Polymer catalyst for efficiently catalyzing hydrogenation of levulinic acid to prepare gamma-valerolactone as well as preparation method and application of polymer catalyst

Abstract

The invention is applicable to the technical field of biomass catalysis, and provides a polymer catalyst for efficiently catalyzing hydrogenation of levulinic acid to prepare gamma-valerolactone. According to the polymer catalyst for efficiently catalyzing hydrogenation of levulinic acid to prepare gamma-valerolactone, a metal complex with a sawhorse structure is used as an active center, the metal center is combined with a coordination group through a stable covalent bond or coordination bond, the metal center is preferably ruthenium or osmium, and the polymer catalyst is suitable for a high-pressure reaction kettle reactor equipped with magnetic stirring or mechanical stirring; the catalyst has the advantages of easily available raw materials, low cost, simple preparation, no need of phosphine ligand and amine ligand, high efficiency catalysis of levulinic acid hydrogenation under mild conditions to prepare gamma-valerolactone, easy separation and recycling, good recycling performance, no need of complex equipment, convenient large-scale production, and good industrial application prospects.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biomass catalysis, and particularly relates to a polymer catalyst for efficiently catalyzing the hydrogenation of levulinic acid to γ-valerolactone as well as a preparation method and application thereof. BACKGROUND

[0002] Biomass resources are attracting worldwide attention due to their core advantages such as universality, abundance and renewability. At present, research on the high-value utilization of biomass resources has become an important goal for energy transformation and sustainable development in the world, in order to supplement and even partially replace fossil resources such as petroleum and coal. For example, the preparation route of the key platform molecule levulinic acid has significant advantages: it can be generated by hydrolysis of common biomass resources such as cellulose and starch under mild and simple reaction conditions, and the overall preparation cost is relatively low. Moreover, the molecular structure of levulinic acid is rich in various functional groups, and based on this characteristic, a series of high-value chemicals such as γ-valerolactone and 1,4-pentanediol can be further derived through controllable transformation processes such as hydrogenation and esterification. Among them, the application potential of γ-valerolactone is particularly outstanding. Due to its excellent physical and chemical properties and safety performance: its toxicity is much lower than that of ethanol (toxicity < ethanol), its melting point is as low as -31℃, its vapor pressure is only 0.235mmHg (25℃), and it also has a high boiling point of 207℃ and a high flash point of 75℃, making it have broad application prospects in the fields of green solvents and renewable fuel additives, and become one of the important terminal products in the chain of biomass high-value conversion.

[0003] The large-scale production of γ-valerolactone can be achieved through the hydrogenation and lactonization of levulinic acid. Currently, the catalysts suitable for this conversion process mainly include supported heterogeneous catalysts and homogeneous metal complex catalysts. Both types of catalysts have their own advantages and disadvantages, and there are certain technical bottlenecks, as follows: on the one hand, although supported heterogeneous catalysts have the advantage of easy separation and recycling, the reaction process needs to be carried out at high temperature and hydrogen pressure, which is relatively harsh. The harsh conditions can easily lead to the formation of 2-methyltetrahydrofuran, an over-hydrogenated product, which further converts to form a dangerous peroxide, ultimately posing a safety hazard to the actual application of γ-valerolactone. On the other hand, homogeneous metal complex catalysts exhibit the outstanding characteristics of mild reaction conditions and high selectivity of target products. However, their popularization and application are also restricted: first, the catalysts are difficult to recycle, leading to rising costs and resource waste; second, in existing reports, these catalysts rely on expensive and less stable phosphine ligands (Ind. Eng. Chem. Res. 2022, 61, 15156-15168; Low Carbon Chemistry and Chemical Industry, 2024, 49, 35-48), which limits their industrial application process in terms of economy and practicality.

[0004] In summary, developing a new catalyst system that can take into account the advantages of both catalysts is one of the key breakthroughs to promote the industrialization of acetic acid production of γ-valerolactone technology, and is also the core problem to be solved. Specifically, the catalyst needs to integrate the convenience of supported heterogeneous catalysts in separation, recovery and recycling, and the outstanding advantages of homogeneous metal complex catalysts in mild reaction conditions and inhibition of side reactions (high target product selectivity), thereby breaking the bottleneck of existing catalytic technology and laying the foundation for the industrial application of the process. SUMMARY

[0005] The present application provides a kind of polymer catalyst for efficient catalysis of acetic acid hydrogenation γ-valerolactone, to achieve the convenience in separation, recovery and recycling, and the outstanding advantages of homogeneous metal complex catalysts in mild reaction conditions and inhibition of side reactions (high target product selectivity).

