Catalyst for low-pressure hydrodeoxygenation of methyl laurate as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for low-pressure catalysis of methyl laurate hydrodeoxygenation and a preparation method and application thereof.The catalyst is a hollow eggshell bifunctional catalyst and comprises a first active site, a second active site and a carrier, and the carrier is silicon dioxide of a hollow eggshell structure; the first active site is a first active component metal Ni0 dispersed on the surface of the hollow eggshell, and the second active site is an acid site given by a second active component NiSiO3 dispersed on the surface of the hollow eggshell. When the bifunctional catalyst with the hollow eggshell structure is used for catalyzing the hydrodeoxygenation reaction of methyl laurate, the conversion rate of methyl laurate is 100% and the selectivity of C11 alkane is 99% under the low-pressure reaction condition of 0.3 MPa, and the catalyst is not obviously inactivated after being repeatedly used for more than ten times. And the catalyst has the characteristics of simple preparation method, high activity, good selectivity and good stability.

Description

Technical Field

[0001] The invention belongs to the field of biomass energy catalysis, and particularly relates to a catalyst for low-pressure hydrogenation and deoxygenation of methyl laurate, and a preparation method and application thereof. Background Art

[0002] The rapid development of the global economy has accelerated the consumption of fossil energy, and the energy and environmental problems caused by it have become increasingly serious. The development and utilization of renewable resources has attracted global attention. The preparation of second-generation biodiesel by hydrodeoxygenation of bio-oils can not only alleviate the energy crisis, but also reduce the environmental pollution caused by the use of traditional fossil fuels. Compared with the first-generation biodiesel, the second-generation biodiesel has the characteristics of low oxygen content, low turbidity point, high octane number and high calorific value. With excellent catalytic performance in hydrodeoxygenation, decarboxylation and decarbonylation, supported precious metal (Pd, Pt, Rh, Ru) catalysts have been widely studied in the hydrodeoxygenation reaction of bio-oils. However, the price of precious metals is too high, and with economic development, their prices will gradually increase, which greatly limits their application in the field of biomass energy. In recent years, Ni-based catalysts have gradually attracted the attention of scientific researchers in catalyzing the hydrodeoxygenation of fatty acid methyl esters to generate hydrocarbon fuels. However, compared with precious metal catalysts, Ni-based catalysts have poor activity, require higher reaction pressures, and have strong hydrocracking ability, which is easy to cause carbon deposition and rapid deactivation of the catalyst. Patent CN 111111679 B reports a sulfur-free nickel-molybdenum bimetallic hydrodeoxygenation catalyst, but it requires a high pressure of 3MPa and a temperature of 300°C to achieve excellent catalytic hydrodeoxygenation activity. Patent CN 111909737 B reports a cobalt-based catalyst, which also requires a high pressure of 3MPa and a temperature of 300°C to achieve full conversion of the raw materials. Patent CN 116621676A reports a high-performance nickel-carbon catalyst. Although its reaction temperature has been reduced, its reaction pressure is still as high as 3.5MPa, and the reaction products are relatively complex, and the catalyst stability needs to be improved. Therefore, how to design and prepare a high-performance supported nickel-based catalyst to achieve high yields under relatively mild reaction conditions and a relatively stable catalyst is a problem that needs to be solved at present. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a high-performance catalyst for low-pressure hydrodeoxygenation of methyl laurate, a preparation method and application thereof, and to achieve low-pressure hydrodeoxygenation by regulating the microscopic active sites on the surface of the catalyst, so as to solve the problems of high price of precious metals, poor hydrogenation activity of non-precious metals, high pressure and high temperature in the reaction process, and easy deactivation of the catalyst in the current preparation of second-generation biodiesel by hydrodeoxygenation of methyl laurate.

[0004] In order to solve the above technical problems, the present invention first discloses a catalyst for low-pressure catalytic hydrodeoxygenation of methyl laurate, wherein the catalyst is a hollow eggshell bifunctional catalyst, comprising a first active site, a second active site and a carrier, wherein the carrier is hollow eggshell structured silica, and the first active site is a first active component metal Ni dispersed on the surface of the hollow eggshell. 0 The second active site is the acidic site provided by the second active component NiSiO3 dispersed on the surface of the hollow eggshell.

[0005] Furthermore, in the catalyst, the metal Ni 0 The mass content of NiSiO3 and NiSiO3 is 5-35% based on the mass of Ni single substance, and the rest is carrier.

