Cu-based catalyst, preparation method and application thereof, and method for preparing 1-phenylethanol by hydrogenating acetophenone

Abstract

The application relates to the technical field of catalysts, and provides a Cu-based catalyst, a preparation method and application thereof, and a method for preparing 1-phenylethanol by hydrogenating acetophenone. The Cu-based catalyst comprises Cu, alkali metal oxide M2O and a SiO2 carrier; the particle size of Cu in the catalyst is 8-16 nm, and the average pore size of the catalyst is 15-30 nm. The Cu-based catalyst provided by the application has high conversion rate and high selectivity in the reaction of preparing 1-phenylethanol by hydrogenating acetophenone, has better drainage capacity, has good reaction stability under low-temperature reaction conditions, has a long service life, and is suitable for industrial production of preparing 1-phenylethanol by hydrogenating acetophenone.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically, to a Cu-based catalyst, its preparation method and application, and a method for preparing 1-phenylethanol by hydrogenation of acetophenone. Background Technology

[0002] Aromatic alcohols have wide applications in fine chemicals and bulk chemicals, primarily in food flavorings, cosmetics, and pharmaceuticals. 1-Phenylenol (PhE) is a representative compound among aromatic alcohols and is frequently used as an intermediate in perfumes, analgesics, and nonsteroidal anti-inflammatory drugs (NSAIDs). The selective hydrogenation of acetophenone (ACP) to 1-phenylethanol is a commonly used route for its preparation.

[0003] Common catalysts for the selective hydrogenation of acetophenone to 1-phenylethanol include noble metal catalysts with Pd, Pt, Ru, Rh, etc. as active components, Ni-based catalysts, and Cu-based catalysts. While noble metal and Ni-based catalysts are used for the hydrogenation of acetophenone under mild reaction conditions, the selectivity for 1-phenylethanol is poor, resulting in the formation of more hydrogenolysis products and benzene ring hydrogenation products. Cu-based catalysts, on the other hand, exhibit good low-temperature activity and possess high selectivity for C=O bond hydrogenation and relatively weak benzene ring hydrogenation ability, thus improving the selectivity for 1-phenylethanol.

[0004] After acetophenone is hydrogenated to 1-phenylethanol, 1-phenylethanol is highly likely to undergo further hydrogenolysis to produce ethylbenzene and water. If the water generated by the side reaction cannot be discharged from the catalyst channels in time, it will accumulate there. Under high-temperature reaction conditions, acetophenone has high solubility in water, and water is more easily carried away by the generated 1-phenylethanol. Therefore, the catalyst is less prone to deactivation under high-temperature reaction conditions. However, the selectivity of the target product 1-phenylethanol decreases, while the selectivity of the byproduct ethylbenzene increases. Low-temperature reaction conditions are more conducive to improving the selectivity of the target product 1-phenylethanol, but the poor solubility of acetophenone in water at low temperatures makes it difficult for acetophenone to reach the active site, thus causing the catalyst to gradually deactivate during the reaction. Therefore, the key to the selective hydrogenation of acetophenone to 1-phenylethanol lies in developing a highly active catalyst with high water removal capacity, thereby improving the catalyst's stability at low temperatures.

[0005] Patent CN1315226A discloses a Cu / SiO2 catalyst for the hydrogenation reaction of acetophenone. This catalyst is prepared by reducing a copper-based catalyst with hydrogen in the liquid phase, maintaining extremely low catalyst activity. Patent WO 2016198379 prepared a CuSiO2 precursor using a co-precipitation method, added an alkaline earth metal silicate, and extruded it to obtain a catalyst. This catalyst was then used for the hydrogenation reaction of acetophenone. Under optimized conditions, the conversion rate of acetophenone was 95-96%, and the selectivity for 1-phenylethanol was 99%. However, none of these patents address how to extend the low-temperature reaction life of the catalyst in the hydrogenation reaction of acetophenone.

[0006] Therefore, there is a need to develop a catalyst for the selective hydrogenation of acetophenone to 1-phenylethanol with better drainage capacity and better reaction stability under low-temperature reaction conditions. Summary of the Invention

[0007] The purpose of this invention is to provide a Cu-based catalyst, its preparation method and application, and a method for preparing 1-phenylethanol by hydrogenation of acetophenone, so as to solve the technical problem in the prior art that the catalyst is easily deactivated by water accumulation under low temperature reaction conditions during the hydrogenation of acetophenone to prepare 1-phenylethanol.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] In a first aspect, the present invention provides a Cu-based catalyst comprising Cu, an alkali metal oxide M2O, and a SiO2 support; wherein the Cu particle size in the catalyst is 8–16 nm, and the average pore size of the catalyst is 15–30 nm.