[0006] The present application is realized, a kind of polymer catalyst for efficient catalysis of acetic acid hydrogenation γ-valerolactone, its structural formula is as follows:

[0007]

[0008] Wherein, M is selected from one of Ru, Os, Mn, Fe, Mo, Co or Re;

[0009] X is the power supply atom or group coordinated with the metal center;R is the power supply group.

[0010] Preferably, the M and O, X coordination group are combined in the form of covalent bond or coordination bond, and the action can be stably present in solid state or solution.

[0011] Preferably, the X is preferably O or NH;R is the power supply group, preferably amine group, straight chain or branched C1-C 20 alkyl, C3-C 20 cycloalkyl, C1-C 10 alkoxy;n is an integer selected from 0-8.

[0012] A preparation method of a kind of polymer catalyst for efficient catalysis of acetic acid hydrogenation γ-valerolactone, including raw material L and B, its structural formula is as follows:

[0013]

[0014] Specific preparation steps are as follows:

[0015] S1: under anaerobic and water-free conditions, at 40℃-reflux temperature range, L and metal carbonyl compound M x (CO) yThe intermediate i was obtained by heating under reflux in an organic solvent at a ratio of x: 0.5-2 for 10-72 hours, followed by vacuum concentration, filtration, washing with a polar solvent, and vacuum drying.

[0016] S2: Under oxygen- and water-free conditions, weigh the intermediate i, substituted benzene (B), and metal halide obtained in step S1 in a molar ratio of 1:1-5:1-10, add anhydrous solvent, and place in a Schiller bottle; under an inert atmosphere, react the reaction solution in a programmed temperature control manner within the range of 0℃ to reflux temperature for 12-72 hours.

[0017] S3: Add hydrochloric acid aqueous solution to the final reaction solution obtained in step S2, stir for 0.5-2 hours, filter and collect the solid product, wash with ethanol, water and ethanol in sequence, and dry under reduced pressure to obtain the polymer catalyst.

[0018] Preferably, in S1, the organic solvent is selected from toluene, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, and 1,4-dioxane;

[0019] The polar solvent is selected from one of toluene, dichloromethane, chloroform, and tetrahydrofuran;

[0020] In S2, the metal halide is selected from one of AlCl3, FeCl3, and ZnCl2;

[0021] The anhydrous solvent is selected from one of acetonitrile, nitrobenzene, and carbon disulfide;

[0022] In S2, the volume of the hydrochloric acid aqueous solution is 30-100 mL.

[0023] Application of a polymer-based metal complex catalyst as described above in the efficient catalytic hydrogenation of levulinic acid to γ-valerol.

[0024] The application method is as follows: Under a hydrogen atmosphere, with an initial hydrogen pressure in the range of 1-100 bar and a temperature of 60-160℃, the polymer catalyst and levulinic acid are added to the solvent at a mass ratio of 1:100-1000000 and an alkali is added to carry out the reaction. The reaction time is 0.1-300 hours to obtain the hydrogenation reaction product γ-valerolactone.

[0025] The operation steps are as follows:

[0026] a: Under an inert atmosphere, weigh the polymer catalyst, base, and levulinic acid into the reactor and then assemble the reactor body;

[0027] b: After cooling the vessel body to 0-10℃ with ice water, add 0-200ml of solvent under an inert atmosphere, then replace the atmosphere inside the vessel with hydrogen and purge with hydrogen to the specified pressure;

[0028] c: Place the vessel in a heating device to heat and react;

[0029] d: After the reaction is complete, quickly cool the vessel to 0-10℃, remove the remaining hydrogen gas from the vessel, and centrifuge to separate the reaction liquid and catalyst;

[0030] e: After the reaction solution is filtered through a silica gel column, it is concentrated and dried under reduced pressure to obtain the hydrogenation product γ-valerolactone.

[0031] Preferably, the alkali is one of potassium carbonate, potassium bicarbonate, potassium hydroxide, potassium tert-butoxide, potassium ethoxide, potassium methoxide, sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium tert-butoxide, sodium ethoxide, or sodium methoxide; and the solvent is one of toluene, xylene, trimethylbenzene, ethylbenzene, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, or acetonitrile.

