Cu-x / al2o3+y / sio2 catalyst and preparation and application thereof in catalytic coupling of alcohol and aldehyde to prepare higher alcohols

Abstract

The application discloses a Cu-X / Al2O3+Y / SiO2 catalyst and a preparation method and application thereof in alcohol aldehyde catalytic coupling for preparing high carbon alcohol, the Cu-X / Al2O3+Y / SiO2 catalyst is composed of a Cu-X / Al2O3 component and a Y / alkali metal modified SiO2 component, wherein X is one of Ni, Co, Mo, Au and Ag; Y is one of La, Ce and Y rare earth metal; and the catalyst component mass percentage is as follows: Cu-X / Al2O3 metal active component, 40-80%; Y / alkali metal modified SiO2 basic active component, 20-60%. The application adopts an ethanol and low alcohol aldehyde mixed feed system, and matches the catalyst system made of a multi-metal active component and a hydrophobic composite carrier, so that the ethanol conversion rate and C6+ high carbon alcohol selectivity can be remarkably improved, and the application has good technical economy and wide market prospect.

Description

Technical Field

[0001] This invention belongs to the field of ethanol to higher alcohols technology, specifically relating to a Cu-X / Al2O3+Y / SiO2 catalyst, its preparation, and its application in the catalytic coupling of alcohols and aldehydes to higher alcohols. Background Technology

[0002] Existing technologies for producing higher alcohols from ethanol mostly rely on single-metal catalysts (such as Cu-based or Ni-based catalysts), which suffer from low selectivity for C6+ higher alcohol products and poor catalyst stability. For example, in traditional methods, Cu-based catalysts are prone to deactivation due to carbon deposition, while Ni-based catalysts, although promoting carbon chain growth, result in numerous side reactions leading to a wide product distribution and increased separation costs. Furthermore, support design often neglects the acid-base synergistic effect, making it difficult to precisely control the ethanol condensation reaction pathway. This patent overcomes the existing technological bottlenecks by introducing a multi-metal component and a hydrophobic composite support, employing a coupling method between ethanol and n-butyraldehyde, to achieve the directed and efficient synthesis of C6+ higher alcohols.

[0003] CN113443964A discloses a method for the catalytic conversion of ethanol to higher alcohols. The method uses ethanol as a raw material to react and generate higher alcohols under the action of a catalyst. The catalyst used is a homogeneous mixture of catalyst I and catalyst II in a mass ratio of 1:10 to 10:1. Catalyst I is a solid catalyst for the dehydrogenation condensation of ethanol to generate higher alcohols, and catalyst II is a catalyst containing α-hydroxyl radicals. A solid catalyst capable of performing aldol condensation reactions of aldehydes or ketones with H is introduced based on catalyst I, with more aldol condensation active centers introduced, and the two work together to catalyze the conversion of ethanol into higher alcohols.

[0004] The above methods also have problems such as low selectivity of C6+ higher alcohols and long diffusion distance of intermediate products.

[0005] Therefore, seeking a simple, stable, and highly selective catalyst preparation route and application for ethanol-to-higher-alcohol production is of great industrial significance and prospect. Summary of the Invention

[0006] To overcome the shortcomings of the existing technology, the present invention aims to provide a Cu-X / Al2O3+Y / SiO2 catalyst, its preparation, and its application in the catalytic coupling of alcohols and aldehydes to produce higher alcohols. The method uses a mixed feed system of ethanol and lower alcohols and aldehydes, and matches it with a catalyst system made of multi-metal active components and hydrophobic composite supports. It can significantly improve the ethanol conversion rate and the selectivity of C6+ higher alcohols, and has both good technical and economic advantages and broad market prospects.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A Cu-X / Al2O3+Y / SiO2 catalyst, comprising a Cu-X / Al2O3 component and a Y / alkali metal modified SiO2 component, wherein: X is one of Ni, Co, Mo, Au, and Ag; Y is one of the rare earth metals La, Ce, and Y; The mass percentage of the catalyst component is: The active metal component of Cu-X / Al2O3 is 40-80%; The alkaline active component of Y / alkali metal modified SiO2 is 20~60%.

[0008] The Cu-X / Al2O3+Y / SiO2 catalyst has a ladder-like pore structure. The Cu-X / Al2O3 catalyst is mainly composed of micropores and small mesopores, which can provide sufficient metal active sites to support the ethanol dehydrogenation activation reaction. The alkali metal modified Y / SiO2 is mainly composed of large mesopores, which can construct basic active sites and is suitable for aldol condensation reaction.

