Cu-based catalyst, preparation method and application thereof, and method for preparing 1-phenethyl alcohol through acetophenone hydrogenation

Abstract

The invention 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-phenethyl alcohol through acetophenone hydrogenation. The Cu-based catalyst comprises Cu, an 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 invention has high conversion rate and high selectivity in a reaction for preparing 1-phenethyl alcohol through acetophenone hydrogenation, has better drainage capacity, has good reaction stability under a low-temperature reaction condition, is long in service life, and is suitable for industrial production for preparing 1-phenethyl alcohol through acetophenone hydrogenation.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and more specifically, to a Cu-based catalyst and its preparation method and application, and a method for preparing 1-phenylethanol by hydrogenation of acetophenone. Background Art

[0002] Aromatic alcohols are widely used in fine chemicals and bulk chemicals, mainly for food flavors, cosmetics, and the pharmaceutical industry. 1-Phenylethanol (PhE) is a representative compound among aromatic alcohols and is often used as an intermediate for perfumes, analgesics, and non-steroidal anti-inflammatory drugs. Selective hydrogenation of acetophenone (ACP) to produce 1-phenylethanol is a common preparation route for 1-phenylethanol.

[0003] Common catalysts for the selective hydrogenation of acetophenone to produce 1-phenylethanol include noble metal catalysts with Pd, Pt, Ru, Rh, etc. as active components, Ni-based catalysts, Cu-based catalysts, etc. When noble metal catalysts and Ni-based catalysts are used in the acetophenone hydrogenation reaction, although the reaction conditions are mild, the selectivity of 1-phenylethanol is poor, and more hydrogenolysis products and benzene ring hydrogenation products are generated. The Cu-based catalyst has good low-temperature activity, and has a high selectivity for C=O bond hydrogenation and a weak benzene ring hydrogenation ability, which can improve the selectivity of 1-phenylethanol.

[0004] Since after acetophenone is hydrogenated to produce 1-phenylethanol, 1-phenylethanol is very likely to continue to undergo hydrogenolysis to produce ethylbenzene and water. If the water generated by side reactions cannot be discharged in time in the catalyst pores, it will accumulate in the catalyst pores. Under high-temperature reaction conditions, the solubility of acetophenone in water is relatively high, and water is more easily carried away by the generated 1-phenylethanol. Therefore, under high-temperature reaction conditions, the catalyst is not easily deactivated, but at this time, the selectivity of the target product 1-phenylethanol decreases, and the selectivity of the by-product ethylbenzene increases. Low-temperature reaction conditions are more conducive to improving the selectivity of the target product 1-phenylethanol. However, under low-temperature conditions, the solubility of acetophenone in water is relatively poor, resulting in acetophenone being difficult to approach the active center, thereby causing the catalyst to gradually deactivate during the reaction process. Therefore, the key to the selective hydrogenation of acetophenone to produce 1-phenylethanol lies in developing a catalyst with high activity, which should also have a high water discharge capacity, thereby improving the low-temperature operation stability of the catalyst.

[0005] Patent CN1315226A discloses a Cu / SiO 2 catalyst for the acetophenone hydrogenation reaction. The catalyst is prepared by a method of reducing a copper-based catalyst with hydrogen in the presence of a liquid phase, and can maintain the catalyst activity reduction to an extremely low level. Patent WO 2016198379 prepared CuSiO 2Precursors, and alkaline earth metal silicates were added for extrusion to obtain a catalyst. The acetophenone hydrogenation reaction was carried out. Under optimized conditions, the conversion rate of acetophenone was 95 - 96%, and the selectivity for 1-phenylethanol was 99%. However, none of the above patents mentioned how to extend the low-temperature reaction life of the catalyst in the acetophenone hydrogenation reaction.

[0006] Therefore, it is necessary to develop a catalyst for the selective hydrogenation of acetophenone to prepare 1-phenylethanol, which has better drainage ability and better reaction stability under low-temperature reaction conditions. Summary of the Invention

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

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

[0009] In the first aspect, the present invention provides a Cu-based catalyst, comprising Cu, alkali metal oxide M 2 O and SiO 2 support; the particle size of Cu in the catalyst is 8 - 16 nm, and the average pore diameter of the catalyst is 15 - 30 nm.

