A catalyst for the preparation of alpha-phenylethanol by acetophenone hydrogenation, its preparation method, and its applications.

Abstract

DEPCT64 The revealed method is for preparing the catalyst for the hydrogenation of the liquid state of... Acetophenone in the preparation of alpha-phenylethanol includes: the addition of water, a small amount of alcohol, and reducing agents. The dual surface tension and organic pore-forming agents in the reactor were followed by the addition of silica sol and stirring. Mix the ingredients thoroughly to prepare an aqueous spread of silica sol; prepare a precipitate of Al. Kaline and mixed solutions containing copper salts, zinc compounds, and minerals. Rare metals with compounds and alkali metal ores with compounds, precipitation addition of Al. The kaline and aqueous solutions of silica sol were then mixed together for diffusion, followed by... Sedimentation, maturation, filtration, leaching, drying, calcination, and molding to obtain the catalyst. The reaction involves using silica sol and silicate as silicon composite sources, with the addition of organic porosity agents. Prior to the precipitation and catalytic modification process using Zn, rare earth metals, and Al metal ores. Kaline, when used in the liquid hydrogenation of acetophenone to prepare alpha-phenylethanol. The catalyst in this invention is not only highly active and has good selectivity, but it is also improveable. Effective in its fluid resistance, the catalyst also exhibits strength. High height and good stability. -----------------------------------------------------------

Description

Catalysts, preparation methods and applications of hydrogenation of acetophenone to α-phenylethanol Technical Field

[0001] This invention belongs to the field of catalytic hydrogenation technology, specifically relating to a catalyst for the liquid-phase hydrogenation of acetophenone to prepare α-phenylethanol, its preparation method, and its application. Background Technology

[0002] α-Phenylacetyl alcohol is an important chemical intermediate widely used in pharmaceuticals, fragrance manufacturing, cosmetics, food, and fine chemicals industries. Existing methods for synthesizing α-phenylethanol mainly include microbial fermentation and acetophenone reduction / catalytic hydrogenation.

[0003] Microbial fermentation typically uses phenylalanine and fluorophenylalanine as raw materials to produce α-phenylethanol through microbial fermentation. However, the raw materials used in this method are expensive, resulting in high production costs. Currently, the industrial production of α-phenylethanol commonly employs the acetophenone hydrogenation method. This method offers advantages such as low production cost, fewer byproducts, high product yield, and high product purity, making it suitable for large-scale production of α-phenylethanol.

[0004] Catalysts for the hydrogenation of acetophenone mainly include platinum-palladium noble metal catalysts, nickel-based catalysts, and copper-based catalysts. Noble metal catalysts and nickel-based catalysts are expensive, prone to aromatic ring saturation and phenylethanol hydrogenolysis, and exhibit poor selectivity for α-phenylethanol. Compared with noble metal catalysts and nickel-based catalysts, copper-based catalysts offer advantages such as high activity and selectivity, and low cost in the hydrogenation reaction of acetophenone.

[0005] Catalysts for the hydrogenation of acetophenone to α-phenylethanol have been reported in many patents. CN1557545A prepared a Ni-Sn-B / SiO2 catalyst by impregnation, and after low-temperature calcination, it was reduced by KBH4 as a reducing agent. During the catalytic reaction, the selectivity of phenylethanol reached a maximum of 97.5%, but the interaction between its active component Ni and the support SiO2 was weak and it was easy to be lost.

[0006] US4996374 discloses a Pd-C catalyst, but its catalyst stability is poor, requiring continuous increases in reaction temperature when used. CN1315226A discloses a reduction-treated copper-based catalyst and a method for preparing α-phenylethanol using it, but it requires liquid-phase reduction to improve catalyst stability, resulting in a complex and costly process. CN1911883A discloses a method for preparing α-phenylethanol using Raney nickel as a catalyst, but its acetophenone hydrogenation product contains a large number of aromatic ring hydrogenation products, α-cyclohexylethanol, indicating low selectivity for α-phenylethanol.

[0007] EP0714877B1 significantly suppressed the formation of the byproduct ethylbenzene by modifying copper-silicon catalysts with alkali metal and / or alkaline earth metal carbonates. However, the addition of silicon sources in the form of fumed silica or diatomaceous earth is not conducive to enhancing the interaction between the active components and the support, which is detrimental to the catalyst strength.

[0008] In catalyst WO2016198379, some of the silicon source is added during extrusion in the form of silica sol, which cannot effectively disperse the active component, copper. None of the aforementioned publicly available reports mention the dispersing or stabilizing effects of additives on the active component, nor the mechanical stability and post-use strength of the shaped catalyst.

[0009] Because the hydrogenation of acetophenone readily involves the hydrogenolysis / dehydration of α-phenylethanol to produce ethylbenzene / styrene, both the hydrogenolysis and dehydration rates increase rapidly with increasing reaction temperature. To improve the selectivity of the acetophenone hydrogenation process, liquid-phase hydrogenation is typically carried out at lower temperatures. Therefore, the acetophenone hydrogenation catalyst is required to possess good resistance to liquid conditions, weak acidity, and good low-temperature activity.

[0010] In the prior art, copper-based catalysts used in liquid-phase hydrogenation reactions are not only subject to various internal or external forces during storage / loading / reduction / reaction processes, but also suffer from a significant decrease in actual catalyst strength due to liquid immersion, swelling, and other reasons. This leads to the catalyst being prone to breakage and pulverization in the liquid-phase hydrogenation system, threatening the stable operation of industrial plants and affecting catalyst lifespan.

