Silicon-based melanoidin-loaded metal nanoparticle catalyst
The silicon-based protein melanin-supported metal nanoparticle catalyst prepared by the Maillard reaction resolves the contradiction between the stability and catalytic activity of metal nanoparticle catalysts in the inert C-H bond activation reaction in the prior art, and achieves a highly efficient and stable catalytic effect in various reactions.
Patent Information
- Application Number
- CN202510067764.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-05-23
AI Technical Summary
Existing metal nanoparticle catalysts exhibit a contradiction between stability and catalytic activity in the inert C-H bond activation reaction, making it difficult for them to maintain efficient activity in the reaction.
Silicone-based melanin was prepared through the Maillard reaction, and used it as a support to support transition metals such as palladium and copper through the impregnation method to prepare a high-load metal nanoparticle catalyst. The unique structure of the catalyst enables it to exhibit excellent catalytic activity and stability in C-H arylation reactions and the like.
The prepared silicon-based protein melanin-supported metal nanoparticle catalyst exhibits excellent catalytic activity and stability in a variety of inert C-H bond activation reactions, can be reused for more than 5 times and still maintains similar catalytic activity, and has high loading and universality.
Smart Images
Figure CN120022945A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the preparation and application of a catalyst, and in particular to the preparation and application of a silicon-based protein melanin-loaded metal nanoparticle catalyst, belonging to the technical field of catalysts. Background Art
[0002] Metal nanoparticle catalysts are considered to be the most effective heterogeneous catalysts and have been widely used in the synthesis of small molecules (H 2 O,CO 2 ) activation, oxidation, hydrogenation, classical coupling and other industrial heterogeneous catalysis fields. However, to the best of our knowledge, there are few reports on the application of metal nanoparticle catalysts in challenging inert C-H bond activation reactions, especially there are only a few reports on metal nanoparticle catalysts used in regioselective activation reactions promoted by directing groups or chelation-assisted strategies. The key challenge comes from the need for metal nanoparticles anchored on the support to maintain nearly saturated coordination to ensure their stability and anti-aggregation as much as possible, which will lead to a lack of coordination sites at the metal center, making it difficult to adsorb substrates with multiple coordination sites. How to balance the stability and catalytic activity of metal nanoparticles on the support is the key to achieving metal nanoparticle-catalyzed inert bond activation reactions.
[0003] Melanoids are a class of brown, complex macromolecular compounds formed in the late stage of the Maillard reaction, which are commonly found in food. Melanoids contain a large number of N and O coordinated atoms, but since common melanoidins are viscous substances, metal catalysts that directly use melanoidins as carriers have not been reported so far. Summary of the invention
[0004] The technical solution adopted by the present invention is to obtain a new type of silicon-based protein melanin through the Maillard reaction of monosaccharide and silane coupling agent, which is characterized by the silicon-based protein melanin containing a unique silicon-based skeleton and a large number of C=N bonds and C-OH bonds. The present invention uses this multi-special protein melanin as a carrier for the first time, and loads transition metals such as palladium and copper by a simple impregnation method to prepare a metal nanoparticle catalyst with a high load. Catalyst characterization proves that the coordination number of the metal active center in the prepared metal nanoparticle catalyst is about 3.3, which is smaller than the reported metal oxide, modified cellulose and MOF-type carrier-loaded metal nanoparticle catalyst, which makes it exhibit excellent catalytic activity in CH arylation reaction, SUZUKI classic coupling, HECK classic coupling and CN coupling reaction. At the same time, because this unique silicon-based protein melanin structure can effectively prevent the accumulation of metal centers, the silicon-based protein melanin-loaded metal nanoparticle catalyst exhibits excellent stability in the above reactions and can be reused for more than 5 times while still maintaining similar catalytic activity.
[0005] The present invention mainly uses various monosaccharides, disaccharides and silane coupling agents to carry out Maillard reaction under acidic or neutral conditions to obtain a silicon-based protein melanin carrier, and then obtains a metal nanoparticle catalyst loaded with silicon-based protein melanin by an impregnation method. A series of characterizations prove that: silicon-based protein melanin contains a large number of C=N bonds; the introduction of silicon makes protein melanin form a powdery solid similar to clay; in the catalyst obtained by the impregnation method, the metal active sites are dispersed on the carrier at the atomic level.
[0006] The preparation method of silicon-based protein melanin loaded metal nanoparticle catalyst comprises the following steps:
[0007] Step (1) dissolving monosaccharide or disaccharide, silane coupling agent and tartaric acid or lysine in a solvent, heating and stirring for a certain period of time to obtain a mixed solution; preferably, the molar ratio of the monosaccharide or disaccharide, silane coupling agent and tartaric acid or lysine is 1:3-5:0.1-0.4.