[0010] By limiting the particle size of Cu in the Cu-based catalyst provided by the present invention to 8 - 16 nm and simultaneously limiting the average pore diameter of the catalyst to 15 - 30 nm, the catalyst can not only have high conversion rate and high selectivity in the reaction of hydrogenating acetophenone to prepare 1-phenylethanol, but also due to the reasonable average pore diameter range, the Cu-based catalyst has better drainage ability, avoiding the problem of catalyst deactivation caused by water aggregation, and greatly extending the service life of the catalyst.

[0011] According to some embodiments of the present invention, the contents of each component in the catalyst are:

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

[0013] M 2 O: 0.5 - 10 parts by weight, preferably 1 - 6 parts by weight;

[0014] SiO 2 support: 10 - 59.5 parts by weight, preferably 24 - 49 parts by weight.

[0015] According to some embodiments of the present invention, the alkali metal oxide M 2 O includes Li2 O, Na 2 O, K 2 O, Rb 2 O and Cs 2 at least one of O.

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

[0017] S1. Simultaneously drop a silica sol solution and a precipitant solution into a copper precursor solution. After the dropping is completed, age the mixture, filter it, and obtain a CuO / SiO 2 precursor;

[0018] S2. Mix the CuO / SiO 2 precursor, an alkali metal oxide precursor, an extrusion aid, and water, then form and calcine to obtain a CuO-M 2 O / SiO 2 precursor;

[0019] S3. Reduce the CuO-M 2 O / SiO 2 precursor in a hydrogen atmosphere to obtain the Cu-based catalyst.

[0020] The preparation method provided by the present invention uses the co-precipitation method to prepare a Cu / SiO 2 precursor. The Cu species and the Si species are precipitated simultaneously, so that the Cu species are more evenly dispersed, and the prepared Cu-based catalyst has higher activity. In addition, an alkali metal oxide precursor is added during the forming process. The alkali metal species can interact with the carrier SiO 2 to increase the average pore diameter of the catalyst, which is beneficial to the discharge of water from the catalyst pores and improves the low-temperature reaction stability of the catalyst. Moreover, the alkali metal species can transfer electrons to Cu, thereby increasing the adsorption capacity of Cu for carbonyl species and improving the low-temperature reaction activity of the catalyst.

[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 can 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 of ammonia water, 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 methyl cellulose, glycerol, sesbania powder, and tetramethylammonium hydroxide (TMAOH).

[0026] According to some embodiments of the present invention, the mass ratio of the copper precursor based on Cu, the alkali metal oxide precursor based on M 2 O, and the silica sol based on SiO 2 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, the concentration of Cu in the copper precursor solution is 0.2 - 2.5 mol / L. 2+ concentration is 0.2 - 2.5 mol / L.

[0028] According to some embodiments of the present invention, the content of SiO in the silica sol solution is 5 - 40 wt%. 2 content is 5 - 40 wt%.

[0029] In the present invention, the amount of the precipitating agent can generally be in excess by 5 - 200 wt%.

[0030] According to some embodiments of the present invention, the total anion concentration in the precipitating agent solution is 0.2 - 4 mol / L.

[0031] According to some embodiments of the present invention, the total anion concentration in the precipitating agent solution is 1 - 3 mol / L.

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

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

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

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

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

[0037] According to some embodiments of the present invention, the reduction conditions include: the hydrogen partial pressure is 0.05 - 2.0 MPa, the volumetric space velocity of hydrogen is 200 - 4000 h -1 ; the reduction temperature is 150 - 350 °C, and the reduction time is 1 - 48 h.

[0038] In a third aspect, 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 preparation method of the present invention is a catalyst in which metal Cu is supported on SiO 2 and modified with an alkali metal oxide M 2 O.

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

[0041] In a fourth aspect, the present invention provides the use 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] In a fifth aspect, the present invention provides a method for hydrogenating acetophenone to prepare 1-phenylethanol, including: dissolving acetophenone in a solvent to form 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 of the hydrogenation reaction include: the reaction temperature is 60 - 120 °C, preferably 65 - 80 °C; the mass space velocity of acetophenone is 0.1 - 1 h -1 , preferably 0.3 - 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 alkanol, preferably methanol and / or ethanol.

