A catalyst for preparing 1,4-pentanediol by hydrogenating levulinate, and its preparation method and application

Abstract

The present invention provides a catalyst for preparing 1,4-pentanediol by hydrogenating levulinate, and its preparation method and application, belonging to the technical field of catalytic hydrogenation. The present invention provides a catalyst comprising Al2O3 nanosheets and metal nanoparticles supported on the Al2O3 nanosheets. Al2O3 nanosheets are a two-dimensional material with a high degree of chemical bond unsaturation on the surface of the sheet, thus containing many oxygen defects and unsaturated five-coordinated Al 3+ sites. Oxygen vacancies and pentacoordinated Al 3+ The sites are conducive to anchoring metal nanoparticles and improving the dispersion of metal nanoparticles, thereby increasing the contact area with the reaction raw materials and improving catalytic activity. In addition, there is a strong metal-support interaction between the metal and the Al2O3 nanosheets to form a metal-Al2O3 interface, so the catalyst has excellent stability.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic hydrogenation, and in particular to a catalyst for preparing 1,4-pentanediol by hydrogenating levulinic acid ester, and a preparation method and application thereof. Background Art

[0002] 1,4-Pentanediol is an important organic and fine chemical raw material, widely used in the pharmaceutical, chemical, textile, paper, automotive, and daily chemical industries. Its most important application is as a monomer for the synthesis of biodegradable polyesters and resin materials. The catalytic hydrogenation of levulinic acid esters to produce high-value-added 1,4-pentanediol has both important academic and economic value.

[0003] At present, the catalyst for the direct hydrogenation of levulinate to produce 1,4-pentanediol is mainly a supported Cu-based catalyst. For example, Jing et al. (Chemistry Select, 2020, 5(11), 924-930) used Cu / ZrOCO3 catalyst to catalyze the hydrogenation of methyl levulinate to produce 1,4-pentanediol. Although methyl levulinate was completely converted, the yield of 1,4-pentanediol was only 23.1%; Tian et al. (Catalysis Communications 2016, 76, 50-53) used Cu / ZrO2 catalyst to catalyze the hydrogenation of methyl levulinate, and the yield of 1,4-pentanediol was only 39%; Fu et al. (ChemSusChem, 2019, 12(16), 3837-3848) used Cu-Fe / SBA-15 catalyst to catalyze the hydrogenation of ethyl levulinate, and the conversion of ethyl levulinate was 99.3%, and the yield of 1,4-pentanediol was 64.4%. Although these preliminary studies have made significant progress, these catalysts still have the following disadvantages: (1) The yield of the target product 1,4-pentanediol is low, generally less than 70%. (2) These catalysts are easily deactivated, and the Cu nanoparticles tend to aggregate and be lost during the reaction. They are also unstable and cannot be operated for a long period of time. Summary of the Invention

[0004] The purpose of the present invention is to provide a catalyst for preparing 1,4-pentanediol by hydrogenating levulinate, a preparation method and application thereof. The catalyst of the present invention has excellent catalytic activity and stability.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The invention provides a catalyst comprising Al2O3 nanosheets and metal nanoparticles supported on the Al2O3 nanosheets.

[0007] Preferably, the metal nanoparticles include one or more of Ru, Pt, Pd, Ni and Cu;

[0008] The particle size of the metal nanoparticles is 1 to 10 nm.

[0009] Preferably, the loading amount of the metal nanoparticles is 0.5 to 20 wt%.

[0010] Preferably, the catalyst further comprises a metal oxide additive supported on the Al2O3 nanosheets.

[0011] Preferably, the metal oxide additive includes one or more of WO3, MoO3, CeO2, Ga2O3 and Re2O3.

[0012] Preferably, the loading amount of the metal oxide additive is 0.5 to 3 wt%.

[0013] The present invention also provides a method for preparing the catalyst described in the above scheme, comprising the following steps:

[0014] The Al2O3 nanosheets are immersed in a precursor solution of metal nanoparticles or in a solution containing a precursor of metal nanoparticles and a precursor of a metal oxide additive, and then dried, calcined and reduced in sequence to obtain the catalyst.