[0006] The present invention also discloses a method for preparing the catalyst for low-pressure catalytic hydrodeoxygenation of methyl laurate, wherein the catalyst is prepared by the following steps:

[0007] (I) adding a certain amount of deionized water, anhydrous ethanol, ammonia water, and tetraethyl orthosilicate (TEOS) into a container, stirring at 400-500 rpm for 2-5 hours at 20-40° C., wherein the mass concentration of ammonia water is 26-28%;

[0008] Subsequently, a quantitative amount of ethyl orthosilicate was added dropwise under stirring, and stirring was continued at 400-500 rpm for 3-4 hours;

[0009] Washing, dispersing in deionized water in an amount of silica: water = 1:15-25 by mass ratio;

[0010] (II) centrifuging the mixture dispersed in ionized water obtained in step (I), transferring it into a diol solvent, ultrasonically treating it at 10-30 kHz for 3-8 h at room temperature, and then stirring it at 400-500 rpm for 3-5 h at 20-40° C.;

[0011] (III) transferring the stirred mixture obtained in step (II) into a sealed pressure-resistant solvent thermal reactor, heating it to 80-150° C. and treating it for 3-8 hours; after cooling it to room temperature, opening the reactor, washing and centrifuging it, and dispersing it into deionized water in an amount of silica: water = 1:15-25 by mass;

[0012] (IV) taking the mixture dispersed in deionized water obtained in quantitative step (III), deionized water, ammonia water, a water-soluble organic amine, and a soluble nickel salt, stirring at 400-500 rpm for 2-5 hours at 20-40° C., wherein the mass concentration of ammonia water is 26-28%;

[0013] Then transfer it to a sealed pressure-resistant hydrothermal reactor, heat it to 120-180°C and treat it for 3-8 hours; after cooling to room temperature, open the reactor, wash and filter it, dry it at 80-120°C for 10-12 hours, and then calcine it at 300-600°C for 2-10 hours to obtain a hollow eggshell Ni / H-SiO2 catalyst.

[0014] Further, in step (I), a quantitative amount of deionized water, anhydrous ethanol, ammonia water, and tetraethyl orthosilicate are added to the container, wherein the mass ratio of anhydrous ethanol to deionized water is 1-2:1, the volume mass ratio of ammonia water to deionized water is 0.4-0.7mL:1g, and the volume mass ratio of tetraethyl orthosilicate to deionized water is 0.01-0.03mL:1g; and the volume mass ratio of tetraethyl orthosilicate to deionized water added under stirring is 0.1-0.3mL:1g. The amount of deionized water used here does not include the amount of deionized water used for dispersion in this step.

[0015] Furthermore, the diol in step (II) is one of ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol, and the diol solution is a solution prepared by diol and deionized water, wherein the mass ratio of diol to deionized water is 1:15-25.

[0016] Furthermore, the water-soluble organic amine in step (IV) is one of ethylenediamine, propylenediamine, butylenediamine, pentanediamine, and hexanediamine; the soluble nickel salt is one of nickel nitrate, nickel acetate, and nickel chloride; in step (IV), based on the mass of solid silicon dioxide in the mixture, the volume mass ratio of ammonia water to silicon dioxide is 3.5-4.5mL:1g, the soluble nickel salt is weighed at 5-35% of the final catalyst mass content based on the mass of nickel element, and the mass ratio of the water-soluble organic amine to silicon dioxide is 0.1-0.2:1.

[0017] The present invention also discloses an application of the above catalyst in low-pressure hydrodeoxygenation of methyl laurate. In the reactor of the hydrodeoxygenation, the temperature is 150-250°C, the initial reaction pressure is 0.2-1.0 MPa, the solvent is one of n-heptane, n-hexane and cyclohexane, the mass ratio of the catalyst to methyl laurate is 7:35-45, and the amount of the solvent does not exceed 50% of the volume of the reactor of the hydrodeoxygenation.

[0018] Furthermore, before use, the catalyst is first loaded into a reduction reactor and reduced in hydrogen or a hydrogen / inert gas mixture under the following reduction conditions: a gas space velocity of 50-3000 h -1 , the reduction pressure is 0.1-0.5MPa, the reduction temperature is 500-750℃, the heating rate is 0.1-10℃ / min, and the reduction time is 1.0-10h; nitrogen is generally used as the inert gas.

[0019] After the reduction is completed, the temperature is lowered to room temperature for passivation treatment.

[0020] Furthermore, the hydrodeoxygenation reactor is a moving bed, fixed bed, bubbling bed, fluidized bed, trickle bed or slurry bed reactor.

[0021] Furthermore, the hydrodeoxygenation reactor is a slurry bed reactor.

[0022] The catalyst of the present invention is a hollow eggshell bifunctional catalyst, comprising a first active site, a second active site and a carrier, wherein the first active site is a first active component metal Ni 0 , the second active site is the acidic site given by the second active component NiSiO3, which are dispersed on the surface of the hollow eggshell-type silica carrier. The two synergistically catalyze and show excellent catalytic activity, selectivity and stability. The present invention also discloses its preparation method and application. The bifunctional catalyst with a hollow eggshell structure of the present invention can achieve a methyl laurate conversion rate of 100% and an undecane selectivity of 99% under a low pressure reaction condition of 0.3MPa in the process of catalyzing the hydrodeoxygenation reaction of methyl laurate, and the catalyst is reused more than ten times without obvious deactivation. The high-performance bifunctional nickel-based catalyst with a hollow eggshell structure of the present invention has the characteristics of simple preparation method, high activity, good selectivity and good stability.