[0011] Currently, copper-based catalysts for the hydrogenation of acetophenone to α-phenylethanol prepared by precipitation methods typically suffer from problems such as low dispersion of the active component copper, strong catalyst acidity, and weak interaction between the support and the active component. These issues lead to low acetophenone conversion, high amounts of byproducts such as ethylbenzene, poor phenylethanol selectivity, and weak catalyst strength. Therefore, improving the dispersion of the active component copper, enhancing the catalyst's mass transfer performance, suppressing catalyst acidity, and improving the catalyst's resistance to liquid runoff are of great significance for preparing highly active, highly selective, and highly liquid-resistant acetophenone hydrogenation catalysts.

[0012] Summary of the Invention

[0013] The purpose of this invention is to provide a method for preparing a catalyst for the liquid-phase hydrogenation of acetophenone to α-phenylethanol, and the catalyst obtained therefrom. The catalyst prepared by this method significantly suppresses side reactions such as hydrogenolysis, and has high activity and good selectivity. At the same time, the catalyst has excellent resistance to liquid and maintains high strength after undergoing reduction and liquid-phase hydrogenation reactions.

[0014] To achieve one aspect of the above objectives, the present invention adopts the following technical solution:

[0015] A method for preparing a hydrogenation catalyst includes the following steps:

[0016] (1) Add deionized water, small molecule alcohol, Gemini surfactant and organic pore-forming agent to the reaction vessel, then add silica sol and stir evenly to prepare a silica sol aqueous dispersion containing small molecule alcohol, Gemini surfactant and organic pore-forming agent.

[0017] (2) Dissolve copper-containing salt, zinc-containing salt, rare earth metal-containing salt and alkaline earth metal-containing salt in water to prepare a mixed salt solution; dissolve silicon-containing alkaline precipitant and silicon-free alkaline precipitant in water to prepare an alkaline precipitant aqueous solution; add the mixed salt solution and the alkaline precipitant aqueous solution together to the silica sol aqueous dispersion for reaction, control the pH of the reaction system to be 5.0-9.0 during the reaction, and then age to obtain a slurry;

[0018] (3) The slurry is filtered and washed to obtain a filter cake;

[0019] (4) The filter cake is dried, calcined and shaped to obtain the catalyst.

[0020] In this invention, step (1) involves uniformly mixing deionized water, a small molecule alcohol, a Gemini surfactant, an organic pore-forming agent, and silica sol to prepare an aqueous dispersion of silica sol containing the small molecule alcohol, the Gemini surfactant, and the organic pore-forming agent. The organic pore-forming agent is preferably selected from one or more of PMMA, microcrystalline cellulose, and methylcellulose. Adding the organic pore-forming agent during the preparation process reduces the diffusion resistance within the raw materials and products, effectively improving activity and selectivity.

[0021] According to the preparation method of the present invention, preferably, the particle size of the organic pore-forming agent is <100μm, more preferably 1-80μm, and even more preferably 3-30μm, such as 5, 10, 15, 20 or 25μm; keeping the particle size of the organic pore-forming agent within a suitable range helps to further improve the diffusion and mass transfer effect of raw materials and products; if the particle size is too large, it is not conducive to effectively improving the mass transfer performance, and if the particle size is too small, it is not conducive to improving the mass transfer effect.

[0022] According to the preparation method of the present invention, preferably, the amount of the organic pore-forming agent accounts for 0.5-20 wt% of the total weight of the catalyst, more preferably 1-10 wt%, and even more preferably 2-5 wt%. Maintaining the amount of organic pore-forming agent added within a suitable range helps to minimize the impact on catalyst strength while achieving good mass transfer performance; too little organic pore-forming agent added is not conducive to improving the mass transfer performance of the catalyst; too much pore-forming agent added will significantly affect the mechanical strength of the catalyst.

[0023] In this invention, the total silicon content in the catalyst is introduced jointly by the silica sol and the silicon-containing alkaline precipitant. Preferably, the silicon introduced by the silica sol accounts for 30-70 wt% of the total silicon content in the catalyst, more preferably 35-65 wt%, and even more preferably 40-60 wt%, such as 50 wt%. Studies have found that using a highly dispersed silica sol and a silicon-containing alkaline precipitant as a composite silicon source results in a catalyst with not only higher activity but also better strength compared to using a single silicon source. Preferably, the silica sol is an alkaline silica sol with a pH value of 8.0-10.0.

[0024] In this invention, the small molecule alcohol refers to an alcohol with a molecular weight not greater than 400, such as a small molecule saturated monohydric alcohol with a molecular weight not greater than 400. According to the preparation method of this invention, preferably, the mass ratio of the small molecule alcohol to deionized water is 1:20 to 1:10, such as 1:18, 1:15 or 1:12; more preferably, the small molecule alcohol in step (1) is one or more of methanol, ethanol, propanol and butanol.