[0009] A method for synthesizing a Cu-X / Al2O3+Y / SiO2 catalyst includes the following steps: Step 1: Obtain powdered Al2O3 support, impregnate the powdered Al2O3 support with equal volumes of Cu and X precursor solutions, and then dry and calcine to obtain Cu-X / Al2O3 material; Step 2: Mix the alkali metal precursor solution with SiO2 powder, stir under constant temperature hydrothermal conditions, filter and dry, and then calcine to obtain alkali metal modified SiO2 support; impregnate the Y rare earth metal precursor solution with the alkali metal modified SiO2 support in equal volumes, dry and then calcine to obtain Y / alkali metal modified SiO2 support. Step 3: Mix the Y / alkali metal modified SiO2 support and Cu-X / Al2O3 material, and dry to obtain Cu-X / Al2O3+Y / SiO2 catalyst.

[0010] In step 1: Powdered Al2O3 support was obtained by calcining boehmite at 600℃ for 4h; Cu and X precursor solutions were impregnated in the powdered Al2O3 support in equal volumes according to the Cu / X / Al2O3 molar ratio of (0.05~0.15):(0.005~0.15):1.

[0011] Furthermore, the impregnation time is 8~24h, and after drying, it is calcined at 350~550℃ for 2~6h to obtain Cu-X / Al2O3 material.

[0012] In step 2, the alkali metal precursor solution and SiO2 powder are mixed at an alkali metal element / SiO2 molar ratio of 0.01~0.1:1 and a liquid-solid ratio of 10:1 (ml / g). The mixture is stirred for 2~4 hours under constant temperature hydrothermal conditions at 50~70℃. After filtration and drying, the mixture is calcined at 350~600℃ for 2~4 hours to obtain the alkali metal modified SiO2 support. The Y rare earth metal precursor solution was impregnated with an equal volume of Y / alkali metal modified SiO2 support at a molar ratio of Y / alkali metal modified SiO2 support (0.001~0.1):1 for 12~60 h. After drying, it was calcined at 350~550℃ for 2~8 h to obtain Y / alkali metal modified SiO2 support.

[0013] In step 3, the Y / alkali metal modified SiO2 support and Cu-X / Al2O3 material are added to distilled water at a ratio of (0.1~5):1 and stirred evenly, with a liquid-solid ratio of 10:1. After drying, Cu-X / Al2O3+Y / SiO2 catalyst is obtained.

[0014] The Cu-X / Al2O3+Y / SiO2 catalyst is applied in the field of catalytic coupling of ethanol and n-butyraldehyde to produce higher alcohols.

[0015] The Cu-X / Al2O3+Y / SiO2 catalyst was shaped and loaded into a fixed-bed reactor. It was then subjected to programmed temperature pre-reduction in a mixed gas (H2 volume fraction 5%~50%, with the remainder being N2) at a temperature of 200~500℃. The reduced catalyst undergoes an ethanol-catalyzed coupling reaction under the following conditions: Reaction temperature: 200~350℃ (preferably 250~300℃); Reaction pressure: atmospheric pressure ~ 7 MPa (preferably 2 ~ 5 MPa); Feed liquid hourly space velocity (LHSV): 0.5~4.0 ml / (g cat·h); Nitrogen / ethanol feed volume ratio: (100 ~ 300): 1; Ethanol / butyraldehyde feed mass ratio: 1:(0.05~0.15); The reaction products obtained were processed by a hydrogenation unit to yield C4~C alcohols, mainly C6 higher alcohols. 12 Mixed higher alcohol products.

[0016] The SiO2 powder is mesoporous silicon oxide with a pore size ranging from 20 to 50 nm and a specific surface area of ​​200 to 500 m². 2 / g; The alkali metal of the metal-modified SiO2 support is one of Na, K, Ba, or Mg nitrates. The powdered Al2O3 carrier has a pore size range of 2-16 nm and a specific surface area of ​​200-400 m². 2 / g; The Cu precursor is one of copper nitrate, copper acetate, or copper sulfate.

[0017] The beneficial effects of this invention are: (1) This invention introduces n-butyraldehyde into an ethanol catalytic coupling system. By utilizing the aldol condensation reaction of n-butyraldehyde with acetaldehyde, an intermediate product of ethanol dehydrogenation, the reaction of acetaldehyde self-condensation to generate C4 alcohol is inhibited, thus directionally promoting the generation of C6+ higher alcohols. Since the added value of C6+ higher alcohols is much higher than that of other low-carbon alcohol products, this process can significantly improve the technical and economic efficiency of the downstream ethanol industry chain, and at the same time open up a practical and feasible technical route for the efficient preparation of C6+ alcohols.

[0018] (2) This invention specifically develops a bifunctional catalyst system adapted to the existing ethanol-n-butyraldehyde catalytic coupling to produce higher alcohols. This catalyst improves the Cu metal chemical environment by introducing a multi-metal active component and a basic functional component, thereby efficiently exerting the synergistic effect of the dual functions of the metal active site and the basic active site, ensuring the efficient progress of the ethanol to higher alcohol reaction; by using a stepwise batch impregnation method of Cu-X / Al2O3 metal active component and Y / SiO2 basic active component, followed by overall mixing, the diffusion distance between the two active sites is further shortened while retaining the two independent active sites of metal dehydrogenation / hydrogenation and basic aldol condensation, effectively suppressing the reaction termination problem caused by the hydrogenation saturation of highly active substances such as n-butyraldehyde and acetaldehyde before participating in the target reaction, thereby significantly improving the ethanol conversion rate and the selectivity of high carbon number higher alcohols.

