An sba-15 supported phosphorus solid acid catalyst for continuously synthesizing furfural acetal and a preparation method thereof

Abstract

The application discloses an SBA-15 supported phosphorus solid acid catalyst for continuously synthesizing furfural acetal and a preparation method thereof, and belongs to the technical field of catalysts. In the application, mesoporous SBA-15 molecular sieves are used as carriers, and an equal-volume impregnation method is used to load phosphorus species; the silicon-based skeleton of the SBA-15 has good thermal stability and mechanical strength, and provides a stable carrier framework for the catalyst; and the loaded phosphorus species is firmly anchored to the inner wall of the pore through chemical bonding with the silicon hydroxyl on the surface of the molecular sieves, effectively preventing the loss or aggregation of the active component in the continuous reaction process, so that the conversion rate, selectivity and stability of the catalyst in the reaction of synthesizing furfural 1,2-propanediol acetal from furfural and 1,2-propanediol are remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, and particularly relates to an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal and its preparation method. Background Technology

[0002] Furfural 1,2-Propylene Glycol Acetal is mainly composed of a mixture of isomers of 2-furan-4-methyl-1,3-dioxolane. It is a colorless to pale yellow transparent liquid with no fixed CAS number and a molecular formula of C8H10. 10 O3. Furfural 1,2-propanediol acetal has a pleasant, mild, and long-lasting aroma of nuts, bread, coffee, and caramel, with a certain fruity note. Its aroma is milder and more stable than furfural itself, with significantly reduced irritation, and it is widely used in food and tobacco flavorings. Its acetal structure can hydrolyze under certain conditions (such as acidic aqueous solutions), releasing furfural back into the form. Therefore, it is sometimes used as a "protective" form of furfural in synthesis to control reactivity or improve stability. Traditionally, furfural 1,2-propanediol acetal is prepared using an acid-catalyzed synthesis process. Specifically, strong acids such as sulfuric acid and hydrochloric acid are used as catalysts, and furfural is synthesized with 1,2-propanediol through an acetalization reaction. In this reaction, the strong acid catalyst provides protons to activate the carbonyl group of furfural, lowering the activation energy and promoting the condensation of the hydroxyl group in the 1,2-propanediol molecule with the carbonyl group of furfural, ultimately forming furfural 1,2-propanediol acetal. This method is a mature technology, but it suffers from a series of problems, including highly corrosive catalysts, difficulty in product separation, numerous side reactions (such as dehydration and carbonization), and environmental pollution. Furthermore, traditional processes often employ batch reaction modes, making catalyst recovery and reuse difficult, resulting in low reaction efficiency and hindering continuous, large-scale production, thus limiting its widespread industrial application.

[0003] Supported catalysts are a type of heterogeneous catalyst in which the active components are uniformly dispersed and immobilized on a support. Their core advantage lies in optimizing the dispersibility, stability, and mechanical strength of the active components through the support's support function, leading to their widespread application in industrial catalysis, energy, and environmental protection. Previously used aluminum phosphate catalysts are inorganic functional materials based on aluminum and phosphorus elements. Due to their unique acidic characteristics, they exhibit high activity and selectivity in chemical reactions. However, these catalysts have the following drawbacks: firstly, their microporous structure limits the diffusion efficiency of reactants; secondly, at high temperatures, the active components tend to agglomerate, causing a decrease in specific surface area. Therefore, how to further improve the diffusion efficiency of reactants while avoiding catalyst agglomeration at high temperatures, thereby improving furfural conversion rate, has become a pressing technical problem to be solved in this field. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal and its preparation method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal, comprising the following steps: (1) The template agent solution was mixed with the silicon source, and after stirring, baking, drying and first calcination, mesoporous SBA-15 molecular sieve was obtained; (2) The mesoporous SBA-15 molecular sieve is immersed in an aqueous solution containing phosphorus compounds, and after standing, drying and second calcination, the SBA-15 supported phosphorus solid acid catalyst (P / SBA-15) for continuous synthesis of furfural acetal is obtained.

[0006] Further, in step (1), the mass ratio of template agent to silicon source in the template agent solution is 8:17.