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

[0046] The Cu-based catalyst provided by the present invention has high conversion rate and high selectivity in the reaction of hydrogenating acetophenone to prepare 1-phenylethanol, and has good water drainage ability, good reaction stability under low-temperature reaction conditions, long service life, and is suitable for industrial production of hydrogenating acetophenone to prepare 1-phenylethanol. Specific Embodiments

[0047] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below in combination with specific embodiments. It should be understood that the specific embodiments described here are only used to explain this patent in detail and do not limit the protection scope of the present invention in any way.

[0048] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which the present invention belongs. The reagents used in the following embodiments are all conventional biochemical reagents unless otherwise specified; the raw materials, instruments and equipment used in the following embodiments can all be obtained through market purchase or can be obtained by existing methods; the dosage of the reagents is the dosage of the reagents in conventional experimental operations unless otherwise specified; the experimental methods are all conventional methods unless otherwise specified.

[0049] The grain size of Cu was analyzed by X-ray powder diffraction (XRD) of type D / max-1400 produced by Rigaku Corporation, Japan. Using Cu-Kα as the radiation source, scanning was carried out at a tube voltage of 40 kV and a tube current of 40 mA.

[0050] The pore size of the catalyst was measured using a ASAP 2020 chemisorption analyzer produced by Micromeritics, USA. The sample to be measured was placed at 100 °C and purged with N 2 for 1 h, then heated to 300 °C for pretreatment for 4 h, and the mass of the degassed sample was recorded. Using N 2 as the adsorption gas, the nitrogen adsorption amount was measured at a liquid nitrogen temperature of -196 °C. The adsorption-desorption isotherm was measured by the static method.

[0051] Example 1

[0052] Weigh 226.8 g of copper nitrate trihydrate, dissolve it in 400 g of water, place it in a 2 L four-necked flask, stir with an external stirrer paddle, set the rotation speed to 500 rpm, and the temperature to 60 °C. Prepare a silica sol solution: weigh 125.1 g of 40 wt% silica sol and dilute it with water to 250 mL. Prepare an ammonium carbonate solution: weigh 94.5 g of ammonium carbonate, dissolve it in water, and dilute it to 500 mL. The silica sol solution and the ammonium carbonate solution were simultaneously added dropwise to the copper nitrate solution in the above four-necked flask, and the dropping speeds were 4.2 mL / min and 8.5 mL / min respectively. After the dropping was completed, stirring was stopped, aged at 60 °C for 2 h, filtered, washed 3 times with deionized water, and dried overnight at 120 °C to obtain the catalyst precursor CS-1.

[0053] All of the obtained catalyst precursor CS-1 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, it was placed in an extruder to extrude clover-shaped strips with a diameter of 1.2 mm and a length of 5 - 15 mm. The clover-shaped 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. The hydrogen pressure was 0.8 MPa, and the hydrogen volumetric space velocity was 800 h -1 , the reduction temperature was 230 °C, and the reduction time was 9 h to obtain the catalyst CAT-1, in which the content of Cu was 52.7 wt%, K 2 O content was 3.3 wt%, and the content of SiO 2 was 44.0 wt%. The crystal grain size of Cu was calculated to be 12.0 nm by the Scherrer formula, and the average pore diameter of the catalyst was 24.5 nm.

[0055] Example 2

[0056] Weighed 234.4 g of copper sulfate pentahydrate, dissolved it in 600 g of water, placed it in a 2 L four-necked flask, and stirred it with an external stirring paddle. Set the rotation speed to 400 rpm and the temperature to 70 °C. Prepared a silica sol solution: weighed 250 g of 30 wt% silica sol and diluted it with water to 300 mL. Prepared a sodium carbonate solution: weighed 104.4 g of sodium carbonate, dissolved it in water, and diluted it to 600 mL. The silica sol solution and the sodium carbonate solution were simultaneously added dropwise to the copper sulfate solution in the above four-necked flask, and the dropping speeds were 4.2 mL / min and 8.5 mL / min respectively. After the dropping was completed, the stirring was stopped. After aging at 60 °C for 2 h, it was filtered, washed 3 times with deionized water, and dried overnight at 120 °C to obtain the catalyst precursor CS-2.

