Disclosure of Invention
Aiming at the defects of the prior art, the invention provides an ester hydrogenation catalyst which can obviously reduce the molar ratio of hydrogen to ester when being applied to ester hydrogenation reaction, has good catalyst activity and stability and has better reaction effect.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
the technical object of the first aspect of the present invention is to provide a preparation method of an ester hydrogenation catalyst, comprising the following steps:
(1) CuCl is added 2 Dissolving in deionized water, heating, and stirring to form Cu (OH) 2 Sol, naturally cooling;
(2) Immersing the alumina hollow spheres in Cu (OH) of step (1) 2 Soaking in sol under negative pressure, filtering, drying and calcining to obtain alumina hollow spheres with copper oxide nanotube substrates embedded in the spheres and on the sphere walls;
(3) NiMoO is deposited by chemical vapor deposition 4 And depositing a film on the copper oxide nanotube substrate to obtain the ester hydrogenation catalyst.
Further, in step (1), cuCl 2 CuCl in solution 2 The mass percentage concentration of the catalyst is 10-30wt%, the heating temperature is 90-100deg.C, the stirring revolution is 100-350 r/min, and preferably 200-250 r/min until the solution changes color to form sol, heating and stirring are stopped, and natural cooling is performed.
Further, the average diameter of the alumina hollow spheres in the step (2) is 0.5-2 mm, preferably 0.5-1 mm; the average specific surface area is 280-380 cm 2 Preferably 300 to 320 cm/g 2 And/g, the thickness of the spherical wall is 0.1-0.2 mm, and the average pore diameter of the spherical wall is 10-40 nm, preferably 20-30 nm.
Further, the alumina hollow spheres are preferably washed before use, the solvent used for washing is absolute ethanol with the concentration of 95%, the washing times are 3-5 times, the washing temperature is 20-50 ℃, preferably 30-35 ℃, and the drying is carried out after washing, and the drying temperature is 50-100 ℃, preferably 70-90 ℃.
Further, the dipping time in the step (2) is 1 to 3 hours, and the dipping pressure is 1000 to 10000Pa, preferably 1500 to 3000Pa.
Further, the drying temperature in the step (2) is 30-40 ℃, the drying time is 12-24 hours, the calcining temperature is 150-200 ℃, and the calcining time is 1-3 hours.
Further, the metal source used in the chemical vapor deposition method in the step (3) is diethyl nickel dichloride and molybdenum naphthenate, and the oxygen source is high-purity oxygen.
Further, the carrier gas used by the diethyl nickel dichloride in the step (3) is hydrogen, the flow rate is 10-30 sccm, the carrier gas used by the molybdenum naphthenate is hydrogen, the flow rate is 20-40 sccm, and the flow rate of the oxygen is 100-500 sccm.
Further, the temperature of the chemical vapor deposition in the step (3) is 500-1000 ℃; the deposition time is 3-6 hours; the vacuum degree for deposition is 5000-10000 Pa.
Further, after the deposition in step (3) is completed, the temperature is reduced to room temperature, and NiMoO 4 The film is deposited on the copper oxide substrate, and the cooling rate is 0.1-1.0 ℃/s.
The technical object of the second aspect of the present invention is to provide an ester hydrogenation catalyst prepared by the above method. The invention adopts alumina hollow sphere as a template, and impregnates the hollow sphere under the condition of negative pressure to ensure Cu (OH) 2 The sol enters into the hollow alumina sphere and the sphere wall pore canal, and is filtered, dried and calcined to obtain the hollow alumina sphere and the sphere wall pore canal embedded copper oxide nanotube substrate, and then the NiMoO is obtained by a chemical vapor deposition method 4 Thin film depositionAnd (3) obtaining the catalyst on the copper oxide nanotube substrate. The method forms a copper oxide nanotube structure with uniform and regular pore diameter in the wall pore canal of the aluminum oxide hollow sphere, the copper oxide nanotube is communicated with the hollow part in the aluminum oxide hollow sphere, and the curved surface structure of the hollow part in the aluminum oxide hollow sphere has an enrichment effect on reaction hydrogen, so that the reaction gas has higher concentration in the hollow sphere, and the hydrogen re-reaction active center has higher concentration and stronger adsorption effect due to the gas sensitivity and the space limiting effect of the copper oxide nanotube. In addition to NiMoO deposited on the surface of copper oxide nanotubes 4 The film and the synergistic effect of the two transition metal oxides can accelerate the hydrogen absorption and release rates of the catalyst, greatly reduce the use amount and the circulation amount of hydrogen, and greatly reduce the consumption of hydrogen and the energy consumption of hydrogen circulation, thereby reducing the production cost. The catalyst has stronger catalytic activity, high mutual contact efficiency and mass transfer efficiency between reaction materials, higher reaction conversion rate and product selectivity, and good stability.