[0007] Further, in step (1), the template agent is selected from P123; the silicon source is selected from tetraethyl orthosilicate.

[0008] Furthermore, in step (1), the stirring temperature is 40°C and the stirring time is 24 hours; The baking temperature is 90~100℃, and the time is 24 hours; The drying temperature is 100°C; The first calcination temperature was 500℃ and the time was 6 hours.

[0009] Further, in step (2), the phosphorus-containing compound in the aqueous solution of the phosphorus-containing compound is selected from one or more of phosphoric acid, ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

[0010] Furthermore, in step (2), the mass ratio of the mesoporous SBA-15 molecular sieve to the phosphorus-containing compound in the aqueous solution of the phosphorus-containing compound is 1: (0.08~0.3).

[0011] Furthermore, in step (2), the second calcination temperature is 450~600℃, the time is 6~8h, and the heating rate is 1~2℃ / min.

[0012] Further, in step (2), the phosphorus loading in the SBA-15 supported phosphorus solid acid catalyst used for the continuous synthesis of furfural acetal is 5-18%, based on the mass fraction of phosphorus pentoxide on the mesoporous SBA-15 molecular sieve.

[0013] This invention provides an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal, which is prepared according to the preparation method described in the above technical solution.

[0014] The present invention also provides the application of the SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal as described above in the catalytic furfural acetalization reaction to prepare furfural acetal.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: This invention uses mesoporous SBA-15 molecular sieve as a support and employs an equal-volume impregnation method to load phosphorus species. The silicon-based framework of SBA-15 has good thermal stability and mechanical strength, providing a stable support framework for the catalyst. The loaded phosphorus species are firmly anchored to the inner wall of the pores through chemical bonding with the silanol groups on the surface of the molecular sieve, effectively preventing the loss or aggregation of active components during continuous reaction. This significantly improves the conversion rate, selectivity, and stability of the catalyst in the acetalization reaction of furfural and 1,2-propanediol to furfural 1,2-propanediol acetal.

[0016] This invention uses furfural and 1,2-propanediol as raw materials and employs a P / SBA-15 solid acid catalyst with phosphorus species supported on mesoporous SBA-15 to synthesize the target product furfural 1,2-propanediol acetal in an atmospheric pressure fixed-bed reactor. This improves the catalytic performance of the catalyst, enhances its environmental friendliness and stability, and enables continuous production, thereby improving the efficiency and controllability of industrial synthesis. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 Small-angle XRD patterns of SBA-15 and SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6; Figure 2 Wide-angle XRD spectra of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6; Figure 3 NH3-TPD spectra of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6; Figure 4 SEM image of SBA-15; Figure 5 SEM image of the 5% P / SBA-15 catalyst prepared in Example 2; Figure 6 SEM image of the 8% P / SBA-15 catalyst prepared in Example 3; Figure 7 SEM image of the 10% P / SBA-15 catalyst prepared in Example 4; Figure 8 SEM image of the 12% P / SBA-15 catalyst prepared in Example 1; Figure 9 SEM image of the 15% P / SBA-15 catalyst prepared in Example 5; Figure 10 SEM image of the 18% P / SBA-15 catalyst prepared in Example 6; Figure 11 EDS energy spectrum of phosphorus in the 12% P / SBA-15 catalyst prepared in Example 1; Figure 12 N2 low-temperature adsorption-desorption curves of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6; Figure 13 BJH pore size distribution of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6; Figure 14 The catalytic performance of the 12% P / SBA-15 catalyst prepared in Example 1 at different reaction space velocities was evaluated, wherein C Furfural S represents furfural conversion rate. Acetal This indicates the selectivity of furfural 1,2-propanediol acetal; Figure 15 The stability results for the 12% P / SBA-15 catalyst prepared in Example 1 are shown, where C Furfural S represents furfural conversion rate. Acetal S represents the selectivity of furfural-1,2-propanediol acetal. Others It indicates selectivity for other substances. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] This invention provides a method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal, comprising the following steps: (1) The template agent solution was mixed with the silicon source, and after stirring, baking, drying and first calcination, mesoporous SBA-15 molecular sieve was obtained; (2) The mesoporous SBA-15 molecular sieve is immersed in an aqueous solution containing phosphorus compounds, and after standing, drying and second calcination, the SBA-15 supported phosphorus solid acid catalyst for continuous synthesis of furfural acetal is obtained.

