A catalyst, a preparation method, applications and a preparation method of tetrahydrofurfuryl alcohol

Abstract

The application provides a catalyst and a preparation method, application and a preparation method of tetrahydrofurfuryl alcohol, the catalyst uses mesoporous silica as a carrier, the surface of the carrier is modified with polyethylene glycol and an alkyl chain to form an amphiphilic surface, and Pd nanoparticles are loaded in the mesopores. The mesoporous silica supported palladium catalyst has an amphiphilic interface formed by polyethylene glycol and an alkyl chain modified on the surface through a covalent bond, the hydrophilic polyethylene glycol chain enriches furfuryl alcohol molecules through hydrogen bonds, and the hydrophobic alkyl chain captures hydrogen microbubbles, which can effectively reduce the gas-liquid interfacial tension, is helpful to the breaking of large bubbles and the stable existence of nanobubbles, and makes the preparation of tetrahydrofurfuryl alcohol realize efficient reaction under significantly reduced pressure.

Description

Technical Field

[0001] This invention relates to the fields of catalyst materials and organic synthesis, and more specifically to a catalyst, its preparation method, its application, and a method for preparing tetrahydrofurfuryl alcohol. Background Technology

[0002] Tetrahydrofurfuryl alcohol, as an important chemical intermediate and green solvent, is widely used in the synthesis of pharmaceuticals, resins, and fragrances. Industrially, it is mainly prepared by the catalytic hydrogenation of furfuryl alcohol. Current technologies generally employ Raney nickel or palladium / carbon (Pd / C) catalysts. However, the traditional reaction process relies on high pressure to "force" hydrogen into the liquid phase, resulting in large bubbles and insufficient hydrogen solubility, necessitating the introduction of excessive hydrogen gas. Therefore, further improvements and development are needed. Summary of the Invention

[0003] To address the shortcomings of existing technologies and solve the aforementioned problems, a catalyst, its preparation method, its application, and a method for preparing tetrahydrofurfuryl alcohol are proposed, along with the following technical solutions:

[0004] A method using mesoporous silica as a carrier, the surface of which is modified with polyethylene glycol and alkyl chains to form an amphiphilic surface, and Pd nanoparticles are loaded inside the mesopores.

[0005] Furthermore, the polyethylene glycol has a molecular weight of 1000-5000 Da, and the alkyl chain is a C12-C18 alkyl chain.

[0006] Furthermore, the alkyl chain is octadecyltrimethoxysilane.

[0007] In addition, a method for preparing a catalyst is provided, comprising the following steps: (1) soaking, washing and drying mesoporous silica in dilute nitric acid; (2) dispersing the pretreated mesoporous silica support in anhydrous toluene, adding alkylsilane under an inert atmosphere and refluxing to obtain alkylated silica; (3) dispersing the alkylated silica in anhydrous toluene, adding methoxy polyethylene glycol propyltrimethoxysilane, and refluxing again under an inert atmosphere to obtain a support with surface-modified polyethylene glycol and alkyl chains; (4) mixing the support obtained in step (3) with chloropalladic acid solution, adding sodium borohydride for reduction, washing and drying to obtain the catalyst.

[0008] Furthermore, the reflux reaction time in step (2) is 10-14 hours, and the reflux reaction time in step (3) is 10-14 hours.

[0009] Furthermore, in step (2), the amount of alkylsilane added is 3%-8% of the mass of the mesoporous silica carrier; in step (3), the amount of methoxy polyethylene glycol propyltrimethoxysilane added is 15%-30% of the mass of the mesoporous silica carrier; and in step (3), the amount of palladium in chloropalladic acid added is 1.5%-5% of the mass of the mesoporous silica carrier.

[0010] The application of the above-mentioned catalyst in the catalytic hydrogenation of furfuryl alcohol to prepare tetrahydrofurfuryl alcohol.