[0015] Preferably, the precursor of the metal nanoparticles includes one or more of nitrates, hydrochlorides and acids corresponding to the metal elements;

[0016] The metal oxide additive precursor includes nitrate and / or ammonium salt corresponding to the metal in the metal oxide additive.

[0017] Preferably, the calcination temperature is 400-800°C and the calcination time is 1-4 hours;

[0018] The reduction is carried out in a H2 / Ar mixed gas at a temperature of 150 to 400°C for 1 to 3 hours.

[0019] The present invention also provides use of the catalyst described in the above scheme or the catalyst prepared by the preparation method described in the above scheme in the preparation of 1,4-pentanediol by hydrogenation of levulinic acid ester.

[0020] The present invention provides a catalyst comprising Al2O3 nanosheets and metal nanoparticles supported on the Al2O3 nanosheets. Al2O3 nanosheets are a two-dimensional material with a high degree of chemical bond unsaturation on the surface of the sheet, thus containing many oxygen defects and unsaturated five-coordinated Al 3+ sites. Oxygen vacancies and pentacoordinated Al 3+The sites facilitate anchoring of metal nanoparticles, improving their dispersion and thus increasing their contact area with the reaction feedstock, thus enhancing catalytic activity. Furthermore, a strong metal-support interaction exists between the metal and the Al2O3 nanosheets, forming a metal-Al2O3 interface, resulting in excellent stability for the catalyst. Experimental results show that when the catalyst of the present invention catalyzes the hydrogenation of levulinate to produce 1,4-pentanediol, the conversion of levulinate is 100%, and the yield of 1,4-pentanediol is 85.4-95.2%. Furthermore, after five cycles of use, the catalyst, which achieves a 100% conversion of ethyl levulinate and a 91.7% yield of 1,4-pentanediol, maintains a 100% conversion of levulinate and a 90.3% selectivity for 1,4-pentanediol. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 TEM image of Al2O3 nanosheets in Example 1;

[0022] Figure 2 This is the TEM image of the Ru-WO3 / Al2O3 catalyst in Example 1. DETAILED DESCRIPTION

[0023] The invention provides a catalyst comprising Al2O3 nanosheets and metal nanoparticles supported on the Al2O3 nanosheets.

[0024] In the present invention, the loading of the metal nanoparticles is preferably 0.5 to 20 wt%, more preferably 1 to 10 wt%, and even more preferably 1 to 5 wt%. In the present invention, the loading refers to the mass fraction of the metal nanoparticles in the catalyst. In the present invention, the metal nanoparticles preferably include one or more of Ru, Pt, Pd, Ni, and Cu; and the particle size of the metal nanoparticles is preferably 1 to 10 nm, more preferably 1 to 5 nm.

[0025] In the present invention, the catalyst preferably further includes a metal oxide promoter supported on the Al2O3 nanosheets; the loading of the metal oxide promoter is preferably 0.5-3wt%, more preferably 1-2.5wt%, and even more preferably 1.5-2wt%. In the present invention, the loading refers to the mass fraction of the metal oxide promoter in the catalyst. The catalyst also preferably includes a metal oxide promoter supported on the Al2O3 nanosheets; the metal oxide promoter preferably includes one or more of WO3, MoO3, CeO2, Ga2O3, and Re2O3. The metal oxide promoter can improve the catalyst's acidity and enhance its stability in high-temperature aqueous solutions.

[0026] In the present invention, the specific surface area of ​​the Al2O3 nanosheets is preferably 160 to 260 m2 / g, more preferably 180 to 240 m 2 / g, more preferably 200 to 220 m 2 / g. The thickness of the Al2O3 nanosheets is preferably 5 to 15 nm.

[0027] The method for preparing the Al2O3 nanosheets preferably comprises the following steps:

[0028] Aluminum salt, urea and water are mixed to undergo hydrothermal reaction and calcination to obtain the Al2O3 nanosheets.

