Molybdenum-quinoline complex, preparation method and method for preparing coupling product through allyl alcohol deoxidation coupling
The deoxygenation coupling of allyl alcohols via molybdenum-quinoline complex catalysts under mild conditions solves the problems of high cost and environmental pollution in traditional methods, achieving efficient and environmentally friendly carbon chain extension, and is suitable for biomass catalytic conversion.
Patent Information
- Application Number
- CN202411162098.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-22
- Publication Date
- 2026-03-03
AI Technical Summary
Traditional allyl alcohol deoxygenation coupling reactions require precious metals and halogen reagents, resulting in high costs and environmental pollution, making it difficult to achieve efficient and environmentally friendly carbon chain extension.
Using molybdenum-quinoline complexes as catalysts, the deoxygenation coupling of allyl alcohols is carried out under mild reaction conditions, avoiding the use of halogen reagents and utilizing the oxygen affinity of molybdenum to achieve efficient carbon chain extension.
This method achieves efficient and environmentally friendly deoxygenation coupling of allyl alcohols, resulting in high product purity, reduced production costs, and improved reaction safety, making it suitable for biomass catalytic conversion.
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Figure CN121591798A_ABST
Abstract
Description
Technical Field
[0001] This application relates to a molybdenum-quinoline complex and its preparation method, as well as a method for preparing coupling products by deoxygenation coupling of allyl alcohol, belonging to the field of catalyst technology. Background Technology
[0002] With increasing global emphasis on renewable energy and green chemistry, the efficient conversion and utilization of biomass, as an abundant and renewable resource, has become a research hotspot. In biomass conversion, allyl alcohols, as common structural units, are widely found in the dehydration products of polyhydroxy biomass, such as furfuryl alcohol. Therefore, developing reactions targeting compounds with allyl alcohol structures is of great significance for biomass conversion.
[0003] Allyl alcohols can extend their carbon chains through carbon-carbon coupling reactions, thus enabling their application in the synthesis of fine chemicals and high-fuel-value fuels. However, traditional alcohol coupling methods typically require reagents such as halogens and expensive metals like palladium, resulting in high conversion costs and potential environmental pollution. Molybdenum, as an inexpensive transition metal with high oxygen affinity, is widely used in oxygen transfer reactions such as epoxidation and deoxygenation, making it an ideal catalyst for the deoxygenation coupling of allyl alcohols. Summary of the Invention
[0004] This application proposes a method for the deoxygenation coupling reaction of allyl alcohol using a molybdenum-quinoline complex, achieving highly efficient deoxygenation coupling of allyl alcohol under mild reaction conditions. Compared with traditional allyl alcohol deoxygenation coupling reactions, this method has advantages such as mild reaction conditions, high catalytic efficiency, high product purity, and low environmental pollution. Furthermore, this application also relates to the catalyst preparation method and the optimization of reaction conditions, providing technical support for the industrial application of this type of reaction.
[0005] According to one aspect of this application, a molybdenum-quinoline complex is provided, the molybdenum-quinoline complex having the structure shown in Formula I:
[0006]
[0007] In Equation I, NQO has one of the structures shown in Equation II;
[0008]
[0009] In Formula II, R1, R2, R3, R4, R5, and R6 are independently selected from one of -H, -NO2, -SO3H, -F, -Cl, -Br, -I, -CF3, -CO2R, -OR, -CH2OR, -CH2R, and -C6H4R, and not all of R1, R2, R3, R4, R5, and R6 are -H;
[0010] The R in -CO2R, -OR, -CH2OR, -CH2R, and -C6H4R is selected from one of H, CH3, C2H5, C3H8, and C6H5.
[0011] Optionally, Mo is coordinated with the nitrogen atom in the structure shown in Formula II.
[0012] According to another aspect of this application, a method for preparing the molybdenum-quinoline complex described above is provided, the method comprising:
[0013] A mixture containing a molybdenum source, a compound of formula II, and a solvent is reacted to obtain the molybdenum-quinoline complex.