[0011] A method for preparing tetrahydrofurfuryl alcohol involves reacting furfuryl alcohol with hydrogen in the presence of the catalyst described above to generate tetrahydrofurfuryl alcohol.

[0012] Furthermore, furfuryl alcohol and hydrogen are subjected to ultrasonic stirring before the reaction, and then the mixture is introduced into a reactor containing a catalyst for the reaction.

[0013] Furthermore, the reaction pressure is 0.5-1.5 MPa.

[0014] Due to the adoption of the above technical solutions, the beneficial technical effects of the present invention are as follows:

[0015] 1. The catalyst of the present invention enriches furfuryl alcohol in the hydrophilic polyvinyl alcohol region and enriches hydrogen in the hydrophobic alkyl chain region. The two are closely adjacent at the nanoscale, so that the two reactants are in contact at the Pd active center, which greatly improves the reaction rate.

[0016] 2. The catalyst of this invention can effectively reduce the gas-liquid interfacial tension, which helps to break up large bubbles and stabilize nanobubbles, enabling the preparation of tetrahydrofurfuryl alcohol to achieve efficient reaction under significantly reduced pressure (0.5-1.5 MPa). Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the tetrahydrofurfuryl alcohol preparation equipment of the present invention;

[0018] The above figures include the following reference numerals:

[0019] 1. Liquid outlet; 2. Reaction vessel; 3. Ultrasonic stirrer; 4. Hydrogen inlet; 5. Liquid inlet. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application.

[0021] A catalyst, using mesoporous silica as a support, has a surface modified with polyethylene glycol and alkyl chains to form an amphiphilic surface, with Pd nanoparticles loaded inside the mesopores. The mesoporous silica-supported palladium catalyst has an amphiphilic interface formed by covalently modifying the surface with polyethylene glycol and alkyl chains. The hydrophilic PEG chains enrich furfuryl alcohol molecules through hydrogen bonds, while the hydrophobic alkyl chains capture hydrogen microbubbles, effectively reducing gas-liquid interfacial tension and facilitating the breakup of large bubbles and the stable existence of nanobubbles. This allows for highly efficient preparation of tetrahydrofurfuryl alcohol under significantly reduced pressures (0.5-1.5 MPa). Specifically, the hydrophobic alkyl chains on the catalyst surface capture and enrich a large number of hydrogen microbubbles, creating a locally high hydrogen concentration environment around the active sites. This eliminates the need for high pressure to increase the average solubility of the liquid throughout the reactor; sufficient hydrogen partial pressure is sufficient.

[0022] Polyethylene glycol (PEG) chains are highly flexible in solution, exhibiting a random coiled shape. This flexibility allows PEG chains to extend into the furfuryl alcohol liquid phase, actively capturing and adsorbing reactant molecules. In contrast, rigid chain segments (such as some aromatic polymers) are much less effective. Furthermore, under the aforementioned hydrogenation reaction conditions, the ether bonds of PEG are very stable, making them less prone to chain breakage, hydrolysis, or hydrogenation reactions, thus ensuring catalyst lifetime. Long alkyl chains, on the other hand, are typical nonpolar groups, exhibiting strong van der Waals forces with nonpolar hydrogen molecules. Specifically, the alkyl chain is octadecyltrimethoxysilane. The chain length of octadecyltrimethoxysilane is sufficient to stabilize the hydrogen gas-liquid interface without being excessively long enough to cause chain entanglement. Moreover, the long alkyl chain is composed of stable C-C and CH bonds, making it extremely inert under hydrogenation reaction conditions. The PEG chains and long alkyl chains work synergistically to promote the reaction on the catalyst surface.

[0023] Example 1

[0024] Catalyst preparation:

[0025] Includes the following steps:

[0026] (1) Soak SBA-15 type mesoporous silica (pore size 8 nm) in 5% nitric acid solution for 6 hours, wash with deionized water until neutral, and dry at 110°C for 12 hours;

[0027] (2) 10 g of pretreated mesoporous silica support was dispersed in 200 ml of anhydrous toluene. Under nitrogen protection, 0.5 g of octadecyltrimethoxysilane was added and refluxed at 110 °C for 12 hours. After cooling, the mixture was filtered and washed with toluene and ethanol in sequence. The mixture was then dried under vacuum at 80 °C for 6 hours to obtain the alkylated support.