[0032] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a highly efficient polymer catalyst for the hydrogenation of levulinic acid to γ-valerol, using a sawmill-frame structured metal complex as the active center. The metal center and ligands are bonded through stable covalent or coordinate bonds. The preferred metal center is ruthenium or osmium. It is suitable for high-pressure reactors equipped with magnetic or mechanical stirring. The catalyst raw materials are readily available, low in cost, and simple to prepare. It eliminates the need for phosphine and amine ligands, efficiently catalyzes the hydrogenation of levulinic acid to γ-valerol under mild conditions, and is easily separated, recycled, and reused. It requires no complex equipment, facilitates large-scale production, and has promising industrial application prospects. This provides a green and efficient technical route for the conversion of levulinic acid to γ-valerol, which can help supplement and partially replace fossil resources such as petroleum and coal, further expanding the application of γ-valerol in green solvents, renewable fuel additives, and other fields, demonstrating significant industrial application prospects and economic and environmental benefits. Attached Figure Description

[0033] Figure 1 The bar graph shows the recycling performance of polymer catalyst 2 in the hydrogenation of levulinic acid to γ-valerol in an embodiment of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] This invention provides a technical solution: a highly efficient polymer catalyst for the hydrogenation of levulinic acid to γ-valerol, the structural formula of which is as follows:

[0036]

[0037] Wherein, M is selected from Ru, Os, Mn, Fe, Mo, Co, or Re; X is a metal-donating atom or group coordinated with the metal center, preferably O or NH; R is a metal-donating group, preferably an amino group, a straight-chain group, or a branched C1-C group. 20 Alkyl, C3-C 20 cycloalkyl, C1-C 10 Alkoxy group; n is an integer selected from 0 to 8.

[0038] It includes raw materials L and B, whose structural formulas are as follows:

[0039]

[0040] In this invention, the synthesis of polymer-based metal complex catalysts was carried out under anhydrous and oxygen-free conditions using standard Schillerk techniques, as follows:

[0041] (1) Within the temperature range of 40℃ to reflux, L is reacted with the metal carbonyl compound M. x (CO) y The reaction mixture was heated under reflux in an organic solvent at a molar ratio of x:0.5-2 for 10-72 hours. After the reaction was complete, intermediate i was obtained by concentration under reduced pressure, filtration to collect the solid precipitate, washing with a polar solvent, and drying under reduced pressure. In this synthesis, the organic solvent can be selected from toluene, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, etc., and the polar solvent can be selected from toluene, dichloromethane, chloroform, tetrahydrofuran, etc.

[0042] (2) Within the temperature range of 0℃ to reflux, the intermediate i obtained in step (1) is reacted with the substituted benzene (B) and the metal halide in an anhydrous solvent at a molar ratio of 1:1-5:1-10 using a temperature-controlled program for 12-72 hours. After the reaction is complete, a certain amount of hydrochloric acid aqueous solution is added, and the mixture is stirred for 0.5-2 hours. The solid is then collected by filtration, washed with ethanol and water, and dried under reduced pressure. In this synthesis process, the metal halide is selected from AlCl3, FeCl3, and ZnCl2, and the volume and concentration of the hydrochloric acid aqueous solution are 30-100 mL and 0.2-1 mol / L, respectively.

[0043] The activity evaluation of the above polymer-based metal complex catalyst for the hydrogenation of levulinic acid to γ-valerate was carried out in a high-pressure reactor equipped with magnetic or mechanical stirring, and the operation method is as follows:

[0044] Within a temperature range of 60-160℃, with an initial hydrogen pressure of 1-100 bar, and a polymer catalyst to levulinic acid mass ratio of 1:100-1000000, the reaction can be carried out under solvent-free conditions or in the presence of organic solvents, with a reaction time of 0.1-300 hours, to obtain the target reaction product. A certain amount of alkali needs to be added to the reaction, such as potassium carbonate, potassium bicarbonate, potassium hydroxide, potassium tert-butoxide, potassium ethoxide, potassium methoxide, sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium tert-butoxide, sodium ethoxide, sodium methoxide, etc., with potassium carbonate and potassium bicarbonate being preferred. The organic solvent is selected from toluene, xylene, trimethylbenzene, ethylbenzene, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, acetonitrile, etc., with toluene and ethylbenzene being preferred. The substrate conversion rate and product yield are detected and analyzed by gas chromatography or liquid nuclear magnetic resonance spectroscopy equipped with a hydrogen ion flame detector.

