Method for preparing gamma-valerolactone by one-pot hydrogenolysis of D-xylose

Abstract

The invention discloses a method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose, which uses isopropyl alcohol as a reaction solvent and Pt / Hβ as a catalyst. In an autoclave, under a hydrogen atmosphere, D-xylose is used as a raw material for one-pot hydrogenolysis to prepare γ-valerolactone. The preparation process of the present invention is simple, the raw materials are easily available, the reaction time is short, the reaction process is environmentally friendly and pollution-free, and the catalytic system is relatively simple, the raw material conversion rate can reach 100%, and the γ-valerolactone yield can reach up to 52.1%. Pt / Hβ has good stability and can be recycled after simple filtration and drying, which can save resources, reduce costs, and has important application value.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of gamma-valerolactone, and particularly relates to a method for preparing gamma-valerolactone by one-pot hydrogenolysis using D-xylose as a raw material. Background Art

[0002] Lignocellulose is a promising biomass feedstock due to its natural abundance and is generally considered more viable than first-generation biofuel feedstocks because it does not compete with food crops for arable land. Therefore, developing appropriate technologies and infrastructure to effectively utilize lignocellulosic feedstocks is of great benefit to society from both a social and economic perspective. γ-Valerolactone (GVL), derived from lignocellulose, has attracted increasing attention as a versatile biomass-derived platform chemical due to its promising properties as a green solvent and fuel additive, as well as a precursor for the production of liquid alkanes and high-value biopolymers.

[0003] GVL is typically produced by converting monosaccharides released by hydrolysis of lignocellulose into levulinic acid (LA) using an acid catalyst, which is then hydrogenated to GVL using hydrogen and a metal catalyst. While this method reportedly provides high GVL yields, it also has some significant drawbacks: the use of mineral acids in the acid-catalyzed step; the multi-step reaction; and high production costs.

[0004] At present, the use of different catalysts to catalyze the one-pot hydrogenolysis of D-xylose can synthesize various high-value-added platform compounds. For example, Deng et al. used a bifunctional Cu / SBA-15-SO3H catalyst to catalyze the conversion of D-xylose into furfuryl alcohol in a water / n-butanol biphasic solvent for 6 hours at the optimized conditions of 140 ° C and 4MPa H2, with a yield of 62.6% (Chinese J. Catal., 2020, 41, 404–414). Canhaci et al. studied the platinum catalyst supported on ordered mesoporous SBA-15 with -SO3H groups (Pt / SBA-15-SO3H )The above-mentioned process for the one-step conversion of D-xylose to furfuryl alcohol achieved a 54% yield of furfuryl alcohol under optimized conditions of 130°C and 3 MPa H₂ for 6 h (Appl. Catal. B-Environ., 2017, 207, 279-285). Insyani et al. reported a one-pot cascade conversion of D-xylose to tetrahydrofurfuryl alcohol over a RuO₂-Ru catalyst supported on Hβ zeolite (RuO₂-Ru / Hβ). In tetrahydrofuran, with an initial H₂ pressure of 3 MPa and reaction time of 1 h at 180°C, D-xylose was nearly completely converted, with a yield of 61.8% for tetrahydrofurfuryl alcohol (Appl. Catal. B-Environ., 2021, 291, 120120). Liang et al. prepared a carbon-nitrogen-coated metal Co catalyst (Co@NC) for the direct conversion of D-xylose. At 200°C and 3.0 MPa H₂ for 3 h, the yield of 1,2-pentanediol was 27.4% (J. Fuel Chem. Technol., 2021, 49, 1898–1910). In a previously published study, our laboratory used a mesoporous nitrogen-carbon-supported platinum catalyst (Pt / NC) with the aid of an organic acid to achieve a one-pot catalytic conversion of D-xylose to 1,2-pentanediol. In the presence of 2.5Pt / NC600 catalyst and propionic acid as a cocatalyst, D-xylose was reacted in water at 200°C and 3 MPa H₂ for 8 h, resulting in a 49.3% yield of 1,2-pentanediol (ChemSusChem, 2024, e202401109).

