A method for preparing porous carbon-supported Ni-based catalyst from lignin residue and its application in hydrogenation of 5-hydroxymethylfurfural and furfural

Abstract

The present invention relates to a method for preparing porous carbon-supported Ni-based catalyst from biomass lignin residue and the field of 5 hydroxymethylfurfural and furfural catalysis, and discloses a method for preparing porous carbon-supported Ni-based hydrogenation catalyst from lignin residue and the application of high substrate concentration catalysis 5 hydroxymethylfurfural and furfural selective hydrogenation. A nickel hydroxide-based catalyst precursor for carbon material support is prepared by a one-pot hydrothermal method using lignin residue, nickel nitrate hexahydrate, sodium gluconate and water, and high-temperature reduction obtains a Ni / C catalyst with high specific surface area. By optimizing temperature, hydrogen pressure, reaction time, etc., the Ni / C catalyst can be used to catalyze 5 hydroxymethylfurfural and furfural selective hydrogenation under high substrate concentration. The catalyst preparation method in the present invention makes full use of the waste generated in the biomass conversion process, not only reduces environmental pollution problems, but also improves the overall economic value of biomass, realizes the comprehensive utilization of resources, and has great industrial application value.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass resource utilization, and in particular to a method for preparing a porous carbon-supported Ni-based catalyst from lignin residue (solid residue from corn cob hydrolysis) and an application thereof in catalyzing the hydrogenation of 5-hydroxymethylfurfural (HMF) and furfural (FF). Background Art

[0002] Lignocellulose has a complex and stable structure, containing multiple components such as lignin, cellulose, and hemicellulose [Mika LT, et al., Catalytic conversion of carbohydrates to initial platform chemicals: chemistry and sustainability [J]. Chemical reviews, 2018, 118(2): 505-613.;Hou Qidong, et al., Biorefinery roadmap based on catalytic production and upgrading 5-hydroxymethylfurfural. Green Chemistry, 2021, 23(1): 119-231.]. In the process of comprehensive utilization of lignocellulose, there are problems such as harsh reaction conditions (strong acid or strong base) and the generation of a large amount of polluting waste (waste liquid and solid residue). For example, after using corn cobs for hydrolysis to produce high-value-added chemicals, a large amount of lignin solid residue remains. How to maximize the pollution-free utilization of biomass resources, improve the overall economic value of biomass, and achieve comprehensive resource utilization is an urgent problem that needs to be solved.

[0003] Furan dimethanol (BHMF) and furfuryl alcohol (FA) can be produced by hydrogenating biomass platform molecules 5-hydroxymethylfurfural and furfural. They can be used as precursors for a variety of chemicals, such as polyesters, polyethers, fungicides, furan resins, etc., and can also be used as precursors for fuel additives (DMF, 2-MF).

[0004] A large number of literature and patents have studied and reported on the hydrogenation of HMF and FF to prepare BHMF and FA (Maki-Arvela, et al., Catalytic hydrogenation / hydrogenolysis of 5-hydroxymethylfurfural to 2,5-dimethylfuran. Chemsuschem 2021, 14(1), 150-168.; Vikanova, K. et al., Advanced room-temperature synthesis of 2,5-bis(hydroxymethyl)furan—a monomer for biopolymers—from 5-hydroxymethylfurfural. ACS Sustainable Chemistry&Engineering2021,9(3),1161-1171.Wang,Q.;Santos,S.;Urbina-Blanco,CA;Zhou,W.;Yang,Y.;Mar inova,M.;Heyte,S.;Joelle,T.-R.;Ersen,O.;Baaziz,W.;Safonova,OV;Saeys,M.;Ordomsky,VV,Ru(III)single site solid micellar catalyst for selective aqueous phasehydrogenation of carbonyl groups in biomass-derived compounds.AppliedCatalysis B:Environmental 2022,300,120730. Methods for producing BHMF, BHMTHF, HDO, and HTO from HMF (CN107001197B); a method for hydrogenating furfural to furfuryl alcohol (CN115974820B), however, generally suffer from low reaction concentrations. Therefore, using solid residues from biomass reactions as a catalyst for high-concentration hydrogenation of HMF and FF to produce BHMF and FA can fully utilize biomass resources and is of great significance to green and sustainable development. Summary of the Invention