[0025] In this invention, the Gemini surfactant used is well known in the art. It is a novel surfactant in which two or more traditional surfactant molecules are linked together at or near the hydrophilic group via a linker group. A Gemini surfactant has at least two hydrophobic hydrocarbon chains, two polar head groups, and one linker group; the linker group can be long or short, rigid or flexible, polar or nonpolar; based on whether the polar head group is cationic, anionic, or nonionic, it can be classified as anionic, cationic, nonionic, and amphoteric Gemini surfactants; based on the structure of the bipolar head group and hydrophobic chain, it can be classified as symmetrical and asymmetrical Gemini surfactants. According to the preparation method of this invention, preferably, the amount of Gemini surfactant added in step (1) is 0.1%-1% of the total mass of deionized water and small molecule organic alcohol. There is no particular limitation on the specific type of Gemini surfactant used in this invention. In some preferred embodiments, the Gemini surfactant has a structure of C m-n-m The bromide; wherein m is preferably 12, 14, or 16, and n is preferably 2, 3, 6, 8, or 10. All Gemini surfactants used can be commercially available reagents, such as those with the structure C from Henan Daochun Chemical Co., Ltd. 16-6-16 C 12-10-12 C 14-8-14 C 12-8-12 C 14-10-14 Gemini surfactants, or for example, those with the structure C 16-2-16 C 12-3-12 C 14-2-14 C 12-3-12 Gemini surfactants, etc.

[0026] Studies have found that in this invention, the addition of Gemini surfactant and small molecule alcohol to modify silica sol improves the dispersibility of silica sol, resulting in higher dispersibility of the active component copper and improved catalyst activity. At the same time, the addition of Gemini surfactant can further cooperate with organic pore-forming agents to promote the formation of mesoporous structures and improve the mass transfer performance of the catalyst.

[0027] In this invention, the precipitant refers to a substance that can react with metal cations in a mixed salt solution to form a corresponding precipitate. Step (2) involves preparing a mixed salt solution and an alkaline precipitant aqueous solution, and adding both together to the silica sol aqueous dispersion so that the mixed salt forms a corresponding precipitate in the silica sol aqueous dispersion containing the organic pore-forming agent. Studies have found that pre-dispersing the pore-forming agent in the silica sol and then forming a precipitate within it facilitates better dispersion of the pore-forming agent in the precipitate.

[0028] According to the preparation method of the present invention, preferably, the silicon-containing alkaline precipitant is a water-soluble silicate, preferably one or two of sodium silicate and potassium silicate; the silicon-free alkaline precipitant is one or more of potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate, urea and ammonia water.

[0029] Those skilled in the art will understand that, in this invention, each metal salt forming the mixed salt solution is a soluble salt of the corresponding metal. According to the preparation method of this invention, preferably, the copper-containing compound salt is one or more of copper nitrate, copper chloride, and copper acetate; the zinc-containing compound salt is one or more of zinc nitrate, zinc chloride, and zinc acetate; the rare earth metal compound salt is one or more of nitrate, chloride, and acetate; and the alkaline earth metal compound salt is one or more of nitrate, chloride, and acetate.

[0030] In this invention, Zn and Cu can form a solid solution during the preparation process, which can effectively promote the dispersion of copper, the active component in the catalyst. The addition of rare earth metals also improves the dispersion of copper and the stability of the catalyst. Preferably, the rare earth metals are lanthanum and / or cerium. The addition of alkaline earth metals significantly suppresses the acidity of the catalyst, effectively suppresses the formation of ethylbenzene, and improves the reaction selectivity. Preferably, the alkaline earth metals are one or more of magnesium, calcium, and barium. Those skilled in the art will understand that the amount of each metal component added is sufficient to achieve the target content of the oxide content of each metal component in the prepared catalyst. In some preferred embodiments, the catalyst prepared contains, by total weight of the catalyst, 20-65 wt% copper oxide, 15-50 wt% silicon oxide, 2-25 wt% zinc oxide, 0.1-5 wt% rare earth metal oxide, and 0.5-15 wt% alkaline earth metal oxide; more preferably, it contains 40-63 wt% copper oxide, 20-45 wt% silicon oxide, 5-20 wt% zinc oxide, 0.2-3 wt% rare earth metal oxide, and 0.5-10 wt% alkaline earth metal oxide; even more preferably, it contains 42-60 wt% copper oxide, 22-40 wt% silicon oxide, 10-18 wt% zinc oxide, 0.5-2 wt% rare earth metal oxide, and 1-5 wt% alkaline earth metal oxide.

[0031] In step (2), the pH of the reaction system is controlled to be 5.0-9.0, such as 5.5-8.0, during the reaction process, followed by aging to obtain a slurry; preferably, the temperature of the reaction process and the aging process is controlled to be 60-90℃, such as 70 or 80℃. The specific reaction process for forming a precipitate and the precipitate aging process are well known in the art. For example, the reaction process for forming a precipitate can be completed within 1-3 hours, followed by aging for another 1-3 hours.

[0032] In this invention, step (3) involves filtering and washing the slurry to obtain a filter cake. The filtering and washing processes can be those commonly used in the art, and are also common catalyst treatment processes. In step (4), drying, calcining, and shaping the filter cake are also common catalyst treatment processes. In one embodiment, the calcination temperature is 300-700℃, such as 400, 500, or 600℃; the calcination time is 4-12 hours, such as 6, 8, or 10 hours; and the shaping can be tableting, etc.

[0033] In one aspect of achieving the above objectives, the present invention also provides a catalyst prepared according to the above preparation method.

