Method for preparing furfuryl alcohol and isopropyl furfuryl ether by efficiently and selectively converting furfural

Abstract

The invention belongs to the field of biomass energy and chemical industry, and particularly relates to a method for preparing furfuryl alcohol and isopropyl furfuryl ether by efficiently and selectively converting furfural. A zirconium-based bifunctional catalyst containing Lewis acid-base sites and # imgabs 0 # acid sites at the same time is prepared by using a strategy of synchronous hydrothermal carbonization sulfonation and subsequent coordination, and the catalytic sequence and catalytic activity of the Lewis acid-base sites and # imgabs 1 # acid sites can be accurately changed through simple operation of adjusting reaction conditions by a system, so that the conversion path and reaction degree of furfural are controlled; finally, directional selective synthesis of furfuryl alcohol and isopropyl furfuryl ether with high additional value can be realized in the same isopropanol system, and the catalyst prepared by the method also shows excellent catalytic stability and catalytic universality in the isopropanol system.

Description

Technical Field

[0001] The invention belongs to the field of biomass energy chemical industry, and specifically relates to a zirconium-based bifunctional catalyst, a preparation method and application in the efficient and selective conversion of furfural to prepare furfuryl alcohol and isopropylfurfuryl ether. Background Art

[0002] Biomass is the most abundant and renewable green carbon source in nature. Converting it into high-value-added fine chemicals is an important way to achieve sustainable development of the chemical industry. It is also a frontier field that countries around the world are competing to develop and a hot topic in current scientific research. As we all know, furfural is an extremely important biomass-based platform compound. It can be used to prepare high-value-added furfuryl alcohol or isopropyl furfuryl ether chemicals through hydrogenation or reductive etherification reactions. As multifunctional green chemical raw materials, they are widely used in synthetic resins, solvents, coatings, dyes and fuels. Therefore, the use of furfural to prepare furfuryl alcohol and isopropyl furfuryl ether is an important way to efficiently utilize biomass resources, which is of great significance to the green and sustainable development of the chemical industry.

[0003] As we all know, furfural molecules contain both an aldehyde group and a furan ring, and their chemical properties are relatively active, and a variety of reaction products will be produced during hydrogenation and reductive etherification. Therefore, it is crucial to develop a suitable catalytic reaction system to ensure the preferential hydrogenation of the aldehyde group and avoid deep hydrogenation of the furan ring as much as possible for the selective conversion of furfural to prepare furfuryl alcohol and isopropyl furfuryl ether. At present, the most typical synthesis system of furfuryl alcohol and isopropyl furfuryl ether is an exogenous hydrogen system, which is usually composed of hydrogen, a noble metal hydrogenation reduction catalyst and an acidic dehydration etherification catalyst. However, it should be pointed out that this system still has many shortcomings: (1) The use of exogenous hydrogen as a hydrogen donor requires many precautions in its production, transportation and use, has a high risk factor, and has low atomic utilization, resulting in serious waste of resources; (2) The catalyst raw material cost is high, the production process is cumbersome, and the active site is single, resulting in poor catalytic efficiency; (3) The reaction solvents, catalyst types and optimal conditions required for furfural hydrogenation reduction and furfuryl alcohol dehydration etherification are different, and their tandem reactions have poor compatibility and are difficult to perfectly match; (4) The generation of by-products during the tandem reaction is difficult to avoid, resulting in low yield and selectivity of the final target product. Therefore, the construction of a simple, controllable, green, efficient, economical and safe directional preparation technology is of great significance for the selective synthesis of furfuryl alcohol and isopropylfurfuryl ether.

[0004] Compared with the traditional exogenous hydrogen system, the alcohol endogenous hydrogen system can realize the conversion of furfural to furfuryl alcohol by MPV transfer hydrogenation reaction without the use of exogenous hydrogen. In addition, in the alcohol endogenous hydrogen system, alcohol can be used as an etherification agent in addition to being an in-situ hydrogen donor and reaction solvent. Therefore, the alcohol endogenous hydrogen system can also be used for the conversion of furfural to isopropyl furfuryl ether in theory. However, it should be pointed out that in the alcohol endogenous hydrogen system, whether furfural is converted to furfuryl alcohol or continues to be converted to isopropyl furfuryl ether depends largely on the reaction conditions, catalyst type, and the order of action and reaction activity of the catalytic sites. In other words, in the process of selective conversion of furfural to furfuryl alcohol or isopropyl furfuryl ether in the same alcohol endogenous hydrogen system, there is a problem of difficulty in controlling the reaction conversion rate and selectivity. Summary of the invention