[0005] To solve the problems in the above-mentioned prior art, the present invention provides a method for preparing porous carbon-supported Ni-based hydrogenation catalyst from lignin residue and an application of high substrate concentration catalysis for selective hydrogenation of 5-hydroxymethylfurfural and furfural. A nickel hydroxide-based catalyst precursor loaded on carbon material is prepared by a one-pot hydrothermal method using lignin residue (solid residue from corncob hydrolysis), nickel nitrate hexahydrate, sodium gluconate and water, and a high-specific-surface-area Ni / C catalyst is obtained by high-temperature reduction. By optimizing temperature, hydrogen pressure, reaction time, etc., the Ni / C catalyst can be used to catalyze the selective hydrogenation of 5-hydroxymethylfurfural and furfural under high substrate concentration. The catalyst preparation method in the present invention makes full use of the waste generated in the biomass conversion process, not only reduces environmental pollution problems, but also improves the overall economic value of biomass, realizes the comprehensive utilization of resources, meets the development goals of green sustainable chemistry, and has great industrial application value.

[0006] In order to achieve the above object, the present invention provides a carbon-supported nickel-based catalyst prepared by the following method:

[0007] (1) Weigh a certain amount of lignin residue, nickel nitrate hexahydrate, and sodium gluconate in deionized water, then transfer the mixture into a sealable autoclave, heat the mixture to 160-200°C under magnetic stirring, and retain the mixture for 15-30 hours. After cooling to room temperature, filter the mixture under reduced pressure, wash the filter cake, and dry it under vacuum at 60-100°C to obtain a solid, named Ni(OH)2 / C. The ratio of the added amount of lignin residue, nickel nitrate hexahydrate, sodium gluconate, and deionized water is (4-10) g:(3-8) g:(4-10) g (120-300) mL.

[0008] (2) The catalyst precursor (Ni(OH)2 / C) obtained in step (1) is reduced in a hydrogen atmosphere at a programmed temperature to obtain a porous carbon-supported nickel-based catalyst (Ni / CT, where T represents the reduction temperature, such as 350, 400, 500, or 600°C).

[0009] The invention is characterized in that the addition ratio of the lignin residue, nickel nitrate hexahydrate, sodium gluconate and deionized water is (6-8) g: (4-6) g: (5-8) g (150-250) mL.

[0010] Furthermore, the heating temperature in step (1) is 180° C. and maintained for 24 hours.

[0011] Furthermore, the retention time in step (1) is 24 hours.

[0012] Furthermore, the reduction process in step (2) is as follows: heating to 350-600°C at 5°C / min in a tubular furnace with hydrogen, keeping the temperature for 2-4 hours, and then naturally cooling to room temperature.

[0013] Preferably, the temperature is raised to 500° C. at 5° C. / min in a tubular furnace filled with hydrogen, kept at this temperature for 2 h, and then naturally cooled to room temperature.

[0014] The present invention also provides an application of the porous carbon-supported nickel-based (Ni / CT) catalyst in the hydrogenation of 5-hydroxyfurfural and furfural to prepare furandimethanol and furfuryl alcohol.

[0015] It is characterized by comprising the following steps:

[0016] Catalyst (Ni / CT) (0.02-0.2) g and 3 ml of a 5-hydroxymethylfurfural aqueous solution (4-20 wt / %) are added to a high-pressure reactor. The reactor is sealed and filled with 10-40 bar of hydrogen. The reaction is carried out at 30-100° C. with magnetic stirring at 300-800 rpm for 1-5 hours to obtain furandimethanol.

[0017] Catalyst (Ni / CT) (0.02-0.2) g and 3 ml of a furfural aqueous solution (20 wt / %) are added to a high-pressure reactor. The reactor is sealed and filled with 10-20 bar of hydrogen. The reaction is carried out at 30-100° C. with magnetic stirring at 300-800 rpm for 1-5 hours to obtain furfuryl alcohol and tetrahydrofurfuryl alcohol.