[0045] Example 1

[0046] Preparation of polymer catalyst 1:

[0047] Step (1): Weigh 1.28g of Ru3(CO) under an inert atmosphere. 12 2.0 mmol of chlorobutyric acid (4-chlorobutyric acid) and 0.86 g of chlorobutyric acid (7.0 mmol) were placed in a Schiller flask (200 mL) containing about 60 mL of toluene. After reflux heating for 48 hours, the reaction solution was cooled to room temperature under an inert atmosphere and concentrated under reduced pressure until a large amount of yellow precipitate precipitated. The precipitate was collected by filtration and washed with toluene. The product was dried under reduced pressure and weighed to 1.46 g (yield 87%), yielding the intermediate Ru2(CO)4[Cl(CH2)3COO]2(ia).

[0048] Step (2): Under an inert atmosphere, weigh 0.56 g (1.0 mmol) of intermediate ia obtained in step (1), 0.28 g (3.0 mmol) of toluene, and 0.67 g (5.0 mmol) of AlCl3 into a 200 mL Schiller flask containing 60 mL of acetonitrile. Under stirring conditions, react at 10 °C for 6 hours, 20 °C for 6 hours, 40 °C for 8 hours, 60 °C for 12 hours, and 80 °C for 24 hours, respectively. After the reaction is complete, add 30 mL of hydrochloric acid aqueous solution to the reaction solution, stir for 1 hour, filter to collect the solid, and wash successively with ethanol (30 mL), water (20 mL), and ethanol (30 mL), then dry under reduced pressure. The solid weighs 0.62 g, yielding polymer catalyst 1.

[0049]

[0050] Example 2

[0051] Preparation of polymer catalyst 2:

[0052] Step (1): Weigh 1.28g of Ru3(CO) under an inert atmosphere. 12 2.0 mmol of 5-chlorovalerate and 0.96 g of 5-chlorovalerate (7.0 mmol) were placed in a Schiller flask (200 mL) containing about 60 mL of toluene. After reflux heating for 48 hours, the reaction solution was cooled to room temperature under an inert atmosphere and concentrated under reduced pressure until a large amount of yellow precipitate precipitated. The precipitate was collected by filtration and washed with toluene. The product was dried under reduced pressure and weighed to 1.54 g (yield 88%) to give the intermediate Ru2(CO)4[Cl(CH2)4COO]2(ib).

[0053] Step (2): Under an inert atmosphere, weigh 0.58 g (1.0 mmol) of intermediate ib obtained in step (1), 0.28 g (3.0 mmol) of toluene, and 0.67 g (5.0 mmol) of AlCl3 into a 200 mL Schiller flask containing 60 mL of acetonitrile. Under stirring conditions, react at 10 °C for 6 hours, 20 °C for 6 hours, 40 °C for 8 hours, 60 °C for 12 hours, and 80 °C for 24 hours, respectively. After the reaction is complete, add 30 mL of hydrochloric acid aqueous solution to the reaction solution, stir for 1 hour, filter to collect the solid, and wash successively with ethanol (30 mL), water (20 mL), and ethanol (30 mL), then dry under reduced pressure. The solid weighs 0.64 g, yielding polymer catalyst 2.

[0054]

[0055] Example 3

[0056] Preparation of polymer catalyst 3:

[0057] Step (1): Weigh 1.28g of Ru3(CO) under an inert atmosphere. 12 2.0 mmol of 6-chlorohexanoic acid and 1.05 g of 6-chlorohexanoic acid (7.0 mmol) were placed in a Schiller flask (200 mL) containing about 60 mL of toluene. After reflux and heating for 48 hours, the reaction solution was cooled to room temperature under an inert atmosphere and concentrated under reduced pressure until a large amount of yellow precipitate precipitated. The solid product was collected by filtration and washed with toluene. It was dried under reduced pressure and weighed to 1.67 g (yield 91%) to give intermediate Ru2(CO)4[Cl(CH2)5COO]2(ic).

[0058] Step (2): Under an inert atmosphere, weigh 0.61 g (1.0 mmol) of intermediate ic obtained in step (1), 0.28 g (3.0 mmol) of toluene, and 0.67 g (5.0 mmol) of AlCl3 into a 200 mL Schiller flask containing 60 mL of acetonitrile. Under stirring conditions, react at 10 °C for 6 hours, 20 °C for 6 hours, 40 °C for 8 hours, 60 °C for 12 hours, and 80 °C for 24 hours, respectively. After the reaction is complete, add 30 mL of hydrochloric acid aqueous solution to the reaction solution, stir for 1 hour, filter to collect the solid, and wash successively with ethanol (30 mL), water (20 mL), and ethanol (30 mL), then dry under reduced pressure. The solid weighs 0.66 g, yielding polymer catalyst 3.