[0019] (3) The present invention uses an alkali metal modified hydrophobic SiO2 support as a dedicated aldol condensation center, which has advantages in two dimensions: on the one hand, the alkali metal loading is used to construct alkaline active sites for the neutral SiO2 support, providing sufficient active sites and reaction space for the aldol condensation reaction; on the other hand, the hydrophobic properties of the SiO2 support can inhibit the accumulation of water, a byproduct of aldol condensation, on the catalyst surface, avoiding the disadvantages such as increased diffusion resistance and inhibition of reaction equilibrium caused by water enrichment, thereby promoting the smooth progress of the aldol condensation reaction.

[0020] (4) The method provided by the present invention is simple to operate, has good repeatability, good economic benefits, and is relatively environmentally friendly. Detailed Implementation

[0021] Example 1: Cu-Ni / Al2O3+Ce / potassium modified SiO2 bifunctional catalyst and its application: 1. Catalyst composition: This catalyst is physically composed of a Cu-Ni / Al2O3 metal hydrogenation / dehydrogenation functional component and a Ce / potassium-modified SiO2 alkaline functional component; the mass percentage of each component is as follows: Cu-Ni / Al2O3 metal active component: 65%; Ce / potassium-modified SiO2 alkaline active component: 35%; the molar ratio of Cu, Ni and Al2O3 is 0.12:0.08:1; the molar ratio of Ce to potassium-modified SiO2 support is 0.006:1.

[0022] 2. Catalyst Synthesis Methods: (1) Preparation of Al2O3 support: Powdered Al2O3 support was prepared by calcining boehmite at 600℃ for 4 h. The support had a pore size of 10 nm and a specific surface area of ​​320 m². 2 / g. (2) Preparation of potassium-modified SiO2 support: Selected with a pore size of 35nm and a specific surface area of ​​380 m² 2 / g of mesoporous silica was used as the matrix SiO2 powder; potassium nitrate was selected as the alkali metal precursor. The potassium nitrate precursor solution and SiO2 powder were mixed at a K element / SiO2 molar ratio of 0.06:1 and a liquid-solid ratio of 10:1 (ml / g). The mixture was stirred hydrothermally at 60℃ for 4h, filtered, dried at 90℃ for 6h, and then calcined at 450℃ for 2h to obtain potassium-modified SiO2 support. (3) Preparation of Ce / potassium-modified SiO2 alkaline component: Cerium nitrate was used as the rare earth precursor. The Ce / potassium-modified SiO2 was impregnated by the equal volume impregnation method at a Ce / potassium-modified SiO2 molar ratio of 0.006:1 for 28h. After drying at 110℃ for 6h, it was calcined at 500℃ for 4h to obtain Ce / potassium-modified SiO2 alkaline functional component. (4) Preparation of Cu-Ni / Al2O3 metal component: Copper nitrate was selected as the Cu precursor and nickel nitrate was selected as the Ni precursor. A mixed precursor solution was prepared according to the Cu / Ni / Al2O3 molar ratio of 0.12:0.08:1. The solution was impregnated in the above Al2O3 support in equal volume for 24 h. After drying at 110 °C for 6 h, it was calcined at 450 °C for 4 h to obtain the Cu-Ni / Al2O3 metal hydrogenation / dehydrogenation functional component. (5) Composite molding of bifunctional catalyst: Ce / potassium modified SiO2 and Cu-Ni / Al2O3 were mixed at a mass ratio of 0.54:1 and added to distilled water. The liquid-solid ratio was controlled at 10:1 (ml / g). The mixture was stirred and mixed evenly and dried at 110 °C for 6 h. The dried solid was pressed into tablets and sieved to obtain 20-40 mesh particles, which are the target Cu-Ni / Al2O3+Ce / potassium modified SiO2 bifunctional catalyst.

[0023] 3. Catalyst application performance evaluation: A 20-40 mesh catalyst was packed into a fixed-bed reactor and pre-reduced at a programmed temperature of 350°C in a mixed atmosphere with 10% H2 volume fraction and N2 as the equilibrium gas. After reduction, the catalyst underwent an ethanol-n-butyraldehyde catalytic coupling reaction under the following conditions: reaction temperature 280°C, reaction pressure 5 MPa, liquid hourly space velocity (LHSV) of 1.8 ml / (g cat·h); nitrogen / ethanol feed volume ratio 280:1, ethanol / n-butyraldehyde mass ratio 1:0.10. The reaction product was then processed by a downstream hydrogenation unit to obtain C4-C6 compounds. 12 The mixed higher alcohol products showed an ethanol conversion rate of 53.89%, a total higher alcohol selectivity of 93.02%, and a C6+ higher alcohol selectivity of 42.54%.

