A hydrogenation and deoxygenation catalyst of palladium nanoparticles with reduced stability by alkali lignin nitrogen phenolic resin

Abstract

The present invention relates to a biomass-based carrier-based reduction-stabilized metal nanoparticle catalyst and a preparation method thereof, specifically an alkali lignin nitrogen phenolic resin in-situ reduction-stabilized palladium nanoparticle catalyst and a preparation method thereof, belonging to the technical field of novel catalytic materials and their preparation. The present invention uses inexpensive and readily available industrial by-product alkali lignin as one of the raw materials, and utilizes the multiple functional group characteristics in its structure to introduce multifunctional active groups and nitrogen elements into the phenolic resin structure by chemical bonding. This catalyst can not only effectively disperse and stabilize the metal palladium, but also has an in-situ reduction effect. Therefore, the preparation of the catalyst does not require hydrogen or other chemical reducing agents. The catalyst is a green catalytic material that effectively utilizes biomass resources and can efficiently catalyze the hydrodeoxygenation reaction of vanillin under mild conditions.

Description

Technical Field

[0001] The present invention relates to a metal nanoparticle catalyst for vanillin hydrodeoxygenation reaction and a preparation method thereof, specifically a method for preparing a nanoparticle hydrodeoxygenation catalyst by directly reducing and stabilizing Pd with an alkali lignin nitrogen phenolic resin in an aqueous phase, belonging to the technical field of catalytic materials and their preparation. Background Art

[0002] Lignin is abundant in nature. It is a complex, three-dimensional, amorphous natural polymer composed of various methoxylated phenylpropane units. Its structure is rich in functional groups such as aromatic groups, hydroxyl groups, and double bonds, making it challenging to process. Its high-value utilization is currently a hot topic in the biomass refining field. Pulping processes in my country's papermaking industry annually separate a large amount of lignin as a byproduct from plants, often discharged as wastewater and causing environmental pollution. Compared with natural lignin, these pulping byproducts exhibit varying degrees of depolymerization of their structural units and the introduction of new active groups such as sulfur, which improves their solubility and other properties. Therefore, in addition to being a raw material for the production of liquid fuels and high-value-added platform chemicals, these lignin resources have also attracted research attention in recent years by leveraging their structural characteristics to develop carbonaceous and catalytic materials. Lignin-based resins, lignin charcoal and sulfonated charcoal, and lignin-based aqueous-phase-stabilized metal nanoparticles all show promising application prospects in fuel cells, electrocatalysis, acid catalysis, catalytic hydrogenation, and hydrodeoxygenation.

[0003] In the reported prior art, lignin and its derivatives can partially or completely replace phenol monomers to synthesize bio-based phenolic resins [Journal of Applied Polymer Science, 2017, 134(30):45124; Industrial Crops and Products, 2018, 120(15):25-33; Industrial Crops and Products, 2018, 125:520-528; ACS Sustainable Chemistry and Engineering, 2020, 8(51):18789-18809]. Lignin-based phenolic resin materials can be used as excellent metal nanoparticle carriers after high-temperature carbonization. However, the preparation of these carbon-supported metal catalysts often requires the use of reducing agents such as sodium borohydride and polyols, or high-temperature reduction in an atmosphere such as hydrogen. The preparation process is complex, energy-intensive, and uses non-environmentally friendly reducing agents [Applied Catalysis B: Environmental, 2020, 268: 118425; Applied Surface Science, 2020, 506: 144681; Journal of Catalysis, 2020, 386: 19-29; ACS Sustainable Chemistry and Engineering, 2021, 9(29): 9891-9902; Fuel, 2022, 310(B): 122432]. On the other hand, water-soluble derivatives of lignin, due to their stable macromolecular structure and multiple reducing functional groups, have been found to simultaneously reduce and stabilize metals in aqueous solution under mild conditions, and can prepare water-dispersed precious metal nanoparticle catalysts without adding any other reagents [International Journal of Biological Macromolecules, 2016, 82: 39-47; ACS Omega, 2020, 5(15): 8902-8911; Industrial Crops and Products, 2023, 192: 116055]. Similarly, it has been found that phenolic resins prepared by using lignin instead of phenol can retain the functional group characteristics in the lignin structure without carbonization, significantly increase the surface roughness of the resin material, and have better dispersion properties for metals.More importantly, the active hydroxyl groups on the surface of the lignin-based phenolic resin material can reduce the loaded precious metal salt in situ, thus avoiding the use of high temperatures, hydrogen, or chemical reducing agents, making the preparation of metal nanoparticles mild and environmentally friendly [Green Chemistry, 2020, 22: 2879-2888; Industrial Crops and Products, 2020, 145: 112-164; International Journal of Biological Macromolecules, 2021, 166: 893-901]. However, to date, there have been no reports of using lignin-based phenolic resin materials to disperse and reduce metals in situ to prepare metal nanoparticle catalysts with excellent performance for the hydrodeoxygenation reaction of vanillin. Summary of the Invention