[0010] The Cu-based catalyst provided by this invention, by limiting the particle size of Cu to 8-16 nm and the average pore size of the catalyst to 15-30 nm, can not only achieve high conversion and high selectivity in the hydrogenation of acetophenone to 1-phenylethanol, but also, due to the reasonable average pore size range, the Cu-based catalyst has better water drainage capacity, avoiding the problem of catalyst deactivation caused by water accumulation, and greatly extending the service life of the catalyst.

[0011] According to some embodiments of the present invention, the content of each component in the catalyst is as follows:

[0012] Cu: 40-80 parts by weight, preferably 50-70 parts by weight;

[0013] M2O: 0.5 to 10 parts by weight, preferably 1 to 6 parts by weight;

[0014] SiO2 support: 10 to 59.5 parts by weight, preferably 24 to 49 parts by weight.

[0015] According to some embodiments of the present invention, the alkali metal oxide M2O includes at least one of Li2O, Na2O, K2O, Rb2O and Cs2O.

[0016] Secondly, the present invention provides a method for preparing a Cu-based catalyst, comprising:

[0017] S1. The silica sol solution and the precipitant solution are simultaneously added dropwise to the copper precursor solution. After the addition is complete, the mixture is aged and filtered to obtain the CuO / SiO2 precursor.

[0018] S2. The CuO / SiO2 precursor, alkali metal oxide precursor, extrusion aid and water are mixed and shaped, and then calcined to obtain CuO-M2O / SiO2 precursor;

[0019] S3. The CuO-M2O / SiO2 precursor is reduced under a hydrogen atmosphere to obtain the Cu-based catalyst.

[0020] The preparation method provided by this invention employs a co-precipitation method to prepare a Cu / SiO2 precursor. Cu and Si species precipitate simultaneously, resulting in more uniform dispersion of Cu species and higher activity of the prepared Cu-based catalyst. Furthermore, the addition of an alkali metal oxide precursor during the molding process allows the alkali metal species to interact with the SiO2 support, increasing the average pore size of the catalyst, facilitating water drainage from the catalyst channels, and improving the catalyst's low-temperature reaction stability. Moreover, the alkali metal species can transfer electrons to Cu, thereby increasing Cu's adsorption capacity for carbonyl species and enhancing the catalyst's low-temperature reaction activity.

[0021] According to some embodiments of the present invention, the copper precursor includes at least one of copper nitrate, copper chloride, copper sulfate, and copper bromide.

[0022] According to some embodiments of the present invention, the silica sol may be an alkaline silica sol or an acidic silica sol.

[0023] According to some embodiments of the present invention, the precipitant includes at least one selected from ammonia, ammonium carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium hydroxide, and potassium hydroxide.

[0024] According to some embodiments of the present invention, the alkali metal oxide precursor includes at least one of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, and cesium nitrate.

[0025] According to some embodiments of the present invention, the extrusion aid includes at least one of methylcellulose, glycerol, guar gum powder, and tetramethylammonium hydroxide (TMAOH).

[0026] According to some embodiments of the present invention, the mass ratio of copper precursor (calculated as Cu), alkali metal oxide precursor (calculated as M2O), and silica sol (calculated as SiO2) is (40-80):(0.5-10):(10-59.5), preferably (50-70):(1-6):(24-49).

[0027] According to some embodiments of the present invention, Cu in the copper precursor solution 2+ The concentration is 0.2–2.5 mol / L.

[0028] According to some embodiments of the present invention, the SiO2 content in the silica sol solution is 5-40 wt%.

[0029] In this invention, the amount of precipitant used can generally be 5-200 wt% excess.

[0030] According to some embodiments of the present invention, the total concentration of anions in the precipitant solution is 0.2 to 4 mol / L.

[0031] According to some embodiments of the present invention, the total concentration of anions in the precipitant solution is 1 to 3 mol / L.

[0032] According to some embodiments of the present invention, the amount of the extrusion aid is 2 to 40 wt% of the CuO / SiO2 precursor.

[0033] According to some embodiments of the present invention, the dropwise addition is carried out under stirring conditions.

[0034] According to some embodiments of the present invention, the temperature of the dripping is 20-95°C and the time is 0.5-20h.

[0035] According to some embodiments of the present invention, the aging temperature is 20–95°C and the time is 1–30 h.

[0036] According to some embodiments of the present invention, the calcination temperature is 300–750°C and the time is 2–24 hours.

[0037] According to some embodiments of the present invention, the reduction conditions include: a hydrogen partial pressure of 0.05–2.0 MPa and a hydrogen volume hourly space velocity of 200–4000 h⁻¹. -1 The reduction temperature is 150–350℃, and the reduction time is 1–48h.

[0038] Thirdly, the present invention provides a Cu-based catalyst prepared by the preparation method described in the second aspect.

[0039] The Cu-based catalyst prepared by the method of the present invention is a SiO2-supported metallic Cu catalyst modified with alkali metal oxide M2O.