[0024] Example 2: Cu-Co / Al2O3+La / Modified SiO2 Bifunctional Catalyst and Its Application: 1. Catalyst composition: This catalyst is physically composed of a Cu-Co / Al2O3 metal hydrogenation / dehydrogenation functional component and a La / sodium-modified SiO2 alkaline functional component; the mass percentage of each component is as follows: Cu-Co / Al2O3 metal active component: 60%; La / sodium-modified SiO2 alkaline active component: 40%; the molar ratio of Cu, Co and Al2O3 is 0.14:0.12:1; the molar ratio of La and sodium-modified SiO2 support is 0.009:1.

[0025] 2. Catalyst Synthesis Methods: (1) Preparation of Al2O3 support: Powdered Al2O3 support was prepared by calcining boehmite at 600℃ for 4h. The support had a pore size of 12nm and a specific surface area of ​​360m². 2 / g. (2) Preparation of sodium-modified SiO2 support: Select a pore size of 45nm and a specific surface area of ​​420 m². 2 / g of mesoporous silica was used as the matrix SiO2 powder; sodium nitrate was selected as the alkali metal precursor. The sodium nitrate precursor solution and SiO2 powder were mixed at a Na element / SiO2 molar ratio of 0.09:1 and a liquid-solid ratio of 10:1 (ml / g). The mixture was stirred hydrothermally at 65℃ for 6h, filtered, dried at 110℃ for 4h, and then calcined at 450℃ for 2h to obtain sodium-modified SiO2 support. (3) Preparation of La / sodium-modified SiO2 alkaline component: Lanthanum nitrate was used as the rare earth precursor. The La / sodium-modified SiO2 was impregnated by the equal volume impregnation method at a La / sodium-modified SiO2 molar ratio of 0.009:1 for 36h. After drying at 110℃ for 4h, it was calcined at 500℃ for 6h to obtain the La / sodium-modified SiO2 alkaline functional component. (4) Preparation of Cu-Co / Al2O3 metal component: Copper nitrate was selected as the Cu precursor and cobalt nitrate was selected as the Co precursor. A mixed precursor solution was prepared according to the Cu / Co / Al2O3 molar ratio of 0.14:0.12:1. The solution was impregnated in the above Al2O3 support in equal volume for 48 h. After drying at 110 °C for 6 h, it was calcined at 400 °C for 4 h to obtain the Cu-Co / Al2O3 metal hydrogenation / dehydrogenation functional component. (5) Composite molding of bifunctional catalyst: La / sodium modified SiO2 and Cu-Co / Al2O3 were added to distilled water at a mass ratio of 0.66:1, and the liquid-solid ratio was controlled at 10:1 (ml / g). The mixture was stirred and mixed evenly, and dried at 110 °C for 10 h. The dried solid was pressed into tablets and sieved to obtain 20-40 mesh particles, which is the target Cu-Co / Al2O3+La / modified SiO2 bifunctional catalyst.

[0026] 3. Catalyst application performance evaluation: A 20-40 mesh catalyst was packed into a fixed-bed reactor and pre-reduced at a programmed temperature of 300℃ in a mixed atmosphere with 20% H2 volume fraction and N2 as the equilibrium gas. After reduction, the catalyst underwent an ethanol-n-butyraldehyde catalytic coupling reaction under the following conditions: reaction temperature 300℃, reaction pressure 4MPa, and liquid hourly space velocity (LHSV) of 2.0 ml / (g cat). h); nitrogen / ethanol feed volume ratio 220:1, ethanol / n-butyraldehyde mass ratio 1:0.12; the reaction product is processed by a downstream hydrogenation unit to obtain C4~C 12 The mixed higher alcohol products showed an ethanol conversion rate of 55.90%, a total higher alcohol selectivity of 95.26%, and a C6+ higher alcohol selectivity of 45.74%.

[0027] Example 3: Cu-Au / Al2O3+Y / Modified SiO2 Bifunctional Catalyst and Its Application: 1. Catalyst composition: This catalyst is physically composed of a Cu-Au / Al2O3 metal hydrogenation / dehydrogenation functional component and a Y / barium modified SiO2 alkaline functional component; the mass percentage of each component is as follows: Cu-Au / Al2O3 metal active component: 70%; Y / barium modified SiO2 alkaline active component: 30%; the molar ratio of Cu, Au and Al2O3 is 0.09:0.02:1; the molar ratio of Y and barium modified SiO2 support is 0.004:1.