[0023] The reasons why the present invention has such excellent performance are as follows: the present invention first uses sol-gel to prepare nano-spherical silica, and uses the hydroxyl groups on the surface of diol to modify the surface of spherical silica to increase the surface hydroxyl content, and synthesizes nano-silica balls with a large number of C-OH functional groups on the surface. Subsequently, ammonia water and diamino ligands are used to coordinate and protect metallic nickel, and Ni is loaded onto the surface of silica under hydrothermal conditions. With the help of the abundant C-OH functional groups on the surface of the nano-silica balls, a strong metallic force is formed between the coordinated and protected Ni and the carrier. After the metal is loaded on the surface of the carrier, a strong chemical reaction will occur under further hydrothermal conditions to generate partial nickel silicate, and then the inside of the silicon ball will be etched to form a hollow eggshell structure. Finally, after reduction activation, a hollow eggshell structure is formed, and the surface has highly dispersed Ni 0 and NiSiO3. In the process of methyl laurate hydrogenation, highly dispersed Ni 0 It can promote hydrogen dissociation and reduce the amount of H2 used in the reaction process, thereby obtaining 100% conversion and 99% selectivity of undecane at a low pressure of 0.3MPa. NiSiO3 can enhance the adsorption of ester groups and improve the catalytic hydrogenation activity, so that the selectivity of undecane in the reaction results is extremely high. According to the reaction mechanism of lauric acid hydrogenation, the synergistic effect of the acidic sites and metal active sites of NiSiO3 can significantly improve the hydrogenation decarbonylation activity, so that the conversion rate is maintained at 100%. The catalyst of the present invention utilizes the Ni on the catalyst surface to0 and NiSiO3 dual active sites, synergistically catalyze to improve the CC bond breaking ability, thereby improving the catalytic hydrogenation and deoxygenation ability. In addition, from the perspective of the microscopic reaction structure, the catalyst of the present invention has a hollow eggshell structure, in which the hollow cavity can locally form an enrichment effect on the substrate molecules, thereby increasing the concentration around the active site and promoting the hydrogenation reaction. Based on this, the catalyst of the present invention utilizes the enrichment effect of the hollow eggshell structure and the synergistic catalytic effect of the dual active sites to enable methyl laurate to undergo efficient hydrogenation and deoxygenation reactions under low temperature, low pressure and mild reaction conditions, thereby improving the catalytic activity. Under the conditions of 240°C, 0.3MPa, 300rpm, and a reaction time of 15h, the conversion rate of methyl laurate was 100%, and the selectivity of C11 alkanes was 99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is an electron microscope test image of the catalyst of Example 1 (showing a hollow structure).

[0025] Figure 2 This is the infrared (IR) test image of the catalyst of Example 1 (IR shows a nickel silicate structure).

[0026] Figure 3 The XRD pattern of the catalyst in Example 1 after calcination (Ni 0 and NiSiO3 as two active components).

[0027] Figure 4 This is a performance stability test chart of the catalyst obtained in Example 1 in the hydrogenation reaction of methyl laurate.

[0028] Figure 5 This is a performance stability test chart of the catalyst obtained in Example 1 in the hydrogenation reaction of methyl laurate. DETAILED DESCRIPTION

[0029] The present invention is further explained below in conjunction with the examples and drawings. The following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0030] Example 1

[0031] (I) At room temperature, 100g of deionized water, 170g of anhydrous ethanol, 52mL of ammonia water, and 2.4mL of TEOS were stirred and mixed, and then stirred at 35°C and 400rpm for 2h. 20mL of TEOS was added to the above mixture, and the stirring reaction was continued for 4h. After washing with deionized water, the mixture was dispersed in 118.8g of deionized water in a mass ratio of silicon dioxide: water = 1:20. The content of SiO2 in the purchased TEOS raw material is 28.4%, and the other embodiments are the same. The total amount of TEOS used in this embodiment is 22.4mL, and it can be calculated that the mass of SiO2 is 5.94g.

[0032] (II) The mixture was centrifuged and transferred into 20 mL of ethylene glycol solution (ethylene glycol mass concentration was 5%), and ultrasonically treated at 15 kHz for 3 h at room temperature, followed by vigorous stirring at 400 rpm for 3 h at 30°C.

[0033] (III) The mixture obtained above was transferred to a sealed pressure-resistant solvent thermal reactor, heated to 120° C. for 3 h; after cooling to room temperature, the reactor was opened, washed and centrifuged, and then dispersed in 118.8 g of deionized water in a mass ratio of silica: water = 1:20 for storage.