[0040] According to some embodiments of the present invention, the Cu particle size in the catalyst is 8-16 nm, and the average pore size of the catalyst is 15-30 nm.

[0041] Fourthly, the present invention provides the application of the Cu-based catalyst described in the first aspect or the Cu-based catalyst described in the third aspect in the hydrogenation of acetophenone to prepare 1-phenylethanol.

[0042] Fifthly, the present invention provides a method for preparing 1-phenylethanol by hydrogenation of acetophenone, comprising: dissolving acetophenone in a solvent to prepare an acetophenone solution, and subjecting the acetophenone solution to a hydrogenation reaction in the presence of the Cu-based catalyst described in the first aspect or the Cu-based catalyst described in the third aspect to obtain 1-phenylethanol.

[0043] According to some embodiments of the present invention, the conditions for the hydrogenation reaction include: a reaction temperature of 60–120°C, preferably 65–80°C; and a mass hourly space velocity (WHSV) of acetophenone of 0.1–1 h⁻¹. -1 Preferably, it is 0.3 to 0.6 h. -1 The hydrogen pressure is 1-5 MPa, preferably 1.5-4 MPa; the feed molar ratio of hydrogen to acetophenone is 1-20, preferably 1.2-15.

[0044] According to some embodiments of the present invention, the solvent includes alkanols, preferably methanol and / or ethanol.

[0045] The beneficial effects of this invention are at least as follows:

[0046] The Cu-based catalyst provided by this invention exhibits high conversion and selectivity in the hydrogenation of acetophenone to 1-phenylethanol, as well as good water displacement capacity, good reaction stability under low temperature reaction conditions, and long service life, making it suitable for industrial production of acetophenone to 1-phenylethanol. Detailed Implementation

[0047] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for illustrating this patent and do not limit the scope of protection of this invention in any way.

[0048] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0049] The grain size of Cu was analyzed using a Rigaku D / max-1400 polycrystalline powder diffractometer (XRD) from Japan. Cu-Kα was used as the radiation source, and scanning was performed at a tube voltage of 40 kV and a tube current of 40 mA.

[0050] The catalyst pore size was measured using an ASAP 2020 chemisorption analyzer from Micromeritics, USA. The sample was purged with N2 at 100℃ for 1 h, then pretreated at 300℃ for 4 h. The mass of the degassed sample was recorded. Using N2 as the adsorbed gas, the nitrogen adsorption amount was measured at liquid nitrogen temperature -196℃. The adsorption-desorption isotherms were measured using a static method.

[0051] Example 1

[0052] Weigh 226.8 g of copper nitrate trihydrate, dissolve it in 400 g of water, and place the solution in a 2 L four-necked flask. Stir with an external stirrer at 500 rpm and 60 °C. Prepare the silica sol solution: Weigh 125.1 g of 40 wt% silica sol and dilute it with water to 250 mL. Prepare the ammonium carbonate solution: Weigh 94.5 g of ammonium carbonate, dissolve it in water, and dilute it to 500 mL. Add the silica sol solution and ammonium carbonate solution dropwise to the copper nitrate solution in the four-necked flask simultaneously at rates of 4.2 mL / min and 8.5 mL / min, respectively. After the addition is complete, stop stirring, age at 60 °C for 2 h, filter, wash three times with deionized water, and dry overnight at 120 °C to obtain the catalyst precursor CS-1.

[0053] The catalyst precursor CS-1 obtained above was placed in a kneader, 6.0 g of methylcellulose was added, and 120 mL of potassium carbonate solution (containing 5.54 g of potassium carbonate) was added. After kneading for 20 min, the mixture was placed in an extruder and extruded into clover strips with a diameter of 1.2 mm and a length of 5–15 mm. The clover strips were dried overnight at 120 °C and calcined at 350 °C for 4 h to obtain the alkali metal modified catalyst precursor CMS-1.

[0054] CMS-1 was loaded into a fixed-bed reactor and reduced with hydrogen at a pressure of 0.8 MPa and a volume hourly space velocity (HHSV) of 800 h⁻¹. -1The reduction temperature was 230℃ and the reduction time was 9h, and the resulting catalyst was CAT-1, in which the content of Cu was 52.7wt%, the content of K2O was 3.3wt%, the content of SiO2 was 44.0wt%, the grain size of Cu was 12.0nm calculated by Scherrer's formula, and the average pore size of the catalyst was 24.5nm.