[0005] The technical problems to be solved by the present invention are: (1) the existing catalysts have low catalytic selectivity for the preparation of furfuryl alcohol or isopropyl furfuryl ether from furfural; (2) it is difficult to achieve precise control of the reaction path and reaction degree of furfural with the existing catalysts; (3) it is difficult to achieve selective and controllable synthesis of furfuryl alcohol and isopropyl furfuryl ether in the same reaction system with the existing catalysts. The present invention provides a catalyst having both Lewis acid-base sites and The acidic site of zirconium-based bifunctional catalyst can precisely change the Lewis acidic and basic sites by simply adjusting the reaction conditions. The catalytic order and catalytic activity of the acidic sites can control the conversion path and reaction degree of furfural, and ultimately achieve the directional and selective synthesis of furfuryl alcohol and isopropylfurfuryl ether in the same isopropanol system.

[0006] A bifunctional catalyst comprising a carbon support, and Lewis acid-base sites and Acidic sites;

[0007] The The acidic site is -SO3H;

[0008] The Lewis acid-base site is a chemical structure formed by Zr, -COOH and Ar-OH through coordination bonds. 4+ -O 2- .

[0009] The preparation method of the above-mentioned bifunctional catalyst comprises the following steps:

[0010] Step 1, adding glucose and a sulfonating agent into water to carry out hydrothermal carbonization and sulfonation reaction, and washing and drying the product to obtain sulfonated organic carbon;

[0011] Step 2, adding sulfonated organic carbon and zirconium metal salt into an organic solvent to carry out a solvothermal coordination reaction, and washing and drying the product to obtain a bifunctional catalyst.

[0012] In step 1, the sulfonating agent is one of methanesulfonic acid, chlorosulfonic acid or concentrated sulfuric acid, preferably methanesulfonic acid; the concentration of glucose in water is 50-150 g / L, the mass ratio of glucose to the sulfonating agent is 10:1-5:1, the temperature of the simultaneous hydrothermal carbonization and sulfonation reaction is 160-200°C, and the reaction time is 6-12h.

[0013] In step 2, the zirconium metal salt is one of zirconium tetrachloride, zirconium dichloride or zirconium nitrate, preferably zirconium tetrachloride; the concentration of the zirconium salt in the organic solvent is 10-15 g / L, the mass ratio of the zirconium salt to the sulfonated organic carbon is 0.5:1-2:1, the solvent thermal coordination reaction temperature is 100-160°C, and the reaction time is 12-36h.

[0014] A method for preparing furfuryl alcohol compounds or isopropyl furfuryl ether compounds from furfural compounds, comprising the following steps:

[0015] Add the above-mentioned bifunctional catalyst, furfural compound and alcohol endogenous hydrogen reagent into the reaction device;

[0016] When the target product is a furfuryl alcohol compound, a first reaction is performed to perform transfer hydrogenation;

[0017] When the target product is an isopropyl furfuryl ether compound, a second reaction is carried out to carry out transfer hydrogenation and dehydration etherification.

[0018] The furfural compound is selected from furfural, 5-methylfurfural or 5-hydroxymethylfurfural; the furfuryl alcohol compound is selected from furfuryl alcohol, 5-methylfurfuryl alcohol or 2,5-furan dimethanol; the isopropyl furfuryl ether compound is selected from isopropyl furfuryl ether, 5-methyl-2-isopropoxymethyl furan or 2,5-diisopropoxymethyl furan.

[0019] The alcohol endogenous hydrogen reagent is selected from alkyl alcohols having 1 to 4 carbon atoms.

[0020] The first reaction temperature range is 90-140° C., and the reaction time is 1-5 h. The second reaction temperature range is 150-180° C., and the reaction time is 6-14 h.

[0021] The amount of furfural used is 1-3wt% of the amount of alcohol endogenous hydrogen reagent used; the amount of zirconium-based bifunctional catalyst used is 20-100wt% of the amount of furfural used.

[0022] A method for preparing a biomass-based product compound from a biomass carbonyl compound comprises the following steps:

[0023] The above-mentioned bifunctional catalyst, biomass carbonyl compound and alcohol endogenous hydrogen reagent are added into a reaction device to react and perform transfer hydrogenation to obtain a biomass-based product compound.

[0024] The biomass carbonyl compound is selected from one of benzaldehyde, cyclohexanone, levulinic acid and methyl levulinate.

[0025] The products are benzyl alcohol, cyclohexanol, γ-valerolactone and γ-valerolactone respectively.

[0026] The reaction temperature is 110-180°C, and the reaction time is 1-15h.

