A super-stable hydrogen-bonded organic framework material and a preparation method and application thereof
By preparing an ultrastable hydrogen-bonded organic framework material HOF-L and combining it with MsAcT enzyme, a one-pot photoenzymatic cascade catalysis of HMF was achieved, solving the problems of low BHMF yield and complex reaction process in existing technologies, and realizing efficient and stable production of BHMF and BHMF diacetate.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUAIYIN TEACHERS COLLEGE
- Filing Date
- 2026-03-12
- Publication Date
- 2026-06-09
AI Technical Summary
Existing photocatalytic technologies for the selective hydrogenation reduction of HMF to prepare BHMF suffer from low yield, high cost, limited operational flexibility, and failure to achieve continuous conversion of HMF to BHMF esterification products, leading to increased process complexity and soaring separation costs.
We developed an ultrastable hydrogen-bonded organic framework material HOF-L, which, by combining with MsAcT enzyme to form HOF-L-MsAcTs, achieves photoenzyme cascade catalysis. Using ambient temperature and pressure, we realize the one-pot conversion of HMF→BHMF→BHMF diacetate.
The material exhibits high stability and high photocatalytic efficiency, with a BHMF yield of up to 52% and a BHMF diacetate yield of up to 46%. It avoids the use of precious metals and high temperature and pressure conditions, simplifying the reaction process.
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Abstract
Description
Technical Field
[0001] This invention relates to an ultrastable hydrogen-bonded organic framework material, its preparation method and application, belonging to the fields of high-value utilization of biomass, preparation of hydrogen-bonded organic framework materials and photo-biocatalysis technology. Background Technology
[0002] The high-value utilization of biomass resources is a key pathway to replace fossil fuels. 5-Hydroxymethylfurfural (HMF) serves as a core platform molecule, and its selective hydrogenation product, 2,5-bis(hydroxymethyl)furan (BHMF), and esterification derivatives are important precursors for the synthesis of biodiesel additives. Traditional catalytic processes rely on precious metals (such as Pt and Ru) and high-temperature, high-pressure hydrogen, resulting in inherent drawbacks such as high energy consumption and poor sustainability.
[0003] Photocatalysis technology, with its green and environmentally friendly characteristics, has become an ideal alternative. However, research in the field of HMF conversion shows a significant imbalance: current research on the selective oxidation of HMF to prepare derivatives such as DFF and FDCA is relatively comprehensive, while progress in photocatalytic-mediated selective hydrogenation reduction of HMF to prepare BHMF is significantly lagging behind. In 2016, Guo and Chen first reported a graphite carbon nitride-supported metal-pure photocatalytic system with a BHMF yield of only 6.5%, indicating a pressing need to improve reaction efficiency. In 2022, Alok Kumar's team developed a visible light photocatalytic system that increased the yield to 79.2%, but it still requires a precious metal catalyst and methanol as a hydrogen donor, resulting in high costs and limited operational flexibility. In 2023, Marco Weers et al. reported a polymeric carbon nitride (PCN) material system with a yield of 43%, but its synthesis process relies on high temperature and high pressure conditions. Furthermore, current technologies have not achieved continuous conversion of HMF to BHMF esterification products, requiring stepwise hydrogenation and esterification reactions, leading to process complexity and a surge in separation costs.
[0004] Hydrogen-bonded organic frameworks (HOFs) have shown great potential in photocatalysis due to their mild synthesis, biocompatibility, and photosensitivity. Current research focuses on gas adsorption and CO2 reduction, but their application in the photoenzymatic cascade reduction of hydrogen-bonded organic frameworks (HMFs) has not yet been reported. Furthermore, conventional HOFs lack stability and struggle to maintain structural integrity in complex reaction systems.
[0005] Therefore, developing HOFs materials that combine high stability, high efficiency photocatalytic activity, and enzyme immobilization function to achieve continuous one-pot conversion of HMF is a key direction to overcome the current technological bottlenecks. Summary of the Invention
[0006] The purpose of this invention is to provide an ultrastable hydrogen-bonded organic framework material, its preparation method, and its application. This material exhibits excellent stability and high photocatalytic efficiency. Furthermore, when encapsulated with MsAcTs enzymes and applied to a photoenzyme cascade catalytic system, it can achieve a one-pot conversion of HMF → BHMF → BHMF diacetate.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] A method for preparing an ultrastable hydrogen-bonded organic framework material involves mixing a deprotonated solution of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) with a solution of 4,4',4'',4'''-methanetetraphenylamidine tetrahydrochloride, allowing the mixture to stand in the dark, and then centrifuging, washing, and freeze-drying to obtain the final product.