[0055] Example 2

[0056] Weigh 234.4 g of copper sulfate pentahydrate, dissolve it in 600 g of water, and place the solution in a 2 L four-necked flask. Stir with an external stirrer at 400 rpm and 70 °C. Prepare the silica sol solution: Weigh 250 g of 30 wt% silica sol and dilute it with water to 300 mL. Prepare the sodium carbonate solution: Weigh 104.4 g of sodium carbonate, dissolve it in water, and dilute it to 600 mL. Simultaneously add the silica sol solution and sodium carbonate solution dropwise to the copper sulfate solution in the four-necked flask at rates of 4.2 mL / min and 8.5 mL / min, respectively. After the addition is complete, stop stirring, age at 60 °C for 2 h, filter, wash three times with deionized water, and dry overnight at 120 °C to obtain the catalyst precursor CS-2.

[0057] The catalyst precursor CS-2 obtained above was placed in a kneader, 6.0 g of guar gum powder was added, and 150 mL of potassium nitrate solution (containing 4.3 g of potassium nitrate) was added. After kneading for 20 min, the mixture was placed in an extruder to extrude clover strips with a diameter of 1.2 mm and a length of 5–15 mm. The clover strips were dried overnight at 120 °C and calcined at 350 °C for 4 h to obtain the alkali metal modified catalyst precursor CMS-2.

[0058] CMS-2 was loaded into a fixed-bed reactor and reduced with hydrogen at a pressure of 1.5 MPa and a hydrogen volume hourly space velocity of 1200 h⁻¹. -1 The reduction temperature was 180℃ and the reduction time was 4h, and the catalyst obtained was CAT-2, in which the content of Cu was 43.8wt%, the content of K2O was 1.5wt%, the content of SiO2 was 54.7wt%, the grain size of Cu was 10.4nm calculated by Scherrer formula, and the average pore size of the catalyst was 20.5nm.

[0059] Example 3

[0060] Weigh 126.6 g of copper chloride, dissolve it in 600 g of water, and place the solution in a 2 L four-necked flask. Stir with an external stirrer at 400 rpm and 70 °C. Prepare the silica sol solution: Weigh 187.5 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare the ammonia solution: Weigh 133.9 g of 25% ammonia solution, dissolve it in water, and dilute it to 600 mL. Add the silica sol solution and ammonia solution dropwise to the copper chloride solution in the four-necked flask simultaneously at rates of 4.2 mL / min and 8.5 mL / min, respectively. After the addition is complete, stop stirring, age at 60 °C for 2 h, filter, wash three times with deionized water, and dry overnight at 120 °C to obtain the catalyst precursor CS-3.

[0061] The catalyst precursor CS-3 obtained above was placed in a kneader, and 20g of 25wt% TMAOH solution and 130mL of potassium carbonate solution (containing 1.47g of potassium carbonate) were added. After kneading for 20min, the mixture was placed in an extruder to extrude clover strips with a diameter of 1.2mm and a length of 5-15mm. The clover strips were dried overnight at 120℃ and calcined at 350℃ for 4h to obtain the alkali metal modified catalyst precursor CMS-3.

[0062] CMS-3 was loaded into a fixed-bed reactor and reduced with hydrogen at a pressure of 1.5 MPa and a hydrogen volume hourly space velocity of 1200 h⁻¹. -1 The reduction temperature was 180℃ and the reduction time was 4h, and the catalyst obtained was CAT-3, in which the content of Cu was 44.2wt%, the content of K2O was 0.7wt%, the content of SiO2 was 55.1wt%, the grain size of Cu was 14.3nm calculated by Scherrer formula, and the average pore size of the catalyst was 15.5nm.

[0063] Example 4

[0064] Weigh 226.9 g of copper nitrate trihydrate, dissolve it in 600 g of water, and place the solution in a 2 L four-necked flask. Stir with an external stirrer at 400 rpm and 70 °C. Prepare the silica sol solution: Weigh 62.5 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare the ammonium carbonate solution: Weigh 96.5 g of ammonium carbonate, dissolve it in water, and dilute it to 600 mL. Add the silica sol solution and ammonium carbonate solution dropwise to the copper nitrate solution in the four-necked flask at rates of 4.2 mL / min and 8.5 mL / min, respectively. After the addition is complete, stop stirring, age at 60 °C for 2 h, filter, wash three times with deionized water, and dry overnight at 120 °C to obtain the catalyst precursor CS-4.

[0065] The catalyst precursor CS-4 obtained above was placed in a kneader, 6g of guar gum powder was added, and 100mL of potassium carbonate solution (containing 7.35g of potassium carbonate) was added. After kneading for 20min, the mixture was placed in an extruder to extrude clover strips with a diameter of 1.2mm and a length of 5-15mm. The clover strips were dried overnight at 120℃ and calcined at 450℃ for 8h to obtain the alkali metal modified catalyst precursor CMS-4.