[0057] All of the obtained catalyst precursor CS-2 was placed in a kneader, 6.0 g of sesbania powder was added, and 150 mL of potassium nitrate solution (containing 4.3 g of potassium nitrate) was added. After kneading for 20 min, it was placed in an extruder to extrude clover-shaped strips with a diameter of 1.2 mm and a length of 5 - 15 mm. The clover-shaped 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. The hydrogen pressure was 1.5 MPa, and the hydrogen volumetric space velocity was 1200 h -1 , the reduction temperature was 180 °C, and the reduction time was 4 h to obtain the catalyst CAT-2, in which the content of Cu was 43.8 wt%, K 2 O content was 1.5 wt%, and SiO2 The content is 54.7 wt%, and the grain size of Cu is calculated to be 10.4 nm by the Scherrer formula. The average pore diameter of the catalyst is 20.5 nm.

[0059] Example 3

[0060] Weigh 126.6 g of copper chloride and dissolve it in 600 g of water. Place it in a 2 L four-necked flask and stir it with an external stirrer paddle. Set the rotation speed to 400 rpm and the temperature to 70 °C. Prepare a silica sol solution: Weigh 187.5 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare an ammonia water solution: Weigh 133.9 g of 25% ammonia water, dissolve it in water, and dilute it to 600 mL. Add the silica sol solution and the ammonia water solution to the copper chloride solution in the above four-necked flask simultaneously, and the dropping speeds are 4.2 mL / min and 8.5 mL / min respectively. After the dropping is completed, stop stirring. Age at 60 °C for 2 h, then filter, wash with deionized water 3 times, and dry overnight at 120 °C to obtain the catalyst precursor CS-3.

[0061] Put all the obtained catalyst precursor CS-3 into a kneader, add 20 g of 25 wt% TMAOH solution, and add 130 mL of potassium carbonate solution (containing 1.47 g of potassium carbonate). Knead for 20 min, then place it in an extruder and extrude into three-leaf bars with a diameter of 1.2 mm and a length of 5 - 15 mm. Dry the three-leaf bars overnight at 120 °C and calcine at 350 °C for 4 h to obtain the alkali metal-modified catalyst precursor CMS-3.

[0062] Load CMS-3 into a fixed-bed reactor and reduce it with hydrogen. The hydrogen pressure is 1.5 MPa, the hydrogen volumetric space velocity is 1200 h -1 , the reduction temperature is 180 °C, and the reduction time is 4 h to obtain the catalyst CAT-3, in which the content of Cu is 44.2 wt%, K 2 The content of O is 0.7 wt%, and the content of SiO 2 is 55.1 wt%. The grain size of Cu is calculated to be 14.3 nm by the Scherrer formula, and the average pore diameter of the catalyst is 15.5 nm.

[0063] Example 4

[0064] Weigh 226.9 g of copper nitrate trihydrate, dissolve it in 600 g of water, place it in a 2-L four-necked flask, stir it with an external stirrer paddle, set the rotation speed at 400 rpm, and the temperature at 70 °C. Prepare a silica sol solution: Weigh 62.5 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare an ammonium carbonate solution: Weigh 96.5 g of ammonium carbonate, dissolve it in water, and dilute it to 600 mL. Drop the silica sol solution and the ammonium carbonate solution simultaneously into the copper nitrate solution in the above four-necked flask at dropping rates of 4.2 mL / min and 8.5 mL / min respectively. After the dropping is completed, stop stirring, age at 60 °C for 2 h, then filter, wash with deionized water 3 times, and dry overnight at 120 °C to obtain the catalyst precursor CS-4.

[0065] Put all of the obtained catalyst precursor CS-4 into a kneader, add 6 g of carob powder, and add 100 mL of potassium carbonate solution (containing 7.35 g of potassium carbonate). After kneading for 20 min, extrude it in an extruder to obtain clover-shaped strips with a diameter of 1.2 mm and a length of 5 - 15 mm. Dry the clover-shaped strips overnight at 120 °C and calcine at 450 °C for 8 h to obtain the alkali metal-modified catalyst precursor CMS-4.