[0034] According to the preparation method of the present invention, preferably, the catalyst composition, based on the total weight of the catalyst, comprises: 20-65 wt% copper oxide, 15-50 wt% silicon oxide, 2-25 wt% zinc oxide, 0.1-5 wt% rare earth metal oxide, and 0.5-15 wt% alkaline earth metal oxide; more preferably, it comprises 40-63 wt% copper oxide, 20-45 wt% silicon oxide, 5-20 wt% zinc oxide, 0.2-3 wt% rare earth metal oxide, and 0.5-10 wt% alkaline earth metal oxide; even more preferably, it comprises 42-60 wt% copper oxide, for example 50 wt%, 22-40 wt% silicon oxide, for example 30 wt%, 10-18 wt% zinc oxide, for example 15 wt%, 0.5-2 wt% rare earth metal oxide, for example 1 wt% or 1.5 wt%, and 1-5 wt% alkaline earth metal oxide, for example 2 wt% or 3 wt%.

[0035] The present invention also provides the application of the above-mentioned catalyst in the liquid-phase hydrogenation of acetophenone to prepare α-phenylethanol.

[0036] Those skilled in the art will understand that the catalyst needs to be reduced and activated to acquire the corresponding catalytic activity for the hydrogenation of acetophenone to prepare α-phenylethanol.

[0037] In a preferred embodiment, the method for reducing and activating the catalyst according to the present invention includes: maintaining the volume hourly space velocity (VHSV) of the mixed gas of hydrogen and nitrogen at 300-1000 h⁻¹. -1 Preferably, the reactor temperature is first raised to 160-180℃ and held at that temperature for 1-2 hours to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing no more than 10v% H2 (e.g., (5v% ± 2v%)) H2 is introduced to pre-reduce the catalyst for at least 0.5 hours (e.g., 1 hour, 1.5 hours, or 2 hours). After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased (e.g., gradually increased to 10v%, 20v%, 50v%, or 100v%), while controlling the catalyst bed hot spot temperature to not exceed 220℃. Finally, the temperature is raised to 200-220℃ and reduced in a pure hydrogen atmosphere for 2-5 hours (e.g., 3 or 4 hours) to obtain an activated catalyst.

[0038] In a preferred embodiment, when the obtained reduced catalyst is used for the hydrogenation of acetophenone to prepare α-phenylethanol, the reaction pressure is 2.5-5 MPa (relative pressure), for example 3-5 MPa (relative pressure), the reaction temperature is 70-140°C, for example 120-140°C, the H2 / HPA (acetophenone) molar ratio is 2-20:1, for example 5:1, 10:1 or 15:1, and the catalyst dosage is 0.2-0.6 g. HPA ·g cat -1 ·h -1 .

[0039] Compared with the prior art, the catalyst prepared by the present invention has a uniform distribution of active components, high copper dispersion, unobstructed catalyst channels, weak acidity, and excellent activity, selectivity and mechanical strength when used in the liquid-phase hydrogenation of acetophenone to prepare α-phenylethanol.

[0040] In addition, the catalyst prepared by the method of the present invention can effectively improve the mass transfer performance of the catalyst by adding a pore-forming agent, which is beneficial to improving the catalyst activity; the use of a composite silicon source can obtain a liquid-phase hydrogenation catalyst with high activity and good mechanical strength; the addition of Zn, rare earth and alkaline earth metals in the catalyst composition is beneficial to improve the dispersion of the active component Cu, suppress the acidity of the catalyst, and improve the catalyst activity and selectivity. Detailed Implementation

[0041] The method of the present invention will be described in detail below with reference to embodiments, but is not limited to the embodiments.

[0042] The lateral compressive strength of the catalyst was measured using a particle strength tester. After use, the catalyst was soaked in ethylbenzene for protection to prevent oxidation. The lateral compressive strength of 40 catalyst particles after reaction was measured and the average value was taken.

[0043] The copper ion content in the hydrogenation solution was determined using inductively coupled plasma atomic emission spectrometry (ICP).

[0044] Unless otherwise specified, all reagents used below are of analytical grade and are commercially available products.

[0045] Example 1

[0046] 200g water, 10g methanol, 4.0g PMMA with a particle size of 10-30μm, and 2.0g of C44-4 ... 16-6-16The Gemini surfactant (purchased from Henan Daochun Chemical Co., Ltd.) was mixed evenly, and then 120.0 g of 30 wt% alkaline silica sol with a pH of 9 was added and stirred evenly. 332.2 g of copper nitrate, 73.1 g of zinc nitrate, 21.3 g of lanthanum nitrate, and 12.7 g of magnesium nitrate were dissolved in 1.5 kg of water to prepare a mixed salt solution. 113.5 g of sodium silicate and 142.5 g of sodium carbonate were dissolved in water to prepare a precipitant solution. Both solutions were heated to 70°C. Using a co-precipitation method, both solutions were simultaneously added dropwise to the reaction vessel, controlling the temperature inside the vessel at 70°C, the system pH at 7.0, and the reaction time at 1 h. After both solutions were added dropwise, the pH of the system was adjusted to >7.5 using a 10wt% sodium carbonate solution. The mixture was aged at 75℃ for 3 hours, then filtered, washed, and the filter cake was dried at 110℃ for 12 hours and calcined at 350℃ for 8 hours. Then, 1.5wt% of graphite powder was mixed in and pressed into 3*3mm cylindrical catalysts (3mm in diameter and 3mm in height), yielding approximately 200g of catalyst A. Based on oxides, this catalyst contains 55% copper oxide, 30% silicon oxide, 10% zinc oxide, 1% lanthanum oxide, and 4% magnesium oxide.