[0018] Compared with existing technologies, the present invention offers the following advantages and effects: It utilizes biomass reaction residues as a carrier to prepare a highly dispersed, small-particle nickel-based catalyst, and produces a high-specific surface area Ni / C catalyst through high-temperature calcination and reduction. This not only reduces the problem of solid residue generation during biomass conversion but also enables comprehensive utilization of biomass resources, increasing the overall economic value of biomass. The catalyst prepared in this invention can be used for high-concentration selective hydrogenation of 5-hydroxymethylfurfur and furfural. Furthermore, the catalyst preparation process is simple and cost-effective, making it suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 1 is the X-ray diffraction pattern (XRD pattern) of the lignin solid residue and the prepared catalyst precursor in Example 1.

[0020] Figure 2 X-ray diffraction patterns (XRD patterns) of the carbon-supported nickel-based catalyst (Ni / CT, T represents the reduction temperature: 350, 400, 500, 600) prepared in Example 1.

[0021] Figure 3 This is a graph showing the N2 adsorption and desorption curves of the carbon-supported nickel-based catalyst (Ni / CT, T represents the reduction temperature: 350, 400, 500, 600) prepared in Example 1.

[0022] Figure 4This is a scanning electron microscope image (SEM) of the carbon-supported nickel-based catalyst (Ni / C-500) prepared in Example 1.

[0023] Figure 5 This is the Ni2p spectrum of the carbon-supported nickel-based catalyst (Ni / C-500) prepared in Example 1. DETAILED DESCRIPTION

[0024] The technical solutions of the present invention are described in detail below with reference to specific embodiments and the accompanying drawings. However, the following embodiments are not intended to limit the scope of protection claimed in the present invention.

[0025] Unless otherwise specified, the reagents and instruments used in the following examples are commercially available products. Specific implementation examples are as follows:

[0026] Example 1: A porous carbon-supported nickel-based catalyst (Ni / CT) was prepared by the following method:

[0027] 7g of lignin residue, 5.8g of nickel nitrate hexahydrate, and 6g of sodium gluconate were weighed and dissolved in 200ml of deionized water. The mixture was then transferred to a sealable autoclave and heated to 180°C under magnetic stirring for 24 hours. After cooling to room temperature, the mixture was filtered under reduced pressure, the filter cake was washed, and dried under vacuum at 70°C to obtain a solid, named Ni(OH)2 / C. The Ni(OH)2 / C was then heated to 500°C in a hydrogen atmosphere at a rate of 5°C / min, held for 2 hours, and cooled naturally to room temperature to obtain the Ni / C-500 catalyst. Following the same method, varying the calcination temperature yielded a series of Ni / CT catalysts (T represents the reduction temperature: 350, 400, 500, and 600°C).

[0028] X-ray diffraction (XRD) analysis was performed on the biomass solid reaction residue and the prepared catalyst precursor (Ni(OH)2 / C) used in Example 1. Figure 1 As shown, the biomass solid residue contains a certain amount of silica impurities. After high-temperature loading, new diffraction peaks are generated, indicating that Ni-related substances are successfully loaded onto the carrier.

[0029] Figure 2 This is the X-ray diffraction pattern (XRD pattern) of the Ni / CT series catalyst prepared in Example 1. When the catalyst was calcined and reduced at 350°C, there was no obvious nickel-related diffraction peak in the diffraction pattern of the Ni / C-350 catalyst. As the calcination temperature increased, the Ni species was reduced to Ni 0 , 2θ=44.4°, 51.7°, 75.9° correspond to Ni 0(111), (200) and (220) crystal planes (PFD:04-002-77521). As the calcination temperature increases, the crystallinity of Ni increases. N2 adsorption-desorption curve ( Figure 3 ) Analysis shows that the specific surface area of ​​Ni / C-500 is 320m 2 / g. SEM shows that the surface of Ni / C-500 catalyst is rough and contains a lot of wrinkles, which may be one of the reasons why Ni / C-500 has a large specific surface area, increasing the contact probability between the substrate and the active center, which may be the reason why Ni / C-500 catalyst has high activity ( Figure 4 ).

[0030] Figure 5 This is the Ni2p diagram of the Ni / C-500 prepared in Example 1. At 500°C, the Ni in the catalyst was almost completely reduced to Ni 0 , which is consistent with the XRD data.