[0004] The present invention aims to transform waste into valuable resources by utilizing inexpensive and readily available industrial by-product alkali lignin as a raw material. The invention also provides a novel alkali lignin nitrogen-based phenolic resin reduction-stable Pd nanoparticle hydrodeoxygenation catalyst and a method for preparing the catalyst. The invention also provides the use of the catalyst in the hydrodeoxygenation reaction of vanillin.

[0005] According to the present invention, the novel alkali lignin nitrogen phenolic resin reduction-stabilized Pd nanoparticle hydrodeoxygenation catalyst is provided with the following general formula:

[0006] Pd x -AL n NPR

[0007] Where AL n NPR is an alkali lignin nitrogen phenolic resin prepared from alkali lignin, resorcinol, formaldehyde and ammonia water. The value of n is 20-50, which means that the mass fraction of alkali lignin in the raw material phenol is 20-50%. Pd is metal palladium, and the value of x is 0.7-1.0, which means that one of Na2PdCl4, PdCl2 or K2PdCl6 is used as the Pd source in AL. n When loaded on NPR, the feeding amount calculated as Pd is 0.7 to 1.0 wt%.

[0008] According to another aspect of the present invention, the present invention also provides a method for preparing the above-mentioned alkali lignin nitrogen phenolic resin reduction-stabilized Pd nanoparticle hydrodeoxygenation catalyst having both self-reduction characteristics and high catalytic performance, the preparation steps of which are as follows:

[0009] (1) Alkali lignin nitrogen phenolic resin (AL n Preparation of NPR:

[0010] Add 1.0g of 28% ammonia water to a mixture of 20mL of water and 8mL of ethanol, and then add 5.4g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 20-50% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9g of 37% formaldehyde solution, heat to 65℃ and stir for 1h, then heat to 90℃ and stir for 30min. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120℃ for 10h. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100℃ for 10h, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL. n NPR.

[0011] (2) Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin (Pd x -AL n Preparation of NPR:

[0012] Alkali lignin nitrogen phenolic resin AL prepared in step (1) n NPR was used as the carrier, and one of Na2PdCl4, PdCl2 or K2PdCl6 was used as the Pd source. The amount of the Pd was 0.7-1.0 wt% of the carrier. Deionized water was added at a ratio of 200 mL of water per gram of carrier, and stirred at 80°C for 3 hours. The solid product was separated by centrifugation, washed three times with deionized water and anhydrous ethanol, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin-based phenolic resin. x -AL n NPR.

[0013] The present invention also discloses the Pd nanoparticles Pd x -AL n Application of NPR catalyst in the hydrodeoxygenation reaction of vanillin.

[0014] The present invention provides a metal Pd nanoparticle catalyst Pd that is stable in reducing the alkali lignin nitrogen phenolic resin. x -AL n Compared with existing metal nanoparticle hydrodeoxygenation catalysts and technologies, NPR has the following characteristics:

[0015] (1) The present invention provides a method for converting industrial by-product alkali lignin into valuable materials to prepare alkali lignin nitrogen phenolic resin, which is then used to in-situ reduce and stabilize metallic Pd to obtain a novel Pd nanoparticle hydrodeoxygenation catalyst.

