN103934021A uses alkyl diethers and / or aromatic diethers as additives, and CN104549496A discloses crown ethers as additives to improve catalyst activity. Besides improving activity, organic additives are also used to reduce the benzene content in the product to improve product quality. For example, CN104437626A uses fullerenes, CN114177939A uses cucurbita, CN115707512A uses acyl chloride organic compounds, and CN115228508A uses p-benzoquinone, etc., as additives to modify zinc acetate activated carbon catalysts. CN113620802A, however, simply reduces the benzene content in the product by controlling the zinc content.
[0009] In existing technologies, it is common to add or replace different elements. For example, in the catalyst disclosed in CN103285878A, the support is activated carbon, and the active components are impregnated with elements such as zinc, lanthanum, iron, calcium, copper, potassium, zirconium, and platinum. The catalyst is calcined using furnace gas from a combustion furnace. When the resulting catalyst is used to prepare vinyl acetate, it lowers the reaction initiation temperature and achieves a better space-time yield. CN101391229A is a fixed-bed catalyst containing rare earth metals, which also lowers the reaction initiation temperature. CN102039180A also uses cerium and scandium rare earth salts to improve single-pass conversion and service life. CN105944757A uses compounds of Group V nonmetallic elements to obtain a doped activated carbon support, and the catalyst has good activity and stability.
[0010] The Shanghai Research Institute of Petrochemical Technology has disclosed numerous existing technologies involving element modification. These technologies modify the basic structure of activated carbon support and zinc acetate active components using different elements such as platinum group metals and rare earth elements to improve catalyst activity and stability, or reduce benzene content in the product. Examples include patents such as CN104549497A, CN105498778A, CN106423(157, 267)A, CN1077722(76, 79)A, CN107778169A, CN1077743(04, 08, 12-14, 19-24, 32, 38)A, CN1077901(81-90)A, CN114054010A, and CN115970754A, which essentially cover the periodic table.
[0011] Besides focusing on elemental modification research, the modification of the support for zinc acetate activated carbon catalysts has also attracted attention. For example, CN116870888A increases the pore volume of the activated carbon catalyst support, providing more developed pore channels that allow raw material and product molecules to freely enter and exit, and also increases the catalyst's strength and apparent density. CN105457683A uses titanium-modified activated carbon support, along with zinc acetate active components and potassium acetate promoters, to improve the catalyst's activity and the single-pass conversion rate of acetylene. 12439453A uses ionic liquids to modify the activated carbon support, improving the catalyst's lifetime and stability; CN102029193A uses hydrogen peroxide to modify the activated carbon support, improving pore size distribution and surface charge distribution; CN102284304A uses oxidants such as hydrogen peroxide, sulfuric acid, potassium permanganate, and ammonium persulfate to perform surface oxidation modification on the activated carbon support, improving its loading capacity for zinc acetate; CN108636392A improves the activation method to enhance catalyst quality.
[0012] Among the publicly available technologies, some physical methods have been attempted for modification. For example, CN103111325A, CN113649082A, and CN103447083A introduce an electric current during the drying of the impregnated activated carbon to improve activity and lifespan; CN102671698A uses ultrasonic impregnation technology to disperse the active components evenly and improve activity; CN108144648A combines ultrasonic impregnation with microwave drying technology to improve catalyst activity and lifespan; CN104437627A also uses microwave drying; and CN104549498A uses... 60The method of Co-γ ray irradiation of activated carbon support can improve the activity of catalyst; in CN102218340A, the prepared zinc acetate solution is impregnated in a sealed impregnation and drying tower filled with dry activated carbon, so that the zinc acetate is impregnated into the pores of the activated carbon as much as possible, and the excess solution and water are discharged by gravity. The water is evaporated and carried away by indirect heating with heat transfer oil or hot water, which reduces the breakage of activated carbon.