[0031] Examples 2-4

[0032] A series of Ni-based catalysts (Ni / CT, T represents the reduction temperature: 350, 400, 500, 600°C) prepared in Example 1 were used for the selective hydrogenation of HMF to produce BHMF, the steps of which are as follows:

[0033] A Ni / CT catalyst (0.04 g) and 3 mL of a 4 wt% aqueous solution of 5-hydroxymethylfurfural were added to an autoclave. The air in the reactor was replaced with hydrogen. The reaction was heated to 50°C with a stirring speed of 500 rpm for 1 hour. The reaction solution was cooled to room temperature, and liquid chromatography (Agilent-1260 Infinity II) was performed on the reaction solution. Examples 2-5 show that the catalyst calcination temperature is closely related to the BHMF selectivity, with the catalyst calcined at 500°C exhibiting the best BHMF selectivity (91%).

[0034] Table 1

[0035]

[0036] Examples 6-9

[0037] The Ni / C-500 catalyst from Example 4 was used in subsequent studies. Reaction temperature significantly affects HMF conversion and BHMF selectivity. With increasing temperature, HMF conversion increases, while BHMF selectivity initially increases and then decreases, suggesting excessive hydrogenation of BHMF at high temperatures. 50°C was the optimal temperature for BHMF preparation, and this temperature was subsequently used to further optimize hydrogen pressure and reaction time.

[0038] Table 2

[0039]

[0040] Examples 10-13

[0041] The selective hydrogenation of HMF is a three-phase reaction involving gas, solid, and liquid. The higher the hydrogen pressure, the more hydrogen dissolved in the solution. Experimental data show that hydrogen pressure significantly affects BHMF. Higher hydrogen pressure increases the amount of BHMF over-hydrogenation products and reduces BHMF selectivity. At 2 MPa, BHMF selectivity is 91%.

[0042] Table 3

[0043]

[0044] Examples 14-18

[0045] Further study of the effect of reaction time on the selective hydrogenation of HMF to produce BHMF revealed that, as shown in Examples 14-18, the conversion of HMF gradually increased with increasing reaction time. At a reaction time of 5 min, the conversion of HMF was 15%. As the reaction time was extended to 60 min, HMF was essentially completely converted, and the selectivity for BHMF reached 91%.

[0046] Table 4

[0047]

[0048] Example 19

[0049] Ni / C-500 catalyst (0.095 g) and 3 mL of a 10 wt% aqueous 5-hydroxymethylfurfural solution were added to an autoclave. The reactor was sealed, and the air in the reactor was replaced with hydrogen 5-6 times. The reactor was then filled with 2 MPa of hydrogen. The reaction was stirred at 500 rpm and maintained at 50°C for 2 hours. The reaction mixture was cooled to room temperature, and the reaction solution was analyzed by liquid chromatography (Agilent-1260 Infinity II). The calculated HMF conversion was 69%, and the BHMF selectivity was 84%.

[0050] Example 20

[0051] Ni / C-500 catalyst (0.19 g) and 3 mL of a 20 wt% aqueous solution of 5-hydroxymethylfurfural were added to an autoclave. The reactor was sealed, and the air in the reactor was replaced with hydrogen 5-6 times. The reactor was then filled with 2 MPa of hydrogen. The reaction was stirred at 500 rpm and maintained at 50°C for 4 hours. The reaction mixture was cooled to room temperature, and the reaction solution was analyzed by liquid chromatography (Agilent-1260 Infinity II). The calculated HMF conversion was >99%, and the BHMF selectivity was 90%.

[0052] Example 21

[0053] Ni / C-500 catalyst (0.25 g) and 3 mL of a 20 wt% furfural aqueous solution were added to an autoclave. The reactor was sealed, and the air in the reactor was replaced with hydrogen 5-6 times. The reactor was then filled with 2 MPa of hydrogen. The reaction was stirred at 500 rpm and maintained at 50°C for 2 hours. The reaction mixture was cooled to room temperature, and the reaction solution was analyzed by liquid chromatography (Agilent-1260 Infinity II). The calculated furfural conversion was >97%, the selectivity for furfuryl alcohol was 67%, and the selectivity for tetrahydrofurfural was 13%.