[0005] The catalyst, using H₂ as a hydrogen donor, catalyzes the cascade conversion of D-xylose into various high-value-added platform compounds, showing promising results. Therefore, providing a synthetically simple, environmentally friendly, and high-yielding, one-pot method for the efficient hydrogenolysis of D-xylose to produce GVL is of great research value. Summary of the Invention

[0006] In order to solve the problem of complex process of preparing γ-valerolactone by hydrogenolysis of D-xylose as raw material in the prior art, the present invention provides a method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose with high catalytic activity, easy raw materials, simple process and environmental friendliness.

[0007] The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose provided by the present invention comprises the following steps: placing D-xylose and isopropanol in a high-pressure reactor, adding a Pt / Hβ catalyst, stirring and reacting for 8 to 20 hours in a hydrogen atmosphere at a pressure of 1.5 to 4.5 MPa and a temperature of 130 to 210° C., cooling to room temperature after the reaction is completed, and separating the catalyst by centrifugation to obtain γ-valerolactone.

[0008] In the above method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose, the mass ratio of D-xylose to Pt / Hβ catalyst is 0.5-4:1, preferably the mass ratio of D-xylose to Pt / Hβ catalyst is 1.5-2.5:1.

[0009] In the above-mentioned method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose, the reaction is preferably stirred for 12 to 16 hours under a hydrogen atmosphere, a pressure of 2.5 to 3.5 MPa, and a temperature of 170 to 190°C.

[0010] The preparation method of the above-mentioned Pt / Hβ catalyst is as follows: commercially available Hβ zeolite is calcined at 500-600°C for 3-5 hours in an air atmosphere to obtain activated Hβ zeolite; then, using the activated Hβ zeolite as a carrier, H2PtCl6 is loaded by an impregnation method, and then calcined at 350-450°C for 3-5 hours in an air atmosphere, and finally reduced at 200-400°C for 1-3 hours in a mixed atmosphere of hydrogen and argon to obtain a Pt / Hβ catalyst; based on the mass of the catalyst as 100%, the Pt loading amount in the Pt / Hβ catalyst is 0.5% to 5%.

[0011] In the preparation method of the Pt / Hβ catalyst, commercially available Hβ zeolite is preferably calcined at 550° C. for 4 hours in an air atmosphere to obtain activated Hβ zeolite.

[0012] In the preparation method of the above-mentioned Pt / Hβ catalyst, it is preferred to use activated Hβ zeolite as a carrier, load H2PtCl6 by impregnation method, and then calcine at 400°C for 4h in an air atmosphere.

[0013] In the preparation method of the Pt / Hβ catalyst, the heating rate of the calcination is preferably 3 to 5° C. / min.

[0014] In the preparation method of the Pt / Hβ catalyst, the reduction is preferably carried out at 300° C. for 1 to 3 hours in a mixed atmosphere of hydrogen and argon with a volume ratio of 1:9.

[0015] In the preparation method of the Pt / Hβ catalyst, the temperature increase rate of the reduction in a mixed atmosphere of hydrogen and argon is preferably 1 to 3° C. / min.

[0016] In the above method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose, based on the mass of the catalyst as 100%, the Pt loading amount in the Pt / Hβ catalyst is preferably 2% to 3%.

[0017] The beneficial effects of the present invention are as follows:

[0018] The present invention uses isopropyl alcohol as the reaction solvent and a Pt / Hβ catalyst as the catalyst to produce γ-valerolactone using D-xylose as the raw material through a one-pot hydrogenolysis process in an autoclave under a hydrogen atmosphere. The preparation process is simple, the raw materials are readily available, the reaction process is environmentally friendly and pollution-free, and the catalytic system is relatively simple. The raw material conversion rate can reach 100%, and the γ-valerolactone yield can reach a maximum of 52.1%. The Pt / Hβ catalyst also exhibits excellent stability and can be recycled after simple filtration and drying, thus conserving resources and reducing costs. The present invention has significant application value and is suitable for industrial production and application. DETAILED DESCRIPTION

[0019] The technical solutions of the present invention are described in detail below with reference to the embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0020] The Pt / Hβ catalysts used in the following examples were prepared according to the following method:

