Modified silicon carbide catalyst, preparation method thereof and application of modified silicon carbide catalyst in preparation of dihydrohonokiol through honokiol hydrogenation

Abstract

The invention discloses a modified silicon carbide catalyst, a preparation method thereof and application of the modified silicon carbide catalyst in preparation of dihydrohonokiol through honokiol hydrogenation. The catalyst is composed of a modified SiC carrier and metal active components (nanoparticles such as Pd, Cu and Fe) loaded on the surface of the modified SiC carrier, and the mass fraction of the metal active components is 0.1%-2.0%. Dissolving honokiol in an absolute ethyl alcohol solution, adding the prepared catalyst, and stopping the reaction after a certain temperature and time; the catalyst is applied to research on generation of dihydrohonokiol through hydrogenation, and the yield of dihydrohonokiol can reach 85.2%.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogenation reaction catalysts, and particularly relates to a modified SiC catalyst and its application in the reaction of hydrogenation to produce dihydromagnolol. Background Art

[0002] Neurological diseases are difficult to cure in the short term. For example, patients with depression need to take antidepressant drugs for a long time. Currently, commonly used sedative drugs such as diazepam and paroxetine often have side effects such as drowsiness, dizziness, and fatigue when used. Patients who take them for a long time will also become addicted. Therefore, it is of great significance to study a neurological drug with sedative effects and fewer side effects.

[0003] It has been reported in the literature that dihydromagnolol has a sedative effect. Compared with benzodiazepine drugs such as diazepam and paroxetine, dihydromagnolol has no obvious side effects, so it has the potential to be a new drug for neurological diseases. The latest preparations of dihydromagnolol are all synthetic processes, which have problems such as complex processes, numerous steps, and low yields. Chinese Patent CN117902954A discloses a method for preparing dihydromagnolol by using Wilkinson's catalyst to hydrogenate magnolol in a caustic alkali solution. Wilkinson's catalyst belongs to a homogeneous catalyst, which cannot be reused, and the content of the active metal rhodium (Rh) in the catalyst is ≥11.1%. Moreover, it has high requirements for the reaction solvent, high catalyst cost, and is not environmentally friendly.

[0004] Therefore, it is extremely important to develop a method for hydrogenating natural magnolol to produce dihydromagnolol. Summary of the Invention

[0005] Aiming at the problems of the existing synthesis process of dihydromagnolol, such as complex process, numerous steps, and low yield, and the problems of the preparation process of catalytic hydrogenation of magnolol, such as high catalytic cost and non-recyclability, the present invention aims to provide a modified silicon carbide catalyst for hydrogenating to produce dihydromagnolol, its preparation method and application.

[0006] The present invention first provides a modified silicon carbide (SiC) catalyst, which comprises a modified SiC support and metal nanoparticles loaded on the surface of the modified SiC support.

[0007] Among them, the modified SiC support is obtained by mixing a SiC support and a modifier by a liquid-phase mixing method and then drying; the modifier is one or more of cerium oxide (CeO2), polydimethylsiloxane (PDMS), and polyvinylpyrrolidone (PVP), preferably one or more of PDMS or PVP, more preferably PDMS; the mass fraction of the modifier in the modified SiC support is 5-7%.

[0008] The metal nanoparticles described above include one or more of Pd, Cu, and Fe. Preferably, the metal nanoparticles are Pd or composed of Pd and one of Cu and Fe. The loading amount (mass fraction) of the metal nanoparticles in the modified SiC catalyst is 0.1% - 2.0%, and preferably the loading amount is 0.1% - 1.1%.

[0009] Furthermore, the modifier is PDMS, and its mass fraction in the modified SiC support is 6.4% - 6.7%. The metal nanoparticles are Pd, and its loading amount is 0.1%.

[0010] The present invention further provides a preparation method of the above-mentioned modified SiC catalyst, which includes the following steps: (1) Stir the SiC support and the modifier in water and mix them evenly, and then perform a drying treatment to obtain a modified silicon carbide support; (2) Add the modified silicon carbide support and the metal precursor solution into water and mix them evenly. Use the chemical reduction method to in-situ synthesize metal nanoparticles on the surface of the modified silicon carbide support, and obtain the modified silicon carbide catalyst after post-treatment.

[0011] Among them, the specific steps of step (1) are: Add the SiC support and the modifier or its aqueous solution into water, stir for 2 h, then use a rotary evaporator to evaporate the mixed solution to dryness, and then put it into an oven for drying to obtain the modified silicon carbide support.