[0029] In the present invention, the aluminum salt comprises one or more of aluminum chloride, aluminum sulfate, and aluminum nitrate. The mass ratio of the aluminum salt to urea is preferably 1:1 to 3, more preferably 1:2 to 2.5. The mass ratio of the aluminum salt to water is preferably 1:10 to 20, more preferably 1:15 to 18.

[0030] In the present invention, the temperature of the hydrothermal reaction is preferably 60-150°C, more preferably 80-120°C; the time is preferably 36-72h, more preferably 48-56h. During the hydrothermal reaction, Al in the aluminum salt 3+ The hydroxide ions released from the urea aqueous solution form aluminum hydroxide.

[0031] Before the calcination, the hydrothermal reaction product is preferably cooled to room temperature, filtered, and dried in sequence. The filtration and drying are not particularly limited in the present invention, and methods well known to those skilled in the art can be used.

[0032] In the present invention, the calcination temperature is preferably 400-800° C., more preferably 450-750° C., and further preferably 500-600° C.; the calcination time is preferably 1-4 h, and more preferably 2-3 h.

[0033] The present invention also provides a method for preparing the catalyst described in the above scheme, comprising the following steps:

[0034] The Al2O3 nanosheets are immersed in a precursor solution of metal nanoparticles or in a solution containing a precursor of metal nanoparticles and a precursor of a metal oxide additive, and then dried, calcined and reduced in sequence to obtain the catalyst.

[0035] In the present invention, the precursor of the metal nanoparticles includes one or more of nitrates, hydrochlorides and acids corresponding to the metal element; when the metal is nickel, the nitrate corresponding to the metal nickel is nickel nitrate; when the metal is copper, the nitrate corresponding to the metal copper is copper nitrate; when the metal is palladium, the hydrochloride corresponding to the metal palladium is palladium chloride; when the metal is ruthenium, the hydrochloride corresponding to the metal ruthenium is ruthenium chloride; when the metal is platinum, the acid corresponding to the metal platinum element is chloroplatinic acid; the concentration of the metal precursor solution is preferably 0.01 to 0.2 mol / L, more preferably 0.1 to 0.15 mol / L.

[0036] In the present invention, the metal oxide auxiliary agent precursor preferably includes a nitrate and / or ammonium salt corresponding to the metal in the metal oxide auxiliary agent; when the metal oxide auxiliary agent is cerium dioxide, the nitrate is cerium nitrate; when the metal oxide auxiliary agent is gallium trioxide, the nitrate is gallium nitrate; when the metal oxide auxiliary agent is tungsten trioxide, the ammonium salt is ammonium metatungstate; when the metal oxide auxiliary agent is molybdenum trioxide, the ammonium salt is ammonium molybdate; when the metal oxide auxiliary agent is rhenium trioxide, the ammonium salt is ammonium perrhenate. The concentration of the metal nanoparticle precursor in the solution containing the metal nanoparticle precursor and the metal oxide auxiliary agent precursor is preferably 0.01 to 0.2 mol / L, more preferably 0.1 to 0.15 mol / L; the concentration of the metal oxide auxiliary agent precursor is preferably 0.005 to 0.1 mol / L, more preferably 0.06 to 0.08 mol / L.

[0037] In the present invention, the impregnation method is preferably standing still, and the standing still time is preferably 5 to 30 hours, more preferably 10 to 25 hours, and even more preferably 15 to 20 hours.

[0038] In the present invention, the drying temperature is preferably 80° C., and the drying time is preferably 10 h.

[0039] In the present invention, the calcination temperature is preferably 400-800°C, more preferably 450-750°C, and even more preferably 500-600°C; the calcination time is preferably 1-4 hours, more preferably 2-3 hours. During the calcination process, the metal precursor and the metal oxide additive precursor both generate corresponding metal oxides.

[0040] In the present invention, the reduction is preferably carried out in a H2 / Ar mixed gas, and the volume fraction of H2 in the mixed gas is preferably 10%; the reduction temperature is preferably 150-400°C, more preferably 200-350°C, and further preferably 250-300°C; the time is preferably 1-3h, more preferably 1.5-2h.