[0014]
[0015] In Formula II, R1, R2, R3, R4, R5, and R6 are the same as those mentioned above.
[0016] Optionally, the molybdenum source is selected from at least one of molybdenum acetylacetonate, molybdenum dichlorodioxide, molybdenum trioxide, sodium molybdate, and ammonium molybdate.
[0017] Optionally, the molar ratio of the molybdenum source to the compound shown in Formula II is 1:(1-2).
[0018] Optionally, the molar ratio of the molybdenum source to the compound represented by Formula II is independently selected from any value of 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.8, 1:2 or a range between any two of the above.
[0019] Optionally, the solvent is selected from at least one of water, methanol, ethanol, propanol, isopropanol, diethyl ether, tetrahydrofuran, and 1,4-dioxane.
[0020] Optionally, the mass-to-volume ratio of the molybdenum source to the solvent is 0.5–1.5 g: 10 mL.
[0021] Optionally, the mass-to-volume ratio of the molybdenum source to the solvent is independently selected from any value among 0.5g:10mL, 0.8g:10mL, 1g:10mL, 1.2g:10mL, 1.5g:10mL, or a range between any two of the above.
[0022] Optionally, the reaction temperature is 20–100°C, and the reaction time is 2–24 h.
[0023] Optionally, the temperature of the reaction is independently selected from any value of 20°C, 30°C, 40°C, 50°C, 60°C, 80°C, 90°C, 100°C, or a range between any two of the above.
[0024] Optionally, the reaction time is independently selected from any value of 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h or a range between any two of the above.
[0025] Optionally, the reaction includes at least one of aging, hydrothermal treatment, solvothermal treatment, etc.
[0026] According to another aspect of this application, a method for preparing a coupling product by deoxygenation coupling of allyl alcohol is provided, the method comprising:
[0027] In a closed reactor, a mixture containing allyl alcohol, reducing agent, and catalyst is subjected to a deoxygenation coupling reaction to obtain the coupling product.
[0028] The catalyst is selected from the molybdenum-quinoline complex described above.
[0029] Optionally, the allyl alcohol is selected from at least one of the compounds shown in Formula III, cinnamyl alcohol, furfuryl alcohol, 5-hydroxymethylfurfural, and 2-thiophene methanol;
[0030]
[0031] In Formula III, R7, R8, and R9 are independently selected from one of -H, -NO2, -F, -Cl, -Br, -I, -CF3, -CO2R, -OR, -CH2OR, -CH2R, and -C6H4R;
[0032] The R in -CO2R, -OR, -CH2OR, -CH2R, and -C6H4R is selected from one of H, CH3, C2H5, C3H8, and C6H5.
[0033] Optionally, R7, R8, and R9 are each independently selected from one of -H, -OH, -NO2, -F, -Cl, -Br, -I, -CO2H, -CO2R, -OR, -CH2OR, -CH3, -CH2R, -CF3, and -C6H4R; or, the carbon-carbon double bond in Formula III is part of at least one of a benzene ring, a pyridine ring, a furan ring, a thiophene ring, and a pyrrole ring.
[0034] Optionally, the molar ratio of the allyl alcohol to the reducing agent is 1:(0.5-5).
[0035] Optionally, the molar ratio of the allyl alcohol to the reducing agent is independently selected from any value of 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5 or a range between any two of the above.
[0036] Optionally, the molar ratio of the allyl alcohol to the catalyst is 1:(0.001~1).
[0037] Optionally, the molar ratio of the allyl alcohol to the catalyst is independently selected from any value of 1:0.001, 1:0.005, 1:0.01, 1:0.05, 1:0.1, 1:0.5, 1:1 or a range between any two of the above.
[0038] Optionally, the reducing agent is selected from at least one of methanol, ethanol, isopropanol, n-butanol, 2-pentanol, 3-pentanol, 3-octanol, triphenylphosphine, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite, and hydrogen.