[0012] Preferably, the ratio of the total mass of the SiC support and the modifier to water is 300 mg: 20 - 25 mL.

[0013] Among them, the specific steps of step (2) are: Add the modified silicon carbide support and the metal precursor solution into deionized water, stir evenly, then dropwise add lysine solution. After the addition is completed, stir for at least 30 min, and then sequentially dropwise add the reducing agent aqueous solution and hydrochloric acid. After the addition is completed, stir and react for at least 20 h. After the reaction is completed, filter the reaction solution successively, wash it with deionized water and anhydrous ethanol solution, and then dry it to obtain the modified SiC catalyst.

[0014] Preferably, the concentration of the metal precursor solution is 0.01 mol / L.

[0015] Preferably, the metal precursor is a soluble salt of the metal, such as one or more of palladium nitrate, iron nitrate, and copper nitrate.

[0016] Preferably, the concentration of the lysine solution in step (2) is 0.3 - 0.4 mol / L.

[0017] Preferably, the concentration of the reducing agent aqueous solution in step (2) is 0.3 - 0.35 mol / L.

[0018] Preferably, the concentration of hydrochloric acid in step (2) is 0.25 - 0.35 mol / L, and hydrochloric acid is added to adjust the pH of the system to 6 - 7.

[0019] Preferably, the reducing agent in step (2) is sodium borohydride.

[0020] The present invention also provides the application of the above-mentioned modified silicon carbide catalyst in the catalytic hydrogenation of honokiol to produce dihydrohonokiol.

[0021] Specifically, an application method for hydrogenation to produce dihydrohonokiol includes the following steps: Weigh the above-mentioned modified SiC catalyst and place it in a reaction device, add a solvent and honokiol, seal the reaction device and purge it with hydrogen, then fill the reaction device with hydrogen, and heat the reaction under stirring conditions to obtain dihydrohonokiol.

[0022] Preferably, the solvent includes any one of anhydrous ethanol, isopropanol, and methanol solvent.

[0023] Preferably, the ratio of the above-mentioned modified silicon carbide catalyst to honokiol is 20 mg:1 mmol.

[0024] Preferably, the pressure of hydrogen in the reaction system is 0.1 - 0.5 MPa.

[0025] Preferably, the rotation speed of the stirring is 500 - 600 rpm.

[0026] Preferably, the reaction temperature is 30 - 70 °C.

[0027] Preferably, the reaction time is 50 - 80 min.

[0028] Preferably, the above-mentioned application method further includes that after the reaction ends, after cooling to room temperature, collecting the reaction solution and removing the catalyst particles through a filter.

[0029] The present invention has the following beneficial effects: By modifying the silicon carbide (SiC) support, the present invention improves the performance of the support SiC-M, successfully prepares a catalyst (X / SiC-M) by loading transition metal X nanoparticles, and applies it to the reaction of hydrogenation to produce dihydrohonokiol, achieving a yield of dihydrohonokiol of 85.2%.

[0030] Secondly, through the modification treatment of the carrier, the present invention can greatly improve the product yield under the condition of loading a relatively low amount of metal nanoparticles, and significantly reduce the cost required for the catalyst. In addition, the catalyst prepared by the present invention is a heterogeneous catalyst and can be recycled multiple times. After five cycles of experiments, the catalyst still maintains high catalytic performance, demonstrating good cycle stability. In the catalyst recovery stage, it can be recycled after recovery, with simple operation and short reaction cycle, making it an efficient, stable, and environmentally friendly catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Cyclic experiment diagram of the Pd 0.1 / SiC-PDMS catalyst prepared in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0032] The present invention will be described in detail below in conjunction with examples. However, the following examples are only illustrative examples of the embodiments of the present invention, rather than limiting the scope of the present invention.

[0033] In the following specific examples of the present invention, the silicon carbide carrier used was purchased from Changzhou Ruizhen Materials Technology Co., Ltd., and the specific surface area was 20 - 90 m 2 / g. Example 1

[0034] Using polydimethylsiloxane (PDMS) as a modifier, palladium metal nanoparticles were loaded to prepare a Pd 0.1 / SiC-PDMS catalyst, including the following steps: (1) Take 280 mg of SiC carrier and 2 mL of 1% (mass concentration) PDMS solution and put them into 20 mL of deionized water and stir for 2 h. After stirring, remove the water in the solution through a rotary evaporator, and then dry it in an oven to obtain the modified carrier SiC-PDMS, where the mass ratio of PDMS is about 6.7%.