[0041] The present invention also provides use of the catalyst described in the above scheme or the catalyst prepared by the preparation method described in the above scheme in the preparation of 1,4-pentanediol by hydrogenation of levulinic acid ester.

[0042] The hydrogenation of levulinate to prepare 1,4-pentanediol preferably comprises the following steps:

[0043] A mixture of levulinic acid ester, a polar solvent and a catalyst is introduced into hydrogen gas for hydrogenation reaction to obtain 1,4-pentanediol;

[0044] The catalyst is the catalyst described in the above scheme or the catalyst prepared by the preparation method described in the above scheme.

[0045] In the present invention, the levulinate preferably includes one or more of methyl levulinate, ethyl levulinate, propyl levulinate and butyl levulinate.

[0046] In the present invention, the mass of the catalyst is preferably 3-15% of the mass of the levulinic ester, more preferably 5-10%. The polar solvent preferably includes water. The mass of the polar solvent is preferably 10-30 times the mass of the levulinic ester. The catalyst of the present invention has high activity, thereby reducing the amount of catalyst used.

[0047] In the present invention, the hydrogenation temperature is preferably 200-300°C, more preferably 230-270°C; the hydrogen pressure is preferably 4-8 MPa, more preferably 5-6 MPa; and the time is preferably 6-24 h, more preferably 10-16 h.

[0048] After the hydrogenation reaction, the present invention preferably cools the obtained hydrogenation reaction product to room temperature and then centrifuges it to obtain the 1,4-pentanediol.

[0049] The catalyst for preparing 1,4-pentanediol by hydrogenation of levulinic acid ester provided by the present invention, its preparation method and application are described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0050] Example 1

[0051] 6.44 g of aluminum nitrate and 9.28 g of urea were added to 80 mL of deionized water and stirred vigorously at room temperature for 25 minutes. The product was then hydrothermally heated at 100°C in a crystallization kettle for 48 hours, cooled to room temperature, filtered, and dried in an oven at 80°C. The product was then calcined in a muffle furnace at 600°C in air for 2 hours to obtain Al2O3 nanosheets.

[0052] 2g of Al2O3 nanosheets were added to 3mL of a solution containing RuCl3 (0.1mol / L) and ammonium metatungstate (0.01mol / L). The mixture was allowed to stand for 12h, dried at 80°C for 10h, and then calcined in a muffle furnace at 500°C for 3h. Finally, the sample was reduced in a tube furnace at 300°C for 2h in a 10% H2 / Ar mixture to obtain a Ru-WO3 / Al2O3 catalyst with a Ru loading of 1.5wt% and a WO3 loading of 2.5wt%.

[0053] The Al2O3 nanosheets prepared in Example 1 were subjected to TEM analysis, and the results were as follows: Figure 1 As shown. Figure 1 It can be seen that the Al2O3 nanosheets have a thickness of 5 to 10 nm. The specific surface area of ​​the Al2O3 nanosheets tested by the BET method is 230 m 2 / g.

[0054] The Ru-WO3 / Al2O3 catalyst prepared in Example 1 was subjected to TEM analysis. Figure 2 As shown. Figure 2 It can be seen that all Ru nanoparticles are evenly distributed on the surface of Al2O3 nanosheets, and the particle size of Ru nanoparticles is 2 to 4 nm.

[0055] Application Example 1

[0056] In an autoclave, 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of Ru-WO3 / Al2O3 catalyst were introduced and flushed with 5 MPa of H2. The temperature was then raised to 240°C and maintained for 10 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed by gas chromatography. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 91.7%. After five cycles of use, the catalyst achieved 100% ethyl levulinate conversion and 90.3% 1,4-pentanediol selectivity, demonstrating the catalyst's high stability.