[0016] (2) The catalyst provided by the present invention fully utilizes the structural characteristics of alkali lignin and introduces its multifunctional active groups and nitrogen elements into the phenolic resin structure in a chemically bonded manner, so that it can not only well disperse and stabilize metal palladium but also has an in-situ reduction function, thereby preparing a highly efficient hydrodeoxygenation catalyst without the need for chemical reagents or hydrogen reduction;

[0017] (3) The Pd nanoparticle catalyst provided by the present invention can efficiently catalyze the hydrodeoxygenation reaction of vanillin under mild conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Attachment Figure 1 The alkali lignin nitrogen phenolic resin AL prepared in Example 2 30 SEM image of NPR.

[0019] Attachment Figure 2 The alkali lignin nitrogen phenolic resin prepared in Example 2 is a reduction-stabilized Pd nanoparticle. 0.8 -AL 30 TEM image of NPR.

[0020] Attachment Figure 3 The alkali lignin nitrogen phenolic resin prepared in Example 2 is a reduction-stabilized Pd nanoparticle. 0.8 -AL 30 TEM-EDS elemental mapping of NPR.

[0021] Attachment Figure 4 The alkali lignin nitrogen phenolic resin prepared in Example 2 is a reduction-stabilized Pd nanoparticle. 0.8 -AL 30 XPS spectrum of NPR. DETAILED DESCRIPTION

[0022] The following examples are intended to further illustrate the present invention but are not intended to limit the present invention.

[0023] [Example 1] Pd 0.8 -AL 20 Preparation of NPR and its catalytic effect on the hydrodeoxygenation of vanillin

[0024] Add 1.0g of 28% ammonia water to a mixture of 20mL of water and 8mL of ethanol, and then add 5.4g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 20% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9g of 37% formaldehyde solution, heat to 65℃ and stir for 1h, then heat to 90℃ and stir for 30min. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120℃ for 10h. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100℃ for 10h, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL. 20 NPR.

[0025] Take 0.1g alkali lignin nitrogen phenolic resin AL 20 NPR added 8mL9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin. 0.8 -AL 20 NPR.

[0026] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pd nanoparticles Pd 0.8 -AL 20 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 1.

[0027] [Example 2] Pd 0.8 -AL 30 Preparation of NPR and its catalytic effect on the hydrodeoxygenation of vanillin

[0028] To a mixture of 20 mL of water and 8 mL of ethanol, add 1.0 g of 28% ammonia water, and then add 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 30% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9 g of 37% formaldehyde solution, heat to 65 ° C and stir for 1 hour, then heat to 90 ° C and stir for 30 minutes. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120 ° C for 10 hours. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100 ° C for 10 hours, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL.30 NPR.

[0029] Take 0.1g alkali lignin nitrogen phenolic resin AL 30 NPR added 8mL 9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin. 0.8 -AL 30 NPR.

[0030] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pd nanoparticles Pd 0.8 -AL 30 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 1.

[0031] [Example 3] Pd 0.8 -AL 50 Preparation of NPR and its catalytic effect on the hydrodeoxygenation of vanillin

[0032] To a mixture of 20 mL of water and 8 mL of ethanol, add 1.0 g of 28% ammonia water, and then add 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 50% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9 g of 37% formaldehyde solution dropwise, heat to 65 ° C and stir for 1 hour, then heat to 90 ° C and stir for 30 minutes. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120 ° C for 10 hours. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100 ° C for 10 hours, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL. 50 NPR.

[0033] Take 0.1g alkali lignin nitrogen phenolic resin AL 50 NPR added 8mL 9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin. 0.8 -AL 50 NPR.

[0034] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pd nanoparticles Pd 0.8 -AL 50 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 1.

[0035] [Example 4] Pd 0.7 -AL 30 Preparation of NPR and its catalytic effect on the hydrodeoxygenation of vanillin

[0036] To a mixture of 20 mL of water and 8 mL of ethanol, add 1.0 g of 28% ammonia water, and then add 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 30% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9 g of 37% formaldehyde solution, heat to 65 ° C and stir for 1 hour, then heat to 90 ° C and stir for 30 minutes. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120 ° C for 10 hours. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100 ° C for 10 hours, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL. 30 NPR.