[0039] Optionally, the temperature of the deoxygenation coupling reaction is 150–250°C, and the time of the deoxygenation coupling reaction is 0.5–24 h.
[0040] Optionally, the temperature of the deoxygenation coupling reaction is independently selected from any value of 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, or a range between any two of the above.
[0041] Optionally, the time for the deoxygenation coupling reaction is independently selected from any value among 0.5h, 1h, 2h, 4h, 6h, 8h, 10h, 12h, 18h, 20h, and 24h, or a range between any two of the above.
[0042] Optionally, the deoxygenation coupling reaction is carried out in a pressure-resistant reactor with a heating jacket.
[0043] Optionally, the deoxygenation coupling reaction is shown in the following reaction formula:
[0044]
[0045] R7, R8, and R9 in the above reaction formula are the same as those mentioned above.
[0046] The beneficial effects that this application can produce include:
[0047] The quinoline chelating ligands provided in this application form stable molybdenum-quinoline complexes, significantly enhancing the oxygen-binding ability of the molybdenum active center. This allows for direct binding and deoxygenation coupling with allyl alcohol compounds, avoiding the use of harmful reagents such as halogens. Since allyl alcohol structures are very common in biomass platform compounds and their derivatives, this method also provides an efficient means for biomass catalytic conversion and carbon chain elongation.
[0048] This molybdenum-quinoline complex is used for the efficient catalysis of deoxygenation coupling of compounds with allyl alcohol structures, eliminating the need for harmful reagents such as halogens, greatly increasing the safety of the reaction and reducing production costs. Attached Figure Description
[0049] Figure 1 The infrared spectrum of the molybdenum-2-methyl-8-hydroxyquinoline complex Mo-2M-Q in Example 1 of this application is shown.
[0050] Figure 2 This is an XRD image of the molybdenum-2-methyl-8-hydroxyquinoline complex Mo-2M-Q from Example 1 of this application. Detailed Implementation
[0051] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0052] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0053] Gas phase analysis was performed using an Agilent 7890 AGC.
[0054] In the embodiments of this application, the conversion rate and yield are calculated as follows:
[0055] Conversion rate [mol%] = (n0-n) / n0 × 100%
[0056] Yield [mol%] = 2*n x / n0×100%
[0057] In the above formula, n0 is the amount of substrate (calculated as allyl alcohol) added before the reaction [mol], and n is the amount of substrate remaining after the reaction [mol]. x The amount of substance of the product generated during the reaction is expressed in mol.
[0058] Example 1: Preparation of molybdenum-2-methyl-8-hydroxyquinoline
[0059] Add 2 mmol (0.32 g) of 2-methyl-8-hydroxyquinoline dissolved in 20 mL of anhydrous ethanol to a 100 mL beaker. Separately, dissolve 1 mmol (0.18 g) of ammonium molybdate in 20 mL of deionized water. Mix the two solutions with vigorous stirring and incubate at 60 °C for 6 h. After cooling to room temperature, filter, wash with ethanol, and dry under vacuum to obtain the molybdenum-2-methyl-8-hydroxyquinoline complex in 95% yield, designated Mo-2M-Q. Figure 1 As shown, from Figure 1 It can be seen that Mo-O and Mo-N coordination bonds are formed; for example Figure 2 As shown, from Figure 2 It can be seen that the complex formed crystals.
[0060] The structure of the complex is as follows:
[0061]
[0062] Example 2: Preparation of molybdenum-5-methyl-8-hydroxyquinoline
[0063] Add 2 mmol (0.32 g) of 5-methyl-8-hydroxyquinoline to a 100 mL beaker and dissolve it in 20 mL of anhydrous ethanol. Separately, dissolve 1 mmol (0.18 g) of ammonium molybdate in 20 mL of deionized water. Mix the two solutions with vigorous stirring and incubate at 60 °C for 6 h. After cooling to room temperature, filter, wash with ethanol, and dry under vacuum to obtain the molybdenum-5-methyl-8-hydroxyquinoline complex in 93% yield, designated Mo-5M-Q.