[0057] Comparative Example 1

[0058] 2g of Al2O3 (a three-dimensional material without specific morphology) purchased from Sinopharm Chemical Reagent Co., Ltd. was added to 3mL of a solution containing RuCl3 (0.1mol / L) and ammonium metatungstate (0.01mol / L). The solution was allowed to stand for 12 hours, dried at 80°C for 10 hours, and then calcined in a muffle furnace at 500°C for 3 hours. Finally, the sample was reduced in a tube furnace at 300°C for 2 hours in a 10% H2 / Ar mixture to obtain a Ru-WO3 / Al2O3 catalyst with a Ru loading of 1.5wt%, Ru nanoparticles with a particle size of 3-6nm, and a WO3 loading of 2.5wt%.

[0059] Comparative Application Example 1

[0060] The performance of the catalyst of Comparative Example 1 was tested according to the reaction conditions of Application Example 1.

[0061] The evaluation results of the Ru-WO3 / Al2O3 catalyst showed that the conversion rate of ethyl levulinate was 94.2% and the yield of 1,4-pentanediol was 35.7%.

[0062] After the catalyst was recycled twice, the conversion rate of ethyl levulinate decreased to 95.6% and the yield of 1,4-pentanediol decreased to 28.6%, indicating that the commercial Al2O3-loaded Ru-WO3 catalyst had begun to deactivate after being recycled twice.

[0063] Example 2

[0064] 2 g of the Al2O3 nanosheets synthesized in Example 1 were added to 3 mL of a solution containing RuCl3 (0.1 mol / L), allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C for 2 h in a 10% H2 / Ar mixture to obtain a Ru / Al2O3 catalyst with a Ru loading of 1.5 wt% and Ru nanoparticles with a particle size of 2 to 5 nm.

[0065] Application Example 2

[0066] The only difference from Application Example 1 is that the Ru / Al2O3 catalyst of Example 2 is used.

[0067] Evaluation results of the Ru / Al2O3 catalyst showed that the conversion rate of ethyl levulinate was 96.7% and the yield of 1,4-pentanediol was 42.8%.

[0068] Example 3

[0069] 2 g of the Al2O3 nanosheets synthesized in Example 1 were added to 3 mL of a solution containing PdCl2 (0.1 mol / L) and ammonium metatungstate (0.01 mol / L), allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C for 2 h in a 10% H2 / Ar mixture to obtain a Pd-WO3 / Al2O3 catalyst with a Pd loading of 1.5 wt%, a Pd nanoparticle size of 1 to 5 nm, and a WO3 loading of 2.5 wt%.

[0070] Application Example 3

[0071] In an autoclave, 2 mmol of methyl levulinate, 5 mL of water, and 0.02 g of Pd-WO3 / Al2O3 catalyst were introduced. 5 MPa of H2 was then injected. The temperature was then raised to 240°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The methyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 92.2%.

[0072] Example 4

[0073] 2 g of the Al2O3 nanosheets synthesized in Example 1 were added to 3 mL of a solution containing H2PtCl4 (0.1 mol / L) and ammonium metatungstate (0.01 mol / L), allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 200°C in a 10% H2 / Ar mixture for 2 h to obtain a Pt-WO3 / Al2O3 catalyst with a Pt loading of 1.5 wt%, a Pt nanoparticle size of 2 to 6 nm, and a WO3 loading of 2.5 wt%.

[0074] Application Example 4

[0075] An autoclave was charged with 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of Pt-WO3 / Al2O3 catalyst. The autoclave was then flushed with 5 MPa of hydrogen. The temperature was then raised to 240°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 94.8%.

[0076] Example 5

[0077] 2 g of the Al2O3 nanosheets synthesized in Example 1 were added to 3 mL of a solution containing Co(NO3)2 (0.1 mol / L) and ammonium metatungstate (0.01 mol / L), allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 400°C for 2 h in a 10% H2 / Ar mixture to obtain a Co-WO3 / Al2O3 catalyst with a Co loading of 5 wt%, a Co nanoparticle size of 3 to 10 nm, and a WO3 loading of 2.5 wt%.