[0013] Existing technologies have also explored different types of activated carbon. For example, CN102774834A discloses the preparation of bamboo activated carbon to replace the more expensive coconut shell activated carbon, thereby reducing the raw material cost of the catalyst; CN101402052A uses lignin precipitated from papermaking as raw material to prepare activated carbon as a support for catalyst preparation; CN101385984A uses acrylonitrile-vinylidene chloride copolymer precursor to prepare polymer-derived carbon as a support; CN101439302A uses resin-based derived carbon as a catalyst support, which has the advantages of good catalytic performance and mechanical strength, regular structure, and easy packing; in CN109382084A and CN103934030A, mesoporous carbon materials are used as supports for zinc acetate activated carbon catalysts, giving the catalysts good catalytic activity.
[0014] For a long time, experiments using silica gel, alumina, aluminum silicate, and molecular sieves to replace activated carbon as a support have been unsuccessful. The catalysts prepared using these materials as supports have much lower activity than those using activated carbon as a support. Activated carbon has been difficult to completely replace as a catalyst support in the acetylene synthesis of vinyl acetate.
[0015] However, some existing technologies also disclose techniques involving non-activated carbon supports. For example, CN103962178A uses zinc acetate and copper acetate as active components and silicon carbide or activated carbon as supports to improve catalyst activity; CN103769218A uses only silicon carbide as the catalyst support; CN103934025A uses carbon-deposited silicon carbide as a support to solve the problem of low catalyst activity; CN102600899A uses carbon-coated alumina composite material as a support and zinc acetate as the active component, achieving good space-time yield, selectivity, and stability; CN106268962A mainly... The catalyst uses nano-ceramic spheres as a support and zinc acetate as the active component. The co-catalyst uses diatomaceous earth as a support and copper chloride and nano-zinc oxide as active components. It is prepared under the assistance of ultrasound and microwave. The ratio of the main catalyst to the co-catalyst is 7:3, which improves the loading rate of active components and catalytic activity, and the activity decreases slowly. CN109382084A uses zinc-containing mesoporous carbon material with ordered mesoporous channels. The template agent, organic solvent, carbon source and zinc-containing precursor are mixed, the organic solvent in the colloidal solution is removed and solidified, and the template agent is removed and carbonized under an inert atmosphere. Its zinc content is controllable, the dispersibility and activity are good, and it is simple and easy to implement. Summary of the Invention
[0016] The purpose of this invention is to provide an improved method for preparing a catalyst for vinyl acetate, as well as the catalyst and its application technology. Improvements are made to address problems such as easy loss of zinc, limited loading, low activity and stability, side reaction impurities and coking, and poor strength affecting service life. The invention employs a carbon-based composite support with inorganic binder functions, loads two types of zinc active components and additives with different properties, and improves loading and activation effect. It also adjusts the physicochemical properties of the pore surface, improves diffusion and thermal conductivity, catalytic performance and mechanical strength, reduces side reactions and carbon deposition, and lowers the severity of the preparation process.
[0017] The present invention provides a catalyst for preparing vinyl acetate and a method for preparing the same, comprising:
[0018] The catalyst composition satisfies the chemical formula: Zn α Bi β Si γ B λ Al μ P η O χ / C 100 In the formula, the atomic ratios are α = 1.4–3.8, β = 0.001–0.002, γ = 1.8–3.8, λ = 0.01–0.02, μ = 0.9–1.8, and η = 0.9–1.8. χ is the number of oxygen atoms required to satisfy the atomic valence of each element. After uniformly mixing 200–300 mesh carbon powder, silicon carbide powder, and basic zinc carbonate (whose zinc element accounts for 10wt%–40wt% of the total zinc content of the catalyst), it is impregnated with an equal volume of a mixed solution of bismuth nitrate and boric acid. Aluminum phosphate sol is added, and the mixture is kneaded for more than 40 minutes before shaping. After drying, it is activated at 300–700℃ by passing water vapor containing 1wt%–5wt% hydrogen peroxide for 1–8 hours. After saturation impregnation with zinc acetate solution, it is dried at 80–100℃ for 1–6 hours.
[0019] In the preparation method of the catalyst for preparing vinyl acetate provided by the present invention, the carbon powder is selected from wood carbon powder, bamboo carbon powder, coal-based carbon powder, fruit shell carbon powder, petroleum coke carbon powder, and resin-based carbon powder.