[0009] Preferably, the concentration of the 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) solution is 2-5 mg / mL;
[0010] The concentration of 4,4',4'',4'''-methanetetrabenzamide tetrahydrochloride solution is 2-5 mg / mL;
[0011] The molar ratio of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) in the 6,6',6''',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) solution to 4,4',4'',4'''-methanetetraphenylamidine tetrahydrochloride in the 4,4',4''',4'''-methanetetraphenylamidine tetrahydrochloride solution was (0.5-10):1.
[0012] Preferably, the reagent used for deprotonation is an aqueous solution of tetrabutylammonium hydroxide (35-50 wt.%).
[0013] The molar ratio of tetrabutylammonium hydroxide in the aqueous solution to 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) in the solution is (5-15):1.
[0014] Preferably, the time for keeping the container in the dark is 10-15 hours.
[0015] Preferably, MsAcT enzyme powder is also added to the 4,4',4'',4'''-methanetetrabenzamide tetrahydrochloride solution; the solution is left to stand in the dark for 10-15 hours.
[0016] Application of hydrogen-bonded organic framework materials prepared by any of the above methods in the photocatalytic preparation of BHMF from HMF.
[0017] Preferably, the concentration of the 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) solution is 1-3 mg / mL;
[0018] The concentration of 4,4',4'',4'''-methanetetrabenzamide tetrahydrochloride solution is 1-3 mg / mL;
[0019] The molar ratio of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) in the 6,6',6''',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) solution to 4,4',4'',4'''-methanetetraphenylamidine tetrahydrochloride in the 4,4',4''',4'''-methanetetraphenylamidine tetrahydrochloride solution was (0.5-10):1.
[0020] Preferably, the amount of MsAcT enzyme powder added is 1-3 times the mass of methanetetraphenylamidine tetrahydrochloride in the methanetetraphenylamidine tetrahydrochloride solution.
[0021] Preferably, the reagent used for deprotonation is an aqueous solution of tetrabutylammonium hydroxide (35-50 wt.%).
[0022] The molar ratio of tetrabutylammonium hydroxide in the aqueous solution to 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) in the solution is (5-15):1.
[0023] Application of hydrogen-bonded organic framework materials prepared by any of the above methods in the photoenzymatic preparation of BHMF diacetate from HMF.
[0024] The beneficial effects of this invention are as follows: The resulting hydrogen-bonded organic framework material exhibits high stability, with the π-π stacking of the two ligands ensuring structural integrity during the reaction (TGA weight loss ≤42.1%). It also demonstrates high photocatalytic efficiency, improved carrier separation efficiency, and a BHMF yield of up to 52%. HOF-L-MsAcTs composite materials were developed using these materials to encapsulate enzymes. These composites were then applied to a photoenzyme cascade catalyst, enabling a continuous photocatalytic and enzymatic esterification reaction. The reaction process was conducted at ambient temperature and pressure, avoiding the use of precious metals and hydrogen, and achieving a one-pot conversion of HMF → BHMF → BHMF diacetate with a yield of up to 46%. Attached Figure Description
[0025] Figure 1 SEM images of HOF-L; Figure 2 TGA spectral analysis of HOF-L; Figure 3 TGA spectral analysis of HOF-C10; Figure 4 The photocurrent response spectrum of HOF-L; Figure 5 The fluorescence intensity (PL) spectrum of HOF-L; Figure 6 The FTIR spectra of HOF-L-MsAcTs; Figure 7 The zeta potentials of HOF-L and MsAcTs; Figure 8 The circular dichroism (CD) spectrum of HOF-L-MsAcTs; Figure 9 Liquid phase diagram showing the yield of BHMF under HOF-L photocatalysis; Figure 10 The graph shows the conversion rate of HMF catalyzed by HOF-L-MsAcTs photoenzyme coupling. Detailed Implementation
[0026] Comparative Example 1: Preparation of HOF-C10.
[0027] 6 mg of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) was dissolved in 3 mL of DMF, incubated in an oil bath at 120 °C for 3 h with stirring at 200 rpm, and then centrifuged at 10,000 rpm for 5 min. 4.8 mL of 50% ethanol solution was added to the supernatant, and the mixture was allowed to stand in the dark for 72 h. The mixture was then washed once with ethanol by centrifugation. Finally, the mixture was washed three times with water by centrifugation and dried in a freeze dryer to obtain a yellow powder, namely the hydrogen-bonded organic framework material HOF-C10.
[0028] Example 1: Preparation of HOF-L material.