[0047] Catalyst reduction: Catalyst A was loaded into a fixed-bed hydrogenation reactor with a loading volume of 100 ml. Before use, the catalyst was reduced under a nitrogen and hydrogen mixture, maintaining a gas hourly space velocity (VHSV) of 300 h⁻¹ during the reduction process. -1 First, the reactor temperature is raised to 160℃ and held at that temperature for 2 hours to remove the physical water adsorbed on the catalyst. Then, a mixture of hydrogen and nitrogen containing 5% H2 by volume is introduced for pre-reduction for 1 hour. After that, the proportion of hydrogen in the hydrogen and nitrogen mixture is gradually increased to 10%, 20%, 50%, and 100%, while controlling the hot spot temperature of the catalyst bed to not exceed 220℃. Finally, the temperature is raised to 220℃ and reduced for 3 hours in a pure hydrogen atmosphere.

[0048] The hydrogenation feedstock consisted of a 15 wt% acetophenone ethylbenzene solution, and the reaction was carried out at a pressure of 2.5 MPa, a temperature of 70 °C, an H₂ / acetophenone molar ratio of 5:1, and a catalyst loading of 0.3 g. HPA / g cat The reaction was carried out under the condition of / h. The hydrogenation solution was sampled every 24 hours, and the copper ion content in the hydrogenation solution was measured. After 100 hours of reaction, the catalyst was removed from the reactor and sieved using a 2mm stainless steel sieve. The proportion of catalyst particles <1mm in diameter to the total catalyst mass was calculated as the catalyst breakage rate. The lateral pressure strength of the catalyst after the reaction was measured using a particle strength tester. The hydrogenation reaction results and the average copper ion content in the hydrogenation solution are shown in Table 1. The comparison of the catalyst before and after the reaction is shown in Table 2.

[0049] Example 2

[0050] 200g water, 15g ethanol, 6.0g microcrystalline cellulose with a particle size of 5-30μm, and 0.5g of C34-4 ... 12-10-12 Gemini surfactant (purchased from Henan Daochun Chemical Co., Ltd.) was added, followed by 61.3g of 30wt% silica sol, and stirred until homogeneous. A mixed salt solution was prepared by dissolving 362.4g of copper nitrate, 87.7g of zinc nitrate, 22.7g of cerium nitrate, and 4.21g of calcium nitrate in 1.45kg of water. A precipitant solution was prepared by dissolving 130.5g of sodium silicate and 149.0g of sodium carbonate in water. Both solutions were heated to 75℃. A co-precipitation method was used, with both solutions simultaneously added dropwise to the reaction vessel. The temperature inside the vessel was controlled at 75℃, the pH at 7.2, and the reaction time at 1 hour. After both solutions were added dropwise, the pH of the system was adjusted to >7.5 using a 10wt% sodium carbonate solution. The mixture was aged at 80℃ for 3 hours, then filtered, washed, and the filter cake was dried at 100℃ for 24 hours and calcined at 400℃ for 12 hours. Afterward, 1.0wt% of graphite powder was mixed in and pressed into 3*3mm cylindrical catalysts (3mm in diameter and 3mm in height), yielding approximately 200g of catalyst B. Based on oxides, this catalyst contains 60% copper oxide, 23% silicon oxide, 12% zinc oxide, 0.5% cerium oxide, and 4.5% calcium oxide.

[0051] The remaining conditions are the same as in Example 1.

[0052] Example 3

[0053] 200g water, 10g propanol, 10.0g methylcellulose with a particle size of 5-20μm, and 1.0g of C34-4 ... 14-8-14 The Gemini surfactant (purchased from Henan Daochun Chemical Co., Ltd.) was mixed evenly, and then 116.7g of 30wt% silica sol was added and stirred evenly. 302g of copper nitrate, 87.7g of zinc nitrate, 5.0g of cerium nitrate, and 6.8g of barium nitrate were dissolved in 1.37kg of water to prepare a mixed salt solution. 198.7g of sodium silicate and 93.6g of sodium carbonate were dissolved in water to prepare a precipitant solution. Both solutions were heated to 80℃. Using a co-precipitation method, both solutions were simultaneously added dropwise to the reaction vessel, controlling the temperature inside the vessel at 80℃, the pH of the system at 8.0, and the reaction time at 1h. After the two solutions were added dropwise, the pH of the system was adjusted to >7.3 using a 10wt% sodium carbonate solution. The mixture was aged at 85℃ for 3 hours, then filtered, washed, and the filter cake was dried at 120℃ for 12 hours and calcined at 550℃ for 8 hours. Then, 1.2wt% of graphite powder was mixed in and pressed into 3*3mm cylindrical catalysts (3mm in diameter and 3mm in height), yielding approximately 200g of catalyst C. Based on oxides, this catalyst contains 50% copper oxide, 35% silicon oxide, 12% zinc oxide, 1% cerium oxide, and 2% barium oxide.

[0054] The remaining conditions are the same as in Example 1.