[0078] Application Example 5

[0079] In an autoclave, 2 mmol of propyl levulinate, 5 mL of water, and 0.02 g of Co-WO3 / Al2O3 catalyst were introduced. 5 MPa of H2 was then injected. The temperature was then raised to 260°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The conversion of propyl levulinate was 100%, and the yield of 1,4-pentanediol was 89.7%.

[0080] Example 6

[0081] 2 g of the Al2O3 nanosheets synthesized in Example 1 were added to 3 mL of a solution containing Ni(NO3)2 (0.1 mol / L) and ammonium metatungstate (0.01 mol / L), allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 400°C in a 10% H2 / Ar mixture for 2 h to obtain a Ni-WO3 / Al2O3 catalyst with a Ni loading of 5 wt%, a Ni nanoparticle size of 2 to 10 nm, and a WO3 loading of 2.5 wt%.

[0082] Application Example 6

[0083] An autoclave was charged with 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of Ni-WO3 / Al2O3 catalyst. The mixture was then flushed with 5 MPa of hydrogen. The temperature was then raised to 260°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 86.9%.

[0084] Example 7

[0085] 2 g of the Al2O3 nanosheets synthesized in Example 1 were added to 3 mL of a solution containing Cu(NO3)2 (0.1 mol / L) and ammonium metatungstate (0.01 mol / L), allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C in a 10% H2 / Ar mixture for 2 h to obtain a Cu-WO3 / Al2O3 catalyst with a Cu loading of 5 wt%, a Cu nanoparticle size of 4 to 10 nm, and a WO3 loading of 2.5 wt%.

[0086] Application Example 7

[0087] An autoclave was charged with 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of Cu-WO3 / Al2O3 catalyst. The mixture was then flushed with 5 MPa of hydrogen. The temperature was then raised to 260°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 85.4%.

[0088] Example 8

[0089] 2 g of the Al2O3 nanosheets synthesized in Example 1 were added to 3 mL of a solution containing RuCl3 (0.05 mol / L), PdCl2 (0.05 mol / L), and ammonium metatungstate (0.01 mol / L). The mixture was allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C in a 10% H2 / Ar mixture for 2 h to obtain a RuPd-WO3 / Al2O3 catalyst with a total RuPd loading of 2 wt%, Ru and Pd nanoparticle sizes of 1-4 nm and 2-5 nm, respectively, and a WO3 loading of 2.5 wt%.

[0090] Application Example 8

[0091] An autoclave was charged with 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of RuPd-WO3 / Al2O3 catalyst. The autoclave was then flushed with 5 MPa of hydrogen. The temperature was then raised to 240°C and maintained for 12 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 93.3%.

[0092] Example 9

[0093] 6.44 g of aluminum nitrate and 9.28 g of urea were added to 90 mL of deionized water, stirred vigorously at room temperature for 25 min, and kept hydrothermally at 120 ° C in a crystallization kettle for 60 h. After cooling to room temperature, the mixture was filtered and dried in an oven at 80 ° C. The mixture was calcined in a muffle furnace at 500 ° C in air atmosphere for 3 h to obtain a surface area of ​​215 m 2 / g, Al2O3 nanosheets with a thickness of 6 to 12 nm.

[0094] 2g of Al2O3 nanosheets were added to 3mL of a solution containing RuCl3 (0.05mol / L), H2PtCl4 (0.05mol / L), and ammonium metatungstate (0.01mol / L). The solution was allowed to stand for 12h, dried at 80°C for 10h, and then calcined in a muffle furnace at 500°C for 3h. Finally, the sample was reduced in a tube furnace at 300°C for 2h in a 10% H2 / Ar mixture to obtain a RuPt-WO3 / Al2O3 catalyst with a RuPt loading of 2wt%, Ru and Pt nanoparticle sizes of 1-4nm and 2-6nm, respectively, and a WO3 loading of 2.5wt%.

[0095] Application Example 9

[0096] In an autoclave, 3 mmol of butyl levulinate, 5 mL of water, and 0.04 g of RuPt-WO3 / Al2O3 catalyst were introduced. 5 MPa of H2 was then injected. The temperature was then raised to 240°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The conversion of butyl levulinate was 100%, and the yield of 1,4-pentanediol was 95.2%.