[0028] 2. Catalyst Synthesis Methods: (1) Preparation of Al2O3 support: Powdered Al2O3 support was prepared by calcining boehmite at 600℃ for 4h. The support had a pore size of 8nm and a specific surface area of ​​280m². 2 / g. (2) Preparation of barium-modified SiO2 support: Select a pore size of 28nm and a specific surface area of ​​300 m². 2 / g of mesoporous silica as the matrix SiO2 powder; barium nitrate was selected as the alkali metal precursor. The barium nitrate precursor solution and SiO2 powder were mixed at a Ba element / SiO2 molar ratio of 0.04:1 and a liquid-solid ratio of 10:1 (ml / g). The mixture was stirred hydrothermally at 60℃ for 4h, filtered, dried at 105℃ for 6h, and then calcined at 350℃ for 6h to obtain the barium-modified SiO2 support. (3) Preparation of Y / barium-modified SiO2 alkaline component: Yttrium nitrate was used as the rare earth precursor. The Y / barium-modified SiO2 was impregnated by the equal volume impregnation method at a molar ratio of 0.004:1 for 60h. After drying at 105℃ for 6h, it was calcined at 450℃ for 4h to obtain the Y / barium-modified SiO2 alkaline functional component. (4) Preparation of Cu-Au / Al2O3 metal component: Copper sulfate was selected as the Cu precursor and chloroauric acid was selected as the Au precursor. A mixed precursor solution was prepared according to the Cu / Au / Al2O3 molar ratio of 0.09:0.02:1. The solution was impregnated in the above Al2O3 support in equal volume for 18 hours. After drying at 105℃ for 6 hours, it was calcined at 500℃ for 4 hours to obtain the Cu-Au / Al2O3 metal hydrogenation / dehydrogenation functional component. (5) Composite molding of bifunctional catalyst: Y / barium modified SiO2 and Cu-Au / Al2O3 were added to distilled water at a mass ratio of 0.40:1, and the liquid-solid ratio was controlled at 10:1 (ml / g). The mixture was stirred and mixed evenly, and dried at 90℃ for 12 hours. The dried solid was pressed into tablets and sieved to obtain 20-40 mesh particles, which are the target Cu-Au / Al2O3+Y / modified SiO2 bifunctional catalyst.

[0029] 3. Catalyst application performance evaluation: A 20-40 mesh catalyst was packed into a fixed-bed reactor and pre-reduced at a programmed temperature of 330°C in a mixed atmosphere with 28% H2 volume fraction and N2 as the equilibrium gas. After reduction, the catalyst underwent an ethanol-n-butyraldehyde catalytic coupling reaction under the following conditions: reaction temperature 300°C, reaction pressure 3 MPa, and liquid hourly space velocity (LHSV) of 1.2 ml / (g cat). h); Nitrogen / ethanol feed volume ratio 280:1, ethanol / n-butyraldehyde mass ratio 1:0.08; the reaction product is processed by a downstream hydrogenation unit to obtain C4-C6 compounds. 12 The mixed higher alcohol products showed an ethanol conversion rate of 48.23%, a total higher alcohol selectivity of 92.01%, and a C6+ higher alcohol selectivity of 41.32%.

[0030] Example 4: Cu-Mo / Al2O3+Ce / Modified SiO2 Bifunctional Catalyst and Its Applications: 1. Catalyst composition: This catalyst is physically composed of a Cu-Mo / Al2O3 metal hydrogenation / dehydrogenation functional component and a Ce / magnesium modified SiO2 alkaline functional component; the mass percentage of each component is as follows: Cu-Mo / Al2O3 metal active component: 68%; Ce / magnesium modified SiO2 alkaline active component: 32%; the molar ratio of Cu, Mo and Al2O3 is 0.10:0.05:1; the molar ratio of Ce to magnesium modified SiO2 support is 0.007:1.