[0055] Example 4

[0056] 200g water, 20g butanol, 6.0g microcrystalline cellulose with a particle size of 3-20μm, and 0.2g of the following compound were added to the reactor: 12-8-12 The Gemini surfactant (purchased from Henan Daochun Chemical Co., Ltd.) was mixed evenly, and then 105g of 30wt% silica sol was added and stirred evenly. 271.8g of copper nitrate, 109.7g of zinc nitrate, 10.6g of lanthanum nitrate, and 25.3g of calcium nitrate were dissolved in 1.39kg of water to prepare a mixed salt solution. 182.1g of sodium silicate and 105.6g of sodium carbonate were dissolved in water to prepare a precipitant solution. Both solutions were heated to 60℃. Using a co-precipitation method, both solutions were simultaneously added dropwise to the reaction vessel, controlling the temperature inside the vessel at 60℃, the pH of the system at 6.5, and the reaction time at 1h. After both solutions were added dropwise, the pH of the system was adjusted to >7.2 using a 10wt% sodium carbonate solution. The mixture was aged at 70℃ for 3 hours, then filtered, washed, and the filter cake was dried at 100℃ for 12 hours and calcined at 450℃ for 6 hours. Then, 1.0wt% of graphite powder was mixed in and pressed into 3*3mm cylindrical catalysts (3mm in diameter and 3mm in height), yielding approximately 200g of catalyst D. Based on oxides, this catalyst contains 45% copper oxide, 35% silicon oxide, 15% zinc oxide, 2% lanthanum oxide, and 3% calcium oxide.

[0057] The remaining conditions are the same as in Example 1.

[0058] Example 5

[0059] 200g water, 20g ethanol, 10.0g PMMA with a particle size of 10-30μm, and 1.5g of the compound with the structural formula C were added to the reactor. 14-10-14The Gemini surfactant (purchased from Henan Daochun Chemical Co., Ltd.) was mixed evenly, and then 177.3g of 30wt% silica sol was added and stirred evenly. 24.6g of copper nitrate, 131.6g of zinc nitrate, 7.97g of lanthanum nitrate, and 31.8g of magnesium nitrate were dissolved in 1.65kg of water to prepare a mixed salt solution. 107.8g of sodium silicate and 128.7g of sodium carbonate were dissolved in water to prepare a precipitant solution. Both solutions were heated to 85℃. Using a co-precipitation method, both solutions were simultaneously added dropwise to the reaction vessel, controlling the temperature inside the vessel at 85℃, the pH of the system at 7.0, and the reaction time at 1h. After the two solutions were added dropwise, the pH of the system was adjusted to >7.5 using a 10wt% sodium carbonate solution. The mixture was aged at 90℃ for 3 hours, then filtered, washed, and the filter cake was dried at 110℃ for 12 hours and calcined at 650℃ for 4 hours. Then, 1.2wt% of graphite powder was mixed in and pressed into 3*3mm cylindrical catalysts (3mm in diameter and 3mm in height), yielding approximately 200g of catalyst E. Based on oxides, this catalyst contains 40% copper oxide, 38% silicon oxide, 18% zinc oxide, 1.5% lanthanum oxide, and 2.5% calcium oxide.

[0060] The remaining conditions are the same as in Example 1.

[0061] Example 6

[0062] 200g water, 15g methanol, 4.0g methylcellulose with a particle size of 3-30μm, and 0.8g of the compound with the structural formula C were added to the reactor. 12-8-12 The Gemini surfactant (purchased from Henan Daochun Chemical Co., Ltd.) was mixed evenly, and then 117.3g of 30wt% silica sol was added and stirred evenly. A mixed salt solution was prepared by dissolving 314.1g of copper nitrate, 73.1g of zinc nitrate, 5.0g of cerium nitrate, and 17.0g of barium nitrate in 1.5kg of water. A precipitant solution was prepared by dissolving 136.2g of sodium silicate and 121.2g of sodium carbonate in water. Both solutions were heated to 65℃. Using a co-precipitation method, both solutions were simultaneously added dropwise to the reaction vessel, controlling the temperature inside the vessel at 65℃, the pH of the system at 6.8, and the reaction time at 1h. After both solutions were added dropwise, the pH of the system was adjusted to >7.5 using a 10wt% sodium carbonate solution. The mixture was aged at 70℃ for 3 hours, then filtered, washed, and the filter cake was dried at 110℃ for 24 hours and calcined at 450℃ for 8 hours. Afterward, 1.5wt% of graphite powder was mixed in and pressed into 3*3mm cylindrical catalysts (3mm in diameter and 3mm in height), yielding approximately 200g of catalyst F. Based on oxides, this catalyst contains 52% copper oxide, 32% silicon oxide, 10% zinc oxide, 1% cerium oxide, and 5% barium oxide.

[0063] The remaining conditions are the same as in Example 1.

[0064] Examples 7-12

[0065] Example 7 is basically the same as Example 1, except that the Gemini surfactant used has a C3 structure. 16-2-16 Gemini surfactant ethylene bis(hexadecyl dimethyl ammonium bromide) (purchased from Henan Daochun Chemical Co., Ltd.)

[0066] Example 8 is basically the same as Example 2, except that the Gemini surfactant used has a C360-400-400-400-400-400-400-400-400-400-400-400-400-400-5 ...600-5 12-3-12 Gemini surfactant propylene bis(dodecyl dimethyl ammonium bromide) (purchased from Henan Daochun Chemical Co., Ltd.)