[0066] CMS-4 was loaded into a fixed-bed reactor and reduced with hydrogen at a pressure of 1.5 MPa and a hydrogen volume hourly space velocity of 1200 h⁻¹. -1 The reduction temperature was 300℃ and the reduction time was 4h, and the catalyst obtained was CAT-4, in which the content of Cu was 66.7wt%, the content of K2O was 5.6wt%, the content of SiO2 was 27.7wt%, the grain size of Cu was 15.3nm calculated by Scherrer formula, and the average pore size of the catalyst was 22.5nm.

[0067] Example 5

[0068] Weigh 226.9 g of copper nitrate trihydrate, dissolve it in 600 g of water, and place the solution in a 2 L four-necked flask. Stir with an external stirrer at 400 rpm and 70 °C. Prepare the silica sol solution: Weigh 100 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare the ammonium carbonate solution: Weigh 98.0 g of ammonium carbonate, dissolve it in water, and dilute it to 600 mL. Add the silica sol solution and ammonium carbonate solution dropwise to the copper nitrate solution in the four-necked flask at rates of 4.2 mL / min and 8.5 mL / min, respectively. After the addition is complete, stop stirring, age at 60 °C for 2 h, filter, wash three times with deionized water, and dry overnight at 120 °C to obtain the catalyst precursor CS-5.

[0069] The catalyst precursor CS-5 obtained above was placed in a kneader, 10g of guar gum powder was added, and 100mL of potassium carbonate solution (containing 7.34g of potassium carbonate) was added. After kneading for 20min, the mixture was placed in an extruder to extrude clover strips with a diameter of 1.2mm and a length of 5-15mm. The clover strips were dried overnight at 120℃ and calcined at 350℃ for 4h to obtain the alkali metal modified catalyst precursor CMS-5.

[0070] CMS-5 was loaded into a fixed-bed reactor and reduced with hydrogen at a pressure of 1.5 MPa and a volume hourly space velocity (HHSV) of 2500 h⁻¹. -1The reduction temperature was 250℃ and the reduction time was 24h, and the resulting catalyst was CAT-5, in which the content of Cu was 57.1wt%, the content of K2O was 4.8wt%, the content of SiO2 was 38.1wt%, the grain size of Cu was 14.3nm calculated by Scherrer's formula, and the average pore size of the catalyst was 23.5nm.

[0071] Example 6

[0072] Weigh 226.9 g of copper nitrate trihydrate, dissolve it in 600 g of water, and place the solution in a 2 L four-necked flask. Stir with an external stirrer at 400 rpm and 80 °C. Prepare the silica sol solution: Weigh 62.5 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare the ammonium carbonate solution: Weigh 96.5 g of ammonium carbonate, dissolve it in water, and dilute it to 600 mL. Add the silica sol solution and ammonium carbonate solution dropwise to the copper nitrate solution in the four-necked flask at rates of 4.2 mL / min and 8.5 mL / min, respectively. After the addition is complete, stop stirring, age at 80 °C for 2 h, filter, wash three times with deionized water, and dry overnight at 120 °C to obtain the catalyst precursor CS-6.

[0073] The catalyst precursor CS-6 obtained above was placed in a kneader, 10g of guar gum powder was added, and 100mL of potassium carbonate solution (containing 7.34g of potassium carbonate) was added. After kneading for 20min, the mixture was placed in an extruder to extrude clover strips with a diameter of 1.2mm and a length of 5-15mm. The clover strips were dried overnight at 120℃ and calcined at 350℃ for 4h to obtain the alkali metal modified catalyst precursor CMS-6.

[0074] CMS-6 was loaded into a fixed-bed reactor and reduced with hydrogen at a pressure of 1.5 MPa and a volume hourly space velocity (HHSV) of 2500 h⁻¹. -1 The reduction temperature was 250℃ and the reduction time was 24h, and the catalyst obtained was CAT-6, in which the content of Cu was 66.7wt%, the content of K2O was 5.5wt%, the content of SiO2 was 27.8wt%, the grain size of Cu was 15.2nm calculated by Scherrer formula, and the average pore size of the catalyst was 26.9nm.

[0075] Example 7

[0076] Weigh 226.9 g of copper nitrate trihydrate, dissolve it in 600 g of water, and place the solution in a 2 L four-necked flask. Stir with an external stirrer at 400 rpm and 80 °C. Prepare the silica sol solution: Weigh 62.5 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare the ammonium carbonate solution: Weigh 96.5 g of ammonium carbonate, dissolve it in water, and dilute it to 600 mL. Add the silica sol solution and ammonium carbonate solution dropwise to the copper nitrate solution in the four-necked flask at rates of 4.2 mL / min and 8.5 mL / min, respectively. After the addition is complete, stop stirring, age at 80 °C for 2 h, filter, wash three times with deionized water, and dry overnight at 120 °C to obtain the catalyst precursor CS-7.