[0031] 2. Catalyst Synthesis Methods: (1) Preparation of Al2O3 support: Pseudoboehmite was calcined at 600℃ for 4h to obtain powdered Al2O3 support with a pore size of 12nm and a specific surface area of ​​300 m² / g. (2) Preparation of magnesium-modified SiO2 support: Mesoporous silica with a pore size of 32nm and a specific surface area of ​​340 m² / g was selected as the matrix SiO2 powder; magnesium nitrate was selected as the alkali metal precursor. The magnesium nitrate precursor solution and SiO2 powder were mixed at a Mg element / SiO2 molar ratio of 0.07:1 and a liquid-solid ratio of 10:1 (ml / g). The mixture was hydrothermally stirred at 60℃ for 3h, filtered, dried at 110℃ for 6h, and then calcined at 400℃ for 3h to obtain magnesium-modified SiO2 support. (3) Preparation of Ce / magnesium modified SiO2 alkaline component: Cerium nitrate was used as a rare earth precursor. The Ce / magnesium modified SiO2 was impregnated by an equal volume impregnation method at a molar ratio of 0.007:1 for 32 h. After drying at 110 °C for 4 h, it was calcined at 450 °C for 6 h to obtain the Ce / magnesium modified SiO2 alkaline functional component. (4) Preparation of Cu-Mo / Al2O3 metal component: Copper nitrate was used as the Cu precursor and ammonium molybdate was used as the Mo precursor. A mixed precursor solution was prepared at a molar ratio of Cu / Mo / Al2O3 of 0.10:0.05:1. The solution was impregnated in the above Al2O3 support by an equal volume for 18 h. After drying at 110 °C for 6 h, it was calcined at 500 °C for 4 h to obtain the Cu-Mo / Al2O3 metal hydrogenation / dehydrogenation functional component. (5) Bifunctional catalyst composite molding: Ce / magnesium modified SiO2 and Cu-Mo / Al2O3 are added to distilled water at a mass ratio of 0.47:1, and the liquid-solid ratio is controlled at 10:1 (ml / g). The mixture is stirred and mixed evenly, and dried at 110℃ for 12h. The dried solid is pressed into tablets and sieved to obtain 20-40 mesh particles, which are the target Cu-Mo / Al2O3+Ce / modified SiO2 bifunctional catalyst.

[0032] 3. Catalyst application performance evaluation: A 20-40 mesh catalyst was packed into a fixed-bed reactor and pre-reduced at a programmed temperature of 360°C in a mixed atmosphere with 30% H2 volume fraction and N2 as the equilibrium gas. After reduction, the catalyst underwent an ethanol-n-butyraldehyde catalytic coupling reaction under the following conditions: reaction temperature 260°C, reaction pressure 3.0 MPa, and liquid hourly space velocity (LHSV) of 1.6 ml / (g cat). h); Nitrogen / ethanol feed volume ratio 260:1, ethanol / n-butyraldehyde mass ratio 1:0.09; the reaction product is processed by a downstream hydrogenation unit to obtain C4-C6 compounds. 12 The mixed higher alcohol products showed an ethanol conversion rate of 50.67%, a total higher alcohol selectivity of 91.45%, and a C6+ higher alcohol selectivity of 40.98%.

[0033] Example 5: Cu-Ag / Al2O3+La / Modified SiO2 Bifunctional Catalyst and Its Application: 1. Catalyst composition This catalyst is physically composed of a Cu-Ag / Al2O3 metal hydrogenation / dehydrogenation functional component and a La / potassium-modified SiO2 alkaline functional component; the mass percentage of each component is as follows: Cu-Ag / Al2O3 metal active component: 55%; La / potassium-modified SiO2 alkaline active component: 45%; the molar ratio of Cu, Ag and Al2O3 is 0.13:0.09:1; the molar ratio of La and potassium-modified SiO2 support is 0.008:1.

[0034] 2. Catalyst Synthesis Methods: (1) Preparation of Al2O3 support: Boehmite was calcined at 600℃ for 4h to obtain powdered Al2O3 support with a pore size of 15nm and a specific surface area of ​​380 m² / g. (2) Preparation of potassium-modified SiO2 support: Mesoporous silica with a pore size of 48nm and a specific surface area of ​​480 m² / g was selected as the matrix SiO2 powder; potassium nitrate was selected as the alkali metal precursor. The potassium nitrate precursor solution and SiO2 powder were mixed at a K element / SiO2 molar ratio of 0.08:1 and a liquid-solid ratio of 10:1 (ml / g). The mixture was hydrothermally stirred at 70℃ for 2h, filtered, dried at 120℃ for 4h, and then calcined at 400℃ for 2h to obtain potassium-modified SiO2 support. (3) Preparation of La / potassium modified SiO2 alkaline component: Lanthanum nitrate was used as a rare earth precursor. The La / potassium modified SiO2 was impregnated by an equal volume impregnation method at a molar ratio of 0.008:1 for 24 h. After drying at 120 °C for 3 h, it was calcined at 400 °C for 2 h to obtain the La / potassium modified SiO2 alkaline functional component. (4) Preparation of Cu-Ag / Al2O3 metal component: Copper acetate was used as the Cu precursor and silver nitrate was used as the Ag precursor. A mixed precursor solution was prepared at a molar ratio of Cu / Ag / Al2O3 of 0.13:0.09:1. The solution was impregnated in the above Al2O3 support by an equal volume for 24 h. After drying at 120 °C for 4 h, it was calcined at 400 °C for 3 h to obtain the Cu-Ag / Al2O3 metal hydrogenation / dehydrogenation functional component. (5) Bifunctional catalyst composite molding: La / potassium modified SiO2 and Cu-Ag / Al2O3 were added to distilled water at a mass ratio of 0.82:1, and the liquid-solid ratio was controlled at 10:1 (ml / g). The mixture was stirred and mixed evenly, and dried at 120℃ for 9h. The dried solid was pressed into tablets and sieved to obtain 20-40 mesh particles, which are the target Cu-Ag / Al2O3+La / modified SiO2 bifunctional catalyst.