[0067] Example 9 is basically the same as Example 3, except that the Gemini surfactant used has a C360-400-400-400-400-400-400-400-400-400-400-400-400-5 ...600-500-6 14-2-14 Gemini surfactant ethylene bis(tetradecyl dimethyl ammonium bromide) (purchased from Henan Daochun Chemical Co., Ltd.)

[0068] Example 10 is basically the same as Example 4, except that the Gemini surfactant used has the structural formula C 12-3-12 Gemini surfactant propylene bis(dodecyl dimethyl ammonium bromide) (purchased from Henan Daochun Chemical Co., Ltd.)

[0069] Example 11 is basically the same as Example 5, except that the Gemini surfactant used has the structural formula C 14-2-14 Gemini surfactant ethylene bis(tetradecyl dimethyl ammonium bromide) (purchased from Henan Daochun Chemical Co., Ltd.)

[0070] Example 12 is basically the same as Example 6, except that the Gemini surfactant used has the structural formula C 12-3-12 Gemini surfactant propylene bis(dodecyl dimethyl ammonium bromide) (purchased from Henan Daochun Chemical Co., Ltd.)

[0071] Comparative Example 1

[0072] 200g of water and 60g of fumed silica were added to the reactor and stirred until homogeneous. 332.2g of copper nitrate was dissolved in 1.5kg of water to prepare a mixed salt solution. A 10wt% sodium carbonate aqueous solution was prepared as a precipitant. Both solutions were heated to 65℃. Using a co-precipitation method, both solutions were simultaneously added dropwise to the reactor, controlling the temperature inside the reactor at 65℃, the system pH at 7.0, and the reaction time at 1h. After the solutions were added, the mixture was aged at 70℃ for 3h, then filtered, washed, and the filter cake was dried at 110℃ for 24h and calcined at 450℃ for 8h. Then, 1.2wt% of graphite powder was mixed in and pressed into 3*3mm cylindrical catalysts (3mm in diameter and 3mm in height), yielding approximately 170g of catalyst G.

[0073] The remaining conditions are the same as in Example 1.

[0074] Comparative Example 2

[0075] 332.2g of copper nitrate and 292.4g of zinc nitrate were dissolved in 1.65kg of water to prepare a mixed salt solution. Sodium carbonate was dissolved in water to prepare a 10wt% sodium carbonate solution. Both solutions were heated to 65℃. Using a co-precipitation method, both solutions were simultaneously added dropwise to the reactor. The temperature inside the reactor was controlled at 65℃ and the pH of the precipitation was 7.0. After precipitation, the mixture was aged at 70℃ for 3 hours. 10.0g of alumina was added to the filtered and washed filter cake, and the cake was dried at 110℃ for 12 hours and calcined at 350℃ for 4 hours. Then, 1.5wt% of graphite powder was mixed in and the mixture was pressed into 3*3mm cylindrical catalysts (3mm in diameter and 3mm in height), yielding approximately 190g of catalyst H.

[0076] The remaining conditions are the same as in Example 1.

[0077] Comparative Example 3

[0078] The catalyst preparation process did not involve the addition of small molecule alcohols and Gemini surfactants, but was otherwise the same as in Example 1, yielding approximately 200g of catalyst I.

[0079] The remaining conditions are the same as in Example 1.

[0080] Comparative Example 4

[0081] The organic pore-forming agent PMMA was not added during the catalyst preparation process, and the rest was the same as in Example 1. Approximately 200g of catalyst J was prepared.

[0082] The remaining conditions are the same as in Example 1.

[0083] The hydrogenation reaction results of the catalysts in Examples 1-6 and the average copper ion content in the hydrogenation solution are shown in Table 1. The comparison of the catalysts before and after the reaction is shown in Table 2. The experimental results of the catalysts prepared in Examples 7-12 are basically the same as the corresponding experimental results of Examples 1-6. The conversion rate of acetophenone is above 98.1%, the selectivity of α-phenylethanol is above 99.3%, and the detection result of the average copper ion content in the hydrogenation solution is "not detected" in all examples. The side pressure strength of the catalysts before the reaction is above 188 N / particle, and the side pressure strength of the catalysts after the reaction is above 48.5 N / particle. The catalysts after the reaction are all in an intact state, without pulverization or breakage.

[0084] Table 1 Results of hydrogenation reaction and average copper ion content in hydrogenation solution

[0085]

[0086]

[0087] Note: "Not detected" indicates that the average copper ion content in the hydrogenation solution is <0.1 μg / g.

[0088] Table 2 Comparison of catalysts before and after the reaction

[0089]

[0090] *N / piece is a unit of catalyst strength, which is the force exerted when one catalyst piece breaks.

[0091] As shown in Tables 1 and 2, when using catalysts A to F, as well as catalysts I and J, no copper was detected in the hydrogenation solution, and the catalysts remained intact after the reaction with a lateral pressure strength exceeding 30 N / particle. In contrast, the catalysts described in Comparative Examples 1 and 2 showed severe catalyst breakage and low lateral pressure strength after the reaction. Catalyst H was pulverized to the point that its lateral pressure strength could not be measured. ICP analysis revealed a high copper content in the hydrogenation solution, indicating significant catalyst loss. Furthermore, catalysts A to F exhibited high activity and effectively suppressed side reactions such as hydrogenolysis to ethylbenzene and dehydration to styrene, while the catalysts described in Comparative Examples 1 to 4 not only had low activity but also poor selectivity.