[0020] In the preparation method of the catalyst for preparing vinyl acetate provided by the present invention, the equal-volume impregnation of the bismuth nitrate and boric acid mixed solution is carried out by impregnating the powdered raw material with the mixed solution of bismuth nitrate and boric acid dissolved by nitric acid at an equal volume at 20-100°C.
[0021] In the preparation method of the catalyst for preparing vinyl acetate provided by the present invention, the aluminum phosphate sol is prepared by dissolving and reacting phosphoric acid solution with one or more of aluminum oxide, aluminum hydroxide, boehmite, pseudoboehmite, aluminum isopropoxide, and aluminum isobutoxide in an equimolar ratio of phosphorus and aluminum at 40-100°C.
[0022] In the method for preparing a catalyst for vinyl acetate provided by this invention, the molding process for preparing columnar, block, sheet, and strip-shaped catalysts suitable for fixed-bed reaction processes is achieved through hydraulic pressing or extrusion and pelletizing; the preparation of spherical granular catalysts suitable for fluidized bed and boiling bed reaction processes is achieved through rolling in a catalyst rolling device. It is generally believed that the product quality of fixed-bed processes is superior to that of fluidized bed processes, but the operational labor intensity of fixed-bed processes is higher than that of fluidized bed processes.
[0023] In the preparation method of the catalyst for preparing vinyl acetate provided by the present invention, the saturated impregnation with zinc acetate solution is carried out by placing the support composition in a zinc acetate solution with a pH of 4-6 and a zinc acetate content of 20wt%-35wt% at 50-100°C for 1-10 hours.
[0024] This invention provides a catalyst for preparing vinyl acetate, which is prepared according to the above-described preparation method and steps. The catalyst is characterized by an average pore size ≥ 2 nm, a pore volume of 0.4–0.6 ml / g, and a surface area of 600–900 m². 2 / g, bulk density is 0.3~0.6g / ml.
[0025] This invention also provides a method for preparing vinyl acetate, comprising using acetic acid and acetylene as raw materials, wherein, in the presence of the catalyst prepared by the method of this invention, the molar ratio of acetylene to acetic acid is 1:(5-8), and the raw material volume hourly space velocity is 250-350 h⁻¹. -1 The reaction temperature is 170-200℃ and the reaction pressure is 0.1-0.14MPa. Vinyl acetate is obtained through a synthesis reaction.
[0026] In the preparation method of the catalyst for preparing vinyl acetate provided by the present invention, the amount of deionized water and methanol / ethanol solvents used in the dilution and salt dissolution processes is mainly to meet operational requirements and convenience, and has no impact on the performance of the final catalyst. When it does not affect the convenience of operation, the minimum amount of water and alcohol solvents should be used for dilution and dissolution to reduce consumption.
[0027] The chemicals involved in this invention are commonly used industrial chemical products and laboratory reagents, which can be easily obtained through commercial purchase.
[0028] The chemical unit operations involved in this invention are conventional operating techniques in the field, well known to those skilled in the art, and routinely used in chemical experiments and industrial production processes.
[0029] The beneficial effects of this invention are as follows: the provided method for preparing the catalyst and the catalyst obtained therefrom utilize widely available and inexpensive raw materials, and reduce the harsh conditions in the preparation process, thus facilitating manufacturing. When the prepared catalyst is applied to the acetylene process for preparing vinyl acetate, it exhibits better catalytic performance, with good vinyl acetate space-time yield, selectivity, and activity stability, as well as good mechanical strength and thermal conductivity. During the reaction, it reduces harmful byproducts and carbon deposits, effectively extending the catalyst's lifespan, making it suitable for industrial production processes.
[0030] Other features and advantages of the present invention will be described in detail in the following specific embodiments. Detailed Implementation
[0031] The following examples are used to further describe the content and effects of the present invention. The examples are illustrative explanations of the implementation of the present invention, but do not limit the broad interpretation of the present invention.