[0059]

[0060] Example 4

[0061] Preparation of polymer catalyst 4:

[0062] Step (1): Weigh 1.28g of Ru3(CO) under an inert atmosphere. 12 2.0 mmol of 7-chloroheptanoic acid and 1.15 g of 7-chloroheptanoic acid (7.0 mmol) were placed in a Schiller flask (200 mL) containing about 60 mL of toluene. After reflux and heating for 48 hours, the reaction solution was cooled to room temperature under an inert atmosphere and concentrated under reduced pressure until a large amount of yellow precipitate precipitated. The precipitate was collected by filtration and washed with toluene. The solid product was dried under reduced pressure and weighed to 1.75 g (yield 91%) to give the intermediate Ru2(CO)4[Cl(CH2)4COO]2(ib).

[0063] Step (2): Under an inert atmosphere, weigh 0.64 g (1.0 mmol) of intermediate id obtained in step (1), 0.28 g (3.0 mmol) of toluene, and 0.67 g (5.0 mmol) of AlCl3 into a 200 mL Schiller flask containing 60 mL of acetonitrile. Under stirring conditions, react at 10 °C for 6 hours, 20 °C for 6 hours, 40 °C for 8 hours, 60 °C for 12 hours, and 80 °C for 24 hours, respectively. After the reaction is complete, add 30 mL of hydrochloric acid aqueous solution to the reaction solution, stir for 1 hour, filter to collect the solid, and wash successively with ethanol (30 mL), water (20 mL), and ethanol (30 mL), then dry under reduced pressure. The solid weighs 0.72 g, yielding polymer catalyst 4.

[0064]

[0065] Example 5

[0066] Preparation of polymer catalyst 5:

[0067] Step (1): Weigh 1.28g of Ru3(CO) under an inert atmosphere. 12 2.0 mmol and 0.95 g of 5-chloropentanamide (7.0 mmol) were placed in a Schiller flask (200 mL) containing about 60 mL of toluene. After reflux heating for 48 hours, the reaction solution was cooled to room temperature under an inert atmosphere and concentrated under reduced pressure until a large amount of pale yellow precipitate precipitated. The precipitate was collected by filtration and washed with toluene. The product was dried under reduced pressure and weighed to 1.45 g (yield 83%) to give intermediate Ru2(CO)4[Cl(CH2)4CONH]2(ie);

[0068] Step (2): Under an inert atmosphere, weigh 0.58 g (1.0 mmol) of the intermediate ie obtained in step (1), 0.28 g (3.0 mmol) of toluene, and 0.67 g (5.0 mmol) of AlCl3 into a 200 mL Schiller flask containing 60 mL of acetonitrile. Under stirring conditions, react at 10 °C for 6 hours, 20 °C for 6 hours, 40 °C for 8 hours, 60 °C for 12 hours, and 80 °C for 24 hours, respectively. After the reaction is complete, add 30 mL of hydrochloric acid aqueous solution to the reaction solution, stir for 1 hour, filter to collect the solid, and wash successively with ethanol (30 mL), water (20 mL), and ethanol (30 mL), then dry under reduced pressure. The solid weighs 0.63 g, yielding polymer catalyst 5.

[0069]

[0070] Examples 6-22 describe methods for the hydrogenation of levulinic acid to γ-valerate using polymer catalysts 1-5.

[0071] Example 6:

[0072] In an argon-atmospheric glove box, polymer catalyst 1 (5.0 mg), levulinic acid (5.0 g, levulinic acid to catalyst mass ratio 1000:1), and potassium carbonate (0.30 g, levulinic acid to potassium carbonate molar ratio 20:1) were weighed into a 50 mL high-pressure reactor equipped with a magnetic stirrer. The reactor body was then assembled and transferred out of the glove box. Subsequently, the reactor body was cooled to approximately 10°C with ice water, and 6 mL of toluene was added under nitrogen protection. After replacing the atmosphere inside the reactor with hydrogen, hydrogen was purged to 50 bar. The reactor body was placed in a heating device and heated to 100°C with stirring, and maintained at this temperature for 2 hours. After the reaction was completed, the reactor body was rapidly cooled to approximately 10°C, and the remaining hydrogen gas in the reactor was purged. The catalyst and reaction solution were separated by centrifugation. The reaction solution was filtered through a silica gel column, concentrated and dried under reduced pressure, and a small amount was prepared into a toluene solution and analyzed by gas chromatography with a flame ionization detector (the column model was HB-Wax, and the specifications were 30m×0.32mm×0.33μm). The conversion rate of levulinic acid was 96%, and the yield of the target reaction product γ-valerolactone was 96%.