[0008] The monosaccharides are glucose, fructose, mannose, galactose, xylose, ribose and arabinose, and the disaccharides are lactose and sucrose.
[0009] The silane coupling agent is 3-aminopropyltrimethoxysilane (APTM), 3-aminopropyltriethoxysilane (APTE), and phenyltrimethoxysilane (BTMO).
[0010] The organic solvent is toluene, benzene, acetonitrile or chlorobenzene.
[0011] Step (2) filtering the mixed solution obtained in step (1), performing Soxhlet extraction on the filter cake using acetone, and vacuum drying the filter cake to obtain a silicon-based protein melanin carrier.
[0012] In step (2), the heating temperature is 80-100° C., the amount of acetone is 100-200 mL, and the Soxhlet extraction time is 10-24 h.
[0013] Step (3) Place 1 g of the silica-based protein melanin carrier obtained in step (2) into 25 mL of secondary water, adjust the pH to 9 with 0.1 M NaOH, and stir at room temperature for about 10 minutes; add a certain amount of soluble metal salt to a beaker, and stir the resulting suspension at room temperature for 24 hours.
[0014] The soluble metal salt used was PdCl 2 ,Pd(OAc) 2 ,H 2 PdCl 4 ,Cu(OAc) 2 ,CuCl 2 ,Cu(NO 3 ) 2 ,HAuCl 4 .
[0015] Step (4) The suspension obtained in step (3) is centrifuged, and the obtained solid is washed with deionized water for 3-4 times until the pH of the supernatant is close to 7, and then rinsed again with acetone for 3-4 times. The obtained solid is vacuum dried for 24 hours to obtain a silicon-based protein melanin-loaded metal nanoparticle catalyst.
[0016] Compared with the prior art, the present invention has the following beneficial effects:
[0017] The present invention uses monosaccharide as raw material for the first time, utilizes Maillard reaction to prepare silicon-based protein melanin, and applies it to the carrier of metal nanoparticle catalyst. The prepared silicon-based protein melanin-loaded metal nanoparticle catalyst exhibits excellent catalytic activity and stability in CH arylation reaction, SUZUKI classic coupling, HECK classic coupling and CN coupling reaction. Compared with other metal nanoparticle catalysts currently reported, the silicon-based protein melanin-loaded metal nanoparticle catalyst prepared by the present invention has the advantages of excellent stability, high-valent metal loading and universality for various inert CH bond activation reactions, and is suitable for application in industrial production. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is the XPS spectrum of the sample of the present invention.
[0019] Figure 2 It is the synchrotron radiation diagram of the sample of the present invention.
[0020] Figure 3 This is a spectrum for comparison with GLC.
[0021] Figure 4 It is an application diagram in classic coupling reactions, CN coupling reactions, and various CH bond arylation reactions. DETAILED DESCRIPTION
[0022] Example 1
[0023] In this example, 1.1 g of glucose (GLC), tartaric acid (148 mg), 3-aminopropyltrimethoxysilane (APTM, 4.3 mL) and 40 mL of toluene were weighed and placed in a 250 mL round-bottom flask, and refluxed and stirred at 80 ° C for 48 h. Filter, and use 150 mL of acetone at 90 ° C for Soxhlet extraction for 16 h, vacuum drying to obtain a silica-based protein melanin carrier. Take 1 g of silica-based protein melanin carrier and put it into 25 mL of secondary water, adjust the pH to 9 with 0.1 M NaOH, and stir at room temperature for about 10 min; add PdCl to the beaker. 2(67.6 mg), the resulting suspension was stirred at room temperature for 24 h. The resulting suspension was centrifuged, the resulting solid was washed with deionized water 3-4 times until the pH of the supernatant was close to 7, and then washed again with acetone 3-4 times. The resulting solid was vacuum dried for 24 h to obtain a silica-based protein melanin-supported palladium nanoparticle catalyst, named Pd / APTM-GLC.
[0024] Figure 1 Among, a)Pd / APTM-GLC(fresh),Pd / APTM-GLC(used 1 st cycle), XRD spectra of APTM-GLC; b) Pd / APTM-GLC (fresh), Pd / APTM-GLC (used 1 st cycle), Pd / APTM-GLC(used 5 th cycle) 3d XPS spectrum; c) Si of Pd / APTM-GLC (fresh) 2p XPS spectrum; c) N of Pd / APTM-GLC (fresh) 1s XPS spectrum.
[0025] like Figure 1 As shown in a), the XRD patterns of the three samples all showed a broad diffraction peak at 23.5, corresponding to the (002) plane of the carbon structure, which is the characteristic diffraction peak of APTM-modified glucose. st The XRD spectrum of the 2θ cycle showed a diffraction peak at 40.09°, which was compared with the standard card number of palladium JCPDS No.99-000-2792, corresponding to the (111) crystal plane of palladium.