[0028] (3) The alkylated support was dispersed in 150 ml of anhydrous toluene, and 2.5 g of methoxy polyethylene glycol propyltrimethoxysilane (PEG molecular weight 2000 Da) was added. Under nitrogen protection, the reaction was refluxed again at 110 °C for 12 hours. After filtration, the physical adsorbent was removed by Soxhlet extraction (ethanol, 48 hours). The surface-modified polyethylene glycol and alkyl chain support was obtained by vacuum drying at 60 °C.

[0029] (4) Take 8 g of the support obtained in step (3) and disperse it in 100 mL of ethanol / water (1:1) mixed solvent. Add 0.5 g of chloropalladium acid, stir for 4 hours, add 0.1 M sodium borohydride solution dropwise until no bubbles are generated, continue the reaction for 2 hours, filter and wash, and dry under vacuum at 40 °C to obtain the catalyst.

[0030] Example 2

[0031] Catalyst preparation:

[0032] Includes the following steps:

[0033] (1) Soak SBA-15 type mesoporous silica (pore size 8 nm) in 5% nitric acid solution for 6 hours, wash with deionized water until neutral, and dry at 110°C for 12 hours;

[0034] (2) 10 g of pretreated mesoporous silica support was dispersed in 200 ml of anhydrous toluene. Under nitrogen protection, 0.3 g of octadecyltrimethoxysilane was added and refluxed at 110 °C for 12 hours. After cooling, the mixture was filtered and washed with toluene and ethanol in sequence. The mixture was then dried under vacuum at 80 °C for 6 hours to obtain the alkylated support.

[0035] (3) The alkylated support was dispersed in 150 ml of anhydrous toluene, and 1.8 g of methoxy polyethylene glycol propyltrimethoxysilane (PEG molecular weight 2000 Da) was added. Under nitrogen protection, the reaction was refluxed again at 110 °C for 12 hours. After filtration, the physical adsorbent was removed by Soxhlet extraction (ethanol, 48 hours). The surface-modified polyethylene glycol and alkyl chain support was obtained by vacuum drying at 60 °C.

[0036] (4) Take 8 grams of the support obtained in step (3) and disperse it in 100 mL of ethanol / water (1:1) mixed solvent. Add 0.24 g of chloropalladium acid, stir for 4 hours, add 0.1 M sodium borohydride solution dropwise until no bubbles are generated, continue the reaction for 2 hours, filter and wash, and dry under vacuum at 40℃ to obtain the catalyst.

[0037] Example 3

[0038] Catalyst preparation:

[0039] Includes the following steps:

[0040] (1) Soak SBA-15 type mesoporous silica (pore size 8 nm) in 5% nitric acid solution for 6 hours, wash with deionized water until neutral, and dry at 110°C for 12 hours;

[0041] (2) 10 g of pretreated mesoporous silica support was dispersed in 200 ml of anhydrous toluene. Under nitrogen protection, 0.8 g of octadecyltrimethoxysilane was added and refluxed at 110 °C for 12 hours. After cooling, the mixture was filtered and washed with toluene and ethanol in sequence. The mixture was then dried under vacuum at 80 °C for 6 hours to obtain the alkylated support.

[0042] (3) The alkylated support was dispersed in 150 ml of anhydrous toluene, and 3 g of methoxy polyethylene glycol propyltrimethoxysilane (PEG molecular weight 2000 Da) was added. Under nitrogen protection, the reaction was refluxed again at 110 °C for 12 hours. After filtration, the physical adsorbent was removed by Soxhlet extraction (ethanol, 48 hours). The surface-modified polyethylene glycol and alkyl chain support was obtained by vacuum drying at 60 °C.