[0021] In a preferred embodiment, in step (1), the mass ratio of the template agent to the silicon source in the template agent solution is 8:17; the template agent is selected from P123; and the silicon source is selected from tetraethyl orthosilicate. This invention uses P123 as a template for an amphiphilic block copolymer, which can guide the formation of a highly ordered, uniformly sized, and thick-walled two-dimensional hexagonal mesoporous structure. Tetraethyl orthosilicate is used as the silicon source, with a moderate hydrolysis-condensation rate and mild interaction with P123, facilitating precise control of the material's structure and morphology. SBA-15 is a typical two-dimensional hexagonal mesoporous molecular sieve material. Its unique structure is formed by a hydrothermal crystallization synthesis process using triblock copolymer P123 as a template agent. This material possesses a highly ordered hexagonal pore structure, and the pore size can be precisely controlled within the range of 5~30 nm. This characteristic allows it to completely overcome the diffusion limitations of traditional microporous materials. SBA-15's large pore size allows for the free diffusion of macromolecular reactants, and its high specific surface area provides dispersion anchoring points for active components. Meanwhile, the thick pore wall structure enhances the material's hydrothermal stability, ensuring that the pore framework remains intact under high temperature or high pressure reaction conditions, thus avoiding performance degradation due to structural collapse.

[0022] In a preferred embodiment, in step (1), the stirring temperature is 40°C and the time is 24 hours; In a preferred embodiment, in step (1), the baking temperature is 90~100℃ and the time is 24h.

[0023] In a preferred embodiment, the drying temperature in step (1) is 100°C.

[0024] In a preferred embodiment, in step (1), the temperature of the first calcination is 500°C and the time is 6 hours. This invention completely removes the template agent through the first calcination, forming an SBA-15 molecular sieve with an ordered mesoporous structure, providing a high specific surface area carrier.

[0025] In a preferred embodiment, in step (2), the phosphorus-containing compound in the aqueous solution of the phosphorus-containing compound is selected from one or more of phosphoric acid, ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

[0026] In a preferred embodiment, in step (2), the mass ratio of the mesoporous SBA-15 molecular sieve to the phosphorus-containing compound in the aqueous solution is 1:(0.08~0.3); the ratio of the phosphorus-containing compound to water in the aqueous solution is (0.08~0.3) g:(6~8) mL. The present invention uses an equal-volume impregnation method to support phosphorus species, and the prepared P / SBA-15 catalyst exhibits high conversion rate, selectivity, and excellent stability in the acetalization reaction of furfural and 1,2-propanediol to furfural 1,2-propanediol acetal.

[0027] In a preferred embodiment, in step (2), the second calcination temperature is 450~600℃, the time is 6~8h, and the heating rate is 1~2℃ / min.

[0028] In a preferred embodiment, in step (2), the phosphorus loading in the SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal is 5-18%, more preferably 5-12%, based on the mass fraction of phosphorus pentoxide on the mesoporous SBA-15 molecular sieve. Phosphorus species loading is a key parameter for regulating catalyst performance, significantly affecting the catalyst's acidity / basicity, thermal stability, and the activity and selectivity of the target reaction. This invention, by controlling the phosphorus loading, enables the catalyst to exhibit excellent catalytic performance.

[0029] This invention provides an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal, which is prepared according to the preparation method described in the above technical solution.

[0030] The present invention also provides the application of the SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal as described above in the catalytic furfural acetalization reaction to prepare furfural acetal.

[0031] In this embodiment of the invention, room temperature refers to "25±2℃".

[0032] Unless otherwise specified, all raw materials used in the embodiments of this invention were purchased through commercial channels.