Claims

DEPCT641. Preparation method for hydrogenation catalyst which consists of the following steps: (1) Adding water, small molecular alcohol, dual surfactant and organic porosity agent to the reactor followed by the addition of silica sol and stirring the mixture thoroughly to prepare an aqueous dispersion of silica sol containing small molecular alcohol, dual surfactant and organic porosity agent; (2) Dissolving compound copper salts, compound zinc salts, compound rare earth metal salts and compound alkaline metal salts in water to prepare mixed salt solutions; dissolving alkaline precipitated silicon and non-alkaline precipitated silicon in water to prepare an aqueous solution of alkaline precipitate; adding the mixed salt solution and the aqueous solution of alkaline precipitate together with the aqueous dispersion of silica sol for the reaction, with the pH of the reaction system during the reaction process being controlled at 5.0-9.0 and followed by curing to obtain a slurry solution; (3) filtration and leaching of the slurry solution to obtain filter press sludge; (4) drying, calcination and shaping of the filter press sludge to obtain the catalyst.

2. Preparation method according to claim 1 in which the total amount of silicon in the catalyst is introduced by silica sol and alkaline precipitated silicon and the amount of silicon introduced by silica sol is proportional to 30-70% by weight, preferably 35-65% by weight and preferably more than 40-60% by weight of the total amount of silicon. For silicon in catalysts, it is advisable to select alkaline silica sol, with a pH of 8.0-10.

03. The preparation method according to claims 1 or 2, where alkaline precipitated silicon is a water-soluble silicate, should ideally be one or two of sodium silicate and potassium silicate; and non-silicon alkaline precipitates are one or more of potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, ammonium carbonate, ammonium bicarbonate, carbamide, and ammonia water.Preparation methods under one of the claims 1-3 where the particle size of the organic pore-forming agent is <100 µm, preferably 1-80 µm, or greater than 3-30 µm; where the organic pore-forming agent is one or more of PMMA, microcrystalline cellulose, and methyl cellulose; 5. Preparation methods under one of the claims 1-4 where the amount of organic pore-forming agent is 0.5-20% by weight, or preferably 1-10% by weight.

6. In one of the preparation methods of claims 1-5, where in step (1) the mass ratio of small molecular alcohol to water is 1:20 to 1:10, the small molecular alcohol chosen in step (1) is one or more of methanol, ethanol, propanol and butanol.

7. In one of the preparation methods of claims 1-6, where a dual surfactant in step (1) is added in an amount of 0.1%-1% of the total mass of water and small molecular weight alcohols; a dual surfactant should be chosen as a bromide with a Cm-n-m structure where m is 12, 14, or 16, and n is 2, 3, 6, 8, or 108. The preparation method follows one of claims 1-7 where the rare earth metal is lanthanum and / or cerium; the alkali metal is one, two, or more of magnesium, calcium, and barium; a copper salt containing one or more compounds of copper nitrate, copper chloride, and copper acetic acid should be chosen.

9. Any preparation method according to any of the claims 1-8 in which the temperature of the reaction process and the curing process in step (2) is 60-90 degrees Celsius; in step (4) the firing temperature is 300-700 degrees Celsius and the firing time is 4-12 hours. 10.The catalyst was prepared by one of the preparation methods of claims 1-9; the choice of which to use depended on the total weight of the catalyst. The prepared catalyst contained 20-65% by weight of copper oxide, 15-50% by weight of silicon oxide, 2-25% by weight of zinc oxide, 0.1-5% by weight of rare earth metal oxides, and 0.5-15% by weight of alkaline metal oxides; the choice of which to use more than 40-63% of water. The preferred catalyst composition is a heavy copper oxide, 20-45% by weight of silicon oxide, 5-20% by weight of zinc oxide, 0.2-3% by weight of rare earth metal oxides, and 0.5-10% by weight of alkaline metal oxides; however, a more suitable catalyst should be one with 42-60% by weight of copper oxide, 22-40% by weight of silicon oxide, 10-18% by weight of zinc oxide, 0.5-2% by weight of rare earth metal oxides, and 1-5% by weight of alkaline metal oxides;11.The use of the catalyst is prepared by one of the methods specified in claims 1-9 for the hydrogenation of the liquid state of acetophenone to produce alpha-phenylethanol.

12. The use according to claim 11, where prior to the catalytic hydrogenation of acetophenone to produce alpha-phenylethanol, the catalyst is reduced and reactive; where the reduction and reactive reactions of the catalyst should be selected, includes the following steps: introduction of a mixed gas of hydrogen and nitrogen with a volume ratio of H2 not exceeding 10% by volume, while maintaining the spatial velocity at the volume of the mixed gas of hydrogen and nitrogen of 300-1000 rpm to pre-reduce the catalyst by at least 0.5 hours are followed by gradually increasing the proportion of hydrogen in the gas mixture of hydrogen and nitrogen, and controlling the hot spot temperature of the catalyst layer in this process, which must not exceed 220°C. Finally, the temperature is increased to 200-220°C and reduced in a pure hydrogen atmosphere for 2-5 hours to obtain a catalyst that is suitable for use. The process conditions for the hydrogenation of acetophenone to produce alpha-phenylethanol using the obtained catalyst include: reaction pressure of 2.5-5 MPa, reaction temperature of 70-140°C, molar ratio of H2 / HPA of 2-20:1, and the amount of catalyst is 0.2-0.6 g HPA•g cat-1•h-1.