[0034] (IV) 42g of the above mixture (based on 2g of silica mass), 8mL of ammonia water, 0.4g of ethylenediamine, and 4.8g of nickel nitrate hexahydrate were stirred at 30°C and 500rpm for 4h. The above mixture was transferred to a sealed pressure-resistant hydrothermal reactor, heated to 180°C for 8h; after cooling to room temperature, the reactor was opened, washed and filtered, dried at 80°C for 10h, and then calcined at 450°C for 10h to obtain 3.23g of the hollow eggshell 1-Ni / H-SiO2 catalyst. ICP-OES measurement showed that the nickel content of the prepared catalyst was 29.8%, which was close to the theoretical value (30%).

[0035] The catalyst 1-Ni / H-SiO2 prepared in this embodiment, such as Figure 1-4 As shown, Figure 1 It shows that the catalyst has an obvious hollow eggshell structure at the nanoscale. Figure 2 It shows that the catalyst still has obvious Ni-O-Si vibration peaks after reduction activation (i.e., nickel silicate), which indicates that the catalyst prepared in this embodiment can enhance its reduction temperature by enhancing the interaction between the metal carrier and the surface of Ni 0 and NiSiO3 active components. Further XRD results show that Ni 0 and NiSiO3, which is similar to Figure 2 The results in accord with each other.

[0036] The catalyst 1-Ni / H-SiO2 prepared in this embodiment needs to be reduced and activated before being used in the hydrodeoxygenation reaction of methyl laurate, comprising the following steps: firstly loading the catalyst into a reduction reactor and reducing it in hydrogen under the conditions of a gas space velocity of 1000 h -1, the reduction pressure is 0.3MPa, the reduction temperature is 650℃, the heating rate is 1℃ / min, and the reduction time is 6h; after the reduction is completed, the temperature is lowered to room temperature for passivation treatment. After the passivation is completed, the temperature is lowered to room temperature, and 0.07g of the catalyst is transferred to a 100mL slurry bed reactor. Then 10.8mL of n-heptane and 0.4g of methyl laurate are added in sequence, hydrogen is charged to a pressure of 0.3MPa, the temperature is raised to 240℃, and after 15 hours of reaction, the temperature is lowered to room temperature in an ice water bath, and the components in the solution are analyzed by gas chromatography, and the conversion rate of methyl laurate is calculated to be 100%, and the selectivity of C11 alkane is 99.7%.

[0037] Example 2: Diol replaced with propylene glycol

[0038] (I) 100 g of deionized water, 170 g of anhydrous ethanol, 52 mL of ammonia water, and 2.4 mL of TEOS were stirred at room temperature, and then stirred at 35°C and 400 rpm for 2 h. 20 mL of TEOS was added to the above mixture, and the stirring reaction was continued for 4 h. After washing, the mixture was dispersed in deionized water in an amount of silica: water = 1:20 by mass.

[0039] (II) The mixture was centrifuged and transferred into 20 mL of propylene glycol solvent (propylene glycol mass concentration was 5%), and ultrasonically treated at 15 kHz for 3 h at room temperature, followed by vigorous stirring at 400 rpm for 3 h at 30°C.

[0040] (III) The mixture obtained above was transferred to a sealed pressure-resistant solvent thermal reactor, heated to 120° C. for 3 h; after cooling to room temperature, the reactor was opened, washed and centrifuged, and then dispersed in deionized water in an amount of a mass ratio of silica to water = 1:20 for storage.

[0041] (IV) The above mixture (based on 2g of silica mass), 8mL of ammonia water, 0.4g of ethylenediamine, 4.8g of nickel nitrate hexahydrate, were stirred at 500rpm at 30°C for 4h. The above mixture was transferred to a sealed pressure-resistant hydrothermal reactor, heated to 180°C for 8h; after cooling to room temperature, the reactor was opened, washed and filtered, dried at 80°C for 10h, and then calcined at 450°C for 10h to obtain 3.23g of the hollow eggshell 2-Ni / H-SiO2 catalyst. ICP-OES measurement showed that the nickel content of the prepared catalyst was 30.1%, which was close to the theoretical value (30%).

[0042] The catalyst 2-Ni / H-SiO2 prepared in this embodiment needs to be reduced and activated before being used in the hydrodeoxygenation reaction of methyl laurate, comprising the following steps: firstly loading the catalyst into a reduction reactor and reducing it in hydrogen under the conditions of a gas space velocity of 1000 h -1, the reduction pressure is 0.3MPa, the reduction temperature is 650℃, the heating rate is 1℃ / min, and the reduction time is 6h; after the reduction is completed, the temperature is lowered to room temperature for passivation treatment. After the passivation is completed, the temperature is lowered to room temperature, and 0.07g of the catalyst is transferred to a 100mL slurry bed reactor. Then 10.8mL of n-heptane and 0.4g of methyl laurate are added in sequence, hydrogen is charged to a pressure of 0.3MPa, the temperature is raised to 240℃, and after 15 hours of reaction, the temperature is lowered to room temperature in an ice water bath, and the components in the solution are analyzed by gas chromatography, and the conversion rate of methyl laurate is calculated to be 100%, and the selectivity of C11 alkane is 99.6%.