[0026] like Figure 1 As shown in b), the Pd / APTM-GLC (fresh) 3d There are two peaks in the XPS spectrum, namely Pd 3d 5 / 2 Peak and Pd 3d 3 / 2 The peaks are located at 337.28eV and 342.58eV, respectively, indicating that the valence state of palladium is divalent. In the XPS spectra of the catalyst after being used once and five times, new peaks appear at 338eV and 344eV, respectively, indicating that Pd Ⅱ and Pd Ⅳ coexistence.
[0027] like Figure 1 As shown in c), the Si 2pThere are two peaks at 102.64 eV and 101.52 eV in the XPS spectrum, corresponding to the presence of Si-O bonds and Si-C bonds, respectively.
[0028] like Figure 1 As shown in d), the N 1s Free amino groups, N-Pd, C=N and N + The characteristic peaks of Pd indicate that C=N bond may be the main coordination site of Pd. Figure 2 k 2 -weightedχ(k)function of FT-EXAFS spectra ofPd / APTM-GLC(fresh),Pd / APTM-GLC(used 1 st cycle).
[0029] like Figure 2 As shown, Pd / APTM-GLC (fresh) and Pd / APTM-GLC (used 1 st cycle) in the synchrotron radiation diagram. The peaks of Pd-O or Pd-N appeared at A weak Pd-Pd characteristic peak appeared at , proving that Pd is dispersed on the carrier in the form of nanoparticles.
[0030] Pd / APTM-GLC exhibited excellent catalytic activity and stability in the following CH activation reaction. The catalytic activity did not decrease after 5 cycles of reaction, and the Pd loading did not decrease significantly.
[0031]
[0032] Example 2
[0033] In this example, 1.1 g of glucose (GLC), L-lysine (144 mg), 3-aminopropyltriethoxysilane (APTE, 4.3 mL), phenyltrimethoxysilane (BTMO, 3.5 mL) and 40 mL of toluene were weighed and placed in a 250 mL round-bottom flask and refluxed at 80 ° C for 48 h. Filter, and use 150 mL of acetone at 90 ° C for Soxhlet extraction for 16 h, vacuum drying to obtain a silica-based protein melanin carrier. Take 1 g of silica-based protein melanin carrier and put it into 25 mL of secondary water, adjust the pH to 9 with 0.1 M NaOH, and stir at room temperature for about 10 min; add PdCl to the beaker. 2(67.6 mg), the resulting suspension was stirred at room temperature for 24 h. The resulting suspension was centrifuged, and the resulting solid was washed with deionized water 3-4 times until the pH of the supernatant was close to 7, and then washed again with acetone 3-4 times. The resulting solid was vacuum dried for 24 h to obtain a silica-based protein melanin-supported palladium nanoparticle catalyst, named 3wt% Pd II / NH 2 ,Ph@GLC.
[0034] from Figure 3 In a), compared with the spectrum of GLC, the XRD patterns of the three samples all showed a broad diffraction peak of 23.5, corresponding to the (002) plane of the carbon structure, which is the characteristic diffraction peak of APTE and BTMO modified glucose. II / NH 2 ,Ph@GLC(fresh),3wt%Pd II / NH 2 ,Ph@GLC(used 1 st The XRD pattern of the 2θ cycle showed a diffraction peak at about 40°, which corresponds to the (111) crystal plane of palladium.
[0035] like Figure 3 b), 3c), 3wt% Pd II / NH 2 ,Pd nanoparticles in Ph@GLC(fresh) catalyst are uniformly loaded on the carrier, and the average particle size is 2.32nm.
[0036] like Figure 3 d), 3wt% Pd II / NH 2 ,Ph@GLC(fresh) 3d There are two peaks in the XPS spectrum, namely Pd 3d 5 / 2 Peak and Pd 3d 3 / 2 The peaks are located at 337.62eV and 342.94eV, respectively, indicating that the valence state of palladium is divalent. In the XPS spectra of the catalyst after being used once and five times, new peaks appear at around 338eV and 344eV, respectively, indicating that Pd Ⅱ and Pd Ⅳ coexistence.
[0037] like Figure 3 As shown in e), 3wt% Pd II / NH 2 ,Ph@GLC(fresh) 1s Free amino groups, N-Pd, C=N and N +The characteristic peaks of Pd indicate that C=N bond may be the main coordination site of Pd.
[0038] like Figure 3 f), 3wt% Pd II / NH 2 ,Ph@GLC(fresh) and NH 2 , the FTIR spectrum of Ph@GLC is at 1573 cm -1 A peak appears, corresponding to the presence of C=N bond. The peaks appearing at 1200, 1160, and 1020 correspond to the presence of the benzene ring carbon skeleton.