[0035] 3. Catalyst application performance evaluation: A 20-40 mesh catalyst was packed into a fixed-bed reactor and pre-reduced at a programmed temperature of 350°C in a mixed atmosphere with 40% H2 volume fraction and N2 as the equilibrium gas. After reduction, the catalyst underwent an ethanol-n-butyraldehyde catalytic coupling reaction under the following conditions: reaction temperature 300°C, reaction pressure 4.0 MPa, and liquid hourly space velocity (LHSV) of 2.4 ml / (g cat). h); Nitrogen / ethanol feed volume ratio 290:1, ethanol / n-butyraldehyde mass ratio 1:0.14; the reaction product is processed by a downstream hydrogenation unit to obtain C4-C6 compounds. 12 The mixed higher alcohol products showed an ethanol conversion rate of 50.87%, a total higher alcohol selectivity of 91.98%, and a C6+ higher alcohol selectivity of 42.66%.

[0036] Comparative Example 1: Preparation and performance evaluation of Cu-La / Al2O3 catalyst: The amounts of Cu and La catalysts added were the same as in Example 2. Al₂O₃ support preparation: Boehmite was calcined at 600°C for 4 hours to obtain a powdered Al₂O₃ support with a pore size of 12 nm and a specific surface area of ​​360 m². 2 / g. (2) Preparation of Cu-La / Al2O3 metal components: Copper nitrate was selected as the Cu precursor, and lanthanum nitrate was selected as the La precursor. Cu-lanthanum mixed precursor solution was prepared according to the same Cu / La / Al2O3 ratio as in the previous example. The solution was impregnated in the above Al2O3 support in equal volume for 36 h. After drying at 110 °C for 4 h, it was calcined at 400 °C for 4 h to obtain Cu-La / Al2O3 catalyst. The catalyst application evaluation conditions were the same as in Example 2, and the performance results are shown in Table 1.

[0037] Comparative Example 2: Preparation and evaluation of Cu / Al2O3+La / Al2O3 catalysts: The amounts of Cu and La catalysts added were the same as in Example 2. Al₂O₃ support preparation: Boehmite was calcined at 600°C for 4 hours to obtain a powdered Al₂O₃ support with a pore size of 12 nm and a specific surface area of ​​360 m². 2 / g. (2) Preparation of Cu / Al2O3 catalyst: Cu precursor is copper nitrate, which is prepared into a copper solution according to the same Cu / Al2O3 ratio as in the example. The solution is impregnated into the above Al2O3 support with an equal volume for 24h. After drying at 110℃ for 4h, it is calcined at 400℃ for 4h to obtain Cu / Al2O3 catalyst. (3) Preparation of La / Al2O3 catalyst: La precursor is lanthanum nitrate, which is prepared into a lanthanum solution according to the same La / Al2O3 ratio as in the example. The solution is impregnated into the above Al2O3 support with an equal volume for 24h. After drying at 110℃ for 4h, it is calcined at 400℃ for 2h to obtain La / Al2O3 catalyst. (4) Cu / Al2O3 catalyst and La / Al2O3 catalyst are loaded into a fixed bed reactor at a mass ratio of 1:1 (the overall mass of the catalyst is the same as in Example 2). The other preparation and evaluation conditions are completely consistent with those in Example 2. The performance results are shown in Table 1.

[0038] Comparative Example 3: Cu-Co / Al2O3+La / Modified SiO2 Bifunctional Catalyst and Its Applications: The catalyst preparation method was the same as in Example 2. In the catalyst evaluation, only ethanol was used as the single feedstock, and the other conditions were completely consistent with those in Example 2. The performance results are shown in Table 1.

[0039] Table 1. Comparison of performance data of different catalytic systems Conversion rate (%) Total selectivity of higher alcohols (%) C6+ higher alcohol selectivity (%) Example 1 53.89 93.02 42.54 Example 2 55.90 95.26 45.74 Example 3 48.23 92.01 41.32 Example 4 50.67 91.45 40.98 Example 5 50.87 91.98 42.66 Comparative Example 1 40.25 80.25 30.56 Comparative Example 2 47.82 84.83 35.79 Comparative Example 3 52.64 90.23 33.27 Note: In this invention, total higher alcohols refer to C4~C6 alcohols. 12 Mixed higher alcohol products, C6+ higher alcohols are C6~C 12 Target: Higher alcohol products.

Claims

1. A Cu-X / Al2O3+Y / SiO2 catalyst, characterized in that, The Cu-X / Al2O3+Y / SiO2 catalyst is composed of Cu-X / Al2O3 component and Y / alkali metal modified SiO2 component, wherein: X is one of Ni, Co, Mo, Au, and Ag; Y is one of the rare earth metals La, Ce, and Y; The mass percentage of the catalyst component is: The active metal component of Cu-X / Al2O3 is 40-80%; The alkaline active component of Y / alkali metal modified SiO2 is 20~60%.