[0032] In the embodiments, atomic emission spectroscopy and X-ray fluorescence were used to determine the element content, low-temperature nitrogen adsorption method was used to determine the specific surface area and pore volume, and gas chromatography was used to analyze the composition of raw materials and reaction products.
[0033] For other analytical tests, please refer to the relevant analytical methods in (National Standard for Testing Methods of Petroleum and Petroleum Products, published by China Standards Press, 1989) and (Analytical Methods for Petrochemical Products (RIPP Test Methods), published by Science Press, 1990).
[0034] Example 1
[0035] A solution of chemically pure phosphoric acid and industrial-grade boehmite powder were added to deionized water and mixed in an equimolar ratio under stirring and at 50–60°C to carry out a dissolution reaction, thus preparing a dilute aluminum phosphate sol.
[0036] According to Zn α Bi β Si γ B λ Al μ P η O χ / C 100The molar ratios constrained by α = 2.6, β = 0.0012, γ = 2.8, λ = 0.012, μ = 1.4, and η = 1.4 were used to uniformly mix 250-mesh industrial-grade wood charcoal powder, industrial-grade silicon carbide powder, and industrial-grade basic zinc carbonate powder. The mixture was then impregnated in equal volumes with a chemically pure bismuth nitrate and boric acid solution at 20–40°C. The prepared aluminum phosphate sol was then added, and the mixture was kneaded in a laboratory mini-kneader for over 1 hour. The mixture was then extruded into strips with a diameter of 2.4 mm and a length of 1.5 cm using a laboratory mini-extruder. The strips were dried in an oven at 105°C for 4 hours, and then activated in a closed tube furnace in a laboratory at 600°C with steam containing 1.5 wt% hydrogen peroxide for 4 hours. Finally, the mixture was saturated with a 25 wt% zinc acetate solution (pH 4.5) at 75°C for 4 hours, and then dried at 100°C for 6 hours to obtain the catalyst of Example 1 of this invention.
[0037] The catalyst has an average pore size of 4 nm, a pore volume of 0.46 ml / g, and a surface area of 690 m². 2 / g, bulk density is 0.46g / ml.
[0038] Comparative Example 1
[0039] Referring to the content of classic research literature on two zinc active components, zinc acetate and zinc chloride were used as active components and charcoal powder was used as a carrier. To facilitate comparison with the present invention, the zinc component content was made similar to that of the present invention to obtain the catalyst of Comparative Example 1.
[0040] Comparative Example 2
[0041] Referring to the content of the patent literature on the preparation of catalysts for the classic acetylene process to produce vinyl acetate, zinc acetate was used as the active component, basic bismuth carbonate as the auxiliary agent, and commercial activated carbon (average pore size 2 nm, pore volume 0.69 ml / g, surface area 1200 m²) was used. 2 The catalyst (with a bulk density of 0.40 g / ml) is used as a carrier and requires harsh temperature conditions exceeding 900°C during its preparation. To facilitate comparison with the present invention, the zinc and bismuth components are made similar to those of the present invention, and a catalyst of Comparative Example 1 is prepared for performance comparison with the catalyst of the present invention.
[0042] Comparative Example 3
[0043] The preparation process and steps were the same as those in Comparative Example 2, but the industrial-grade charcoal powder (bulk density of 0.42 g / ml) from Example 1 was used instead of commercial activated carbon to prepare the catalyst for Comparative Example 3 for performance comparison.
[0044] Comparative Example 4
[0045] The preparation process and steps were the same as in Comparative Example 3, but the industrial-grade silicon carbide powder (with a surface area of 90 m²) from Example 1 was used. 2 The catalyst of Comparative Example 4 was prepared by replacing charcoal powder with a bulk density of 0.6 g / ml (g, bulk density of 0.6 g / ml) to facilitate comparison with Example 1, and was used to compare the performance of the catalyst of the Example.