[0054] Example 22

[0055] A Ni / C-500 catalyst (0.25 g) and 3 mL of a 20 wt% furfural aqueous solution were added to an autoclave. The reactor was sealed, and the air in the reactor was replaced with hydrogen 5-6 times. The reactor was then filled with 2 MPa of hydrogen. The reaction was stirred at 500 rpm and allowed to react at 50°C for 4 hours. The reaction mixture was cooled to room temperature, and the reaction solution was analyzed by liquid chromatography (Agilent-1260 Infinity II). The calculated furfural conversion was >99%, the selectivity for furfuryl alcohol was 47%, and the selectivity for tetrahydrofurfural was 37%.

[0056] The above description is merely a preferred embodiment of the present invention and therefore cannot be used to limit the scope of the present invention. In other words, equivalent changes and modifications made within the scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A porous carbon-supported nickel-based catalyst prepared from lignin residue, prepared by the following method: (1) Weighing lignin residue, nickel nitrate hexahydrate, and sodium gluconate in deionized water, then transferring the mixture into a sealed autoclave, heating the mixture to 160-200°C under magnetic stirring, and retaining the mixture for 15-30 hours for hydrothermal reaction; cooling the mixture to room temperature, filtering the mixture under reduced pressure, washing the filter cake, and drying the mixture under vacuum at 60-100°C to obtain a solid catalyst precursor, named Ni(OH)2 / C; The addition ratio of lignin residue, nickel nitrate hexahydrate, sodium gluconate and deionized water is (4-10) g: (3-8) g: (4-10) g: (120-300) mL; (2) reducing the catalyst precursor Ni(OH)2 / C obtained in step (1) in a hydrogen atmosphere at a programmed temperature to obtain a porous carbon-supported nickel-based catalyst Ni / CT; in, T represents the reduction temperature of 350-600℃.

2. The catalyst according to claim 1, characterized in that: The addition ratio of the lignin residue, nickel nitrate hexahydrate, sodium gluconate and deionized water is (6-7) g: (4-6) g: (5-8) g: (150-250) mL.

3. The catalyst according to claim 1, characterized in that: In step (1), the heating temperature is 180° C. and the retention time is 24 h; the lignin residue is the solid residue of corn cob hydrolysis.

4. The catalyst according to claim 1 or 2, characterized in that: The reduction process in step (2) is as follows: heating to 350-600°C at 5°C / min in a tubular furnace filled with hydrogen, and keeping the temperature for 2 hours to obtain a porous carbon-supported nickel-based catalyst Ni / CT.

5. Use of the porous carbon-supported nickel-based catalyst according to any one of claims 1 to 4 in the hydrogenation of 5-hydroxyfurfural and the catalytic preparation of furandimethanol and furfural from furfural.

6. A method for preparing furandimethanol by hydrogenating 5-hydroxyfurfural, characterized in that: The steps include: The catalyst according to any one of claims 1 to 4 and a 5-hydroxymethylfurfural aqueous solution are added to a high-pressure resistant reactor, the reactor is sealed, 10 bar to 40 bar of hydrogen is introduced, and the reaction is carried out at 300-800 rpm and 30-100° C. for 1-5 hours to obtain furandimethanol.

7. The method according to claim 6, wherein 0.02-0.2g of the catalyst and 4-20g of 5-hydroxymethylfurfural aqueous solution were added. wt / 3 ml of the mixture was added into a high-pressure reactor. The reactor was sealed and filled with 10-40 bar of hydrogen. The reaction was carried out under magnetic stirring at 300-800 rpm and 30-100°C for 1-5 h to obtain furandimethanol.

8. A method for preparing furfuryl alcohol from furfural, characterized in that: The method comprises the following steps: adding the catalyst according to any one of claims 1 to 4 and a furfural aqueous solution into a high-pressure resistant reactor, sealing the reactor, filling it with 10 bar to 20 bar of hydrogen, and reacting for 1 to 5 hours at 30 to 100° C. under magnetic stirring at 300 to 800 rpm to obtain furfural alcohol.

9. The method according to claim 8, wherein The catalyst 0.02-0.2g, 20 wt / 3 ml of % furfural aqueous solution is added to a high-pressure reactor. The reactor is sealed and filled with 10 bar-20 bar of hydrogen. The reaction is carried out under magnetic stirring at 300-800 rpm and 30-100 ° C for 1-5 hours to obtain furfuryl alcohol.

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