The technical object of the third aspect of the present invention is to provide the use of the hydrogenation catalyst for catalyzing the reaction of preparing 1, 6-hexanediol by hydrogenating dimethyl adipate.
In the above application, the dimethyl adipate hydrogenation reaction conditions were as follows: the reaction temperature is 150-250 ℃, preferably 160-200 ℃; the reaction pressure is 2-8 MPa, preferably 3-6 MPa, and the volume airspeed of the dimethyl adipate is 0.2-2: 1, preferably 0.5 to 1:1, molar ratio of hydrogen ester is 50:1 to 100:1, preferably 60:1 to 80:1.
compared with the prior art, the invention has the following advantages:
(1) The hydrogenation catalyst adopts alumina hollow spheres as templates, and is impregnated with Cu (OH) under the condition of negative pressure 2 The sol enters into the hollow alumina sphere and sphere wall pore canal, and after filtering, drying and calcining, the hydrogenation catalyst with copper oxide nanotubes with better continuity embedded in the hollow alumina sphere and sphere wall pore canal is obtained; copper oxide nanotube embedded in spherical wall pore canalThe hollow parts of the alumina balls are communicated with each other, so that the reaction materials and hydrogen can freely and smoothly enter and exit and react.
(2) In the catalyst, the curved surface structure of the hollow part inside the alumina hollow sphere has an enrichment effect on the reaction hydrogen, so that the reaction gas has higher concentration inside the hollow sphere, and the hydrogen re-reaction active center has higher concentration and stronger adsorption effect due to the gas sensitivity and the space confinement effect of the copper oxide nano tube. The consumption and the circulation amount of the hydrogen can be greatly reduced, and the consumption of the hydrogen and the energy consumption of hydrogen circulation are greatly reduced, thereby reducing the production cost.
(3) Copper oxide and NiMoO in the present invention 4 The catalyst with the film composite has strong catalytic activity, high mutual contact efficiency and mass transfer efficiency between reaction materials, high reaction conversion rate and product selectivity, and good stability.
Detailed Description
The following non-limiting examples will enable those of ordinary skill in the art to more fully understand the invention and are not intended to limit the invention in any way.
Example 1
The hydrogenation catalyst was prepared in this example and applied to the dimethyl adipate esterification reaction to prepare 1, 6-hexanediol:
preparing a hydrogenation catalyst:
(1) 60g of CuCl 2 Dissolving in 300g deionized water, reacting at 95 ℃ under the condition of stirring revolution of 250r/min until the solution changes color to form sol, stopping heating and stirring, and naturally cooling for standby;
(2) Immersing 150g of hollow alumina spheres in the sol obtained in the step (1), immersing for 3 hours under the condition that the pressure is 1800Pa, filtering, drying for 12 hours under the condition of 50 ℃, and calcining for 2 hours under the condition of 200 ℃ to obtain the hollow alumina spheres embedded in the copper oxide nanotube substrate.
(3) Placing the hollow alumina balls obtained in the step (2) into chemical vapor deposition reaction equipment, wherein the vacuum degree reaches 8000Pa, the temperature rises to 1000 ℃, diethyl nickel dichloride is used as a nickel source, molybdenum naphthenate is used as a molybdenum source, the flow rate of carrier gas of the nickel source is 10sccm, the flow rate of carrier gas of the molybdenum source is 20sccm, and the flow rate of oxygen is 400sccm; and (3) reacting for 3 hours, closing the organic source and oxygen, and cooling to room temperature at 0.5 ℃/s to obtain the hydrogenation catalyst.
Hydrogenation reaction of dimethyl adipate to prepare 1, 6-hexanediol:
introducing dimethyl adipate and hydrogen into a fixed bed continuous reactor with an embedded copper oxide nanotube catalyst, wherein the materials enter from the top of the reactor and flow out from the bottom of the reactor, the reaction temperature is 160 ℃, the reaction pressure is 3MPa, and the volume space velocity of the dimethyl adipate is 0.8h -1 The molar ratio of the hydrogen ester is 50:1 and the reaction results are shown in Table 1.
Example 2
The hydrogenation catalyst was prepared in this example and applied to the dimethyl adipate esterification reaction to prepare 1, 6-hexanediol:
preparing a hydrogenation catalyst:
(1) 60g of CuCl 2 Dissolving in 300g deionized water, reacting at 95 ℃ under the condition of stirring revolution of 250r/min until the solution changes color to form sol, stopping heating and stirring, and naturally cooling for standby;
(2) Immersing 150g of hollow alumina spheres in the sol obtained in the step (1), immersing for 3 hours under the condition that the pressure is 1800Pa, filtering, drying for 12 hours under the condition of 50 ℃, and calcining for 2 hours under the condition of 200 ℃ to obtain the hollow alumina spheres embedded in the copper oxide nanotube substrate.