[0043] Example 3: Diol replaced with butanediol

[0044] (I) 100 g of deionized water, 170 g of anhydrous ethanol, 52 mL of ammonia water, and 2.4 mL of TEOS were stirred at room temperature, and then stirred at 35°C and 400 rpm for 2 h. 20 mL of TEOS was added to the above mixture, and the stirring reaction was continued for 4 h. After washing, the mixture was dispersed in deionized water in an amount of silica: water = 1:20 by mass.

[0045] (II) The mixture was centrifuged and transferred into 20 mL of butanediol solvent (butanediol mass concentration was 5%), and ultrasonically treated at 15 kHz for 3 h at room temperature, followed by vigorous stirring at 400 rpm for 3 h at 30°C.

[0046] (III) The mixture obtained above was transferred to a sealed pressure-resistant solvent thermal reactor, heated to 120° C. for 3 h; after cooling to room temperature, the reactor was opened, washed and centrifuged, and then dispersed in deionized water in an amount of a mass ratio of silica to water = 1:20 for storage.

[0047] (IV) The above mixture (based on 2g of silica mass), 8mL of ammonia water, 0.4g of ethylenediamine, 4.8g of nickel nitrate hexahydrate, were stirred at 500rpm at 30°C for 4h. The above mixture was transferred to a sealed pressure-resistant hydrothermal reactor, heated to 180°C for 8h; after cooling to room temperature, the reactor was opened, washed and filtered, dried at 80°C for 10h, and then calcined at 450°C for 10h to obtain 3.23g of the hollow eggshell 3-Ni / H-SiO2 catalyst. ICP-OES measurement showed that the nickel content of the prepared catalyst was 29.3%, which was close to the theoretical value (30%).

[0048] The catalyst 3-Ni / H-SiO2 prepared in this embodiment needs to be reduced and activated before being used in the hydrodeoxygenation reaction of methyl laurate, comprising the following steps: firstly loading the catalyst into a reduction reactor and reducing it in hydrogen under the conditions of a gas space velocity of 1000 h -1, the reduction pressure is 0.3MPa, the reduction temperature is 650℃, the heating rate is 1℃ / min, and the reduction time is 6h; after the reduction is completed, the temperature is lowered to room temperature for passivation treatment. After the passivation is completed, the temperature is lowered to room temperature, and 0.07g of the catalyst is transferred to a 100mL slurry bed reactor. Then 10.8mL of n-heptane and 0.4g of methyl laurate are added in sequence, hydrogen is charged to a pressure of 0.3MPa, the temperature is raised to 240℃, and after 15 hours of reaction, the temperature is lowered to room temperature in an ice water bath, and the components in the solution are analyzed by gas chromatography, and the conversion rate of methyl laurate is calculated to be 100%, and the selectivity of C11 alkane is 99.3%.

[0049] Example 4: Diol replaced with hexylene glycol

[0050] (I) 100 g of deionized water, 170 g of anhydrous ethanol, 52 mL of ammonia water, and 2.4 mL of TEOS were stirred at room temperature, and then stirred at 35°C and 400 rpm for 2 h. 20 mL of TEOS was added to the above mixture, and the stirring reaction was continued for 4 h. After washing, the mixture was dispersed in deionized water in an amount of silica: water = 1:20 by mass.

[0051] (II) The mixture was centrifuged and transferred into 20 mL of hexanediol solvent (hexanediol mass concentration was 5%), and ultrasonically treated at 15 kHz for 3 h at room temperature, followed by vigorous stirring at 400 rpm for 3 h at 30°C.

[0052] (III) The mixture obtained above was transferred to a sealed pressure-resistant solvent thermal reactor, heated to 120° C. for 3 h; after cooling to room temperature, the reactor was opened, washed and centrifuged, and then dispersed in deionized water in an amount of a mass ratio of silica to water = 1:20 for storage.

[0053] (IV) The above mixture (based on 2g of silica mass), 8mL of ammonia water, 0.4g of ethylenediamine, 4.8g of nickel nitrate hexahydrate, were stirred at 500rpm at 30°C for 4h. The above mixture was transferred to a sealed pressure-resistant hydrothermal reactor, heated to 180°C for 8h; after cooling to room temperature, the reactor was opened, washed and filtered, dried at 80°C for 10h, and then calcined at 450°C for 10h to obtain 3.23g of the hollow eggshell 4-Ni / H-SiO2 catalyst. ICP-OES measurement showed that the nickel content of the prepared catalyst was 30.2%, which was close to the theoretical value (30%).