[0064] The structure of the complex is as follows:
[0065]
[0066] Example 3: Preparation of molybdenum-5-nitro-8-hydroxyquinoline
[0067] Add 2 mmol (0.38 g) of 5-nitro-8-hydroxyquinoline to a 100 mL beaker and dissolve it in 20 mL of anhydrous ethanol. Separately, dissolve 1 mmol (0.18 g) of ammonium molybdate in 20 mL of deionized water. Mix the two solutions with vigorous stirring and incubate at 60 °C for 6 h. After cooling to room temperature, filter, wash with ethanol, and dry under vacuum to obtain the molybdenum-5-nitro-8-hydroxyquinoline complex in 92% yield, designated Mo-5N-Q.
[0068] The structure of the complex is as follows:
[0069]
[0070] Example 4: Preparation of molybdenum-bisquinoline
[0071] Add 1 mmol (0.29 g) of (6,6'-bisquinoline)-8,8'-diol dissolved in 20 mL of anhydrous ethanol to a 100 mL beaker. Separately, dissolve 1 mmol (0.18 g) of ammonium molybdate in 20 mL of deionized water. Mix the two solutions with vigorous stirring and incubate at 60 °C for 6 h. After cooling to room temperature, filter, wash with ethanol, and dry under vacuum to obtain the molybdenum-bisquinoline complex in 92% yield, designated Mo-biQ.
[0072] The structure of the complex is as follows:
[0073]
[0074] Examples 5-8: Molybdenum-quinoline complex-catalyzed deoxygenation coupling of allyl alcohol
[0075] 2 mmol (0.12 g) of allyl alcohol, 1 mmol (0.26 g) of triphenylphosphine, 100 mg of molybdenum-quinoline catalyst, and 20 mL of dioxane were added sequentially to a 50 mL pressure-resistant reactor. The reactor was sealed and protected with nitrogen, and heated at 200 °C for 2 h. After the reaction was complete, the mixture was filtered, and the filtrate was subjected to gas chromatography and compared with a standard to confirm that the coupling product was 1,5-hexadiene. Quantitative analysis was performed using the internal standard method to determine the conversion rate of allyl alcohol and the yield of 1,5-hexadiene.
[0076] The reaction formula is as follows:
[0077]
[0078] The molybdenum-quinoline complexes prepared in Examples 1-4 were used as catalysts to prepare the coupling products using the above method. The specific reaction results are shown in Table 1.
[0079] Comparative Example 1
[0080] 1,5-hexadiene was prepared using allyl alcohol as a raw material and molybdenum trioxide as a catalyst. The specific results are shown in Table 1.
[0081] Table 1 Results of allyl alcohol deoxycoupling reaction
[0082] catalyst Conversion rate (%) Yield (%) Example 5 Mo-2M-Q 100 52 Example 6 Mo-5M-Q 100 64 Example 7 Mo-5N-Q 100 45 Example 8 Mo-biQ 100 62 Comparative Example 1 <![CDATA[MoO3]]> 87 4
[0083] As can be seen from Table 1, when the molybdenum-quinoline complexes prepared in Examples 1-4 are used as catalysts to catalyze the production of 1,5-hexadiene from allyl alcohol, the reaction conversion rate is 100% and the yield of 1,5-hexadiene can reach 64%. However, when molybdenum trioxide is used as a catalyst, the reaction conversion rate is 87% and the yield of 1,5-hexadiene is only 4%.
[0084] Examples 9-12: Molybdenum-quinoline complex-catalyzed deoxygenation coupling of cinnamyl alcohol
[0085] 2 mmol (0.27 g) of cinnamyl alcohol, 1 mmol (0.26 g) of triphenylphosphine, 100 mg of molybdenum-quinoline catalyst, and 20 mL of dioxane were added sequentially to a 50 mL pressure-resistant reactor. The reactor was sealed and protected with nitrogen, and heated at 200 °C for 2 h. After the reaction was complete, the mixture was filtered, and the filtrate was subjected to gas chromatography and compared with standards to determine that the coupling product was 1,6-diphenyl-1,5-hexadiene and its isomers. Quantitative analysis was performed using the internal standard method to determine the conversion rate of cinnamyl alcohol and the yield of 1,6-diphenyl-1,5-hexadiene.