[0037] Take 0.1g alkali lignin nitrogen phenolic resin AL 30 NPR was added 7mL9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin. 0.7 -AL 30 NPR.

[0038] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pd nanoparticles Pd 0.7 -AL 30 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 1.

[0039] [Example 5] Pd 1.0 -AL30 Preparation of NPR and its catalytic effect on the hydrodeoxygenation of vanillin

[0040] To a mixture of 20 mL of water and 8 mL of ethanol, add 1.0 g of 28% ammonia water, and then add 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 30% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9 g of 37% formaldehyde solution, heat to 65 ° C and stir for 1 hour, then heat to 90 ° C and stir for 30 minutes. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120 ° C for 10 hours. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100 ° C for 10 hours, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL. 30 NPR.

[0041] Take 0.1g alkali lignin nitrogen phenolic resin AL 30 NPR added 10mL 9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin. 1.0 -AL 30 NPR.

[0042] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pd nanoparticles Pd 1.0 -AL 30 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 1.

[0043] [Example 6] Pd 0.8 -AL 30 Preparation of NPR' and its catalytic effect on the hydrodeoxygenation of vanillin

[0044] To a mixture of 20 mL of water and 8 mL of ethanol, add 1.0 g of 28% ammonia water, and then add 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 30% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9 g of 37% formaldehyde solution, heat to 65 ° C and stir for 1 hour, then heat to 90 ° C and stir for 30 minutes. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120 ° C for 10 hours. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100 ° C for 10 hours, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL. 30 NPR.

[0045] Take 0.1g alkali lignin nitrogen phenolic resin AL 30 NPR added 8mL 9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin. 0.8 -AL 30 NPR'.

[0046] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pd nanoparticles Pd 0.8 -AL 30 NPR', 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 1.

[0047] [Example 7] Pd 0.8 -AL 30 Preparation of NPR and its catalytic effect on the hydrodeoxygenation of vanillin

[0048] To a mixture of 20 mL of water and 8 mL of ethanol, add 1.0 g of 28% ammonia water, and then add 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 30% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9 g of 37% formaldehyde solution, heat to 65 ° C and stir for 1 hour, then heat to 90 ° C and stir for 30 minutes. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120 ° C for 10 hours. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100 ° C for 10 hours, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL.30 NPR.

[0049] Take 0.1g alkali lignin nitrogen phenolic resin AL 30 NPR added 8mL 9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed three times with deionized water and anhydrous ethanol, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin. 0.8 -AL 30 NPR".

[0050] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pd nanoparticles Pd 0.8 -AL 30 NPR", 152 mg of vanillin and 10 mL of water were added to a stainless steel autoclave lined with polytetrafluoroethylene. The air was replaced with hydrogen three times, and then 1 MPa of hydrogen was filled in. The reaction was stirred at 80°C for 4 h. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 1.

[0051] Table 1 Hydrodeoxygenation of vanillin catalyzed by palladium nanoparticles stabilized by alkali lignin nitrogen phenolic resin

[0052]

[0053] [Comparative Example 1]

[0054] To a mixture of 20 mL of water and 8 mL of ethanol, 1.0 g of 28% aqueous ammonia and 5.4 g of resorcinol were added. After stirring at room temperature for 10 minutes, 2.9 g of 37% formaldehyde solution was slowly added dropwise. The mixture was heated to 65°C and stirred for 1 hour, then to 90°C and stirred for 30 minutes. The mixture was transferred to a polytetrafluoroethylene-lined hydrothermal autoclave and reacted at 120°C for 10 hours. After the reaction, the solid was centrifuged and washed three times with deionized water, dried at 100°C for 10 hours, and then ground to a mesh size of less than 60 to obtain phenolic resin PR.

[0055] Take 0.1g of phenolic resin PR and add 8mL 9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pd 0.8 -PR catalyst samples.

[0056] 20 mg of the above prepared Pd 0.8A sample of the PR catalyst, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 2.