[0054] The catalyst 4-Ni / H-SiO2 prepared in this embodiment needs to be reduced and activated before being used in the hydrodeoxygenation reaction of methyl laurate, comprising the following steps: firstly loading the catalyst into a reduction reactor and reducing it in hydrogen under the conditions of a gas space velocity of 1000 h -1, the reduction pressure is 0.3MPa, the reduction temperature is 650℃, the heating rate is 1℃ / min, and the reduction time is 6h; after the reduction is completed, the temperature is lowered to room temperature for passivation treatment. After the passivation is completed, the temperature is lowered to room temperature, and 0.07g of the catalyst is transferred to a 100mL slurry bed reactor. Then 10.8mL of n-heptane and 0.4g of methyl laurate are added in sequence, hydrogen is charged to a pressure of 0.3MPa, the temperature is raised to 240℃, and after 15 hours of reaction, the temperature is lowered to room temperature in an ice water bath, and the components in the solution are analyzed by gas chromatography, and the conversion rate of methyl laurate is calculated to be 100%, and the selectivity of C11 alkane is 99.6%.

[0055] Example 5: Water-soluble organic amine replaced with propylene diamine

[0056] (I) 100 g of deionized water, 170 g of anhydrous ethanol, 52 mL of ammonia water, and 2.4 mL of TEOS were stirred at room temperature, and then stirred at 35°C and 400 rpm for 2 h. 20 mL of TEOS was added to the above mixture, and the stirring reaction was continued for 4 h. After washing, the mixture was dispersed in deionized water in an amount of silica: water = 1:20 by mass.

[0057] (II) The mixture was centrifuged and transferred into 20 mL of ethylene glycol solvent (ethylene glycol mass concentration was 5%), and ultrasonically treated at 15 kHz for 3 h at room temperature, followed by vigorous stirring at 400 rpm for 3 h at 30°C.

[0058] (III) The mixture obtained above was transferred to a sealed pressure-resistant solvent thermal reactor, heated to 120° C. for 3 h; after cooling to room temperature, the reactor was opened, washed and centrifuged, and then dispersed in deionized water in an amount of a mass ratio of silica to water = 1:20 for storage.

[0059] (IV) The above mixture (based on 2g of silica mass), 8mL of ammonia water, 0.5g of propylenediamine, 4.8g of nickel nitrate hexahydrate, were stirred at 500rpm at 30°C for 4h. The above mixture was transferred to a sealed pressure-resistant hydrothermal reactor, heated to 180°C for 8h; after cooling to room temperature, the reactor was opened, washed and filtered, dried at 80°C for 10h, and then calcined at 450°C for 10h to obtain 3.23g of the hollow eggshell 5-Ni / H-SiO2 catalyst. ICP-OES measurement showed that the nickel content of the prepared catalyst was 29.6%, which was close to the theoretical value (30%).

[0060] The catalyst 5-Ni / H-SiO2 prepared in this embodiment needs to be reduced and activated before being used in the hydrodeoxygenation reaction of methyl laurate, comprising the following steps: firstly loading the catalyst into a reduction reactor and reducing it in hydrogen under the conditions of a gas space velocity of 1000 h -1, the reduction pressure is 0.3MPa, the reduction temperature is 650℃, the heating rate is 1℃ / min, and the reduction time is 6h; after the reduction is completed, the temperature is lowered to room temperature for passivation treatment. After the passivation is completed, the temperature is lowered to room temperature, and 0.07g of the catalyst is transferred to a 100mL slurry bed reactor. Then 10.8mL of n-heptane and 0.4g of methyl laurate are added in sequence, hydrogen is charged to a pressure of 0.3MPa, the temperature is raised to 240℃, and after 15 hours of reaction, the temperature is lowered to room temperature in an ice water bath, and the components in the solution are analyzed by gas chromatography, and the conversion rate of methyl laurate is calculated to be 100%, and the selectivity of C11 alkane is 99.3%.

[0061] Example 6 Water-soluble organic amine replaced with hexamethylenediamine

[0062] (I) 100 g of deionized water, 170 g of anhydrous ethanol, 52 mL of ammonia water, and 2.4 mL of TEOS were stirred at room temperature, and then stirred at 35°C and 400 rpm for 2 h. 20 mL of TEOS was added to the above mixture, and the stirring reaction was continued for 4 h. After washing, the mixture was dispersed in deionized water in an amount of silica: water = 1:20 by mass.

[0063] (II) The mixture was centrifuged and transferred into 20 mL of propylene glycol solvent (propylene glycol mass concentration was 5%), and ultrasonically treated at 15 kHz for 3 h at room temperature, followed by vigorous stirring at 400 rpm for 3 h at 30°C.

[0064] (IV) The mixture obtained above was transferred to a sealed pressure-resistant solvent thermal reactor, heated to 120° C. for 3 h; after cooling to room temperature, the reactor was opened, washed and centrifuged, and then dispersed in deionized water in an amount of a mass ratio of silica to water = 1:20 for storage.