[0021] 1g of commercially available Hβ zeolite (produced by Tianjin Nanhua Catalyst Co., Ltd. and purchased from the market) was heated to 550°C at a heating rate of 5°C / min in an air atmosphere and calcined at this temperature for 4 hours to obtain activated Hβ zeolite. The activated Hβ zeolite was then poured into a 25mL round-bottom flask, and 3.4649mL of a 0.02g / mL H2PtCl6 aqueous solution (purchased from MacLean (Shanghai) Biochemical Technology Co., Ltd.) was added. After sonication for 30 minutes, the mixture was stirred at room temperature for 12 hours, the solvent was evaporated by rotary evaporation, and the mixture was dried at 100°C for 12 hours to obtain a white solid powder. The resulting white solid powder was then heated to 400°C at a heating rate of 5°C / min in an air atmosphere and calcined at this temperature for 4 hours. Finally, the mixture was heated to 300°C at a heating rate of 2°C / min in a mixed atmosphere of hydrogen and argon (volume ratio: 1:9) and reduced at this temperature for 2 hours to obtain a Pt / Hβ catalyst. The Pt loading in the Pt / Hβ catalyst was 2.5%.

[0022] Example 1

[0023] 0.1869 g of D-xylose and 30 mL of isopropanol were placed in a 50 mL autoclave, and 0.1 g of Pt / Hβ catalyst was added. The autoclave was evacuated with N2 at room temperature, and then hydrogen was introduced into the autoclave. The reaction was carried out under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 180°C, and a stirring rate of 600 rpm for 15 h to complete the conversion of D-xylose. The autoclave was cooled to room temperature in an ice bath, and the catalyst was separated by centrifugation. The product was analyzed by gas chromatography (carrier gas: nitrogen, flow rate: 2.0 mL min -1, initial column temperature: 40°C, final column temperature: 250°C, heating rate: 10°C / min, 40°C for 3 min, 160°C for 1 min, 250°C for 3 min. Detector temperature: 250°C), the yield of γ-valerolactone was 52.1%.

[0024] Example 2

[0025] 0.0934 g of D-xylose and 30 mL of isopropanol were placed in a 50 mL autoclave, and 0.1 g of Pt / Hβ catalyst was added. The autoclave was evacuated with N2 at room temperature, and then hydrogen was introduced into the autoclave. The reaction was carried out under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 180°C, and a stirring rate of 600 rpm for 15 h to complete the conversion of the D-xylose. The mixture was cooled to room temperature in an ice bath, and the catalyst was separated by centrifugation. The product was analyzed by gas chromatography (analysis conditions were the same as in Example 1), and the yield of γ-valerolactone was 34.8%.

[0026] Example 3

[0027] 0.2804 g of D-xylose and 30 mL of isopropanol were placed in a 50 mL autoclave, and 0.1 g of Pt / Hβ catalyst was added. The autoclave was evacuated with N2 at room temperature, and then hydrogen was introduced into the autoclave. The reaction was carried out under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 180°C, and a stirring rate of 600 rpm for 15 h to complete the conversion of the D-xylose. The mixture was cooled to room temperature in an ice bath, and the catalyst was separated by centrifugation. The product was analyzed by gas chromatography (analysis conditions were the same as in Example 1), and the yield of γ-valerolactone was 43.9%.

[0028] Example 4

[0029] 0.1869 g of D-xylose and 30 mL of isopropanol were placed in a 50 mL autoclave, and 0.075 g of Pt / Hβ catalyst was added. The autoclave was evacuated with N2 at room temperature, and then hydrogen was introduced into the autoclave. The reaction was carried out for 15 h under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 180°C, and a stirring rate of 600 rpm to complete the conversion of the D-xylose. The mixture was cooled to room temperature in an ice bath, and the catalyst was separated by centrifugation. The product was analyzed by gas chromatography (analysis conditions were the same as in Example 1), and the yield of γ-valerolactone was 37.0%.

[0030] Example 5

[0031] 0.1869 g of D-xylose and 30 mL of isopropanol were placed in a 50 mL autoclave, and 0.125 g of Pt / Hβ catalyst was added. The autoclave was evacuated with N2 at room temperature, and then hydrogen was introduced into the autoclave. The reaction was carried out under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 180°C, and a stirring rate of 600 rpm for 15 h to complete the conversion of the D-xylose. The mixture was cooled to room temperature in an ice bath, and the catalyst was separated by centrifugation. The product was analyzed by gas chromatography (analysis conditions were the same as in Example 1), and the yield of γ-valerolactone was 45.0%.

[0032] Example 6

[0033] In this example, the reaction was carried out for 15 h under a hydrogen atmosphere, a pressure of 2.5 MPa, a temperature of 180° C., and a stirring rate of 600 rpm. Other steps were the same as in Example 1 to obtain γ-valerolactone with a yield of 40.1%.