[0029] 8 mg of 4,4',4'',4'''-methanetetrabenzamide tetrahydrochloride and 3 mL of water were added to a 10 mL centrifuge tube to dissolve the ligand and obtain a clear solution A. 11.1 mg of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) and 3 mL of water were added to a 10 mL centrifuge tube and ultrasonically dispersed. 0.082 mL of tetrabutylammonium hydroxide aqueous solution (40 wt.%) was added to deprotonate the ligand. The solution was filtered to obtain a clear, yellow-green solution B. The clear, yellow-green solution B was added dropwise to solution A to ensure homogeneous mixing. After standing in the dark for 12 h, the mixture was centrifuged, washed, and lyophilized to obtain a yellow-green powder, namely the ultrastable hydrogen-bonded organic framework material HOF-L.
[0030] Figure 1 The image shows a SEM image of the HOF-L material, which demonstrates that the material has a good morphological structure.
[0031] Figure 2 TGA spectral analysis of HOF-L Figure 3 The TGA spectral analysis of HOF-C10 shows that there are significant differences in the weight loss process and kinetic behavior between the two, with HOF-L exhibiting better thermal stability.
[0032] Figure 4 The photocurrent response spectrum of HOF-L shows a significant photocurrent response, indicating that electrons are rapidly generated and form a current during illumination. Comparison reveals that the photocurrent density of HOF-L is greater than that of HOF-C10, suggesting that HOF-L has a higher electron-hole separation efficiency, thereby enhancing its photocatalytic activity.
[0033] Figure 5 The figure shows the fluorescence intensity spectrum of HOF-L. As can be seen from the figure, the fluorescence intensity of HOF-L is lower than that of HOF-C10, which proves that the recombination rate of photogenerated electrons and holes is greatly reduced after recombination with amidine salt, thus improving the photocatalytic efficiency.
[0034] Example 2: Preparation of HOF-L-MsAcTs material encapsulating acyltransferase (MsAcT).
[0035] 4 mg of 4,4',4'',4'''-methanetetrabenzamide tetrahydrochloride was dissolved in 3 mL of water, and then 4.5 mg of MsAcT pure enzyme powder was dissolved in the same solution to obtain solution A. 5.55 mg of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) was uniformly dispersed in 3 mL of water, and 41 µL of tetrabutylammonium hydroxide aqueous solution (40 wt.%) was added for deprotonation to obtain a clear solution B. Solution B was added dropwise to solution A and mixed thoroughly. After standing in the dark for 12 h, the mixture was washed three times by centrifugation with water and then freeze-dried. The resulting pale yellow-green powder was HOF-L-MsAcTs.
[0036] Figure 6 The figure shows the FTIR spectrum of HOF-L-MsAcTs, which indicates that the enzyme immobilization was successful.
[0037] Figure 7 The figure shows the zeta potentials of HOF-L and MsAcTs. As can be seen from the figure, the enzymes are not bound to the material surface by electrostatic adsorption, but are encapsulated in situ inside HOF-L.
[0038] Figure 8The circular dichroism (CD) spectrum of HOF-L-MsAcTs shows that the secondary structure of MsAcTs enzyme did not change significantly after encapsulation, which provides a structural basis for maintaining good biological activity inside the material.
[0039] Example 3: HOF-L photocatalytic reduction of HMF to BHMF.
[0040] The reaction system consisted of 2 mL PB buffer (0.2 M, pH 5.8), 4 mg HOF-L, 8 mM HMF (final concentration in the reaction system), 0.18 g TEOA, and 0.75 mM [Cp*Rh(bpy)H2O]. 2+ (M + The reaction mixture was composed of (final concentration in the reaction system). The reaction system was added to a 10 mL quartz photocatalytic tube and subjected to photocatalytic reaction for 6 h under LED light irradiation (420 nm) at room temperature (~25℃). Before the photocatalytic reaction, the mixture was placed in the dark for 1 h to allow it to reach adsorption-desorption equilibrium. After the reaction, the supernatant was collected by centrifugation and analyzed by HPLC.
[0041] HMF reduction reaction mixture analysis: A Zorbax Eclipse Plus C18 column (4.6 mm × 250 mm, 5 µm, Agilent) was used. The mobile phase was 4 g / L (NH4)2SO4 solution / acetonitrile, pH 3.5 (90:10, v / v), flow rate was 0.6 mL / min, column temperature was 30 °C, detection wavelength was 223 nm, and injection volume was 10 µL.
[0042] Figure 9 The figure shows the liquid phase diagram of BHMF yield under HOF-L photocatalysis. As can be seen from the figure, HOF-L photocatalysis can achieve highly selective reduction of HMF to BHMF.