[0043] (4) Take 8 g of the support obtained in step (3) and disperse it in 100 mL of ethanol / water (1:1) mixed solvent. Add 0.8 g of chloropalladium acid, stir for 4 hours, add 0.1 M sodium borohydride solution dropwise until no bubbles are generated, continue the reaction for 2 hours, filter and wash, and dry under vacuum at 40 °C to obtain the catalyst.

[0044] Comparative Example 1

[0045] Step (2) was not performed compared to Example 1, while the other steps were the same.

[0046] Comparative Example 2

[0047] Step (3) was not performed compared to Example 1, while the other steps were the same.

[0048] Comparative Example 3

[0049] Pd / C, a catalyst from existing technology, is used.

[0050] Experimental Example 1

[0051] Six sets of experiments were conducted using the catalysts from Examples 1-3 and Comparative Examples 1-3, respectively.

[0052] Adopting such Figure 1The equipment was used, and 5.0 g of catalyst was loaded into the constant temperature zone of reaction vessel 2. After the system was checked for air tightness, it was pretreated by heating to the predetermined reaction temperature of 120°C under a hydrogen atmosphere. Hydrogen and furfuryl alcohol were introduced from hydrogen inlet 4 and liquid inlet 5, respectively, with the hydrogen feed flow rate controlled at 50 ml / min and the furfuryl alcohol feed flow rate controlled at 0.1 ml / min. First, the hydrogen and furfuryl alcohol were ultrasonically mixed by ultrasonic stirrer 3 during the flow, and then entered into reaction vessel 2. The catalysts of Examples 1-3 and Comparative Examples 1-3 were placed in reaction vessel 2, respectively. The reaction temperature was 150°C, the reaction time was 3 h, and the hydrogen pressure during the reaction was 0.5 MPa. After the reaction, the liquid flowed out from liquid outlet 1, cooled, filtered, and the filtrate was distilled under reduced pressure. The fraction at 65°C / 2.5 kPa was collected to obtain tetrahydrofurfuryl alcohol. The experimental results are shown in Table 1.

[0053] Table 1. Experimental results using the catalysts of Examples 1-3 and Comparative Examples 1-3, respectively.

[0054]

[0055] Experimental Example 2

[0056] 5.0 g of the catalyst obtained in Example 1 was loaded into the isothermal zone of reaction vessel 2. After the system was checked for airtightness, it was pretreated by heating to the predetermined reaction temperature of 120°C under a hydrogen atmosphere. Hydrogen and furfuryl alcohol were added to the reaction vessel, with the hydrogen feed flow rate controlled at 50 ml / min and the furfuryl alcohol feed flow rate controlled at 0.1 ml / min. The catalyst prepared in Example 1 was placed in the reaction vessel, the reaction temperature was 150°C, the reaction time was 3 h, and the hydrogen pressure during the reaction was 0.5 MPa. After the reaction was completed, the mixture was cooled, filtered, and the filtrate was distilled under reduced pressure.

[0057] Experimental Example 3

[0058] Adopting such Figure 1 The equipment was used to load 5.0g of the catalyst obtained in Example 1 into the constant temperature zone of reaction vessel 2. After the system underwent an airtightness check, it was pretreated by heating to a predetermined reaction temperature of 120°C under a hydrogen atmosphere. Hydrogen and furfuryl alcohol were introduced into the system through hydrogen inlet 4 and liquid inlet 5, respectively, with the hydrogen feed flow rate controlled at 50ml / min and the furfuryl alcohol feed flow rate controlled at 0.1ml / min. First, the hydrogen and furfuryl alcohol were ultrasonically mixed by ultrasonic stirrer 3 during the flow process, and then entered into reaction vessel 2. The reaction temperature was 150°C, the reaction time was 3 hours, and the hydrogen pressure during the reaction was 1.5MPa. After the reaction was completed, the liquid flowed out from the liquid outlet, cooled, filtered, and the filtrate was distilled under reduced pressure. The fraction at 65°C / 2.5kPa was collected to obtain tetrahydrofurfuryl alcohol.