[0066] Load CMS-4 into a fixed-bed reactor and reduce it with hydrogen. The hydrogen pressure is 1.5 MPa, the hydrogen volumetric space velocity is 1200 h -1 , the reduction temperature is 300 °C, and the reduction time is 4 h to obtain the catalyst CAT-4, where the content of Cu is 66.7 wt%, K 2 The content of O is 5.6 wt%, and the content of SiO 2 is 27.7 wt%. Calculate the crystal grain size of Cu to be 15.3 nm using the Scherrer formula, and the average pore diameter of the catalyst is 22.5 nm.

[0067] Example 5

[0068] Weigh 226.9 g of copper nitrate trihydrate, dissolve it in 600 g of water, place it in a 2-L four-necked flask, stir it with an external stirrer paddle, set the rotation speed at 400 rpm, and the temperature at 70 °C. Prepare a silica sol solution: Weigh 100 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare an ammonium carbonate solution: Weigh 98.0 g of ammonium carbonate, dissolve it in water, and dilute it to 600 mL. Drop the silica sol solution and the ammonium carbonate solution simultaneously into the copper nitrate solution in the above four-necked flask at dropping rates of 4.2 mL / min and 8.5 mL / min respectively. After the dropping is completed, stop stirring, age at 60 °C for 2 h, then filter, wash with deionized water 3 times, and dry overnight at 120 °C to obtain the catalyst precursor CS-5.

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

[0070] CMS-5 was loaded into a fixed-bed reactor and reduced with hydrogen. The hydrogen pressure was 1.5 MPa, and the hydrogen volume space velocity was 2500 h -1 , the reduction temperature was 250 °C, and the reduction time was 24 h to obtain a catalyst CAT-5, in which the content of Cu was 57.1 wt%, and the content of K 2 O was 4.8 wt%, and the content of SiO 2 was 38.1 wt%. The crystallite size of Cu was calculated to be 14.3 nm by the Scherrer formula, and the average pore diameter of the catalyst was 23.5 nm.

[0071] Example 6

[0072] Weighed 226.9 g of copper nitrate trihydrate, dissolved it in 600 g of water, placed it in a 2 L four-necked flask, and stirred it with an external stirrer paddle. The rotation speed was set at 400 rpm and the temperature was 80 °C. Prepared a silica sol solution: weighed 62.5 g of 40 wt% silica sol and diluted it with water to 300 mL. Prepared an ammonium carbonate solution: weighed 96.5 g of ammonium carbonate, dissolved it in water, and diluted it to 600 mL. The silica sol solution and the ammonium carbonate solution were simultaneously added dropwise to the copper nitrate solution in the above four-necked flask at dropping speeds of 4.2 mL / min and 8.5 mL / min respectively. After the dropping was completed, the stirring was stopped, aged at 80 °C for 2 h, filtered, washed 3 times with deionized water, and dried overnight at 120 °C to obtain a catalyst precursor CS-6.

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

[0074] CMS-6 was loaded into a fixed-bed reactor and reduced with hydrogen. The hydrogen pressure was 1.5 MPa, and the hydrogen volume space velocity was 2500 h -1 , the reduction temperature was 250 °C, and the reduction time was 24 h to obtain a catalyst CAT-6, in which the content of Cu was 66.7 wt%, and the content of K 2 O was 5.5 wt%, and the content of SiO2 The content is 27.8 wt%, and the crystal grain size of Cu calculated by the Scherrer formula is 15.2 nm. The average pore diameter of the catalyst is 26.9 nm.

[0075] Example 7

[0076] Weigh 226.9 g of copper nitrate trihydrate, dissolve it in 600 g of water, place it in a 2 L four-necked flask, stir with an external stirrer paddle, set the rotation speed to 400 rpm, and the temperature to 80 °C. Prepare a silica sol solution: Weigh 62.5 g of 40 wt% silica sol and dilute it with water to 300 mL. Prepare an ammonium carbonate solution: Weigh 96.5 g of ammonium carbonate, dissolve it in water, and dilute it to 600 mL. Drop the silica sol solution and the ammonium carbonate solution simultaneously into the copper nitrate solution in the above four-necked flask, and the dropping speeds are 4.2 mL / min and 8.5 mL / min respectively. After the dropping is completed, stop stirring, age at 80 °C for 2 h, then filter, wash 3 times with deionized water, and dry overnight at 120 °C to obtain the catalyst precursor CS-7.