[0033] In the following examples, the preparation method of SBA-15 is as follows: 16 g of P123 was dissolved in 480 mL of 2 mol / L hydrochloric acid solution and stirred continuously at 40 °C for 3 h until the solution became clear and transparent. Then, 34 g of tetraethyl orthosilicate was slowly added dropwise to the solution, and stirring was continued at 40 °C for 24 h. After stirring, the mixture was transferred to a polytetrafluoroethylene bottle and baked in a 90 °C oven for 24 h. After baking, it was removed, cooled to room temperature, and then filtered. The filter cake was dried into powder at 100 °C, and finally calcined in air at a heating rate of 2 °C / min to 500 °C for 6 h to obtain SBA-15 powder.

[0034] Example 1 A method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal, comprising the following steps: Weigh 0.195 g of ammonium dihydrogen phosphate and add it to 6-8 mL of deionized water. Stir at room temperature until completely dissolved to obtain an ammonium dihydrogen phosphate solution. Then weigh 1 g of SBA-15 powder and add it to the above ammonium dihydrogen phosphate solution. Seal and let stand at 30 °C for 12 h to allow the active component to fully diffuse and become uniform. Then slowly dry the solution at 65 °C. After drying, heat it to 500 °C at a heating rate of 2 °C / min and calcine it at this temperature for 6 h to obtain the SBA-15 supported phosphorus solid acid catalyst, denoted as 12%P / SBA-15.

[0035] Example 2 A method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal differs from Example 1 only in that 0.081 g of ammonium dihydrogen phosphate is weighed and added to 6-8 mL of deionized water, and the resulting catalyst is denoted as 5%P / SBA-15.

[0036] Example 3 A method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal differs from Example 1 only in that 0.129 g of ammonium dihydrogen phosphate is weighed and added to 6-8 mL of deionized water, and the resulting catalyst is denoted as 8%P / SBA-15.

[0037] Example 4 A method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal differs from Example 1 only in that 0.162 g of ammonium dihydrogen phosphate is weighed and added to 6-8 mL of deionized water, and the resulting catalyst is denoted as 10%P / SBA-15.

[0038] Example 5 A method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal differs from Example 1 only in that 0.243 g of ammonium dihydrogen phosphate is weighed and added to 6-8 mL of deionized water, and the resulting catalyst is denoted as 15%P / SBA-15.

[0039] Example 6 A method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal differs from Example 1 only in that 0.291 g of ammonium dihydrogen phosphate is weighed and added to 6-8 mL of deionized water, and the resulting catalyst is denoted as 18%P / SBA-15.

[0040] Figure 1 Small-angle XRD spectra of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6. Figure 1 The three diffraction peaks that appeared corresponded to the (100), (110), and (200) crystal planes of SBA-15, respectively, proving that the prepared catalyst has the hexagonal structure of SBA-15. With the increase of phosphorus loading, the first main peak showed a trend of decreasing and shifting to a lower angle. When the loading was 18wt%, the second and third peaks disappeared, indicating that when the loading was relatively large, blockage would occur, interfering with the orderly arrangement of the catalyst and affecting its long-range order.

[0041] Figure 2 Wide-angle XRD spectra of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6. Figure 2 It can be seen that all samples exhibit a broad diffraction peak corresponding to amorphous silica near 2θ=22.5°, with no other sharp characteristic peaks appearing, indicating that the phosphorus compound is uniformly dispersed in a highly amorphous state after loading. As the loading amount increases, the peak shape changes from basically unchanged to gradually becoming sharper, indicating that increasing the loading amount gradually enhances the diffraction peaks of silica.

[0042] Figure 3 NH3-TPD spectra of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6. Figure 3 It can be seen that the SBA-15 support without phosphorus loading has no obvious acidic sites; after phosphorus loading, the catalyst exhibits a broad desorption peak in the range of 50~320℃, which can be analyzed into two parts: weak acid sites and medium-strong acid sites. With the increase of phosphorus loading, the number of medium-strong acid sites increases slightly, indicating that the acidity of this catalyst can be controlled by the amount of phosphorus loading.