[0034] Example 7

[0035] In this example, the reaction was carried out for 15 h under a hydrogen atmosphere, a pressure of 3.5 MPa, a temperature of 180° C., and a stirring rate of 600 rpm. Other steps were the same as in Example 1 to obtain γ-valerolactone with a yield of 41.1%.

[0036] Example 8

[0037] In this example, the reaction was carried out for 15 h under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 170° C., and a stirring rate of 600 rpm. Other steps were the same as in Example 1 to obtain γ-valerolactone with a yield of 33.9%.

[0038] Example 9

[0039] In this example, the reaction was carried out for 15 h under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 190° C., and a stirring rate of 600 rpm. Other steps were the same as in Example 1 to obtain γ-valerolactone with a yield of 49.1%.

[0040] Example 10

[0041] In this example, the reaction was carried out for 14 h under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 180° C., and a stirring rate of 600 rpm. Other steps were the same as in Example 1 to obtain γ-valerolactone with a yield of 50.2%.

[0042] Example 11

[0043] In this example, the reaction was carried out for 16 h under a hydrogen atmosphere, a pressure of 3 MPa, a temperature of 180° C., and a stirring rate of 600 rpm. Other steps were the same as in Example 1 to obtain γ-valerolactone with a yield of 49.1%.

Claims

1. A method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose, characterized in that: D-xylose and isopropanol are placed in a high-pressure reactor, a Pt / Hβ catalyst is added, and the reaction is stirred for 8 to 20 hours under a hydrogen atmosphere, a pressure of 1.5 to 4.5 MPa, and a temperature of 130 to 210°C. After the reaction is completed, the mixture is cooled to room temperature and the catalyst is separated by centrifugation to obtain γ-valerolactone. The mass ratio of D-xylose to Pt / Hβ catalyst is 0.5-4:1; The preparation method of the Pt / Hβ catalyst is as follows: commercially available Hβ zeolite is calcined at 500-600°C for 3-5 hours in an air atmosphere to obtain activated Hβ zeolite; then, the activated Hβ zeolite is used as a carrier to load H2PtCl6 by an impregnation method, and then calcined at 350-450°C for 3-5 hours in an air atmosphere; finally, the catalyst is reduced at 200-400°C for 1-3 hours in a mixed atmosphere of hydrogen and argon to obtain a Pt / Hβ catalyst; based on the mass of the catalyst as 100%, the Pt loading amount in the Pt / Hβ catalyst is 0.5%-5%.

2. The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose according to claim 1, characterized in that: In the preparation method of the Pt / Hβ catalyst, commercially available Hβ zeolite is calcined at 550° C. for 4 h in an air atmosphere to obtain activated Hβ zeolite.

3. The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose according to claim 1, characterized in that: In the preparation method of the Pt / Hβ catalyst, activated Hβ zeolite is used as a carrier, H2PtCl6 is loaded by an impregnation method, and then calcined at 400°C for 4 hours in an air atmosphere.

4. The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose according to any one of claims 1 to 3, characterized in that: In the preparation method of the Pt / Hβ catalyst, the heating rate of the calcination is 3-5°C / min.

5. The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose according to claim 1, characterized in that: In the preparation method of the Pt / Hβ catalyst, the catalyst is reduced at 300° C. for 1 to 3 hours in a mixed atmosphere of hydrogen and argon with a volume ratio of 1:

9.

6. The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose according to claim 1 or 5, characterized in that: In the preparation method of the Pt / Hβ catalyst, the heating rate of reduction in a mixed atmosphere of hydrogen and argon is 1-3°C / min.

7. The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose according to claim 1, characterized in that: Based on 100% of the mass of the catalyst, the loading amount of Pt in the Pt / Hβ catalyst is 2% to 3%.

8. The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose according to claim 1, characterized in that: D-xylose and isopropanol were placed in a high-pressure reactor, Pt / Hβ catalyst was added, and the reaction was stirred for 12 to 16 hours under a hydrogen atmosphere, a pressure of 2.5 to 3.5 MPa, and a temperature of 170 to 190°C.

9. The method for preparing γ-valerolactone by one-pot hydrogenolysis of D-xylose according to claim 1 or 8, characterized in that: The mass ratio of the D-xylose to the Pt / Hβ catalyst is 1.5-2.5:1.