[0035] (2) Take 299.7 mg of SiC-PDMS and 0.28 mL of palladium nitrate solution (0.01M) and add them to 10 mL of deionized water. After stirring evenly, gradually dropwise add lysine solution. After dropping, stir for at least 30 min, and then gradually dropwise add 10 mL of reducing agent NaBH4 (0.3 mol / L) solution in sequence. Subsequently, add hydrochloric acid (0.3 mol / L) to adjust the pH value of the solution to 6 - 7. After dropping, stir and react for at least 20 h. After completion, filter the reaction solution successively, wash it with deionized water and absolute ethanol solution, and then dry it to obtain a Pd 0.1 / SiC-PDMS catalyst.

[0036] The prepared catalyst was used for the catalytic hydrogenation of honokiol to prepare dihydrohonokiol: 20 mg of the above Pd / SiC-PDMS catalyst, 20 mL of anhydrous ethanol solution, and 266.34 mg of honokiol (1 mmol) were weighed and added to the reaction device. After ensuring airtightness, 0.1 MPa of high-purity H2 was charged. The reaction device was placed in a heating device, and the stirring rate was set at 600 rpm, and the reaction temperature and time were set. After the reaction was completed, heating and stirring were turned off. After cooling to room temperature, the reaction solution was collected, and the catalyst particles were removed through a filter, and then gas chromatography-mass spectrometry analysis was performed.

[0037] The reaction temperatures were set at 30 °C, 40 °C, 50 °C, 60 °C, and 70 °C respectively, the reaction time was 1 h, and the yields of dihydrohonokiol were 14.2%, 24.3%, 69.9%, 85.2%, and 68.4% respectively. When the temperature was set at 60 °C and the reaction time was 50 min or 70 min, the yields of dihydrohonokiol were 70.3% and 72.8% respectively.

[0038] In this example, the recycling performance of the catalyst was also investigated. During the recycling experiment, the reaction solution from the previous time was filtered by suction, then washed three times with anhydrous ethanol solution, and placed in a vacuum drying oven for drying. After drying was completed, it could be used for the next experiment. The reaction system was the same as above, the temperature was set at 60 °C, and the reaction time was 1 h. After 5 cycles, it still had high catalytic activity. The yields of dihydrohonokiol are shown in Figure 1 . Example Two

[0039] Preparation of Pd 0.5 / SiC-PDMS catalyst, including the following steps: (1) The same as in Example 1 (2) Take 298.5 mg of SiC-PDMS and 1.4 mL of palladium nitrate solution (0.01 M) and add them to deionized water. After stirring evenly, lysine solution was added drop by drop. After the addition was completed, stirring was carried out for at least 30 min, and then an aqueous reducing agent solution and hydrochloric acid were added drop by drop in turn. After the addition was completed, stirring reaction was carried out for at least 20 h. After completion, the reaction solution was filtered by suction in turn, washed with deionized water and anhydrous ethanol solution, and then dried to obtain Pd 0.5 / SiC-PDMS catalyst.

[0040] Referring to the method of Example 1, the prepared catalyst was used for the catalytic hydrogenation of honokiol to prepare dihydrohonokiol: The reaction temperatures were set at 30 °C, 40 °C, and 50 °C respectively, the reaction time was 1 h, and the yields of dihydrohonokiol were 63.9%, 75.0%, and 58.6% respectively. Example Three

[0041] Using unmodified SiC as the carrier and referring to the preparation method of Example 1, Pd 0.1 / SiC catalyst was prepared, including the following steps: Take 299.7 mg of unmodified SiC and 0.28 mL of palladium nitrate solution (0.01M) and add them to deionized water. After stirring evenly, dropwise add lysine solution. After the addition is completed, stir for at least 30 min, and then successively dropwise add the reducing agent aqueous solution and hydrochloric acid. After the addition is completed, stir and react for at least 20 h. After completion, perform suction filtration on the reaction solution, wash it with deionized water and anhydrous ethanol solution, and then dry it to obtain Pd 0.1 / SiC catalyst.

[0042] Referring to the method of Example 1, the prepared catalyst was used to catalyze the hydrogenation of honokiol to prepare dihydrohonokiol: under the reaction conditions of a temperature of 60 °C and a time of 1 h, the yield of dihydrohonokiol was 64.2%. Example Four In this example, CeO2 was used as the modifier to load palladium metal nanoparticles to prepare Pd 0.1 / SiC-CeO2 catalyst, including the following steps: (1) Take 285 mg of SiC carrier and 15 mg of CeO2 and put them into 20 mL of deionized water and stir for 2 h. After the stirring is completed, remove the moisture in the solution by a rotary evaporator to obtain the modified carrier SiC-CeO2, in which the mass ratio of CeO2 is about 5%.