[0077] The catalyst precursor CS-7 obtained above was placed in a kneader, 10g of guar gum powder was added, and 100mL of potassium carbonate solution (containing 4.41g of potassium carbonate) was added. After kneading for 20min, the mixture was placed in an extruder to extrude clover strips with a diameter of 1.2mm and a length of 5-15mm. The clover strips were dried overnight at 120℃ and calcined at 350℃ for 4h to obtain the alkali metal modified catalyst precursor CMS-7.

[0078] CMS-7 was loaded into a fixed-bed reactor and reduced with hydrogen at a pressure of 1.5 MPa and a volume hourly space velocity (HHSV) of 2500 h⁻¹. -1 The reduction temperature was 250℃ and the reduction time was 24h, and the catalyst obtained was CAT-7, in which the content of Cu was 68.2wt%, the content of K2O was 3.4wt%, the content of SiO2 was 28.4wt%, the grain size of Cu was 14.7nm calculated by Scherrer formula, and the average pore size of the catalyst was 24.3nm.

[0079] Example 8

[0080] The catalyst was prepared according to Example 7, except that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) was replaced with 100 mL of lithium carbonate solution (containing 7.41 g of lithium carbonate).

[0081] The catalyst obtained was CAT-8, in which the content of Cu was 68.2 wt%, the content of Li2O was 3.4 wt%, the content of SiO2 was 28.4 wt%, the grain size of Cu was 14.5 nm calculated by Scherrer formula, and the average pore size of the catalyst was 21.0 nm.

[0082] Example 9

[0083] The catalyst was prepared according to Example 7, except that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) was replaced with 100 mL of sodium carbonate solution (containing 5.13 g of sodium carbonate).

[0084] The catalyst obtained was CAT-9, with a Cu content of 68.2 wt%, a Na2O content of 3.4 wt%, and a SiO2 content of 28.4 wt%. The Cu grain size was calculated to be 14.6 nm using the Scherrer equation, and the average pore size of the catalyst was 22.5 nm.

[0085] Example 10

[0086] The catalyst was prepared according to Example 7, except that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) was replaced with 100 mL of rubidium carbonate solution (containing 3.7 g of rubidium carbonate).

[0087] The catalyst obtained was CAT-10, in which the content of Cu was 68.2 wt%, the content of Na2O was 3.4 wt%, the content of SiO2 was 28.4 wt%, the grain size of Cu was 14.3 nm calculated by Scherrer formula, and the average pore size of the catalyst was 25.5 nm.

[0088] Comparative Example 1

[0089] The catalyst was prepared according to Example 7, except that copper nitrate solution and ammonium carbonate solution were added dropwise to the silica sol solution at a rate of 8.5 mL / min.

[0090] The catalyst obtained was DCAT-1, in which the content of Cu was 68.2 wt%, the content of K2O was 3.4 wt%, the content of SiO2 was 28.4 wt%, the grain size of Cu was 20.7 nm calculated by Scherrer's formula, and the average pore size of the catalyst was 25.2 nm.

[0091] Comparative Example 2

[0092] The catalyst was prepared according to Example 7, except that the silica sol solution and copper nitrate solution were simultaneously added dropwise to the ammonium carbonate solution at rates of 4.2 mL / min and 8.5 mL / min, respectively.

[0093] The catalyst obtained was DCAT-2, in which the content of Cu was 68.2 wt%, the content of K2O was 3.4 wt%, the content of SiO2 was 28.4 wt%, the grain size of Cu was 18.7 nm calculated by Scherrer's formula, and the average pore size of the catalyst was 24.1 nm.

[0094] Comparative Example 3

[0095] The catalyst was prepared according to Example 7, except that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) was replaced with 100 mL of pure water.

[0096] The obtained catalyst was DCAT-3, in which the Cu content was 71.3 wt% and the SiO2 content was 28.7 wt%. The Cu grain size was calculated to be 15.0 nm using the Scherrer equation, and the average pore size of the catalyst was 12.1 nm.

[0097] Comparative Example 4

[0098] The catalyst was prepared according to Example 7, except that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) was replaced with 100 mL of magnesium nitrate solution (containing 11.1 g of magnesium nitrate).

[0099] The catalyst obtained was DCAT-4, in which the content of Cu was 68.1 wt%, the content of MgO was 3.4 wt%, the content of SiO2 was 28.4 wt%, the grain size of Cu was 14.3 nm calculated by Scherrer formula, and the average pore size of the catalyst was 13.2 nm.

[0100] Comparative Example 5

[0101] The catalyst was prepared according to Example 7, except that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) was replaced with 100 mL of calcium nitrate solution (containing 8.79 g of calcium nitrate).

[0102] The catalyst obtained was DCAT-5, in which the content of Cu was 68.4 wt%, the content of CaO was 3.4 wt%, the content of SiO2 was 28.2 wt%, the grain size of Cu was 14.2 nm calculated by Scherrer's formula, and the average pore size of the catalyst was 13.5 nm.