[0073] Example 7:

[0074] Following the same experimental steps as in Example 5, the polymer catalyst was changed to 2 (5.0 mg), the conversion rate of levulinic acid was 100%, and the yield of the target reaction product γ-valerolactone was 100%.

[0075] Example 8:

[0076] Following the same experimental steps as in Example 5, the polymer catalyst was changed to 3 (5.0 mg), the conversion rate of levulinic acid was 98%, and the yield of the target reaction product γ-valerolactone was 98%.

[0077] Example 9:

[0078] Following the same experimental steps as in Example 5, the polymer catalyst was changed to 4 (5.0 mg), the conversion rate of levulinic acid was 93%, and the yield of the target reaction product γ-valerolactone was 93%.

[0079] Example 10:

[0080] Following the same experimental steps as in Example 5, the polymer catalyst was changed to 5 (5.0 mg), the conversion rate of levulinic acid was 96%, and the yield of the target reaction product γ-valerolactone was 96%.

[0081]

[0082] Table 1. Overall results of the hydrogenation of levulinic acid to γ-valerol using polymer catalysts in Examples 6-10.

[0083] Example 11:

[0084] Following the same experimental steps as in Example 7, the mass of potassium carbonate was changed to 0.12 g (molar ratio of levulinic acid to potassium carbonate 50:1), the conversion rate of levulinic acid was 63%, and the yield of the target reaction product γ-valerolactone was 62%.

[0085] Example 12:

[0086] Following the same experimental steps as in Example 7, the mass of potassium carbonate was changed to 0.24 g (molar ratio of levulinic acid to potassium carbonate 25:1), the conversion rate of levulinic acid was 94%, and the yield of the target reaction product γ-valerolactone was 94%.

[0087] Example 13:

[0088] Following the same experimental steps as in Example 7, the mass of potassium carbonate was changed to 0.48 g (molar ratio of levulinic acid to potassium carbonate 25:2), the conversion rate of levulinic acid was 91%, and the yield of the target reaction product γ-valerolactone was 91%.

[0089]

[0090] Table 2 shows the catalytic hydrogenation of levulinic acid to the form shown in Examples 7, 11-13 under different potassium carbonate dosages using polymer catalyst 2.

[0091] Overall results of γ-valerol

[0092] Example 14:

[0093] Following the same experimental steps as in Example 7, without adding solvent, the conversion rate of levulinic acid was 100%, and the yield of the target reaction product γ-valerol was 100%.

[0094] Example 15:

[0095] The experimental steps were the same as in Example 7, except that the solvent was changed to p-ethylbenzene (6 mL), the conversion rate of levulinic acid was 99%, and the yield of the target reaction product γ-valerolactone was 99%.

[0096] Example 16:

[0097] The experimental steps were the same as in Example 7, except that the solvent was changed to tetrahydrofuran (6 mL), the conversion rate of levulinic acid was 86%, and the yield of the target reaction product γ-valerolactone was 86%.

[0098] Example 17:

[0099] The experimental steps were the same as in Example 7, except that the solvent was changed to acetonitrile (6 mL), the conversion rate of levulinic acid was 83%, and the yield of the target reaction product γ-valerolactone was 83%.

[0100]

[0101] Table 3. Overall results of polymer catalyst 2 in Examples 7, 14-17 catalyzing the hydrogenation of levulinic acid to γ-valerol in different solvents.

[0102] Example 18:

[0103] The experimental steps were the same as in Example 7, but the catalyst mass was changed to 2.5 mg (the mass ratio of levulinic acid to catalyst was 2000:1), the conversion rate of levulinic acid was 100%, and the yield of the target reaction product γ-valerolactone was 100%.

[0104] Example 19:

[0105] The experimental steps were the same as in Example 18, except that a 100 mL reactor was used, the mass of levulinic acid was changed to 25.0 g (the mass ratio of levulinic acid to catalyst was 10000:1), the mass of potassium carbonate was changed to 1.5 g (the molar ratio of levulinic acid to potassium carbonate was 20:1), the volume of toluene was changed to 10 mL, the reaction time was changed to 6 hours, the conversion rate of levulinic acid was 89%, and the yield of the target reaction product γ-valerolactone was 88%.