[0057] [Comparative Example 2]

[0058] Add 1.0g of 28% ammonia water to a mixture of 20mL of water and 8mL of ethanol, and then add 5.4g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 10% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9g of 37% formaldehyde solution dropwise, heat to 65℃ and stir for 1h, then heat to 90℃ and stir for 30min. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120℃ for 10h. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100℃ for 10h, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL. 10 NPR.

[0059] Take 0.1g alkali lignin nitrogen phenolic resin AL 10 NPR added 8mL 9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pd nanoparticles stabilized by reduction of alkali lignin nitrogen phenolic resin. 0.8 -AL 10 NPR.

[0060] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pd nanoparticles Pd 0.8 -AL 10 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 2.

[0061] [Comparative Example 3]

[0062] To a mixture of 20 mL of water and 8 mL of ethanol, 1.0 g of 28% aqueous ammonia was added, followed by 5.4 g of resorcinol and sodium lignin sulfonate as the raw phenol, with the mass fraction of sodium lignin sulfonate accounting for 30% of the raw phenol. After stirring at room temperature for 10 minutes, 2.9 g of 37% formaldehyde solution was slowly added dropwise. The mixture was heated to 65°C and stirred for 1 hour, then to 90°C and stirred for 30 minutes. The mixture was transferred to a polytetrafluoroethylene-lined hydrothermal autoclave and reacted at 120°C for 10 hours. After the reaction, the solid was centrifuged and washed three times with deionized water, dried at 100°C for 10 hours, and then ground to a mesh size of less than 60 to obtain the lignin nitrogen phenol-formaldehyde resin SLS. 30 NPR.

[0063] Take 0.1g lignin nitrogen phenolic resin SLS 30 NPR added 8mL 9.4×10 -4 mol·L -1 Add water to 20 mL of Na2PdCl4 aqueous solution and stir at 80℃ for 3 hours. Centrifuge and separate the solid product, wash with deionized water and anhydrous ethanol three times respectively, and dry at 80℃ overnight to obtain lignin nitrogen phenol formaldehyde resin SLS. 30 NPR reduction-stabilized Pd nanoparticles 0.8 -SLS 30 NPR.

[0064] 20 mg of the above-prepared lignin nitrogen phenolic resin SLS 30 NPR reduction-stabilized Pd nanoparticles 0.8 -SLS 30 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 2.

[0065] [Comparative Example 4]

[0066] To a mixture of 20 mL of water and 8 mL of ethanol, add 1.0 g of 28% ammonia water, and then add 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 30% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9 g of 37% formaldehyde solution, heat to 65 ° C and stir for 1 hour, then heat to 90 ° C and stir for 30 minutes. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120 ° C for 10 hours. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100 ° C for 10 hours, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL.30 NPR.

[0067] Take 0.1g alkali lignin nitrogen phenolic resin AL 30 NPR added 8mL 9.4×10 -4 mol·L -1 Add water to 20 mL of RuCl3 aqueous solution and stir at 80℃ for 3h. Centrifuge and separate the solid product, wash it with deionized water and anhydrous ethanol 3 times respectively, and dry it at 80℃ overnight to obtain Ru nanoparticles stabilized by reduction of alkali lignin nitrogen phenol formaldehyde resin. 0.8 -AL 30 NPR.

[0068] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize Ru nanoparticles Ru 0.8 -AL 30 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 2.

[0069] [Comparative Example 5]

[0070] To a mixture of 20 mL of water and 8 mL of ethanol, add 1.0 g of 28% ammonia water, and then add 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin is 30% of the raw material phenol. After stirring at room temperature for 10 minutes, slowly add 2.9 g of 37% formaldehyde solution, heat to 65 ° C and stir for 1 hour, then heat to 90 ° C and stir for 30 minutes. Transfer the mixture to a hydrothermal autoclave with a polytetrafluoroethylene liner and react at 120 ° C for 10 hours. After the reaction is completed, centrifuge and wash the obtained solid three times with deionized water. After air drying at 100 ° C for 10 hours, grind it to below 60 mesh to obtain alkali lignin nitrogen phenol-formaldehyde resin AL. 30 NPR.