[0097] Example 10

[0098] 2 g of the Al2O3 nanosheets synthesized in Example 8 were added to 3 mL of a solution containing RuCl3 (0.05 mol / L), Co(NO3)2 (0.05 mol / L), and ammonium metatungstate (0.01 mol / L). The mixture was allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C for 2 h in a 10% H2 / Ar mixture to obtain a RuCo-WO3 / Al2O3 catalyst with a RuCo loading of 2 wt%, Ru and Co nanoparticle sizes of 1-3 nm and 2-6 nm, respectively, and a WO3 loading of 2.5 wt%.

[0099] Application Example 10

[0100] In an autoclave, 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of RuCo-WO3 / Al2O3 catalyst were introduced. 5 MPa of H2 was then injected. The temperature was then raised to 240°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 92.7%.

[0101] Example 11

[0102] 2 g of the Al2O3 nanosheets synthesized in Example 8 were added to 3 mL of a mixed solution containing RuCl3 (0.1 mol / L) and ammonium molybdate (0.01 mol / L). The mixture was allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C for 2 h in a 10% H2 / Ar mixture to obtain a Ru-MoO3 / Al2O3 catalyst with a Ru loading of 1 wt%, Ru nanoparticles with a particle size of 1 to 4 nm, and a MoO3 loading of 1.5 wt%.

[0103] Application Example 11

[0104] In an autoclave, 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of Ru-MoO₃ / Al₂O₃ catalyst were introduced. 5 MPa of H₂ was then injected. The temperature was then raised to 250°C and maintained for 12 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 91.6%.

[0105] Example 12

[0106] 2 g of the Al2O3 nanosheets synthesized in Example 8 were added to 3 mL of a solution containing RuCl3 (0.1 mol / L) and nitric acid (0.01 mol / L). The mixture was allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C for 2 h in a 10% H2 / Ar mixture to obtain a Ru-CeO2 / Al2O3 catalyst with a Ru loading of 1 wt%, Ru nanoparticles with a particle size of 1 to 6 nm, and a CeO2 loading of 1.5 wt%.

[0107] Application Example 12

[0108] An autoclave was charged with 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of Ru-CeO2 / Al2O3 catalyst. The autoclave was then flushed with 5 MPa of hydrogen. The temperature was then raised to 240°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 90.4%.

[0109] Example 13

[0110] 2 g of the Al2O3 nanosheets synthesized in Example 8 were added to 3 mL of a solution containing RuCl3 (0.1 mol / L) and gallium nitrate (0.01 mol / L). The mixture was allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C for 2 h in a 10% H2 / Ar mixture to obtain a Ru-Ga2O3 / Al2O3 catalyst with a Ru loading of 1 wt%, Ru nanoparticles with a particle size of 1 to 4 nm, and a Ga2O3 loading of 1.5 wt%.

[0111] Application Example 13

[0112] In an autoclave, 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of Ru-Ga2O3 / Al2O3 catalyst were introduced. 5 MPa of hydrogen was then injected. The temperature was then raised to 240°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 92.4%.

[0113] Example 14

[0114] 2 g of the Al2O3 nanosheets synthesized in Example 8 were added to 3 mL of a solution containing RuCl3 (0.1 mol / L) and ammonium perrhenate (0.01 mol / L). The mixture was allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C for 2 h in a 10% H2 / Ar mixture to obtain a Ru-Re2O3 / Al2O3 catalyst with a Ru loading of 1 wt%, Ru nanoparticles with a particle size of 1 to 5 nm, and a Re2O3 loading of 1.5 wt%.

[0115] Application Example 14

[0116] In an autoclave, 2 mmol of methyl levulinate, 5 mL of water, and 0.02 g of Ru-Re2O3 / Al2O3 catalyst were introduced. 5 MPa of H2 was then injected. The temperature was then raised to 240°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The methyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 91.9%.