[0106] Example 20:

[0107] Following the same experimental steps as in Example 19, without adding solvent, the conversion rate of levulinic acid was 99%, and the yield of the target reaction product γ-valerolactone was 99%.

[0108] Example 21:

[0109] The experimental steps were the same as in Example 20, except that a 500 mL reactor was used, the mass of the catalyst was changed to 1 mg, the mass of levulinic acid was changed to 100.0 g (the mass ratio of levulinic acid to catalyst was 100000:1), the mass of potassium carbonate was changed to 6.0 g (the molar ratio of levulinic acid to potassium carbonate was 20:1), the reaction time was changed to 24 hours, the conversion rate of levulinic acid was 96%, and the yield of the target reaction product γ-valerolactone was 96%.

[0110] Example 22:

[0111] Following the same experimental steps as in Example 20, the mass of levulinic acid was changed to 250.0 g (the mass ratio of levulinic acid to catalyst was 250000:1), the mass of potassium carbonate was changed to 15.0 g (the molar ratio of levulinic acid to potassium carbonate was 20:1), the reaction temperature was changed to 120 °C, the reaction time was changed to 72 hours, the conversion rate of levulinic acid was 95%, and the yield of the target reaction product γ-valerolactone was 95%.

[0112]

[0113] Table 4 shows the overall results of the hydrogenation of levulinic acid to γ-valerate using polymer catalyst 2 under different conditions in Examples 18-22.

[0114] Examples 23-27 describe methods for the repeated use of polymer catalyst 2 to catalyze the hydrogenation of levulinic acid to produce γ-valerol.

[0115] Example 23:

[0116] The reaction solution obtained in Example 20 was centrifuged (2000 rpm, 3 minutes) and the solid matter was collected. Following the same experimental procedure as in Example 20, the catalyst was converted to the solid matter obtained by centrifugation. The conversion rate of levulinic acid was 99%, and the yield of the target reaction product γ-valerolactone was 99%.

[0117] Example 24:

[0118] The reaction solution obtained in Example 23 was centrifuged (2000 rpm, 3 minutes) and the solid matter was collected. Following the same experimental procedure as in Example 20, the catalyst was replaced by the solid matter obtained by centrifugation. The conversion rate of levulinic acid was 98%, and the yield of the target reaction product γ-valerolactone was 98%.

[0119] Example 25:

[0120] The reaction solution obtained in Example 24 was centrifuged (2000 rpm, 3 minutes) and the solid matter was collected. Following the same experimental procedure as in Example 20, the catalyst was replaced by the solid matter obtained by centrifugation. The conversion rate of levulinic acid was 98%, and the yield of the target reaction product γ-valerolactone was 98%.

[0121] Example 26:

[0122] The reaction solution obtained in Example 25 was centrifuged (2000 rpm, 3 minutes) and the solid matter was collected. Following the same experimental procedure as in Example 20, the catalyst was converted to the solid matter obtained by centrifugation. The conversion rate of levulinic acid was 96%, and the yield of the target reaction product γ-valerolactone was 96%.

[0123] Example 27:

[0124] The reaction solution obtained in Example 26 was centrifuged (2000 rpm, 3 minutes) and the solid matter was collected. Following the same experimental procedure as in Example 20, the catalyst was converted to the solid matter obtained by centrifugation. The conversion rate of levulinic acid was 95%, and the yield of the target reaction product γ-valerolactone was 95%.

[0125] The experimental results summarized in Tables 1-4 show that the polymer catalyst with a sawmill frame structure as its active center, invented in this patent, can efficiently catalyze the hydrogenation of levulinic acid to γ-valerate under mild conditions. From... Figure 1 The results show that the polymer catalyst has good recyclability. These results effectively overcome the shortcomings of heterogeneous catalysts reported in current literature and patents, such as harsh reaction conditions, numerous side reactions, and the difficulty in separating, recovering, and reusing homogeneous catalysts after reaction.

[0126] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A highly efficient polymer catalyst for the hydrogenation of levulinic acid to γ-valerol, characterized in that: Its structural formula is as follows: M is selected from one of Ru, Os, Mn, Fe, Mo, Co, or Re; X is a metal-electro ...