[0039] 3wt%Pd II / NH 2 Ph@GLC exhibited excellent catalytic activity and stability in the following CH activation reaction. The catalytic activity did not decrease after 5 cycles of reaction, and the Pd loading did not decrease significantly.
[0040]
[0041] Figure 3 a) 3wt% Pd II / NH 2 ,Ph@GLC(fresh),3wt%Pd II / NH 2 ,Ph@GLC(used 1 st cycle),NH 2 , XRD spectra of Ph@GLC and GLC; b) 3wt% Pd II / NH 2 ,TEM image of Ph@GLC (fresh); c) 3wt% Pd II / NH 2 ,Particle size distribution of Ph@GLC(fresh); d) 3wt%Pd II / NH 2 ,Ph@GLC(fresh),3wt%Pd II / NH 2 ,Ph@GLC(used 1 st cycle), 3wt%Pd II / NH 2 ,Ph@GLC(used 5 th cycle) 3d XPS spectrum; e) 3wt% Pd II / NH 2 ,Ph@GLC(fresh) 1s XPS spectrum; f) 3wt% Pd II / NH2 ,FTIR spectrum of Ph@GLC(fresh).
[0042] Likewise, 3wt% Pd II / NH 2 Ph@GLC exhibits excellent catalytic activity in the following SUZUKI classical coupling reaction, CN coupling reaction and various CH bond arylation reactions. This result proves that silica-based protein melanin supported palladium nanoparticle catalyst is a universal arylation catalyst.
[0043] Figure 4 3wt%Pd II / NH 2 ,Application of Ph@GLC in SUZUKI classic coupling reaction, CN coupling reaction and various CH bond arylation reactions.
Claims
1. A silicon-based melanin-loaded metal nanoparticle catalyst, characterized in that: The method comprises the following preparation steps: Step (1), dissolving monosaccharide or disaccharide, silane coupling agent and tartaric acid or lysine in a solvent, heating and stirring for a certain period of time to obtain a mixed solution; Step (2), filtering the mixed solution obtained in step (1), performing Soxhlet extraction on the filter cake using acetone, and vacuum drying the filter cake to obtain a silicon-based protein melanin carrier; in step (2), the heating temperature is 80-100° C., the amount of acetone is 100-200 mL, and the Soxhlet extraction time is 10-24 h; Step (3), placing 1 g of the silica-based protein melanin carrier obtained in step (2) into 25 mL of secondary water, adjusting the pH to 9 with 0.1 M NaOH, and stirring at room temperature for about 10 minutes; adding a certain amount of soluble metal salt to a beaker, and stirring the resulting suspension at room temperature for 24 hours; Step (4), centrifuging the suspension obtained in step (3), washing the obtained solid with deionized water for 3-4 times until the pH of the supernatant is close to 7, and then washing it again with acetone for 3-4 times, and vacuum drying the obtained solid for 24 hours to obtain a silicon-based protein melanin-loaded metal nanoparticle catalyst.
2. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: Melanin was used as a support for metal catalysts for the first time.
3. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: The monosaccharides are glucose, fructose, mannose, galactose, xylose, ribose and arabinose; the disaccharides are lactose and sucrose.
4. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: The silane coupling agent is 3-aminopropyltrimethoxysilane APTM, 3-aminopropyltriethoxysilane APTE, and phenyltrimethoxysilane BTMO.
5. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: The organic solvent is toluene, benzene, acetonitrile or chlorobenzene.
6. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: The molar ratio of the monosaccharide or disaccharide, the silane coupling agent and the tartaric acid or lysine is 1:3-5:0.1-0.
4.
7. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: The crude product is subjected to Soxhlet extraction with acetone and vacuum dried to obtain a silica-based protein melanin carrier.
8. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: The soluble metal salts used in step (3) are PdCl2, Pd(OAc)2, H2PdCl4, Cu(OAc)2, CuCl2, CuNO3, and HAuCl4.
9. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: The prepared silicon-based protein melanin-loaded metal nanoparticle catalysts include: silicon-based protein melanin-loaded palladium nanoparticle catalysts, silicon-based protein melanin-loaded copper nanoparticle catalysts, and silicon-based protein melanin-loaded gold nanoparticle catalysts.
10. The silicon-based melanin-supported metal nanoparticle catalyst according to claim 1, characterized in that: The prepared silicon-based protein melanin-loaded metal nanoparticle catalyst has the following application ranges: SUZUKI classic coupling reaction involving iodobenzene compounds, HECK classic coupling, CN coupling reaction, CH arylation reaction and CH arylation reaction involving benzene compounds.