[0046] Example 2
[0047] According to Zn α Bi β Si γ B λ Al μ P η O χ / C 100 The molar ratios constrained by α = 3.3, β = 0.0011, γ = 2.1, λ = 0.015, μ = 1.1, and η = 1.1 were used to uniformly mix 280-mesh industrial bamboo carbon powder, industrial silicon carbide powder, and industrial basic zinc carbonate powder. The mixture was then impregnated in equal volumes with a mixed solution prepared from chemically pure reagents bismuth nitrate and boric acid at 30°C. Dilute aluminum phosphate sol was added, and the mixture was kneaded in a small laboratory kneader for over 1 hour. The mixture was then pressed into a columnar carrier using a small hydraulic tablet press. It was dried in an oven at 110°C for 2 hours, and activated for 4 hours in a closed tube furnace in a laboratory with airtight conditions at 620°C by introducing water vapor containing 2.0 wt% hydrogen peroxide. Finally, it was saturated with a 20 wt% zinc acetate solution (pH 4.8) at 80°C for 5 hours, and dried at 95°C for 6 hours to obtain the catalyst of Example 2.
[0048] The catalyst has an average pore size of 3.9 nm, a pore volume of 0.41 ml / g, and a surface area of 640 m². 2 / g, bulk density is 0.43g / ml.
[0049] Example 3
[0050] According to Zn α Bi β Si γ B λ Al μ P η O χ / C 100The molar ratios constrained by α = 3.0, β = 0.0012, γ = 1.9, λ = 0.013, μ = 1.0, and η = 1.0 were used to uniformly mix 300-mesh industrial coal-based carbon powder, industrial silicon carbide powder, and industrial basic zinc carbonate powder. The mixture was then impregnated in equal volumes with a chemically pure bismuth nitrate and boric acid solution at 35°C. After kneading in a small laboratory mixer for over 1 hour, the mixture was dried and rolled into spherical carriers on a small roller mill. Dilute aluminum phosphate sol was added during the rolling process. The mixture was then dried in an oven at 105°C for 5 hours, activated for 6 hours in a closed tube furnace in a laboratory with airtight conditions by introducing water vapor containing 2.5 wt% hydrogen peroxide at 650°C. Finally, the mixture was saturated with a 30 wt% zinc acetate solution (pH 4.3) at 95°C for 8 hours, and then dried at 90°C for 6 hours to obtain the catalyst of Example 3.
[0051] The catalyst has an average pore size of 3.5 nm, a pore volume of 0.38 ml / g, and a surface area of 610 m². 2 / g, bulk density is 0.48g / ml.
[0052] Example 4
[0053] This embodiment illustrates the effectiveness of the invention through reaction evaluation, comparative examples, and comparative catalysts.
[0054] The catalyst performance was evaluated using a small-scale fixed-bed laboratory reactor with a catalyst loading volume of 25 mL. Industrial acetylene and industrial acetic acid were used as feedstocks. The composition of the feedstock gas was acetic acid:acetylene = 6 (molar ratio), and the volume hourly space velocity (VHSV) of the feedstock gas was 260 h⁻¹. 1 .
[0055] The reaction pressure during the evaluation was 0.1 MPa, the reaction temperature was 175 °C, and the reaction time was 150 hours.
[0056] The content of each component in the reaction product was analyzed by gas chromatography, and the catalyst evaluation results are listed in Table 1.
[0057] Table 1. Evaluation results of catalysts in Examples 1-3 and Comparative Examples 1-4:
[0058]
[0059] During the reaction time period, the activity decay rate of Examples 1-3 was 4%-6%; the activity decay rate of Comparative Example 2 was 8%; and the activity decay rates of Comparative Examples 1, 3, and 4 reached 14%-18%. Regarding the abrasion resistance of the catalyst, Examples 1-3 and the Comparative Examples achieved 94%-95%; Comparative Example 2 achieved 89%, while Comparative Examples 1 and 3 achieved 65% and 67%, respectively. Furthermore, in terms of byproducts and carbon deposits, Examples 1-3 showed a reduction of approximately 5%-10% compared to Comparative Examples 1-4.