[0065] (IV) The above mixture (based on 2g of silica mass), 8mL of ammonia water, 0.8g of hexamethylenediamine, 4.8g of nickel nitrate hexahydrate, were stirred at 500rpm at 30°C for 4h. The above mixture was transferred to a sealed pressure-resistant hydrothermal reactor, heated to 180°C for 8h; after cooling to room temperature, the reactor was opened, washed and filtered, dried at 80°C for 10h, and then calcined at 450°C for 10h to obtain 3.23g of the hollow eggshell 6-Ni / H-SiO2 catalyst. ICP-OES measurement showed that the nickel content of the prepared catalyst was 30.1%, which was close to the theoretical value (30%).

[0066] The catalyst 6-Ni / H-SiO2 prepared in this embodiment needs to be reduced and activated before being used in the hydrodeoxygenation reaction of methyl laurate, comprising the following steps: firstly loading the catalyst into a reduction reactor and reducing it in hydrogen or a hydrogen-inert gas mixture under the conditions of a gas space velocity of 1000 h / min; -1, the reduction pressure is 0.3MPa, the reduction temperature is 650℃, the heating rate is 1℃ / min, and the reduction time is 6h; after the reduction is completed, the temperature is lowered to room temperature for passivation treatment. After the passivation is completed, the temperature is lowered to room temperature, and 0.07g of the catalyst is transferred to a 100mL slurry bed reactor. Then 10.8mL of n-heptane and 0.4g of methyl laurate are added in sequence, hydrogen is charged to a pressure of 0.3MPa, the temperature is raised to 240℃, and after 15 hours of reaction, the temperature is lowered to room temperature in an ice water bath, and the components in the solution are analyzed by gas chromatography, and the conversion rate of methyl laurate is calculated to be 100%, and the selectivity of C11 alkane is 99.1%.

[0067] Example 7

[0068] The catalyst in Example 1 was used to perform a stability test on the hydrodeoxygenation reaction of methyl laurate. The experiment found that under the same reduction and reaction conditions as in Example 1, the catalyst performance analysis showed that no obvious deactivation of the catalyst was found after the catalyst was reused 16 times. Figure 4 This shows that the catalyst has excellent stability.

[0069] The sealed pressure-resistant solvent thermal reactor used in Examples 1-7 can all be a Yanzheng PPL hydrothermal reactor.

[0070] Comparative Example 1

[0071] The R1-Ni / SiO2 catalyst was prepared by the traditional impregnation method. The specific steps are as follows: 100g of deionized water, 170g of anhydrous ethanol, 52mL of ammonia water, and 2.4mL of TEOS were stirred at room temperature, and then stirred at 35°C and 400rpm for 2h. 20mL of TEOS was added to the above mixture, and the stirring reaction was continued for 4h. After washing, it was dispersed in 40mL of deionized water. The above mixture was centrifuged and dried, and calcined at 450°C for 4h to obtain a silica carrier. 2.12g of nickel nitrate hexahydrate was taken and dissolved in 2mL of water to form a solution. 1g of the obtained silica carrier was impregnated in the above solution, dried at room temperature, dried at 120°C for 5h, and calcined at 450°C for 4h. ICP-OES measurement showed that the nickel content of the prepared catalyst was 16.5%, which was far from the theoretical value (30%).

[0072] The catalyst R1-Ni / SiO2 prepared in this comparative example 1 needs to be reduced and activated before being used in the hydrodeoxygenation reaction of methyl laurate, comprising the following steps: firstly loading the catalyst into a reduction reactor, and reducing it in hydrogen or a hydrogen-inert gas mixture under the conditions of a gas space velocity of 1000 h -1, the reduction pressure is 0.3MPa, the reduction temperature is 450℃, the heating rate is 1℃ / min, and the reduction time is 6h; after the reduction is completed, the temperature is lowered to room temperature for passivation treatment. After the passivation is completed, the temperature is lowered to room temperature, and 0.07g of the catalyst is transferred to a 100mL slurry bed reactor. Then 10.8mL of n-heptane and 0.4g of methyl laurate are added in sequence, hydrogen is charged to a pressure of 0.3MPa, the temperature is raised to 240℃, and after 15 hours of reaction, the temperature is lowered to room temperature in an ice water bath, and the components in the solution are analyzed by gas chromatography, and the conversion rate of methyl laurate is calculated to be 12.34%, and the selectivity of C11 alkane is 47.6%.

[0073] The amounts of nickel salt used in Examples 1-7 and Comparative Example 1 were all weighed based on the theoretical value of the nickel content in the catalyst being 30%.

[0074] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A catalyst for low-pressure catalytic hydrodeoxygenation of methyl laurate, characterized in that: The catalyst is a hollow eggshell bifunctional catalyst, comprising a first active site, a second active site and a carrier, wherein the carrier is silicon dioxide with a hollow eggshell structure, and the first active site is a first active component metal Ni dispersed on the surface of the hollow eggshell. 0 The second active site is the acidic site provided by the second active component NiSiO3 dispersed on the surface of the hollow eggshell.