[0059] Test Example 4

[0060] 5.0 g of the catalyst obtained in Comparative Example 3 was loaded into the isothermal zone of reaction vessel 2. After the system was checked for airtightness, it was pretreated by heating to the predetermined reaction temperature of 120 °C under a hydrogen atmosphere. Hydrogen and furfuryl alcohol were added to the reaction vessel, with the hydrogen feed flow rate controlled at 50 ml / min and the furfuryl alcohol feed flow rate controlled at 0.1 ml / min. The reaction was then carried out at a temperature of 150 °C for 3 hours, with the hydrogen pressure maintained at 1.5 MPa during the reaction. After the reaction was completed, the mixture was cooled, filtered, and the filtrate was distilled under reduced pressure.

[0061] The experimental results of Experiment 2-4 are shown in Table 2 below.

[0062] Table 2. Results of Experiments 2-4

[0063]

[0064] In summary, the catalyst provided in this application does not require high-pressure conditions, which can reduce hydrogen consumption, lower hazards, and is environmentally friendly and energy-saving, while maintaining high catalytic performance. Furthermore, the catalyst of this application achieves optimal results when combined with ultrasonic stirring in the tetrahydrofurfuryl alcohol preparation equipment described in this application.

[0065] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for producing a catalyst, characterized by, The method comprises the following steps: (1) soaking mesoporous silica in dilute nitric acid, washing, and drying; (2) dispersing the pretreated mesoporous silica carrier in anhydrous toluene, adding alkylsilane under the protection of an inert atmosphere, and refluxing to obtain alkylated silica; (3) dispersing the alkylated silica in anhydrous toluene, adding methoxypolyethylene glycol propyltrimethoxysilane, and refluxing again under the protection of an inert atmosphere to obtain a carrier with a surface modified with polyethylene glycol and an alkyl chain; (4) mixing the carrier obtained in step (3) with a chloropalladic acid solution, adding sodium borohydride for reduction, washing, and drying to obtain a catalyst; In step (2), the amount of alkylsilane added is 3%-8% of the mass of the mesoporous silica carrier; in step (3), the amount of methoxypolyethylene glycol propyltrimethoxysilane added is 15%-30% of the mass of the mesoporous silica carrier; and in step (3), the amount of palladium in the chloropalladic acid added is 1.5%-5% of the mass of the mesoporous silica carrier.

2. The method of claim 1, wherein the catalyst is prepared by the steps of: The refluxing time in step (2) is 10-14 hours, and the refluxing time in step (3) is 10-14 hours.

3. A catalyst characterized by, The catalyst is prepared by the method of any one of claims 1-2, has a mesoporous silica carrier, and has an amphiphilic surface formed by polyethylene glycol and an alkyl chain on the surface of the carrier and Pd nanoparticles loaded in the mesopores.

4. The catalyst of claim 3, wherein The molecular weight of the polyethylene glycol is 1000-5000 Da, and the alkyl chain is a C12-C18 alkyl chain.

5. Use of the catalyst of any one of claims 3-4 in a reaction for catalyzing the preparation of tetrahydrofurfuryl alcohol by hydrogenating furfuryl alcohol.

6. A process for the preparation of tetrahydrofurfuryl alcohol, characterized in that, Furfuryl alcohol and hydrogen are reacted in the presence of the catalyst of any one of claims 3-4 to generate tetrahydrofurfuryl alcohol.

7. A process for the preparation of tetrahydrofurfuryl alcohol according to claim 6, characterized in that, The furfuryl alcohol and hydrogen are subjected to ultrasonic stirring treatment before the reaction, and are then introduced into a reactor containing the catalyst for the reaction.

8. The process for preparing tetrahydrofurfuryl alcohol according to claim 6, characterized by, The reaction pressure is 0.5-1.5 MPa.

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