2. The polymer catalyst for the hydrogenation of levulinic acid to γ-valerol as described in claim 1, characterized in that: The interaction between M and O, X ligands is through covalent or coordinate bonds, and this interaction can be stable in both solid and solution states.

3. The polymer catalyst for the hydrogenation of levulinic acid to γ-valerol as described in claim 1, characterized in that: X is preferably O or NH; R is an electron-donating group, preferably an amino group, a straight-chain group, or a branched C1-C group. 20 Alkyl, C3-C 20 cycloalkyl, C1-C 10 Alkoxy group; n is an integer selected from 0 to 8.

4. A method for preparing a highly efficient polymer catalyst for the hydrogenation of levulinic acid to γ-valerol, characterized in that: Including raw materials L and B, their structural formulas are as follows: The specific preparation steps are as follows: S1: Under oxygen- and water-free conditions, within the temperature range of 40℃ to reflux, L is reacted with the metal carbonyl compound M. x (CO) y The intermediate i was obtained by heating under reflux in an organic solvent at a ratio of x: 0.5-2 for 10-72 hours, followed by vacuum concentration, filtration, washing with a polar solvent, and vacuum drying. S2: Under oxygen- and water-free conditions, weigh the intermediate i, substituted benzene (B), and metal halide obtained in step S1 in a molar ratio of 1:1-5:1-10, add anhydrous solvent, and place in a Schiller bottle; under an inert atmosphere, react the reaction solution in a programmed temperature control manner within the range of 0℃ to reflux temperature for 12-72 hours. S3: Add hydrochloric acid aqueous solution to the final reaction solution obtained in step S2, stir for 0.5-2 hours, filter and collect the solid product, wash with ethanol, water and ethanol in sequence, and dry under reduced pressure to obtain polymer catalyst.

5. The method for preparing a highly efficient polymer catalyst for the hydrogenation of levulinic acid to γ-valerate as described in claim 4, characterized in that: In S1, the organic solvent is selected from one of toluene, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, and 1,4-dioxane; The polar solvent is selected from one of toluene, dichloromethane, chloroform, and tetrahydrofuran; In S2, the metal halide is selected from one of AlCl3, FeCl3, and ZnCl2; The anhydrous solvent is selected from one of acetonitrile, nitrobenzene, and carbon disulfide; In S2, the volume of the hydrochloric acid aqueous solution is 30-100 mL.

6. The application of a polymer-based metal complex catalyst according to any one of claims 1-3 in the efficient catalytic hydrogenation of levulinic acid to γ-valerol.

7. The application of the polymer-based metal complex catalyst as described in claim 6 in the highly efficient catalytic hydrogenation of levulinic acid to γ-valerol, characterized in that: The application method is as follows: Under a hydrogen atmosphere, with an initial hydrogen pressure in the range of 1-100 bar and a temperature of 60-160℃, the polymer catalyst and levulinic acid are added to the solvent at a mass ratio of 1:100-1000000 and an alkali is added to carry out the reaction. The reaction time is 0.1-300 hours to obtain the hydrogenation reaction product γ-valerolactone.

8. The application of the polymer-based metal complex catalyst as described in claim 7 in the highly efficient catalytic hydrogenation of levulinic acid to γ-valerol, characterized in that: The operation steps are as follows: a: Under an inert atmosphere, weigh the polymer catalyst, base, and levulinic acid into the reactor and then assemble the reactor body; b: After cooling the vessel body to 0-10℃ with ice water, add 0-200ml of solvent under inert atmosphere protection, then replace the atmosphere inside the vessel with hydrogen and purge with hydrogen to the specified pressure; c: Place the vessel in a heating device to heat and react; d: After the reaction is complete, quickly cool the vessel to 0-10℃, remove the remaining hydrogen gas from the vessel, and centrifuge to separate the reaction liquid and catalyst; e: After the reaction solution is filtered through a silica gel column, it is concentrated and dried under reduced pressure to obtain the hydrogenation product γ-valerolactone.

9. The application of the polymer-based metal complex catalyst as described in claim 8 in the highly efficient catalytic hydrogenation of levulinic acid to γ-valerol, characterized in that: The alkali is one of potassium carbonate, potassium bicarbonate, potassium hydroxide, potassium tert-butoxide, potassium ethoxide, potassium methoxide, sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium tert-butoxide, sodium ethoxide, or sodium methoxide; the solvent is one of toluene, xylene, trimethylbenzene, ethylbenzene, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, or acetonitrile.

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