[0077] Put all the obtained catalyst precursor CS-7 into a kneader, add 10 g of talc powder, and add 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate), knead for 20 min, then place it in an extruder and extrude into clover-shaped strips with a diameter of 1.2 mm and a length of 5 - 15 mm. Dry the clover-shaped strips overnight at 120 °C and calcine at 350 °C for 4 h to obtain the alkali metal-modified catalyst precursor CMS-7.

[0078] Load CMS-7 into a fixed-bed reactor and reduce it with hydrogen. The hydrogen pressure is 1.5 MPa, the hydrogen volume space velocity is 2500 h -1 , the reduction temperature is 250 °C, and the reduction time is 24 h to obtain the catalyst CAT-7, where the content of Cu is 68.2 wt%, and K 2 The content of O is 3.4 wt%, and the content of SiO 2 is 28.4 wt%. The crystal grain size of Cu calculated by the Scherrer formula is 14.7 nm, and the average pore diameter of the catalyst is 24.3 nm.

[0079] Example 8

[0080] The preparation method of the catalyst refers to Example 7, and the only difference is that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) is replaced by 100 mL of lithium carbonate solution (containing 7.41 g of lithium carbonate).

[0081] The obtained catalyst is CAT-8, where the content of Cu is 68.2 wt%, and Li 2 The content of O is 3.4 wt%, and the content of SiO 2The content of [substance] is 28.4 wt%, and the grain size of Cu calculated by the Scherrer formula is 14.5 nm. The average pore diameter of the catalyst is 21.0 nm.

[0082] Example 9

[0083] The preparation method of the catalyst refers to Example 7, with the only difference being that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) is replaced by 100 mL of sodium carbonate solution (containing 5.13 g of sodium carbonate).

[0084] The obtained catalyst is CAT-9, in which the content of Cu is 68.2 wt%, and the content of Na 2 O is 3.4 wt%, and the content of SiO 2 is 28.4 wt%. The grain size of Cu calculated by the Scherrer formula is 14.6 nm, and the average pore diameter of the catalyst is 22.5 nm.

[0085] Example 10

[0086] The preparation method of the catalyst refers to Example 7, with the only difference being that 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) is replaced by 100 mL of rubidium carbonate solution (containing 3.7 g of rubidium carbonate).

[0087] The obtained catalyst is CAT-10, in which the content of Cu is 68.2 wt%, and the content of Na 2 O is 3.4 wt%, and the content of SiO 2 is 28.4 wt%. The grain size of Cu calculated by the Scherrer formula is 14.3 nm, and the average pore diameter of the catalyst is 25.5 nm.

[0088] Comparative Example 1

[0089] The preparation method of the catalyst refers to Example 7, with the only difference being that the copper nitrate solution and the ammonium carbonate solution are simultaneously dropped into the silica sol solution, and the dropping rate is 8.5 mL / min for both.

[0090] The obtained catalyst is DCAT-1, in which the content of Cu is 68.2 wt%, and the content of K 2 O is 3.4 wt%, and the content of SiO 2 is 28.4 wt%. The grain size of Cu calculated by the Scherrer formula is 20.7 nm, and the average pore diameter of the catalyst is 25.2 nm.

[0091] Comparative Example 2

[0092] The preparation method of the catalyst refers to Example 7, with the only difference being that the silica sol solution and the copper nitrate solution are simultaneously dropped into the ammonium carbonate solution, and the dropping rates are 4.2 mL / min and 8.5 mL / min respectively.

[0093] The obtained catalyst is DCAT-2, in which the content of Cu is 68.2 wt%, and the content of K 2 O is 3.4 wt%, and the content of SiO 2 is 28.4 wt%. The crystallite size of Cu is calculated to be 18.7 nm by the Scherrer formula, and the average pore diameter of the catalyst is 24.1 nm.