[0027] Beneficial Effects

[0028] The present invention develops a "simultaneous hydrothermal carbonization and sulfonation + subsequent coordination" strategy, and uses very readily available raw materials to prepare a zirconium-based bifunctional catalyst, which has the following advantages: (1) The "simultaneous hydrothermal carbonization and sulfonation" process not only prepares a suitable catalyst carrier, but also provides a cheap organic ligand for the catalyst, and the organic ligand introduces both -COOH and Ar-OH and -SO3H; (2) The "subsequent coordination" process promotes the formation of coordination bonds between zirconium ions and -COOH and Ar-OH, which can introduce Lewis acid-base sites (Zr 4+ -O 2- ), and can better preserve Acidic site (-SO3H); (3) Lewis acid-base site and The catalytic order and catalytic activity of the acid sites can be precisely controlled; (4) Lewis acidic and basic sites can play a catalytic role under low-temperature reaction conditions, promoting the transfer hydrogenation reaction of furfural to synthesize furfuryl alcohol; Brφnsted acidic sites need to play a catalytic role under high-temperature reaction conditions, further promoting the dehydration etherification reaction of furfuryl alcohol to synthesize isopropyl furfuryl ether. In other words, the present invention can precisely change the Lewis acidic and basic sites and the activity of the acid sites by simply adjusting the reaction conditions. The catalytic order and catalytic activity of the acidic sites can control the conversion path and reaction degree of furfural, and finally the directional selective synthesis of furfuryl alcohol and isopropylfurfuryl ether can be achieved in the same isopropanol system. (5) The zirconium-based bifunctional catalyst also exhibits excellent catalytic stability and catalytic universality in the isopropanol system. It can not only be reused many times, but also can efficiently achieve the selective preparation of biomass-based products such as 5-methylfurfuryl alcohol, 5-methyl-2-isopropoxymethylfuran, 2,5-furan dimethanol, 2,5-diisopropoxymethylfuran, benzyl alcohol, cyclohexanol and γ-valerolactone, showing great application potential. (6) The raw materials of the present invention are cheap, the reaction system is simple, no exogenous hydrogen is required, the safety factor is high, and it is easy to scale up and promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is the FT-IR spectra of HC and Zr-HC prepared in Control Example 1 and Control Example 3.

[0030] Figure 2 It is the FT-IR spectra of HC-SO3H and Zr-HC-SO3H prepared in Control Example 2 and Example 1.

[0031] Figure 3 It is the GC chromatogram and MS spectrum of the selective conversion of furfural to furfuryl alcohol catalyzed by Zr-HC-SO3H in Example 3.

[0032] Figure 4 It is the GC chromatogram and MS spectrum of the selective conversion of furfural to prepare isopropyl furfurfuryl ether by Zr-HC-SO3H catalysis in Example 6. DETAILED DESCRIPTION

[0033] The technical concept of the present invention is to prepare a novel oligomer having rich Lewis acid-base sites and The acidic sites of zirconium-based bifunctional catalysts can be controlled by controlling the reaction conditions to regulate Lewis acidic and basic sites and The catalytic order and catalytic activity of the acidic sites can then control the conversion path and reaction degree of furfural, and ultimately achieve the directional and selective synthesis of furfuryl alcohol and isopropylfurfuryl ether in the same isopropanol system. 4+ -O 2- It is a Lewis acid-base site, which can play a catalytic role under mild reaction conditions to promote the transfer hydrogenation reaction of furfural to synthesize furfuryl alcohol; -SO3H is Acidic sites require drastic reaction conditions to play a catalytic role, and then Lewis acid and alkaline sites are catalyzed to obtain furfuryl alcohol, which is further dehydrated and etherified to convert it into isopropyl furfuryl ether.

[0034] In the specific implementation process of the present invention, the method for preparing furfuryl alcohol and isopropyl furfuryl ether by efficient and selective conversion of furfural comprises the following steps:

[0035] Step 1: A zirconium-based bifunctional catalyst containing both Lewis acidic and basic sites and Brφnsted acidic sites was prepared using the “simultaneous hydrothermal carbonization and sulfonation + subsequent coordination” strategy;

[0036] Step 2, placing the zirconium-based bifunctional catalyst, isopropanol and furfural in a reaction kettle, and replacing the air in the kettle with nitrogen;

[0037] Step 3: Under low temperature reaction conditions, the Lewis acid-base sites of the zirconium-based bifunctional catalyst play a catalytic role, and furfural undergoes transfer hydrogenation to obtain furfuryl alcohol;

[0038] In the fourth step, under high temperature reaction conditions, the Lewis acid-base sites and the Brφnsted acid sites of the zirconium-based bifunctional catalyst successively play a catalytic role, and furfural undergoes transfer hydrogenation and dehydration etherification reaction to obtain isopropyl furfural ether.