(3) Placing the hollow alumina balls obtained in the step (2) into chemical vapor deposition reaction equipment, wherein the vacuum degree reaches 10000Pa, the temperature is raised to 900 ℃, diethyl nickel dichloride is used as a nickel source, molybdenum naphthenate is used as a molybdenum source, the carrier gas flow rate of the nickel source is 15sccm, the carrier gas flow rate of the molybdenum source is 30sccm, and the flow rate of oxygen is 300sccm; and (3) reacting for 4 hours, closing the organic source and oxygen, and cooling to room temperature at 0.5 ℃/s to obtain the hydrogenation catalyst.
Hydrogenation reaction of dimethyl adipate to prepare 1, 6-hexanediol:
introducing dimethyl adipate and hydrogen into a fixed bed continuous reactor with an embedded copper oxide nanotube catalyst, wherein the materials enter from the top of the reactor and flow out from the bottom of the reactor, the reaction temperature is 170 ℃, the reaction pressure is 4MPa, and the volume space velocity of the dimethyl adipate is 1.0h -1 The molar ratio of the hydrogen ester is 60:1 and the reaction results are shown in Table 1.
Example 3
The hydrogenation catalyst was prepared in this example and applied to the dimethyl adipate esterification reaction to prepare 1, 6-hexanediol:
preparing a hydrogenation catalyst:
(1) 60g of CuCl 2 Dissolving in 300g deionized water, reacting at 95 ℃ under the condition of stirring revolution of 250r/min until the solution changes color to form sol, stopping heating and stirring, and naturally cooling for standby;
(2) Immersing 150g of hollow alumina spheres in the sol obtained in the step (1), immersing for 3 hours under the condition that the pressure is 1800Pa, filtering, drying for 12 hours under the condition of 50 ℃, and calcining for 2 hours under the condition of 200 ℃ to obtain the hollow alumina spheres embedded in the copper oxide nanotube substrate.
(3) Placing the hollow alumina balls obtained in the step (2) into chemical vapor deposition reaction equipment, wherein the vacuum degree reaches 9000Pa, the temperature rises to 8000 ℃, diethyl nickel dichloride is used as a nickel source, molybdenum naphthenate is used as a molybdenum source, the flow rate of carrier gas of the nickel source is 20sccm, the flow rate of carrier gas of the molybdenum source is 30sccm, and the flow rate of oxygen is 400sccm; and (3) reacting for 4 hours, closing the organic source and oxygen, and cooling to room temperature at 0.5 ℃/s to obtain the hydrogenation catalyst.
Hydrogenation reaction of dimethyl adipate to prepare 1, 6-hexanediol:
introducing dimethyl adipate and hydrogen into a fixed bed continuous reactor with an embedded copper oxide nanotube catalyst, wherein the materials enter from the top of the reactor and flow out from the bottom of the reactor, the reaction temperature is 170 ℃, the reaction pressure is 5MPa, and the volume space velocity of the dimethyl adipate is 0.8h -1 The molar ratio of the hydrogen ester is 70:1 and the reaction results are shown in Table 1.
Example 4
The hydrogenation catalyst was prepared in this example and applied to the dimethyl adipate esterification reaction to prepare 1, 6-hexanediol:
preparing a hydrogenation catalyst:
(1) 60g of CuCl 2 Dissolving in 300g deionized water, reacting at 95 ℃ under the condition of stirring revolution of 250r/min until the solution changes color to form sol, stopping heating and stirring, and naturally cooling for standby;
(2) Immersing 150g of hollow alumina spheres in the sol obtained in the step (1), immersing for 3 hours under the condition that the pressure is 1800Pa, filtering, drying for 12 hours under the condition of 50 ℃, and calcining for 2 hours under the condition of 200 ℃ to obtain the hollow alumina spheres embedded in the copper oxide nanotube substrate.
(3) Placing the hollow alumina balls obtained in the step (2) into chemical vapor deposition reaction equipment, wherein the vacuum degree reaches 8000Pa, the temperature rises to 1000 ℃, diethyl nickel dichloride is used as a nickel source, molybdenum naphthenate is used as a molybdenum source, the carrier gas flow rate of the nickel source is 20sccm, the carrier gas flow rate of the molybdenum source is 35sccm, and the flow rate of oxygen is 350sccm; and (3) reacting for 4 hours, closing the organic source and oxygen, and cooling to room temperature at 0.5 ℃/s to obtain the hydrogenation catalyst.