[0117] Example 15

[0118] 2 g of the Al2O3 nanosheets synthesized in Example 8 were added to 3 mL of a solution containing RuCl3 (0.05 mol / L), PdCl2 (0.05 mol / L), and ammonium perrhenate (0.01 mol / L). The mixture was allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 300°C for 2 h in a 10% H2 / Ar mixture to obtain a RuPd-Re2O3 / Al2O3 catalyst with a RuPd loading of 2 wt%, Ru and Pd nanoparticle sizes of 2-5 nm and 1-4 nm, respectively, and a Re2O3 loading of 1.5 wt%.

[0119] Application Example 15

[0120] An autoclave was charged with 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of RuPd-Re2O3 / Al2O3 catalyst. The autoclave was then flushed with 5 MPa of hydrogen. The temperature was then raised to 240°C and maintained for 15 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 94.7%.

[0121] Example 16

[0122] 2 g of the Al2O3 nanosheets synthesized in Example 8 were added to 3 mL of a solution containing RuCl3 (0.03 mol / L), H2PtCl4 (0.03 mol / L), Ni(NO3)2 (0.03 mol / L), and nitric acid (0.01 mol / L). The mixture was allowed to stand for 12 h, dried at 80°C for 10 h, and then calcined in a muffle furnace at 500°C for 3 h. Finally, the sample was reduced in a tube furnace at 350°C in a 10% H2 / Ar mixture for 2 h to obtain a RuPtNi-Ce2O3 / Al2O3 catalyst with a RuPtNi loading of 4 wt%, Ru, Pt, and Ni nanoparticle sizes of 1-3 nm, 1-4 nm, and 2-4 nm, respectively, and a Ce2O3 loading of 2.5 wt%.

[0123] Application Example 16

[0124] An autoclave was charged with 2 mmol of ethyl levulinate, 5 mL of water, and 0.02 g of RuPtNi-Ce2O3 / Al2O3 catalyst. The autoclave was then flushed with 5 MPa of hydrogen. The temperature was then raised to 240°C and maintained for 14 hours. The temperature was then cooled to room temperature, and the liquid product was separated by centrifugation and analyzed using a gas chromatograph. The ethyl levulinate conversion was 100%, and the 1,4-pentanediol yield was 93.9%.

[0125] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A catalyst for preparing 1,4-pentanediol by hydrogenation of levulinic acid ester, characterized in that: Comprising Al2O3 nanosheets and metal nanoparticles loaded on the Al2O3 nanosheets; The metal includes one or more of Ru, Pt, Pd and Ni; The catalyst further includes a metal oxide additive supported on the Al2O3 nanosheets; The metal oxide additive is one or more of CeO2, Ga2O3 and Re2O3.

2. The catalyst according to claim 1, characterized in that The particle size of the metal nanoparticles is 1-10 nm.

3. The catalyst according to claim 1 or 2, characterized in that The loading amount of the metal nanoparticles is 0.5-20 wt %.

4. The catalyst according to claim 1, characterized in that The loading amount of the metal oxide additive is 0.5-3 wt%.

5. The method for preparing the catalyst according to any one of claims 1 to 4, characterized in that: The following steps are involved: The Al2O3 nanosheets are immersed in a solution containing a precursor of metal nanoparticles and a precursor of a metal oxide auxiliary agent, and then dried, calcined and reduced in sequence to obtain the catalyst.

6. The preparation method according to claim 5, characterized in that The precursor of the metal nanoparticles includes one or more of nitrates, hydrochlorides and acids corresponding to the metal elements; The metal oxide additive precursor includes nitrate and / or ammonium salt corresponding to the metal in the metal oxide additive.

7. The preparation method according to claim 5, characterized in that The calcination temperature is 400-800°C and the calcination time is 1-4 hours; The reduction is carried out in a H2 / Ar mixed gas at a temperature of 150-400°C for a time of 1-3 hours.

8. Use of the catalyst according to any one of claims 1 to 4 or the catalyst prepared by the preparation method according to any one of claims 5 to 7 in the preparation of 1,4-pentanediol by hydrogenation of levulinic acid ester.

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