[0039] The preparation method of the catalyst in the first step comprises the following steps: adding glucose and a sulfonating agent to water in a certain proportion, performing simultaneous hydrothermal carbonization and sulfonation reaction after complete mixing and dissolving, and obtaining sulfonated organic carbon after the generated precipitated product is fully washed and dried; adding sulfonated organic carbon and zirconium metal salt to dimethylformamide in a certain proportion, performing solvothermal coordination reaction after ultrasonic dispersion, and obtaining a zirconium-based bifunctional catalyst after the generated precipitated product is fully washed and dried.

[0040] The sulfonating agent is one of methanesulfonic acid, chlorosulfonic acid or concentrated sulfuric acid, preferably methanesulfonic acid; the concentration of glucose in water is 50-150 g / L, the mass ratio of glucose to the sulfonating agent is 10:1-5:1, the temperature of the simultaneous hydrothermal carbonization and sulfonation reaction is 160-200°C, and the reaction time is 6-12 hours.

[0041] The zirconium metal salt is one of zirconium tetrachloride, zirconium dichloride or zirconium nitrate, preferably zirconium tetrachloride; the concentration of the zirconium salt in dimethylformamide is 10-15 g / L, the mass ratio of the zirconium salt to the sulfonated organic carbon is 0.5:1-2:1, the solvent thermal coordination reaction temperature is 100-160°C, and the reaction time is 12-36h.

[0042] The isopropanol in the second step can be used as a reaction solvent, an in-situ hydrogen donor and an etherification agent at the same time; the amount of furfural used is 1-3wt% of the amount of isopropanol used; and the amount of the zirconium-based bifunctional catalyst used is 20-100wt% of the amount of furfural used.

[0043] The reaction temperature in the third step is 90-140° C., and the reaction time is 1-5 h.

[0044] The reaction temperature in the fourth step is 150-180° C., and the reaction time is 6-14 h.

[0045] Application of zirconium-based bifunctional catalysts in the selective and controllable conversion of biomass carbonyl compounds.

[0046] The biomass carbonyl compound is selected from 5-methylfurfural, 5-hydroxymethylfurfural, benzaldehyde, cyclohexanone, levulinic acid and methyl levulinate.

[0047] Comparative Example 1

[0048] 15g of glucose was added to 150mL of deionized water to dissolve, stirred and mixed evenly, and then transferred to a reactor for hydrothermal carbonization reaction at 180℃ for 10h to generate a solid precipitate; the solid precipitate was filtered and separated, and then repeatedly washed with anhydrous ethanol and deionized water until the filtrate was clear; the washed solid precipitate was placed in a vacuum drying oven and dried at 80℃ for 12h to obtain HC. FT-IR characterization analysis showed that ( Figure 1 ), 1701cm -1 The stretching vibration peak attributed to the C=O bond is 3436 cm -1 The stretching vibration peaks attributed to the OH bond indicate that the HC obtained by the hydrothermal carbonization process successfully introduced -COOH and Ar-OH. Acidic sites.

[0049] Next, 0.25 g furfural, 19.75 g isopropanol and 0.1 g HC were added to a 100 mL reactor, which was sealed and placed in a heating furnace. The temperature was raised to 120 °C at a stirring speed of 400 rpm. After 2 h of reaction, the conversion rate of furfural was only 1.3%, and the yields of furfuryl alcohol, furfural diisopropyl acetal and isopropyl furfuryl ether were all 0, which indicated that the weaker The acidic sites cannot effectively catalyze the transfer hydrogenation, acetalization or dehydration etherification reactions of furfural.

[0050] Comparative Example 2

[0051] 15g glucose and 2g methanesulfonic acid were added to 150mL deionized water to dissolve, stirred and mixed evenly, and then transferred to a reactor for simultaneous hydrothermal carbonization and sulfonation reaction at 180℃ for 10h to generate a solid precipitate; the solid precipitate was filtered and separated, and then repeatedly washed with anhydrous ethanol and deionized water until no sulfonate ions were detected; the washed solid precipitate was placed in a vacuum drying oven and dried at 80℃ for 12h to obtain HC-SO3H. After FT-IR characterization analysis, it was found that ( Figure 2 ), 536cm -1 The stretching vibration peak attributed to the CS bond is 1202 cm -1 The stretching vibration peak attributed to the O=S=O bond is 1705 cm -1 The stretching vibration peak attributed to the C=O bond is 3426 cm -1 The stretching vibration peaks attributed to the OH bond indicate that -COOH, Ar-OH and -SO3H were successfully introduced into HC-SO3H obtained by the simultaneous hydrothermal carbonization and sulfonation process. Acidic sites.