[0043] Figure 4 This is a SEM image of SBA-15. Figure 5 The image shows a SEM image of the 5% P / SBA-15 catalyst prepared in Example 2. Figure 6SEM image of the 8% P / SBA-15 catalyst prepared in Example 3. Figure 7 SEM image of the 10% P / SBA-15 catalyst prepared in Example 4. Figure 8 SEM image of the 12% P / SBA-15 catalyst prepared in Example 1. Figure 9 SEM image of the 15% P / SBA-15 catalyst prepared in Example 5. Figure 10 SEM image of the 18% P / SBA-15 catalyst prepared in Example 6. Figures 4-10 It can be seen that the SBA-15 support presents a typical strip-like morphology. After loading phosphorus, there is a certain degree of particle agglomeration on the catalyst surface. Comparing with the wide-angle XRD of the catalyst, there are no other obvious characteristic peaks, and this agglomerate is amorphous phosphorus oxide. With the increase of the loading amount, the agglomeration phenomenon becomes gradually significant.

[0044] Figure 11 EDS energy spectrum of phosphorus element in the 12% P / SBA-15 catalyst prepared in Example 1. Figure 11 The results show that except for the local agglomeration area, the phosphorus element is evenly distributed on the catalyst surface.

[0045] Figure 12 N₂ low-temperature adsorption and desorption curves of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6. Figure 12 It can be seen that the isotherm of SBA-15 belongs to Type IV, with an H1-type hysteresis loop, indicating that SBA-15 has a highly ordered mesoporous structure. The P / SBA-15 catalysts with different loading amounts all show the same Type IV isotherm, and the H1 hysteresis loop is within the range of 0.4 < P / P₀ < 0.8. It can be seen that all catalysts have typical mesoporous structures.

[0046] Figure 13 BJH pore size distribution diagrams of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6. Figure 13 It can be seen that the pore size distribution of the catalysts is in the range of 1-50 nm, which also indicates the characteristics of their mesoporous structures.

[0047] The structure parameters of SBA-15 and the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6 are shown in Table 1.

[0048] Table 1 Structure parameters of SBA-15 and catalysts with different phosphorus loadings As shown in Table 1, compared with pure SBA-15, the specific surface area and pore volume of the catalyst decrease, while the pore size increases, with the increase of phosphorus loading. This is because amorphous phosphorus oxides enter the support and block some of the pores, or cover the support surface; both factors contribute to the change in catalyst structure. The isotherm type of the catalyst hardly changes, indicating that the change in structural parameters is only due to the increase in loading, rather than the destruction of the pore structure.

[0049] Performance testing: SBA-15 and the SBA-15 supported phosphorus solid acid catalyst prepared in Examples 1-6 were applied to the acetal reaction of furfural and 1,2-propanediol to prepare furfural 1,2-propanediol acetal. The reaction was carried out in a fixed-bed reactor under normal pressure. The reaction conditions were: 1 g catalyst, a molar ratio of furfural to 1,2-propanediol of 1:4, a reaction temperature of 100 °C, and a reaction space velocity of 40 mL·g. -1 ·h -1 .

[0050] The furfural conversion rate and selectivity of furfural-1,2-propanediol acetal for the SBA-15 supported phosphorus solid acid catalysts prepared in Examples 1-6 are shown in Table 2.

[0051] Table 2 Conversion rate and selectivity of furfural acetal reaction As shown in Table 2, SBA-15, which theoretically has almost no acidic sites, exhibits a furfural conversion rate of 13.4%. This is likely due to the high specific surface area and large pore size of SBA-15, which facilitates the adsorption and activation of reactants on its surface, leading to the acetal reaction at a certain temperature and demonstrating a certain catalytic effect. Compared with unloaded SBA-15, the furfural conversion rate shows a trend of first increasing and then decreasing with the increase of phosphorus species loading. When the phosphorus species loading increases from 0 to 12%, the furfural conversion rate increases from 13.4% to 42.4%. When the phosphorus species loading further increases from 12% to 18%, the furfural conversion rate decreases from 42.4% to 25.8%. This is because phosphorus species loading is a key parameter for regulating catalyst performance, significantly affecting the catalyst's acidity / basicity, thermal stability, and the activity and selectivity of the target reaction. A suitable loading will result in excellent catalytic performance.