[0086] The reaction formula is as follows:
[0087]
[0088] The molybdenum-quinoline complexes prepared in Examples 1-4 were used as catalysts to prepare the coupling products using the above method. The specific reaction results are shown in Table 2.
[0089] Comparative Example 2
[0090] Using cinnamyl alcohol as a raw material and molybdenum trioxide as a catalyst, the coupling product 1,6-diphenyl-1,5-hexadiene was prepared. The specific results are shown in Table 2.
[0091] Table 2 Results of cinnamyl alcohol deoxycoupling reaction
[0092] catalyst Conversion rate (%) Yield (%) Example 9 Mo-2M-Q 100 77 Example 10 Mo-5M-Q 100 89 Example 11 Mo-5N-Q 100 71 Example 12 Mo-biQ 100 92 Comparative Example 2 <![CDATA[MoO3]]> 53 11
[0093] As can be seen from Table 2, when the molybdenum-quinoline complexes prepared in Examples 1-4 are used as catalysts to catalyze the preparation of 1,6-diphenyl-1,5-hexadiene from cinnamyl alcohol, the reaction conversion rate is 100% and the yield of 1,6-diphenyl-1,5-hexadiene can reach 92%. However, when molybdenum trioxide is used as a catalyst, the reaction conversion rate is 53% and the yield of 1,6-diphenyl-1,5-hexadiene is only 11%.
[0094] Examples 13-16: Molybdenum-quinoline complex-catalyzed furfuryl alcohol deoxygenation coupling
[0095] 2 mmol (0.20 g) of furfuryl alcohol, 1 mmol (0.26 g) of triphenylphosphine, 100 mg of molybdenum-quinoline catalyst, and 20 mL of dioxane were added sequentially to a 50 mL pressure-resistant reactor. The reactor was sealed and protected with nitrogen, and heated at 200 °C for 2 h. After the reaction was complete, the mixture was filtered, and the filtrate was subjected to gas chromatography and compared with standards to determine that the coupling product was 1,2-di(furan-2-yl)ethane and its isomers. Quantitative analysis was performed using the internal standard method to determine the conversion rate of furfuryl alcohol and the yield of the coupling product.
[0096] The reaction formula is as follows:
[0097]
[0098] The molybdenum-quinoline complexes prepared in Examples 1-4 were used as catalysts to prepare the coupling products using the above method. The specific reaction results are shown in Table 3.
[0099] Comparative Example 3
[0100] Using furfuryl alcohol as a raw material and molybdenum trioxide as a catalyst, the coupling product 1,2-bis(furan-2-yl)ethane was prepared. The specific results are shown in Table 3.
[0101] Table 3 Results of furfuryl alcohol deoxygenation coupling reaction
[0102] catalyst Conversion rate (%) Yield (%) Example 13 Mo-2M-Q 100 72 Example 14 Mo-5M-Q 100 86 Example 15 Mo-5N-Q 100 69 Example 16 Mo-biQ 100 83 Comparative Example 3 <![CDATA[MoO3]]> 26 5
[0103] As can be seen from Table 3, when using the molybdenum-quinoline complexes prepared in Examples 1-4 as catalysts to catalyze the preparation of 1,2-di(furan-2-yl)ethane from furfuryl alcohol, the reaction conversion rate is 100% and the yield of 1,2-di(furan-2-yl)ethane can reach 86%. However, when using molybdenum trioxide as a catalyst, the reaction conversion rate is 26% and the yield of 1,2-di(furan-2-yl)ethane is only 5%.