[0052] Next, 0.25 g furfural, 19.75 g isopropanol and 0.1 g HC-SO3H were added to a 100 mL reactor, which was sealed and placed in a heating furnace. The temperature was raised to 120 °C at a stirring speed of 400 rpm. After 2 h of reaction, the conversion rate of furfural was only 2.7%, and the yields of furfuryl alcohol, furfural diisopropyl acetal and isopropyl furfuryl ether were all 0, which indicated that the pure stronger The acidic sites also cannot effectively catalyze the transfer hydrogenation, acetalization or dehydration etherification reactions of furfural.

[0053] Comparative Example 3

[0054] 2g of HC in Control Example 1 and 2g of zirconium tetrachloride were added to 160mL of dimethylformamide, and then evenly dispersed by ultrasonic stirring. Then, the mixture was transferred into a reactor and subjected to solvent thermal coordination reaction at 120°C for 24h to generate a solid precipitate. After the solid precipitate was separated by filtration, it was repeatedly washed with anhydrous ethanol and deionized water until no chloride ions were detected. The washed solid precipitate was placed in a vacuum drying oven for drying at 80°C for 12h to obtain Zr-HC. FT-IR characterization analysis showed that ( Figure 1 ), compared with HC, 1701cm -1 The stretching vibration peak of C=O bond at 3436cm -1 The stretching vibration peak intensity of the OH bond at 460cm -1 647cm -1 The stretching vibration peak of the Zr-O bond also appeared, which indicates that the Zr-HC obtained by the solvothermal coordination process successfully introduced abundant Lewis acid-base sites.

[0055] Next, 0.25 g furfural, 19.75 g isopropanol and 0.1 g Zr-HC were added to a 100 mL reactor, which was sealed and placed in a heating furnace. The temperature was raised to 120 ° C at a stirring speed of 400 rpm. After 2 h of reaction, the conversion rate of furfural was 87.4%, the yield of furfuryl alcohol was 84.1%, the yield of furfural diisopropyl acetal was 0, and the yield of isopropyl furfuryl ether was 0, which showed that in the absence of In the case of acidic sites, the main function of the Lewis acid-base site is to promote the transfer hydrogenation reaction of furfural to produce furfuryl alcohol.

[0056] Comparative Example 4

[0057] 0.25 g furfural, 19.75 g isopropanol and 0.1 g Zr-HC (Comparative Example 3) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 130° C. at a stirring speed of 400 rpm. After reacting for 2 h, the conversion rate of furfural was 98.9%, the yield of furfuryl alcohol was 97.3%, the yield of furfural diisopropyl acetal was 0, and the yield of isopropyl furfuryl ether was 0, which indicated that in the absence of In the case of acidic sites, appropriately increasing the reaction temperature can help improve the catalytic performance of Lewis acid-base sites.

[0058] Comparative Example 5

[0059] 0.25 g furfural, 19.75 g isopropanol and 0.1 g Zr-HC (Comparative Example 3) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 140° C. at a stirring speed of 400 rpm. After reacting for 2 h, the conversion rate of furfural was 100.0%, the yield of furfuryl alcohol was 98.4%, the yield of furfural diisopropyl acetal was 0, and the yield of isopropyl furfuryl ether was only 0.5%, which further illustrates that in the absence of In the case of acidic sites, the main function of the Lewis acid-base site is to promote the transfer hydrogenation reaction of furfural to produce furfuryl alcohol, but it is basically ineffective for the acetalization reaction of furfural and the further dehydration etherification of furfuryl alcohol to synthesize isopropyl furfuryl ether.

[0060] Example 1

[0061] 2g HC-SO3H and 2g zirconium tetrachloride in control example 2 were added to 160mL dimethylformamide, and then transferred into a reactor after being dispersed uniformly by ultrasonic stirring. The solvent thermal coordination reaction was carried out at 120°C for 24h to generate a solid precipitate. The solid precipitate was filtered and separated, and then repeatedly washed with anhydrous ethanol and deionized water until no chloride ions were detected. The washed solid precipitate was placed in a vacuum drying oven for drying at 80°C for 12h to obtain Zr-HC-SO3H. FT-IR characterization analysis showed that ( Figure 2 ), compared with HC-SO3H, 1705cm -1 The stretching vibration peak of C=O bond at 3426cm -1 The stretching vibration peak intensity of the OH bond at 649 cm -1 The stretching vibration peak of Zr-O bond also appeared at 536cm -1 The stretching vibration peak of the CS bond at 1202 cm -1 The stretching vibration peak of the O=S=O bond at the position of Zr-HC-SO3H remains intact, which indicates that the Zr-HC-SO3H obtained by the solvothermal coordination process retains Acidic sites were also successfully introduced into the Lewis acid-base sites.