[0094] Comparative Example 3

[0095] The preparation method of the catalyst refers to Example 7, except that: 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) is replaced by 100 mL of pure water.

[0096] The obtained catalyst is DCAT-3, in which the content of Cu is 71.3 wt%, and the content of SiO 2 is 28.7 wt%. The crystallite size of Cu is calculated to be 15.0 nm by the Scherrer formula, and the average pore diameter of the catalyst is 12.1 nm.

[0097] Comparative Example 4

[0098] The preparation method of the catalyst refers to Example 7, except that: 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) is replaced by 100 mL of magnesium nitrate solution (containing 11.1 g of magnesium nitrate).

[0099] The obtained catalyst is DCAT-4, in which the content of Cu is 68.1 wt%, the content of MgO is 3.4 wt%, and the content of SiO 2 is 28.4 wt%. The crystallite size of Cu is calculated to be 14.3 nm by the Scherrer formula, and the average pore diameter of the catalyst is 13.2 nm.

[0100] Comparative Example 5

[0101] The preparation method of the catalyst refers to Example 7, except that: 100 mL of potassium carbonate solution (containing 4.41 g of potassium carbonate) is replaced by 100 mL of calcium nitrate solution (containing 8.79 g of calcium nitrate).

[0102] The obtained catalyst is DCAT-5, in which the content of Cu is 68.4 wt%, the content of CaO is 3.4 wt%, and the content of SiO 2 is 28.2 wt%. The crystallite size of Cu is calculated to be 14.2 nm by the Scherrer formula, and the average pore diameter of the catalyst is 13.5 nm.

[0103] Catalytic performance evaluation of the catalyst

[0104] (1) Comparison of catalyst performance of each example and comparative example

[0105] 20 g of the catalysts of each example and comparative example were respectively loaded into a 12 mm stainless steel reactor, and the reaction was carried out at 65 °C with a hydrogen pressure of 2.0 MPa. The acetophenone raw material was a 30% ethanol solution of acetophenone, and the acetophenone space velocity was 0.4 h -1 , and the molar ratio of hydrogen to ketone (hydrogen and acetophenone) was 2.0. After reacting for 24 h, samples were taken for detection, and the results are shown in Table 1.

[0106] Conversion rate of acetophenone = [acetophenone (in) - acetophenone (out)] / acetophenone (in) × 100% (in mole percentage)

[0107] Selectivity of 1-phenylethanol = {1 - 1-phenylethanol (out) / [acetophenone (in) - acetophenone (out)]} × 100% (in mole percentage)

[0108] Table 1

[0109]

[0110]

[0111] (2) Variation of acetophenone hydrogenation conversion rate and selectivity with reaction conditions

[0112] 20 g of the catalyst CAT-7 of Example 7 was loaded into a 12 mm stainless steel reactor. The acetophenone raw material was a 30 wt% ethanol solution of acetophenone. The reaction temperature, hydrogen pressure, molar ratio of hydrogen to ketone (hydrogen and acetophenone), and acetophenone space velocity are shown in Table 2. After reacting for 24 h, samples were taken for detection, and the results are shown in Table 2.

[0113] Table 2

[0114]

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

[0116] 20 g of the catalyst CAT-7 of Example 7 and 20 g of the catalyst DCAT-3 of Comparative Example 3 were respectively loaded into a 12 mm stainless steel reactor, and the reaction was carried out at 65 °C with a hydrogen pressure of 2.0 MPa. The acetophenone raw material was a 30% ethanol solution of acetophenone, and the acetophenone space velocity was 0.4 h -1 , and the molar ratio of hydrogen to ketone (hydrogen and acetophenone) was 2.0. Samples were taken for detection after reacting for 500 h, 1000 h, 1500 h, 2000 h, 2500 h, and 3000 h respectively, and the results are shown in Table 3.

[0117] Table 3

[0118]

[0119] As can be seen from Table 3, the Cu catalyst provided by the present invention is used in the hydrogenation reaction of acetophenone. Under the reaction conditions of low temperature (65 °C), the catalytic performance has been stably operated for 3000 h without obvious decline, showing good stability and being suitable for the industrial production of 1-phenylethanol by hydrogenation of acetophenone.