[0043] (2) Take 299.7 mg of SiC-CeO2 and 0.28 mL of palladium nitrate solution (0.01M) and add them to deionized water. After stirring evenly, dropwise add lysine solution. After the addition is completed, stir for at least 30 min, and then successively dropwise add the reducing agent aqueous solution and hydrochloric acid. After the addition is completed, stir and react for at least 20 h. After completion, perform suction filtration on the reaction solution, wash it with deionized water and anhydrous ethanol solution, and then dry it to obtain Pd 0.1 / SiC-CeO2 catalyst.

[0044] Referring to the method of Example 1, the prepared catalyst was used to catalyze the hydrogenation of honokiol to prepare dihydrohonokiol: set the reaction temperature to 60 °C, and under the conditions of reaction times of 50 min, 60 min, and 70 min respectively, the yields of dihydrohonokiol were 66.1%, 71.8%, and 65.5% respectively. Example Four

[0045] In this example, PVP was used as the modifier to load palladium metal nanoparticles to prepare Pd 0.1 / SiC-PVP catalyst, including the following steps: (1) Take 280 mg of SiC support and 0.4 mL of PVP solution with a mass concentration of 5% and put them into 20 mL of deionized water and stir for 2 h. After stirring, remove the moisture in the solution by a rotary evaporator to obtain the modified support SiC-PVP, where the mass ratio of PVP is about 6.7%.

[0046] (2) Take 299.7 mg of SiC-PVP and 0.28 mL of palladium nitrate solution (0.01 M) and add them to deionized water. After stirring evenly, dropwise add lysine solution. After the addition is completed, stir for at least 30 min, and then successively dropwise add the reducing agent aqueous solution and hydrochloric acid. After the addition is completed, stir and react for at least 20 h. After completion, filter the reaction solution successively, wash it with deionized water and absolute ethanol solution, and then dry it to obtain Pd 0.1 / SiC-PVP catalyst.

[0047] Refer to the method of Example 1 to use the prepared catalyst for the catalytic hydrogenation of honokiol to prepare dihydrohonokiol: Set the reaction temperature to 60 °C. Under the conditions that the reaction times are 60 min, 70 min, and 80 min respectively, the yields of dihydrohonokiol are 55.8%, 68.8%, and 61.3% respectively. Example Five

[0048] Using polydimethylsiloxane (PDMS) as a modifier, load palladium-copper bimetallic nanoparticles to prepare Pd 0.1 -Cu1 / SiC-PDMS catalyst, including the following steps: (1) The same as Example 1.

[0049] (2) Take 296.7 mg of SiC-PDMS, 0.28 mL of palladium nitrate solution (0.01 M), and 2.14 mL of copper nitrate trihydrate (0.01 M) and add them to deionized water. After stirring evenly, dropwise add lysine solution. After the addition is completed, stir for at least 30 min, and then successively dropwise add the reducing agent aqueous solution and hydrochloric acid. After the addition is completed, stir and react for at least 20 h. After completion, filter the reaction solution successively, wash it with deionized water and absolute ethanol solution, and then dry it to obtain Pd 0.1 -Cu1 / SiC-PDMS catalyst.

[0050] Refer to the method of Example 1 to use the prepared catalyst for the catalytic hydrogenation of honokiol to prepare dihydrohonokiol: Set the reaction temperatures to 40 °C, 50 °C, and 60 °C respectively, and the reaction time is 1 h. The yields of dihydrohonokiol are 65.7%, 80.2%, and 74.4% respectively. Example Six

[0051] Using polydimethylsiloxane (PDMS) as a modifier to load palladium-iron bimetallic nanoparticles to prepare Pd 0.1 -Fe1 / SiC-PDMS catalyst, comprising the following steps: (1) Prepare the modified support SiC-PDMS as in Example 1.

[0052] (2) Take 296.7 mg of SiC-PDMS, 0.28 mL of palladium nitrate solution (0.01M), and 4.04 mL of iron(III) nitrate nonahydrate (0.01M) and add them to deionized water. After stirring evenly, dropwise add lysine solution. After the addition is complete, stir for at least 30 min, and then successively dropwise add the reducing agent aqueous solution and hydrochloric acid. After the addition is complete, stir and react for at least 20 h. After completion, filter the reaction solution successively, wash it with deionized water and absolute ethanol solution, and then dry it to obtain Pd 0.1 -Fe1 / SiC-PDMS catalyst.