[0062] Next, 0.25 g furfural, 19.75 g isopropanol and 0.1 g Zr-HC-SO3H were added to a 100 mL reactor, which was sealed and placed in a heating furnace. The temperature was raised to 120 °C at a stirring speed of 400 rpm. After 2 h of reaction, the conversion rate of furfural was 83.3%, the yield of furfuryl alcohol was 77.6%, the yield of furfural diisopropyl acetal was 0, and the yield of isopropyl furfuryl ether was 0, which indicated that the Lewis acid-base site and When acidic sites exist at the same time and the reaction temperature is mild, Lewis acid-base sites will first play a catalytic role, promoting the transfer hydrogenation reaction of furfural to produce furfuryl alcohol. In other words, Lewis acid-base sites can play a catalytic role at mild reaction temperatures. The acidic sites did not play a catalytic role at mild reaction temperatures, which also indicates that the transfer hydrogenation of furfural to produce furfuryl alcohol is easier than the acetalization reaction of furfural and the dehydration etherification of furfuryl alcohol to produce isopropyl furfuryl ether.

[0063] Example 2

[0064] 0.25 g furfural, 19.75 g isopropanol and 0.1 g Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 120° C. at a stirring speed of 400 rpm. After reacting for 4 h, the conversion rate of furfural was 97.7%, the yield of furfuryl alcohol was 94.6%, the yield of furfural diisopropyl acetal was 0, and the yield of isopropyl furfuryl ether was 0, which indicated that the Lewis acid-base site and When acidic sites exist at the same time and the reaction temperature is mild, appropriately extending the reaction time can improve the catalytic performance of Lewis acid-base sites, but it cannot improve Catalytic properties of acidic sites.

[0065] Example 3

[0066] 0.25 g furfural, 19.75 g isopropanol and 0.125 g Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 120° C. at a stirring speed of 400 rpm. After reacting for 4 h, the conversion rate of furfural was 100.0%, and the yield and selectivity of furfuryl alcohol were 98.9% ( Figure 3 ), which shows that Zr-HC-SO3H has excellent catalytic activity (Table 1). Under mild and appropriate reaction conditions, only Lewis acid-base sites can be regulated to play a catalytic role. The acidic sites remain silent, allowing only the transfer hydrogenation reaction of furfural to selectively synthesize furfuryl alcohol. More importantly, when Zr-HC-SO3H was reused five times under the same reaction conditions, the conversion rate of furfural could still reach 100.0%, and the yield and selectivity of furfuryl alcohol could also reach 97.1%, indicating that Zr-HC-SO3H exhibits good catalytic stability.

[0067] Table 1

[0068]

[0069] Example 4

[0070] 0.25 g furfural, 19.75 g isopropanol and 0.1 g Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 140° C. at a stirring speed of 400 rpm. After reacting for 2 h, the conversion rate of furfural was 100.0%, the yield of furfuryl alcohol was 88.5%, the yield of isopropyl furfuryl ether was 9.2%, and the yield of furfural diisopropyl acetal was 0, which indicated that the Lewis acid-base site and When acidic sites exist simultaneously, The acidic sites need to play a catalytic role at a higher reaction temperature, and then the furfuryl alcohol catalyzed by the Lewis acid-base sites is further dehydrated and etherified to be converted into isopropyl furfuryl ether. In other words, The main function of the acidic site is to promote the dehydration etherification of furfuryl alcohol into isopropyl furfuryl ether, which is more difficult than the Lewis acid-base site-catalyzed transfer hydrogenation reaction of furfural to produce furfuryl alcohol.

[0071] Example 5

[0072] 0.25 g furfural, 19.75 g isopropanol and 0.15 g Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 170° C. at a stirring speed of 400 rpm. After reacting for 10 h, the conversion rate of furfural was 100.0%, the yield of furfuryl alcohol was 20.2%, the yield of isopropyl furfuryl ether was 79.5%, and the yield of furfural diisopropyl acetal was 0. This shows that increasing the reaction temperature, extending the reaction time, and increasing the amount of catalyst can greatly increase the Lewis acid-base site and The catalytic performance of the acidic site increases the synergistic effect between the two and improves the yield of the target product. In addition, this example further illustrates that isopropyl furfural ether is formed by dehydration etherification of furfuryl alcohol, that is, the formation of isopropyl furfural ether requires furfural to first generate furfuryl alcohol, and furfuryl alcohol is further converted.