[0103] Catalytic performance evaluation

[0104] (1) Comparison of catalyst performance in various examples and comparative examples

[0105] 20g of each catalyst from the examples and comparative examples were separately packed into 12mm stainless steel reactors and reacted at 65°C under a hydrogen pressure of 2.0MPa. The acetophenone feedstock was a 30% acetophenone ethanol solution, and the acetophenone space velocity was 0.4h⁻¹. -1 The molar ratio of hydrogen to acetophenone (hydrogen and acetophenone) was 2.0. After 24 hours of reaction, samples were taken for testing, and the results are shown in Table 1.

[0106] Acetophenone conversion rate = [Acetophenone (in) - Acetophenone (out)] / Acetophenone (in) × 100% (in molar percentage)

[0107] 1-Phenylephrine selectivity = {1-Phenylephrine (out) / [Acetophenone (in) - Acetophenone (out)]} × 100% (in molar percentage)

[0108] Table 1

[0109]

[0110]

[0111] (2) Changes in hydrogenation conversion and selectivity of acetophenone with reaction conditions

[0112] 20g of the catalyst CAT-7 from Example 7 was packed into a 12mm stainless steel reactor. The acetophenone feedstock was a 30wt% acetophenone ethanol solution. The reaction temperature, hydrogen pressure, hydrogen-acetophenone (hydrogen and acetophenone) molar ratio and acetophenone space velocity are shown in Table 2. Samples were taken and tested after 24h of reaction, and the results are shown in Table 2.

[0113] Table 2

[0114]

[0115] (3) Evaluation of catalyst low-temperature reaction lifetime

[0116] 20g each of catalyst CAT-7 from Example 7 and catalyst DCAT-3 from Comparative Example 3 were separately packed into 12mm stainless steel reactors and reacted at 65°C under a hydrogen pressure of 2.0MPa. The acetophenone feedstock was a 30% acetophenone ethanol solution, and the acetophenone space velocity was 0.4h⁻¹. -1 The molar ratio of hydrogen to acetophenone was 2.0. Samples were taken and tested after 500h, 1000h, 1500h, 2000h, 2500h and 3000h of reaction. The results are shown in Table 3.

[0117] Table 3

[0118]

[0119] As can be seen from Table 3, the Cu catalyst provided by this invention, when used in the hydrogenation reaction of acetophenone, exhibits stable catalytic performance for 3000 hours under low temperature (65℃) reaction conditions without significant decrease, demonstrating excellent stability and making it suitable for industrial production of 1-phenylethanol by hydrogenation of acetophenone.

[0120] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. The application of a Cu-based catalyst in the hydrogenation of acetophenone to prepare 1-phenylethanol; the Cu-based catalyst comprises Cu, alkali metal oxide M2O and SiO2 support; the particle size of Cu in the catalyst is 8-16 nm, and the average pore size of the catalyst is 15-30 nm.

2. The application according to claim 1, characterized in that, The content of each component in the catalyst is as follows: Cu: 40-80 parts by weight; M2O: 0.5–10 parts by weight; SiO2 support: 10–59.5 parts by weight; And / or, the alkali metal oxide M2O includes at least one of Li2O, Na2O, K2O, Rb2O and Cs2O.

3. The application according to claim 2, characterized in that, The content of each component in the catalyst is as follows: Cu: 50-70 parts by weight; M2O: 1 to 6 parts by weight; SiO2 support: 24-49 parts by weight.

4. The application according to any one of claims 1-3, characterized in that, The preparation method of the Cu-based catalyst includes: S1. The silica sol solution and the precipitant solution are simultaneously added dropwise to the copper precursor solution. After the addition is complete, the mixture is aged and filtered to obtain the CuO / SiO2 precursor. S2. The CuO / SiO2 precursor, alkali metal oxide precursor, extrusion aid and water are mixed, shaped and calcined to obtain CuO-M2O / SiO2 precursor; S3. The CuO-M2O / SiO2 precursor is reduced under a hydrogen atmosphere to obtain the Cu-based catalyst.

5. The application according to claim 4, characterized in that, The copper precursor includes at least one of copper nitrate, copper chloride, copper sulfate, and copper bromide; And / or, the precipitant includes at least one of ammonia, ammonium carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium hydroxide, and potassium hydroxide; And / or, the alkali metal oxide precursor includes at least one of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, and cesium nitrate; And / or, the extrusion aid includes at least one of methylcellulose, glycerin, guar gum, and tetramethylammonium hydroxide.

6. The application according to claim 4, characterized in that, The mass ratio of copper precursor (calculated as Cu), alkali metal oxide precursor (calculated as M2O), and silica sol (calculated as SiO2) is (40–80): (0.5–10): (10–59.5). And / or, Cu in the copper precursor solution 2+ The concentration is 0.2–2.5 mol / L; And / or, the SiO2 content in the silica sol solution is 5-40 wt%; And / or, the amount of the extrusion aid is 2 to 40 wt% of the CuO / SiO2 precursor.