[0043] Example 4: HOF-L-MsAcTs photoenzyme catalysis of HMF to prepare BHMF diacetate.
[0044] First, add 2 mL of PB buffer (0.2 M, pH 5.8), 2 mg / mL HOF-L-MsAcTs, 8 mM HMF (final concentration in the reaction system), 0.18 g TEOA, and 0.75 mM [Cp*Rh(bpy)H2O]. 2+ (M +The final concentration in the reaction system was added to a 10 mL quartz photocatalytic tube, and the reaction temperature was controlled at 30℃. The photocatalytic reaction was carried out under LED light irradiation (420 nm) for 6 h. After 6 h of reaction, the light was turned off, and the reaction system was allowed to equilibrate for 4 h. Then, 10% (v / v) vinyl acetate was added, and the reaction continued for 3 h. The supernatant was collected by centrifugation, and finally, 2 mL of methanol was added to mix the reactants thoroughly. The reaction solution was extracted and analyzed by HPLC.
[0045] Analysis of the BHMF esterification synthesis reaction mixture: A Zorbax Eclipse Plus C18 column (4.6 mm × 250 mm, 5 µm, Agilent) was used. The mobile phase was 0.1% H3PO4 solution / acetonitrile (50:50, v / v), the flow rate was 0.6 mL / min, the column temperature was 30 °C, the detection wavelength was 224 nm, and the injection volume was 20 μL.
[0046] Figure 10 The graph shows the conversion rate of HMF catalyzed by HOF-L-MsAcTs photoenzyme coupling. As can be seen from the graph, HOF-L-MsAcTs photoenzyme cascade catalysis can achieve efficient one-step conversion of HMF to BHMF diacetate.
Claims
1. A method for preparing an ultrastable hydrogen-bonded organic framework material, characterized in that, It is obtained by mixing a deprotonated solution of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) with a solution of 4,4',4'',4'''-methanetetrabenzamide tetrahydrochloride, allowing it to stand in the dark, and then centrifuging, washing, and lyophilizing.
2. The method for preparing the ultrastable hydrogen-bonded organic framework material according to claim 1, characterized in that, The molar ratio of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) in the 6,6',6''',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) solution to 4,4',4'',4'''-methanetetraphenylamidine tetrahydrochloride in the 4,4',4''',4'''-methanetetraphenylamidine tetrahydrochloride solution was (0.5-10):
1.
3. The method for preparing the ultrastable hydrogen-bonded organic framework material according to claim 1, characterized in that, The reagent used for deprotonation was an aqueous solution of tetrabutylammonium hydroxide; The molar ratio of tetrabutylammonium hydroxide in the aqueous solution to 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) in the solution is (5-15):
1.
4. The method for preparing the ultrastable hydrogen-bonded organic framework material according to claim 1, characterized in that, The product should be kept in the dark for 10-15 hours.
5. The method for preparing the ultrastable hydrogen-bonded organic framework material according to claim 1, characterized in that, MsAcT enzyme powder was also added to the 4,4',4'',4'''-methanetetrabenzamide tetrahydrochloride solution.
6. The method for preparing the ultrastable hydrogen-bonded organic framework material according to claim 5, characterized in that, The molar ratio of 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) in the 6,6',6''',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) solution to 4,4',4'',4'''-methanetetraphenylamidine tetrahydrochloride in the 4,4',4''',4'''-methanetetraphenylamidine tetrahydrochloride solution was (0.5-10):
1.
7. The method for preparing the ultrastable hydrogen-bonded organic framework material according to claim 6, characterized in that, The amount of MsAcT enzyme powder added should be 1-3 times the mass of methanetetrabenzamide tetrahydrochloride in the methanetetrabenzamide tetrahydrochloride solution.
8. The method for preparing the ultrastable hydrogen-bonded organic framework material according to claim 6, characterized in that, The reagent used for deprotonation was an aqueous solution of tetrabutylammonium hydroxide; The molar ratio of tetrabutylammonium hydroxide in the aqueous solution to 6,6',6'',6'''-(pyrene-1,3,6,8-tetramethyl)tetra(2-naphthoic acid) in the solution is (5-15):
1.
9. The application of the hydrogen-bonded organic framework material prepared by the method according to any one of claims 1-4 in the photocatalytic preparation of BHMF from HMF.
10. The application of the hydrogen-bonded organic framework material prepared by the method according to any one of claims 5-8 in the photoenzymatic preparation of BHMF diacetate from HMF.