[0104] Examples 17-20: Molybdenum-quinoline complex-catalyzed deoxygenation coupling of 5-methylfurfural
[0105] 2 mmol (0.22 g) of 5-methylfurfural, 1 mmol (0.26 g) of triphenylphosphine, 100 mg of molybdenum-quinoline catalyst, and 20 mL of dioxane were added sequentially to a 50 mL pressure-resistant reactor. The reactor was sealed and protected with nitrogen, and heated at 200 °C for 2 h. After the reaction was complete, the mixture was filtered, and the filtrate was subjected to gas chromatography and compared with standards to determine that the coupling product was 1,2-bis(5-methylfuran-2-yl)ethane and its isomers. Quantitative analysis was performed using the internal standard method to determine the conversion rate of 5-methylfurfural and the yield of the coupling product.
[0106] The reaction formula is as follows:
[0107]
[0108] The molybdenum-quinoline complexes prepared in Examples 1-4 were used as catalysts to prepare the coupling products using the above method. The specific reaction results are shown in Table 4.
[0109] Comparative Example 4
[0110] Using 5-methylfurfural as a raw material and molybdenum trioxide as a catalyst, the coupling product 1,2-bis(5-methylfuran-2-yl)ethane was prepared. The specific results are shown in Table 4.
[0111] Table 4 Results of the 5-methylfurfural deoxygenation coupling reaction
[0112] catalyst Conversion rate (%) Yield (%) Example 17 Mo-2M-Q 100 68 Example 18 Mo-5M-Q 100 79 Example 19 Mo-5N-Q 100 78 Example 20 Mo-biQ 100 81 Comparative Example 4 <![CDATA[MoO3]]> 51 8
[0113] As can be seen from Table 4, when using the molybdenum-quinoline complexes prepared in Examples 1-4 as catalysts to catalyze the preparation of 1,2-bis(5-methylfuran-2-yl)ethane from 5-methylfurfural, the reaction conversion rate is 100% and the yield of 1,2-bis(5-methylfuran-2-yl)ethane can reach 81%. However, when using molybdenum trioxide as a catalyst, the reaction conversion rate is 51% and the yield of 1,2-bis(5-methylfuran-2-yl)ethane is only 8%.
[0114] Examples 21-24: Molybdenum-quinoline complex-catalyzed deoxygenation coupling of 5-hydroxymethylfurfural
[0115] 2 mmol (0.25 g) of 5-hydroxymethylfurfural, 1 mmol (0.26 g) of triphenylphosphine, 100 mg of molybdenum-quinoline catalyst, and 20 mL of dioxane were added sequentially to a 50 mL pressure-resistant reactor. The reactor was sealed and protected with nitrogen, and heated at 200 °C for 2 h. After the reaction was complete, the mixture was filtered. The filtrate was subjected to gas chromatography and compared with standards to determine that the coupling product was 5,5'-(ethane-1,2-diyl)bis(furan-2-carboxaldehyde) and its isomer (C12), or its decarbonylation product 5-(2-(furan-2-yl)ethyl)furan-2-carboxaldehyde and its isomer (C11). Quantitative analysis was performed using the internal standard method to determine the conversion rate of 5-hydroxymethylfurfural and the yield of the coupling product.
[0116] The reaction formula is as follows:
[0117]
[0118] The molybdenum-quinoline complexes prepared in Examples 1-4 were used as catalysts to prepare the coupling products using the above method. The specific reaction results are shown in Table 5.
[0119] Comparative Example 5
[0120] Using 5-hydroxymethylfurfural as a raw material and molybdenum trioxide as a catalyst, coupling products 5,5'-(ethane-1,2-diyl)bis(furan-2-carboxaldehyde) (C12) or 5-(2-(furan-2-yl)ethyl)furan-2-carboxaldehyde and their isomers (C11) were prepared. The specific results are shown in Table 5.
[0121] Table 5 Results of the deoxygenation coupling reaction of 5-hydroxymethylfurfural.