7. The application according to claim 4, characterized in that, The mass ratio of copper precursor (calculated as Cu), alkali metal oxide precursor (calculated as M2O), and silica sol (calculated as SiO2) is (50–70): (1–6): (24–49).

8. The application according to claim 4, characterized in that, The dropping process is carried out under stirring conditions; And / or, the temperature of the dripping is 20–95°C; And / or, the aging temperature is 20–95°C, and the time is 1–30 h; And / or, the calcination temperature is 300–750°C, and the time is 2–24 h; And / or, the reduction conditions include: a hydrogen partial pressure of 0.05–2.0 MPa and a hydrogen volume hourly space velocity of 200–4000 h⁻¹. -1 The reduction temperature is 150–350℃, and the reduction time is 1–48h.

9. A method for preparing 1-phenylethanol by hydrogenation of acetophenone, characterized in that, include: Acetophenone is dissolved in a solvent to prepare an acetophenone solution, and the acetophenone solution is subjected to a hydrogenation reaction in the presence of a Cu-based catalyst to obtain 1-phenylethanol; The Cu-based catalyst comprises Cu, alkali metal oxide M2O, and SiO2 support; the Cu particle size in the catalyst is 8–16 nm, and the average pore size of the catalyst is 15–30 nm.

10. The method according to claim 9, characterized in that, The conditions for the hydrogenation reaction include: a reaction temperature of 60–120 °C; and a mass hourly space velocity (WHSV) of acetophenone of 0.1–1 h⁻¹. -1 The hydrogen pressure is 1–5 MPa; the feed molar ratio of hydrogen to acetophenone is 1–20. And / or, the solvent includes alkanols.

11. The method according to claim 10, characterized in that, The solvent includes methanol and / or ethanol.

12. The method according to any one of claims 9-11, characterized in that, The content of each component in the catalyst is as follows: Cu: 40-80 parts by weight; M2O: 0.5–10 parts by weight; SiO2 support: 10–59.5 parts by weight; And / or, the alkali metal oxide M2O includes at least one of Li2O, Na2O, K2O, Rb2O and Cs2O.

13. The method according to claim 12, characterized in that, The content of each component in the catalyst is as follows: Cu: 50-70 parts by weight; M2O: 1 to 6 parts by weight; SiO2 support: 24-49 parts by weight.

14. The method according to any one of claims 9-11, characterized in that, The preparation method of the Cu-based catalyst includes: S1. The silica sol solution and the precipitant solution are simultaneously added dropwise to the copper precursor solution. After the addition is complete, the mixture is aged and filtered to obtain the CuO / SiO2 precursor. S2. The CuO / SiO2 precursor, alkali metal oxide precursor, extrusion aid and water are mixed, shaped and calcined to obtain CuO-M2O / SiO2 precursor; S3. The CuO-M2O / SiO2 precursor is reduced under a hydrogen atmosphere to obtain the Cu-based catalyst.

15. The method according to claim 14, characterized in that, The copper precursor includes at least one of copper nitrate, copper chloride, copper sulfate, and copper bromide; And / or, the precipitant includes at least one of ammonia, ammonium carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium hydroxide, and potassium hydroxide; And / or, the alkali metal oxide precursor includes at least one of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, and cesium nitrate; And / or, the extrusion aid includes at least one of methylcellulose, glycerin, guar gum, and tetramethylammonium hydroxide.

16. The method according to claim 14, characterized in that, The mass ratio of copper precursor (calculated as Cu), alkali metal oxide precursor (calculated as M2O), and silica sol (calculated as SiO2) is (40–80): (0.5–10): (10–59.5). And / or, Cu in the copper precursor solution 2+ The concentration is 0.2–2.5 mol / L; And / or, the SiO2 content in the silica sol solution is 5-40 wt%; And / or, the amount of the extrusion aid is 2 to 40 wt% of the CuO / SiO2 precursor.

17. The method according to claim 14, characterized in that, The mass ratio of copper precursor (calculated as Cu), alkali metal oxide precursor (calculated as M2O), and silica sol (calculated as SiO2) is (50–70): (1–6): (24–49).

18. The method according to claim 14, characterized in that, The dropping process is carried out under stirring conditions; And / or, the temperature of the dripping is 20–95°C; And / or, the aging temperature is 20–95°C, and the time is 1–30 h; And / or, the calcination temperature is 300–750°C, and the time is 2–24 h; And / or, the reduction conditions include: a hydrogen partial pressure of 0.05–2.0 MPa and a hydrogen volume hourly space velocity of 200–4000 h⁻¹. -1 The reduction temperature is 150–350℃, and the reduction time is 1–48h.

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