2. The catalyst according to claim 1, characterized in that: In this catalyst, metal Ni 0 The mass content of NiSiO3 and NiSiO3 is 5-35% based on the mass of Ni single substance, and the rest is carrier.

3. A method for preparing a catalyst for low-pressure catalytic hydrodeoxygenation of methyl laurate as claimed in claim 1 or 2, characterized in that: The catalyst is prepared by the following steps: (I) adding a certain amount of deionized water, anhydrous ethanol, ammonia water and tetraethyl orthosilicate into a container, stirring at 400-500 rpm for 2-5 hours at 20-40° C., wherein the mass concentration of ammonia water is 26-28%; Subsequently, a quantitative amount of ethyl orthosilicate was added dropwise under stirring, and stirring was continued at 400-500 rpm for 3-4 hours; Washing, dispersing in deionized water in an amount of silica: water = 1:15-25 by mass ratio; (II) centrifuging the mixture dispersed in ionized water obtained in step (I), transferring it to a glycol solution, ultrasonically treating it at 10-30 kHz for 3-8 h at room temperature, and then stirring it at 400-500 rpm for 3-5 h at 20-40° C.; (III) transferring the stirred mixture obtained in step (II) into a sealed pressure-resistant solvent thermal reactor, heating it to 80-150° C. and treating it for 3-8 hours; after cooling it to room temperature, opening the reactor, washing and centrifuging it, and dispersing it into deionized water in an amount of silica: water = 1:15-25 by mass; (IV) taking the mixture dispersed in deionized water obtained in quantitative step (III), deionized water, ammonia water, a water-soluble organic amine, and a soluble nickel salt, stirring at 400-500 rpm for 2-5 hours at 20-40° C., wherein the mass concentration of ammonia water is 26-28%; Then transfer it to a sealed pressure-resistant hydrothermal reactor, heat it to 120-180°C and treat it for 3-8 hours; after cooling to room temperature, open the reactor, wash and filter it, dry it at 80-120°C for 10-12 hours, and then calcine it at 300-600°C for 2-10 hours to obtain a hollow eggshell Ni / H-SiO2 catalyst.

4. The preparation method according to claim 3, characterized in that: In step (I), a quantitative amount of deionized water, anhydrous ethanol, ammonia water and tetraethyl orthosilicate are added to the container, wherein the mass ratio of anhydrous ethanol to deionized water is 1-2:1, the volume mass ratio of ammonia water to deionized water is 0.4-0.7 mL:1 g, and the volume mass ratio of tetraethyl orthosilicate to deionized water is 0.01-0.03 mL:1 g; and the volume mass ratio of tetraethyl orthosilicate to deionized water added under stirring is 0.1-0.3 mL:1 g.

5. The preparation method according to claim 3, characterized in that: The diol in step (II) is one of ethylene glycol, propylene glycol, butanediol, pentanediol and hexanediol, and the diol solvent is a solution prepared by diol and deionized water, wherein the mass ratio of diol to deionized water is 1:15-25.

6. The preparation method according to claim 3, characterized in that: The water-soluble organic amine in step (IV) is one of ethylenediamine, propylenediamine, butylenediamine, pentanediamine and hexanediamine; the soluble nickel salt is one of nickel nitrate, nickel acetate and nickel chloride; in step (IV), based on the mass of solid silicon dioxide in the mixture, the volume mass ratio of ammonia water to silicon dioxide is 3.5-4.5mL:1g, the soluble nickel salt is weighed to account for 5-35% of the final catalyst mass content based on the mass of nickel element, and the mass ratio of the water-soluble organic amine to silicon dioxide is 0.1-0.2:

1.

7. Use of the catalyst according to claim 1 or 2, or the catalyst obtained by the preparation method according to any one of claims 3 to 6 in low-pressure hydrodeoxygenation of methyl laurate, characterized in that: In the hydrodeoxygenation reactor, the temperature is 150-250°C, the initial reaction pressure is 0.2-1.0 MPa, the solvent is one of n-heptane, n-hexane and cyclohexane, the mass ratio of the catalyst to methyl laurate is 7:35-45, and the amount of solvent does not exceed 50% of the volume of the hydrodeoxygenation reactor.

8. The use according to claim 7, characterized in that: Before using the catalyst, it is first loaded into a reduction reactor and reduced in hydrogen or a hydrogen / inert gas mixture. The reduction conditions are: gas space velocity of 50-3000h -1 , the reduction pressure is 0.1-0.5MPa, the reduction temperature is 500-750℃, the heating rate is 0.1-10℃ / min, and the reduction time is 1.0-10h; After the reduction is completed, the temperature is lowered to room temperature for passivation treatment.

9. The use according to claim 7, characterized in that: The reactor for hydrodeoxygenation is a moving bed, fixed bed, bubbling bed, fluidized bed, trickle bed or slurry bed reactor.

10. The use according to claim 9, characterized in that: The reactor for hydrodeoxygenation is a slurry bed reactor.

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