[0060] This invention demonstrates that the catalyst prepared by the present invention exhibits better catalytic performance in the preparation of vinyl acetate via the acetylene process, possessing good vinyl acetate space-time yield, selectivity, and activity stability; it reduces harmful byproducts and carbon deposits, and has good mechanical strength, thereby effectively extending the catalyst's service life. This is of positive significance for improving stable production in industrial applications.
[0061] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for preparing a catalyst for preparing vinyl acetate, comprising: catalyst The composition satisfies the chemical formula: Zn α Bi β Si γ B λ Al μ P η O χ / C 100 In the formula, the atomic ratios are α = 1.4–3.8, β = 0.001–0.002, γ = 1.8–3.8, λ = 0.01–0.02, μ = 0.9–1.8, and η = 0.9–1.
8. χ is the number of oxygen atoms required to satisfy the valence of each element. After uniformly mixing 200–300 mesh carbon powder, silicon carbide powder, and basic zinc carbonate, an equal volume of a mixed solution of bismuth nitrate and boric acid is impregnated. Aluminum phosphate sol is added, and the mixture is kneaded for more than 40 minutes before molding. After drying, the final product is 300–700 mesh. o Activation is performed for 1–8 hours by passing water vapor containing 1 wt%–5 wt% hydrogen peroxide under temperature C; followed by saturation impregnation with zinc acetate solution for 80–100 hours. o The catalyst is obtained by drying at C for 1 to 6 hours; wherein the zinc element in the basic zinc carbonate accounts for 10 wt% to 40 wt% of the total zinc content of the catalyst.
2. The method for preparing a catalyst for preparing vinyl acetate according to claim 1, characterized in that: The toner is one or more of the following: wood-based toner, bamboo-based toner, coal-based toner, nutshell toner, petroleum coke toner, and resin-based toner.
3. The method for preparing a catalyst for preparing vinyl acetate according to claim 1, characterized in that the impregnation is carried out in equal volume with a mixed solution of bismuth nitrate and boric acid, wherein the mixed solution of bismuth nitrate and boric acid dissolved by nitric acid acidification is used to impregnate the powdered raw material in equal volume at 20-100°C.
4. The method for preparing a catalyst for preparing vinyl acetate according to claim 1, characterized in that: The aluminum phosphate sol is composed of a phosphoric acid solution and one or more of the following: aluminum oxide, aluminum hydroxide, boehmite, pseudoboehmite, aluminum isopropoxide, and aluminum isobutoxide, in an equimolar ratio of phosphorus and aluminum and a concentration of 40–100 g / L. o It is prepared by undergoing a dissolution reaction at temperature C.
5. The method for preparing a catalyst for preparing vinyl acetate according to claim 1, characterized in that the molding process for preparing columnar, block, sheet, and strip catalysts suitable for fixed-bed reaction processes is performed by hydraulic pressing or extrusion and pelletizing; and the preparation of spherical granular catalysts suitable for fluidized bed and fluidized bed reaction processes is performed by rolling in a catalyst rolling device.
6. The method for preparing a catalyst for preparing vinyl acetate according to claim 1, characterized in that: Saturated impregnation with zinc acetate solution involves placing the carrier composition in a zinc acetate solution of 20wt%–35wt% pH 4–6 for 50–100 minutes. o Immerse in C for 1 to 10 hours.
7. A catalyst for preparing vinyl acetate, characterized in that... Obtained according to the preparation method according to any one of claims 1 to 6.
8. The catalyst for preparing vinyl acetate according to claim 7, characterized in that the catalyst has an average pore size ≥ 2 nm, a pore volume of 0.4–0.6 ml / g, and a specific surface area of 600–900 m². 2 / g, bulk density is 0.3~0.6g / ml.
9. The use of the catalyst of claim 7 or 8 in the preparation of vinyl acetate, comprising reacting acetylene and acetic acid as raw materials with the catalyst of claim 7 or 8 to obtain vinyl acetate.
10. The application according to claim 9, characterized in that, The molar ratio of acetylene to acetic acid is 1:(5-8), and the feed volume hourly space velocity is 250-350 h⁻¹. -1 Reaction temperature 170-200°C o C. Pressure 0.1~0.14MPa.