2. The method for synthesizing a Cu-X / Al2O3+Y / SiO2 catalyst according to claim 1, characterized in that, Includes the following steps: Step 1: Obtain powdered Al2O3 support, impregnate the powdered Al2O3 support with equal volumes of Cu and X precursor solutions, and then dry and calcine to obtain Cu-X / Al2O3 material; Step 2: Mix the alkali metal precursor solution with SiO2 powder, stir under constant temperature hydrothermal conditions, filter and dry, and then calcine to obtain alkali metal modified SiO2 support; impregnate the Y rare earth metal precursor solution with the alkali metal modified SiO2 support in equal volumes, dry and then calcine to obtain Y / alkali metal modified SiO2 support. Step 3: Mix the Y / alkali metal modified SiO2 support and Cu-X / Al2O3 material, and dry to obtain Cu-X / Al2O3+Y / SiO2 catalyst.

3. The method for synthesizing a Cu-X / Al2O3+Y / SiO2 catalyst according to claim 2, characterized in that, In step 1: Powdered Al2O3 support was obtained by calcining boehmite at 600℃ for 4h; Cu and X precursor solutions were impregnated in the powdered Al2O3 support in equal volumes according to the Cu / X / Al2O3 molar ratio of (0.05~0.15):(0.005~0.15):

1.

4. The method for synthesizing a Cu-X / Al2O3+Y / SiO2 catalyst according to claim 3, characterized in that, The impregnation time is 8~24h, and after drying, it is calcined at 350~550℃ for 2~6h to obtain Cu-X / Al2O3 material.

5. The method for synthesizing a Cu-X / Al2O3+Y / SiO2 catalyst according to claim 2, characterized in that, In step 2, the alkali metal precursor solution and SiO2 powder are mixed at an alkali metal element / SiO2 molar ratio of 0.01~0.1:1 and a liquid-solid ratio of 10:1 (ml / g). The mixture is stirred for 2~4 hours under constant temperature hydrothermal conditions at 50~70℃. After filtration and drying, the mixture is calcined at 350~600℃ for 2~4 hours to obtain the alkali metal modified SiO2 support. The Y rare earth metal precursor solution was impregnated with an equal volume of Y / alkali metal modified SiO2 support at a molar ratio of Y / alkali metal modified SiO2 support (0.001~0.1):1 for 12~60 h. After drying, it was calcined at 350~550℃ for 2~8 h to obtain Y / alkali metal modified SiO2 support.

6. The method for synthesizing a Cu-X / Al2O3+Y / SiO2 catalyst according to claim 2, characterized in that, In step 3, the Y / alkali metal modified SiO2 support and Cu-X / Al2O3 material are added to distilled water at a ratio of (0.1~5):1 and stirred evenly, with a liquid-solid ratio of 10:

1. After drying, Cu-X / Al2O3+Y / SiO2 catalyst is obtained.

7. The method for synthesizing a Cu-X / Al2O3+Y / SiO2 catalyst according to claim 2, characterized in that, The SiO2 powder is mesoporous silica, with a pore size range of 20-50 nm and a specific surface area of 200-500 m 2 / g; The alkali metal of the metal-modified SiO2 support is one of Na, K, Ba, or Mg nitrates. The powdered Al2O3 carrier has a pore size range of 2-16 nm and a specific surface area of ​​200-400 m². 2 / g; The Cu precursor is one of copper nitrate, copper acetate, or copper sulfate.

8. The application of the Cu-X / Al2O3+Y / SiO2 catalyst prepared by the method according to any one of claims 2-6, characterized in that, The Cu-X / Al2O3+Y / SiO2 catalyst is applied in the field of catalytic coupling of ethanol and n-butyraldehyde to produce higher alcohols.

9. The application of the Cu-X / Al2O3+Y / SiO2 catalyst according to claim 8, characterized in that, The Cu-X / Al2O3+Y / SiO2 catalyst was shaped and loaded into a fixed-bed reactor, and pre-reduction was carried out in a mixed gas with programmed temperature rise. The pre-reduction temperature was 200~500℃. The reduced catalyst undergoes an ethanol-catalyzed coupling reaction under the following conditions: Reaction temperature: 200~350℃; Reaction pressure: Atmospheric pressure ~ 7 MPa; Feed liquid hourly space velocity (LHSV): 0.5~4.0 ml / (g cat·h); Nitrogen / ethanol feed volume ratio: (100 ~ 300): 1; Ethanol / butyraldehyde feed mass ratio: 1:(0.05~0.15); The reaction products obtained were processed by a hydrogenation unit to yield C4~C alcohols, mainly C6 higher alcohols. 12 Mixed higher alcohol products.