[0120] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention as provided, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A Cu-based catalyst, characterized in that, including Cu, alkali metal oxide M 2 O and SiO 2 a carrier; the particle size of Cu in the catalyst is 8-16 nm, and the average pore diameter of the catalyst is 15-30 nm.

2. The Cu-based catalyst according to claim 1, characterized in that, the contents of the components in the catalyst are: Cu: 40 to 80 parts by weight, preferably 50 to 70 parts by weight; M 2 O: 0.5 to 10 parts by weight, preferably 1 to 6 parts by weight; SiO 2 Carrier: 10 to 59.5 parts by weight, preferably 24 to 49 parts by weight; and / or, The alkali metal oxide M 2 O includes Li 2 O, Na 2 O, K 2 O, Rb 2 O, and Cs 2 O, and at least one of them.

3. A method for preparing a Cu-based catalyst, characterized in that, comprising: S1. Simultaneously add the silica sol solution and the precipitant solution dropwise to the copper precursor solution. After the addition is completed, age the mixture, filter it to obtain the CuO / SiO 2 precursor; S2. Mix the CuO / SiO 2 precursor, alkali metal oxide precursor, extrusion aid and water, then form, calcine to obtain the CuO-M 2 O / SiO 2 precursor; S3. Reduce the CuO-M 2 O / SiO 2 precursor under a hydrogen atmosphere to obtain the Cu-based catalyst.

4. The preparation method according to claim 3, characterized in that, the copper precursor includes at least one of copper nitrate, copper chloride, copper sulfate, and copper bromide; and / or, the precipitating agent includes at least one of ammonia water, 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 methyl cellulose, glycerol, sesbania powder, and tetramethylammonium hydroxide.

5. The preparation method according to claim 3 or 4, characterized in that, The mass ratio of the copper precursor calculated as Cu, the alkali metal oxide precursor calculated as M 2 O, and the silica sol calculated as SiO 2 is (40 to 80):(0.5 to 10):(10 to 59.5), preferably (50 to 70):(1 to 6):(24 to 49); and / or, Cu in the copper precursor solution 2+ has a concentration of 0.2 to 2.5 mol / L; and / or, the SiO in the silica sol solution 2 content is 5-40 wt%; And / or, the dosage of the extrusion aid is 2-40 wt% of the CuO / SiO 2 precursor.

6. The preparation method according to any one of claims 3-5, characterized in that, the dropping is carried out under stirring conditions; and / or, the temperature of the dropping is 20 to 95 °C; and / or, the temperature of the aging is 20 to 95 °C, and the time is 1 to 30 h; and / or, the temperature of the calcination is 300 to 750 °C, and the time is 2 to 24 h; And / or, the reduction conditions include: the hydrogen partial pressure is 0.05 to 2.0 MPa, and the volumetric space velocity of hydrogen is 200 to 4000 h -1 ; the reduction temperature is 150 to 350 °C, and the reduction time is 1 to 48 h.

7. A Cu-based catalyst prepared by the preparation method according to any one of claims 3-6.

8. Use of the Cu-based catalyst according to claim 1 or 2 or the Cu-based catalyst according to claim 7 in the hydrogenation of acetophenone to prepare 1-phenylethanol.

9. A method for hydrogenating acetophenone to prepare 1-phenylethanol, characterized in that, comprising: dissolving acetophenone in a solvent to form an acetophenone solution, and subjecting the acetophenone solution to a hydrogenation reaction in the presence of the Cu-based catalyst according to claim 1 or 2 or the Cu-based catalyst according to claim 7 to obtain 1-phenylethanol.

10. The method according to claim 9, characterized in that, The conditions for the hydrogenation reaction include: the reaction temperature is 60 - 120 °C; the mass space velocity of acetophenone is 0.1 - 1 h -1 ; the hydrogen pressure is 1 - 5 MPa; the feed molar ratio of hydrogen to acetophenone is 1 - 20; and / or, the solvent includes alkanol, preferably methanol and / or ethanol.

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