[0071] Take 0.1g alkali lignin nitrogen phenolic resin AL 30 NPR added 8mL 9.4×10 -4 mol·L -1 The solid product was separated by centrifugation, washed with deionized water and anhydrous ethanol three times, and dried at 80°C overnight to obtain Pt nanoparticles stabilized by reduction of alkali lignin nitrogen phenol formaldehyde resin. 0.8 -AL 30 NPR.

[0072] 20 mg of the above-prepared alkali lignin nitrogen phenolic resin was reduced to stabilize the Pt nanoparticles Pt0.8 -AL 30 NPR, 152 mg of vanillin, and 10 mL of water were added to a Teflon-lined stainless steel autoclave. The air was replaced with hydrogen three times, and then filled with 1 MPa of hydrogen. The reaction was stirred at 80°C for 4 hours. After the reaction, the organic phase was extracted with ethyl acetate and analyzed by gas chromatography. The results are shown in Table 2, indicating that the vanillin had not reacted.

[0073] Table 2 Hydrodeoxygenation of vanillin catalyzed by phenolic resin reduction-stabilized metal nanoparticles prepared under other conditions

[0074]

Claims

1. Application of an alkali lignin nitrogen phenolic resin reduction-stabilized Pd nanoparticle hydrodeoxygenation catalyst in catalyzing the hydrodeoxygenation reaction of vanillin, characterized in that The general structural formula of the catalyst is as follows: Pd x -AL n NPR, where AL n NPR is an alkali lignin nitrogen phenolic resin prepared from alkali lignin, resorcinol, formaldehyde and ammonia water. n The value of is 20~50, which means that the mass fraction of alkali lignin in the raw material phenol is 20~50%; Pd is metal palladium, x The value of is 0.7~1.0, which means that one of Na2PdCl4, PdCl2 or K2PdCl6 is used as the Pd source in AL n When loaded on NPR, the feed amount calculated as Pd is 0.7~1.0wt%.

2. Use of the alkali lignin nitrogen phenolic resin reduction-stable Pd nanoparticle hydrodeoxygenation catalyst according to claim 1 in catalyzing the hydrodeoxygenation reaction of vanillin, characterized in that The catalyst introduces alkali lignin structural units and nitrogen elements into the phenolic resin material, thereby simultaneously achieving in-situ reduction and good dispersion of metallic palladium.

3. Use of the alkali lignin nitrogen phenolic resin reduction-stable Pd nanoparticle hydrodeoxygenation catalyst according to claim 1 or 2 in catalyzing the hydrodeoxygenation reaction of vanillin, characterized in that The catalyst preparation process is as follows: To a mixture of 20 mL of water and 8 mL of ethanol, 1.0 g of 28% ammonia water was added, followed by 5.4 g of resorcinol and alkali lignin as raw material phenol, wherein the mass fraction of alkali lignin was 20-50% of the raw material phenol. After stirring at room temperature for 10 min, 2.9 g of 37% formaldehyde solution was slowly added dropwise. The mixture was heated to 65°C and stirred for 1 h, then heated to 90°C and stirred for 30 min. The mixture was transferred to a hydrothermal autoclave with a polytetrafluoroethylene liner and reacted at 120°C for 10 h. After the reaction, the solid was separated by centrifugation, washed with deionized water, dried, and ground to a size of less than 60 mesh to obtain an alkali lignin nitrogen phenol-formaldehyde resin. Alkali lignin nitrogen phenolic resin was used as the carrier, deionized water was added at a ratio of 200 mL of water per gram of carrier, and any one of Na2PdCl4, PdCl2 or K2PdCl6 was used as the Pd source. The Pd source was added in an amount of 0.7~1.0wt% of the carrier. The reaction was stirred at 80°C for 3 h, and the solid was separated by centrifugation and washed with deionized water and anhydrous ethanol, respectively. After drying, the alkali lignin-based phenolic resin reduction-stabilized Pd nanoparticle catalyst was obtained.

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