[0122] catalyst Conversion rate (%) product Yield (%) Example 21 Mo-2M-Q 100 C12 86 Example 22 Mo-5M-Q 100 C12 89 Example 23 Mo-5N-Q 100 C11 92 Example 24 Mo-biQ 100 C12 91 Comparative Example 5 <![CDATA[MoO3]]> 85 C12 13
[0123] As can be seen from Table 5, when the molybdenum-quinoline complexes prepared in Examples 1-4 are used as catalysts to catalyze the preparation of C12 or C11 from 5-hydroxymethylfurfural, the reaction conversion rate is 100% and the yield can reach 92%. However, when molybdenum trioxide is used as a catalyst, the reaction conversion rate is 85% and the C12 yield is only 13%.
[0124] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A molybdenum-quinoline complex, characterized in that, The molybdenum-quinoline complex has the structure shown in Formula I: In Equation I, NQO has one of the structures shown in Equation II; In Formula II, R1, R2, R3, R4, R5, and R6 are independently selected from one of -H, -NO2, -SO3H, -F, -Cl, -Br, -I, -CF3, -CO2R, -OR, -CH2OR, -CH2R, and -C6H4R, and not all of R1, R2, R3, R4, R5, and R6 are -H; The R in -CO2R, -OR, -CH2OR, -CH2R, and -C6H4R is selected from one of H, CH3, C2H5, C3H8, and C6H5.
2. The method for preparing the molybdenum-quinoline complex according to claim 1, characterized in that, The preparation method includes: A mixture containing a molybdenum source, a compound of formula II, and a solvent is reacted to obtain the molybdenum-quinoline complex. In Formula II, R1, R2, R3, R4, R5, and R6 are the same as R1, R2, R3, R4, R5, and R6 in claim 1.
3. The preparation method according to claim 2, characterized in that, The molybdenum source is selected from at least one of molybdenum acetylacetonate, molybdenum dioxide, molybdenum trioxide, sodium molybdate, and ammonium molybdate. Preferably, the molar ratio of the molybdenum source to the compound represented by Formula II is 1:(1-2).
4. The preparation method according to claim 2, characterized in that, The solvent is selected from at least one of water, methanol, ethanol, propanol, isopropanol, diethyl ether, tetrahydrofuran, and 1,4-dioxane; Preferably, the mass-to-volume ratio of the molybdenum source to the solvent is 0.5–1.5 g: 10 mL.
5. The preparation method according to claim 2, characterized in that, The reaction temperature is 20–100°C, and the reaction time is 2–24 h.
6. A method for preparing a coupling product by deoxygenation coupling of allyl alcohol, characterized in that, The method includes: In a closed reactor, a mixture containing allyl alcohol, reducing agent, and catalyst is subjected to a deoxygenation coupling reaction to obtain the coupling product. The catalyst is selected from the molybdenum-quinoline complex according to claim 1.
7. The method according to claim 6, characterized in that, The allyl alcohol is selected from at least one of the compounds shown in Formula III, cinnamyl alcohol, furfuryl alcohol, 5-hydroxymethylfurfural, and 2-thiophene methanol; In Formula III, R7, R8, and R9 are independently selected from one of -H, -NO2, -F, -Cl, -Br, -I, -CF3, -CO2R, -OR, -CH2OR, -CH2R, and -C6H4R; The R in -CO2R, -OR, -CH2OR, -CH2R, and -C6H4R is selected from one of H, CH3, C2H5, C3H8, and C6H5.
8. The method according to claim 6, characterized in that, The molar ratio of the allyl alcohol to the reducing agent is 1:(0.5-5); Preferably, the molar ratio of the allyl alcohol to the catalyst is 1:(0.001~1).
9. The method according to claim 6, characterized in that, The reducing agent is selected from at least one of methanol, ethanol, isopropanol, n-butanol, 2-pentanol, 3-pentanol, 3-octanol, triphenylphosphine, trimethyl phosphite, triethyl phosphite, tributyl phosphite, triphenyl phosphite, and hydrogen.
10. The method according to claim 6, characterized in that, The deoxygenation coupling reaction is carried out at a temperature of 150–250°C for 0.5–24 hours.