Hydrogenation reaction of dimethyl adipate to prepare 1, 6-hexanediol:
introducing dimethyl adipate and hydrogen into a fixed bed continuous reactor with an embedded copper oxide nanotube catalyst, wherein the materials enter from the top of the reactor and flow out from the bottom of the reactor, the reaction temperature is 180 ℃, the reaction pressure is 5MPa, and the volume space velocity of the dimethyl adipate is 0.8h -1 The molar ratio of the hydrogen ester is 70:1 and the reaction results are shown in Table 1.
Example 5
The hydrogenation catalyst was prepared in this example and applied to the dimethyl adipate esterification reaction to prepare 1, 6-hexanediol:
preparing a hydrogenation catalyst:
(1) 60g of CuCl 2 Dissolving in 300g deionized water, reacting at 95 ℃ under the condition of stirring revolution of 250r/min until the solution changes color to form sol, stopping heating and stirring, and naturally cooling for standby;
(2) Immersing 150g of hollow alumina spheres in the sol obtained in the step (1), immersing for 3 hours under the condition that the pressure is 1800Pa, filtering, drying for 12 hours under the condition of 50 ℃, and calcining for 2 hours under the condition of 200 ℃ to obtain the hollow alumina spheres embedded in the copper oxide nanotube substrate.
(3) Putting the hollow alumina balls obtained in the step (2) into chemical vapor deposition reaction equipment, wherein the vacuum degree reaches 10000Pa, the temperature rises to 1000 ℃, diethyl nickel dichloride is used as a nickel source, molybdenum naphthenate is used as a molybdenum source, the carrier gas flow rate of the nickel source is 25sccm, the carrier gas flow rate of the molybdenum source is 35sccm, and the flow rate of oxygen is 400sccm; and (3) reacting for 5 hours, closing the organic source and oxygen, and cooling to room temperature at 0.5 ℃/s to obtain the hydrogenation catalyst.
Hydrogenation reaction of dimethyl adipate to prepare 1, 6-hexanediol:
introducing dimethyl adipate and hydrogen into a fixed bed continuous reactor with an embedded copper oxide nanotube catalyst, wherein the materials enter from the top of the reactor and flow out from the bottom of the reactor, the reaction temperature is 180 ℃, the reaction pressure is 4MPa, and the volume space velocity of the dimethyl adipate is 0.8h -1 The molar ratio of the hydrogen ester is 80:1 and the reaction results are shown in Table 1.
Example 6
The hydrogenation catalyst was prepared in this example and applied to the dimethyl adipate esterification reaction to prepare 1, 6-hexanediol:
preparing a hydrogenation catalyst:
(1) 60g of CuCl 2 Dissolving in 300g deionized water, reacting at 95 ℃ under the condition of stirring revolution of 250r/min until the solution changes color to form sol, stopping heating and stirring, and naturally cooling for standby;
(2) Immersing 150g of hollow alumina spheres in the sol obtained in the step (1), immersing for 3 hours under the condition that the pressure is 1800Pa, filtering, drying for 12 hours under the condition of 50 ℃, and calcining for 2 hours under the condition of 200 ℃ to obtain the hollow alumina spheres embedded in the copper oxide nanotube substrate.
(3) Placing the hollow alumina balls obtained in the step (2) into chemical vapor deposition reaction equipment, wherein the vacuum degree reaches 8000Pa, the temperature rises to 800 ℃, diethyl nickel dichloride is used as a nickel source, molybdenum naphthenate is used as a molybdenum source, the carrier gas flow rate of the nickel source is 15sccm, the carrier gas flow rate of the molybdenum source is 25sccm, and the flow rate of oxygen is 400sccm; and (3) reacting for 3 hours, closing the organic source and oxygen, and cooling to room temperature at 0.5 ℃/s to obtain the hydrogenation catalyst.
Hydrogenation reaction of dimethyl adipate to prepare 1, 6-hexanediol:
introducing dimethyl adipate and hydrogen into a fixed bed continuous reactor with an embedded copper oxide nanotube catalyst, wherein the materials enter from the top of the reactor and flow out from the bottom of the reactor, the reaction temperature is 180 ℃, the reaction pressure is 3MPa, and the volume space velocity of the dimethyl adipate is 1.0h -1 The molar ratio of the hydrogen ester is 80:1 and the reaction results are shown in Table 1.
Comparative example 1
Alumina spheres embedded in a copper oxide nanotube substrate were prepared according to the methods of steps (1) and (2) in example 5, metallic nickel and metallic molybdenum were supported on the obtained alumina spheres by impregnation, a hydrogenation catalyst was prepared, and other conditions were copper example 5, and the reaction results are shown in table 1.
Comparative example 2
According to the method of step (3) in example 5, niMoO was directly added 4 The thin film was deposited on the pore canal of the hollow alumina sphere to prepare hydrogenation catalyst, and the reaction results are shown in table 1 under other conditions of copper example 5.
Table 1 reaction results (conversion in moles) for the examples