[0052] Figure 14 The catalytic performance of the 12% P / SBA-15 catalyst prepared in Example 1 at different reaction space velocities was evaluated, wherein C Furfural S represents furfural conversion rate. Acetal This indicates the selectivity of furfural-1,2-propanediol acetal. From Figure 14 As can be seen, the space velocity is 30 mL·g-1 ·h -1 The following conversion rates of furfural were relatively high, approximately 50%, with a space velocity reaching 40 mL·g⁻¹. -1 ·h -1 and 50 mL·g -1 ·h -1 Afterwards, the conversion rate decreased slightly, with a space velocity of 40 mL·g⁻¹. -1 ·h -1 The conversion rate was 42.4% at a space velocity of 50 mL·g⁻¹. -1 ·h -1 The conversion rate was 41.2%.

[0053] Using the 12% P / SBA-15 catalyst prepared in Example 1 as the catalyst, a stability test was conducted for 120 h. The reaction conditions were 100 °C, a furfural to 1,2-propanediol molar ratio of 1:4, and a space velocity of 15 mL·g. -1 ·h -1 .

[0054] Figure 15 The stability results for the 12% P / SBA-15 catalyst prepared in Example 1 are shown, where C Furfural S represents furfural conversion rate. Acetal S represents the selectivity of furfural-1,2-propanediol acetal. Others Indicates selectivity for other substances. From Figure 15 It can be seen that during the 120-hour test, the selectivity of furfural-1,2-propanediol remained relatively stable, consistently above 99%, and the furfural conversion rate was still 40.5% at 120 hours. This is because the high specific surface area and large pore size of SBA-15 itself allow the active sites to be uniformly dispersed on the SBA-15 surface, thereby reducing the probability of carbon deposition. This result further demonstrates the stability of the catalyst and its applicability to flow reaction systems.

[0055] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing an SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal, characterized in that, Includes the following steps: (1) The template agent solution was mixed with the silicon source, and after stirring, baking, drying and first calcination, mesoporous SBA-15 molecular sieve was obtained; (2) The mesoporous SBA-15 molecular sieve is immersed in an aqueous solution containing phosphorus compounds, and after standing, drying and second calcination, the SBA-15 supported phosphorus solid acid catalyst for continuous synthesis of furfural acetal is obtained.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of template agent to silicon source in the template agent solution is 8:

17.

3. The preparation method according to claim 2, characterized in that, In step (1), the template agent is selected from P123; the silicon source is selected from tetraethyl orthosilicate.

4. The preparation method according to claim 1, characterized in that, In step (1), the stirring temperature is 40°C and the stirring time is 24 hours; The baking temperature is 90~100℃, and the time is 24 hours; The drying temperature is 100°C; The first calcination temperature was 500℃ and the time was 6 hours.

5. The preparation method according to claim 1, characterized in that, In step (2), the phosphorus-containing compound in the aqueous solution of the phosphorus-containing compound is selected from one or more of phosphoric acid, ammonium dihydrogen phosphate and diammonium hydrogen phosphate.

6. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of the mesoporous SBA-15 molecular sieve to the phosphorus-containing compound in the aqueous solution of the phosphorus-containing compound is 1: (0.08~0.3).

7. The preparation method according to claim 1, characterized in that, In step (2), the second calcination temperature is 450~600℃, the time is 6~8h, and the heating rate is 1~2℃ / min.

8. The preparation method according to claim 1, characterized in that, In step (2), the phosphorus loading in the SBA-15 supported phosphorus solid acid catalyst used for continuous synthesis of furfural acetal is 5-18%, based on the mass fraction of phosphorus pentoxide on the mesoporous SBA-15 molecular sieve.

9. An SBA-15 supported phosphorus solid acid catalyst for the continuous synthesis of furfural acetal, characterized in that, It is prepared according to any one of claims 1 to 8.

10. The application of the SBA-15 supported phosphorus solid acid catalyst as described in claim 9 for the continuous synthesis of furfural acetal in the catalytic furfural acetalization reaction to prepare furfural acetal.

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