[0073] Example 6

[0074] 0.25 g furfural, 19.75 g isopropanol and 0.2 g Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 170° C. at a stirring speed of 400 rpm. After reacting for 12 h, the conversion rate of furfural was 100.0%, the yield of furfuryl alcohol was 0, the yield of furfural diisopropyl acetal was 0, and the yield of isopropyl furfuryl ether was 95.1% ( Figure 4 ), which is significantly better than the results reported for existing catalysts (Table 2), indicating that Under the sequential and synergistic effects of acidic sites, furfural can be efficiently converted into isopropyl furfural ether. In addition, this example also shows that the Lewis acid-base sites and The catalytic order and catalytic activity of the acidic sites can control the conversion path of furfural and finally achieve the selective synthesis of different target products. More importantly, when Zr-HC-SO3H was reused 5 times under the same reaction conditions, the conversion rate of furfural can still reach 100.0%, and the yield and selectivity of isopropyl furfuryl ether can also reach 93.7%, which further shows that Zr-HC-SO3H exhibits good catalytic stability.

[0075] Table 2

[0076]

[0077]

[0078] In order to further demonstrate the effectiveness and adjustability of Zr-HC-SO3H, the present invention also studied the catalytic universality of Zr-HC-SO3H in Example 1 using biomass carbonyl compounds such as 5-methylfurfural, 5-hydroxymethylfurfural, benzaldehyde, cyclohexanone, levulinic acid and methyl levulinate as substrates. The specific results are shown in Examples 7-14.

[0079] Example 7

[0080] 0.25 g of 5-methylfurfural, 19.75 g of isopropanol and 0.125 g of Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 110° C. at a stirring speed of 400 rpm. After reacting for 6 hours, the conversion rate of 5-methylfurfural was 100.0%, and the yield and selectivity of 5-methylfurfuryl alcohol were 97.7%.

[0081] Example 8

[0082] 0.25 g of 5-methylfurfural, 19.75 g of isopropanol and 0.2 g of Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 170° C. at a stirring speed of 400 rpm. After reacting for 12 hours, the conversion rate of 5-methylfurfural was 100.0%, and the yield and selectivity of 5-methyl-2-isopropoxymethylfuran were 98.4%.

[0083] Example 9

[0084] 0.25 g of 5-hydroxymethylfurfural, 19.75 g of isopropanol and 0.125 g of Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 110° C. at a stirring speed of 400 rpm. After reacting for 8 hours, the conversion rate of 5-hydroxymethylfurfural was 100.0%, and the yield and selectivity of 2,5-furan dimethanol were 96.9%.

[0085] Example 10

[0086] 0.25 g of 5-hydroxymethylfurfural, 19.75 g of isopropanol and 0.2 g of Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 170° C. at a stirring speed of 400 rpm. After reacting for 12 hours, the conversion rate of 5-hydroxymethylfurfural was 100.0%, and the yield and selectivity of 2,5-diisopropoxymethylfuran were 95.7%.

[0087] Embodiment 11

[0088] 0.25 g of benzaldehyde, 19.75 g of isopropanol and 0.125 g of Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 120° C. at a stirring speed of 400 rpm. After reacting for 4 hours, the conversion rate of benzaldehyde was 100.0%, and the yield and selectivity of benzyl alcohol were 99.9%.

[0089] Example 12

[0090] 0.25 g of cyclohexanone, 19.75 g of isopropanol and 0.2 g of Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 170° C. at a stirring speed of 400 rpm. After reacting for 12 hours, the conversion rate of cyclohexanone was 100.0%, and the yield and selectivity of cyclohexanol were 98.5%.

[0091] Example 13

[0092] 0.25 g of levulinic acid, 19.75 g of isopropanol and 0.2 g of Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 170° C. at a stirring speed of 400 rpm. After reacting for 12 hours, the conversion rate of levulinic acid was 100.0%, and the yield and selectivity of γ-valerolactone were 98.3%.

[0093] Embodiment 14

[0094] 0.25 g of methyl levulinate, 19.75 g of isopropanol and 0.2 g of Zr-HC-SO3H (Example 1) were added to a 100 mL reactor, which was sealed and placed in a heating furnace; the temperature was raised to 170° C. at a stirring speed of 400 rpm. After reacting for 12 h, the conversion rate of methyl levulinate was 100.0%, and the yield and selectivity of γ-valerolactone were 97.2%.

[0095] It can be seen from Examples 3, 6 and 7-14 that the Zr-HC-SO3H prepared by the "simultaneous hydrothermal carbonization sulfonation + subsequent coordination" strategy can not only efficiently catalyze the selective conversion of furfural into furfuryl alcohol and isopropylfurfuryl ether, but also efficiently catalyze the conversion of a variety of biomass carbonyl compounds into corresponding high value-added products, demonstrating excellent catalytic universality.

[0096] References:

[0097] [1]ChemSusChem,2017,18:1761-1770.

[0098] [2]Applied Catalysis A:General,2020,602:117719.

[0099] [3]Journal of Energy Chemistry,2022,71:411-417.