[0053] Refer to the method of Example 1 to use the prepared catalyst for the catalytic hydrogenation of honokiol to prepare dihydrohonokiol: Set the reaction temperatures to 40 °C, 50 °C, and 60 °C respectively, the reaction time to 1 h, and the yields of dihydrohonokiol are 60.7%, 80.6%, and 71.1% respectively. Example Seven

[0054] The difference between this example and Example Seven is that the amount of iron(III) nitrate nonahydrate used is 2.02 mL, and Pd 0.1 -Fe 0.5 / SiC-PDMS catalyst is prepared.

[0055] Refer to the method of Example 1 to use the prepared catalyst for the catalytic hydrogenation of honokiol to prepare dihydrohonokiol: Set the reaction temperatures to 40 °C and 50 °C respectively, the reaction time to 1 h, and the yields of dihydrohonokiol are 69.3% and 78.4% respectively.

[0056] Combining the above examples, using Pd 0.1 / SiC-PDMS as a catalyst, the yield of dihydrohonokiol reaches the highest 85.2% at 60 °C and a reaction time of 1 h.

[0057] Based on the above ideal embodiments of the present invention as an inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A modified silicon carbide catalyst, characterized in that, It includes a modified silicon carbide support and metal nanoparticles supported on the surface of the modified silicon carbide support. The modified silicon carbide support is obtained by mixing a silicon carbide support and a modifier by a liquid-phase mixing method and then drying. The modifier is one or more of cerium oxide, polydimethylsiloxane, and polyvinylpyrrolidone. The metal nanoparticles include one or more of Pd, Cu, and Fe. The mass fraction of the metal nanoparticles in the modified silicon carbide catalyst is 0.1% to 2.0%.

2. The modified silicon carbide catalyst according to claim 1, wherein The mass fraction of the modifier in the modified silicon carbide support is 0.5% to 7%.

3. The modified silicon carbide catalyst according to claim 1, characterized in that, The metal nanoparticles are in-situ synthesized on the surface of the modified silicon carbide support.

4. The preparation method of the modified silicon carbide catalyst according to any one of claims 1-3, characterized in that, It includes the following steps: (1) Add the silicon carbide support and the modifier into water, stir and mix evenly, and then perform a drying treatment to obtain the modified silicon carbide support; (2) Add the modified silicon carbide support and the metal precursor solution into water and mix evenly. Use a chemical reduction method to in-situ synthesize metal nanoparticles on the surface of the modified silicon carbide support, and obtain the modified silicon carbide catalyst after post-treatment.

5. The preparation method of the modified silicon carbide catalyst according to claim 4, wherein, In step (1), the ratio of the total mass of the silicon carbide support and the modifier to water is 300 mg: 20 to 25 mL.

6. The preparation method of the modified silicon carbide catalyst according to claim 4, characterized in that, The specific steps of step (2) are: add the modified silicon carbide support and the metal precursor solution into deionized water, stir evenly, then dropwise add lysine solution. After the addition is completed, stir for at least 30 min, and then sequentially dropwise add an aqueous solution of a reducing agent and hydrochloric acid. After the addition is completed, stir and react for at least 20 h. After completion, perform suction filtration, washing, and drying on the reaction solution in sequence to obtain the modified silicon carbide catalyst.

7. The preparation method of the modified silicon carbide catalyst according to claim 6, characterized in that, The concentration of the metal precursor solution is 0.01 mol / L.

8. Use of the modified silicon carbide catalyst according to any one of claims 1-3 in the catalytic hydrogenation of honokiol to produce dihydrohonokiol, characterized in that, Specific application method It includes the following steps: Weigh the modified silicon carbide catalyst and place it in a reaction device, add a solvent and honokiol, seal the reaction device and purge it with hydrogen, then fill the reaction device with hydrogen, and heat and react under stirring conditions to obtain dihydrohonokiol.

9. The application according to claim 8, wherein The solvent includes any one of absolute ethanol, isopropanol, and methanol solvent.

10. The application according to claim 8, wherein The ratio of the modified silicon carbide catalyst to honokiol is 20 mg: 1 mmol; and / or, the pressure of hydrogen in the reaction device is 0.1 MPa; and / or, the reaction temperature is 30 to 70 °C; and / or, the reaction time is 50 to 80 min.

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