[0100] [4]ChemCatChem,2017,10:430-438.

[0101] [5] Fuel, 2023, 331: 125834.

[0102] [6]Catalysis Science&Technology,2018,8:790-797.

[0103] [7]Chemistry-An Asian Journal,2021,16:3194-3201.

[0104] [8]ACS Sustainable Chemistry&Engineering,2017,5:942-947.

[0105] [9]New Journal of Chemistry,2020,44:478-486.

[0106]

[10] Applied Catalysis B:Environmental,2021,298:120575.

[0107]

[11] International Journal of Molecular Sciences,2019,20:828.

[0108]

[12] Molecular Catalysis,2024,559:114093.

[0109]

[13] Chemical Engineering Journal,2024,486:50350.

[0110]

[14] Renewable Energy,2023,212:468-477.

[0111]

[15] Fuel,2024,359:130380。

Claims

1. A bifunctional catalyst, characterized in that: The carbon support includes Lewis acid-base sites and Acidic site; The acidic site is -SO3H; the Lewis acid-base site is the chemical structure Zr formed by Zr, -COOH and Ar-OH through coordination bonds. 4+ -O 2- .

2. The method for preparing the bifunctional catalyst according to claim 1, characterized in that: The steps include: Step 1, adding glucose and a sulfonating agent into water to carry out hydrothermal carbonization and sulfonation reaction, and washing and drying the product to obtain sulfonated organic carbon; Step 2, adding sulfonated organic carbon and zirconium metal salt into an organic solvent to carry out a solvothermal coordination reaction, and washing and drying the product to obtain a bifunctional catalyst.

3. The method for preparing a bifunctional catalyst according to claim 1, characterized in that: In step 1, the sulfonating agent is one of methanesulfonic acid, chlorosulfonic acid or concentrated sulfuric acid, preferably methanesulfonic acid; the concentration of glucose in water is 50-150 g / L, the mass ratio of glucose to the sulfonating agent is 10:1-5:1, the temperature of the simultaneous hydrothermal carbonization and sulfonation reaction is 160-200°C, and the reaction time is 6-12h.

4. The method for preparing a bifunctional catalyst according to claim 1, characterized in that: In step 2, the zirconium metal salt is one of zirconium tetrachloride, zirconium dichloride or zirconium nitrate, preferably zirconium tetrachloride; the concentration of the zirconium salt in the organic solvent is 10-15 g / L, the mass ratio of the zirconium salt to the sulfonated organic carbon is 0.5:1-2:1, the solvent thermal coordination reaction temperature is 100-160°C, and the reaction time is 12-36h.

5. A method for preparing furfuryl alcohol compounds or isopropyl furfuryl ether compounds from furfural compounds, characterized in that: The steps include: Adding the bifunctional catalyst as claimed in claim 1, a furfural compound, and an alcohol endogenous hydrogen reagent into a reaction device; When the target product is a furfuryl alcohol compound, a first reaction is performed to perform transfer hydrogenation; When the target product is an isopropyl furfuryl ether compound, a second reaction is carried out to carry out transfer hydrogenation and dehydration etherification.

6. The method according to claim 5, characterized in that The furfural compound is selected from furfural, 5-methylfurfural or 5-hydroxymethylfurfural; the furfuryl alcohol compound is selected from furfuryl alcohol, 5-methylfurfuryl alcohol or 2,5-furan dimethanol; the isopropyl furfuryl ether compound is selected from isopropyl furfuryl ether, 5-methyl-2-isopropoxymethyl furan or 2,5-diisopropoxymethyl furan.

7. The method according to claim 5, characterized in that The alcohol endogenous hydrogen reagent is selected from alkyl alcohols having 1 to 4 carbon atoms.

8. The method according to claim 5, characterized in that The first reaction temperature range is 90-140°C, and the reaction time is 1-5h. The second reaction temperature range is 150-180°C, and the reaction time is 6-14h.

9. The method according to claim 5, characterized in that The amount of furfural used is 1-3wt% of the amount of alcohol endogenous hydrogen reagent used; the amount of zirconium-based bifunctional catalyst used is 20-100wt% of the amount of furfural used.

10. A method for preparing a biomass-based product compound from a biomass carbonyl compound, characterized in that: The steps include: The above-mentioned bifunctional catalyst, biomass carbonyl compound and alcohol endogenous hydrogen reagent are added into a reaction device for reaction, and transfer hydrogenation is performed to obtain a biomass-based product compound; the biomass carbonyl compound is selected from one of benzaldehyde, cyclohexanone, levulinic acid and methyl levulinate; the products are benzyl alcohol, cyclohexanol, γ-valerolactone and γ-valerolactone respectively.

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