Method for preparing cyclopentanol from furfural through one-pot method

Abstract

The invention discloses a method for preparing cyclopentanol by using furfural through a one-pot method, which comprises the following steps: by using isopropanol as a reaction solvent and Pt / H beta as a catalyst, reacting in a high-pressure reaction kettle at 180-190 DEG C in a hydrogen atmosphere of 4-4.5 MPa for 3-4 hours to prepare cyclopentanol by using furfural as a raw material through the one-pot method. The preparation process is simple, the raw materials are easy to obtain, the reaction time is short, the reaction process is environment-friendly and pollution-free, the catalytic system is relatively simple, the raw material conversion rate can reach 100%, and the highest cyclopentanol yield can reach 95.66%.

Description

Technical Field

[0001] This invention belongs to the field of cyclopentanol preparation technology, specifically relating to a one-pot method for preparing cyclopentanol using furfural as a raw material. Background Technology

[0002] With its abundant reserves and renewable nature, biomass resources have become a key focus in the energy and environmental fields, particularly in their potential to replace traditional energy sources and be converted into high-value-added fine chemicals. This conversion technology can effectively alleviate the energy crisis and improve ecological and environmental issues, while also providing a green and low-carbon raw material supply route, possessing significant strategic energy importance and environmental value. Furfural, as a typical biomass-based platform molecule, serves as a bridge between biomass and high-value chemicals. In its hydrogenation reaction, it can be directionally converted into products such as furfuryl alcohol, tetrahydrofuran, pentanediol, cyclopentanone, and cyclopentanol, forming a high-value-added biomass industrial chain. Therefore, utilizing chemical methods to efficiently catalytically convert furfural into the high-value-added product cyclopentanol has significant social and economic implications.

[0003] Cyclopentanol, a key product in the high-value-added biomass industrial chain, has become a research hotspot in the fine chemical industry due to its rigid demand and broad market. In the synthetic rubber industry, it is used to improve the aging resistance of tires, with an annual demand exceeding 50,000 tons; in the fragrance industry, it is an important raw material for synthesizing high-end fragrance substances, and its market share continues to climb. In recent years, its downstream demand has maintained a strong annual growth rate of approximately 8%.

[0004] Currently, the catalytic conversion of furfural to cyclopentanol has been studied to some extent. For example, the Hronec team pioneered a systematic investigation of this reaction system using a 5% Pt / C catalyst, comparing the differences between using organic solvents such as tetrahydrofuran and n-butanol as reaction media and water. The results showed that in an aqueous system, at a reaction temperature of 175 °C and a hydrogen pressure of 8 MPa, the total yield of cyclopentanone and cyclopentanol could reach 76% (Catal. Commun., 2012, 24, 100-104). Zhou et al. reported the use of Cu... 2.5 Mg 12.5 The Al5 catalyst showed promising results, achieving a cyclopentanol yield of up to 93.4% after 10 h of reaction at 4 MPa H2 and 140 °C. However, the catalyst exhibited significant deactivation after two reuses, primarily attributed to the sintering of Cu particles during the reaction. This stability issue limits its practical application (J. Energy Chem., 2014, 23, 91-96). Huang's team developed a Cu... 0.4 Mg 5.6Al2 catalysts exhibit excellent reactivity, achieving a cyclopentanol yield of 98.6% after 12 h of reaction at 190 °C and 2 MPa H2. However, the reaction conditions are quite demanding, and the reaction system is sensitive to substrate concentration. When the furfural concentration is increased to 30 wt%, the cyclopentanol yield significantly decreases to 62.1% (Ind. Eng. Chem. Res. 2019, 58, 3988–3993). Pan et al. studied the catalytic performance of Cu / Fe3O4 catalysts. A 10% Cu / Fe3O4 catalyst, reacting at 170 °C and 3 MPa for 4 h, achieved a cyclopentanone yield of 91%, while a 50% Cu / Fe3O4 catalyst yielded a maximum cyclopentanol yield of 82%. However, the high Cu loading (50%) in this system resulted in poor atom economy (Chem. Select., 2019, 4, 5845–5852). Researchers such as Mironenko investigated the catalytic behavior of a bimetallic Pd-Ru / C catalyst. In an aqueous furfural hydrogenation system (reaction temperature 200 °C, H2 pressure 8 MPa), the activity of this bimetallic catalyst was significantly superior to that of monometallic Pd / C and Ru / C catalysts. When the furfural conversion reached 100%, the yield of the target product cyclopentanol reached 77% (Kinet. Catal., 2018, 59, 339-346). Wang's team further expanded the application potential of Ru-based catalysts, using a RuMo / CNT composite catalyst (Ru loading 1 wt%, Mo loading 2.5 wt%) to react at 180 °C and 4 MPa H2 for 4 h, achieving a cyclopentanol yield of 89.1% (Front. Bioeng. Biotechnol., 2020, 8, 615235).

[0005] In summary, although existing research on the catalytic conversion of furfural to cyclopentanol has made some progress, problems such as insufficient catalyst stability, harsh reaction conditions, and poor atom economy still exist. Therefore, providing a one-pot method for the efficient preparation of cyclopentanol from furfural that is stable, economical, environmentally friendly, and has excellent catalytic performance has great academic research value and practical application prospects. Summary of the Invention

[0006] To address the problems of complex processes and low yields in the preparation of cyclopentanol from furfural in existing technologies, this invention provides a one-pot method for preparing cyclopentanol from furfural that features high catalytic activity, readily available raw materials, a simple process, and is environmentally friendly.

[0007] The method for preparing cyclopentanol by one-pot method of furfural provided by the present invention is as follows: furfural and isopropanol are placed in a high-pressure reactor, Pt / Hβ catalyst is added, and the reaction is stirred at 180-190 °C for 3-4 h under a hydrogen atmosphere of 4-4.5 MPa. After the reaction is completed, the mixture is cooled to room temperature, and the catalyst is separated by centrifugation to obtain cyclopentanol.

[0008] In the above-described one-pot method for preparing cyclopentanol using furfural, the mass ratio of furfural to Pt / Hβ catalyst is 1:0.3–1.0, preferably 1:0.5–0.8. Specifically, based on the mass of the catalyst (100%), the Pt loading in the Pt / Hβ catalyst is 1.5%–3.5%, preferably 2%–3%.

[0009] In the above one-pot method for preparing cyclopentanol from furfural, the catalyst obtained after centrifugation is washed with ethanol and deionized water, and then vacuum dried at 40–60 °C for 20–24 h for reuse.

[0010] The preparation method of the above-mentioned Pt / Hβ-x catalyst is as follows: Commercially available β-zeolite is calcined at 500–600 °C for 3–5 h in air to obtain activated β-zeolite; sodium hydroxide, sodium aluminate, tetraethylammonium hydroxide, and deionized water are mixed, and the activated β-zeolite is added, and a dissolution-recrystallization reaction is carried out at 120–160 °C for 3–5 h; after the reaction is completed, the mixture is washed, dried, and calcined at 500–600 °C for 3–5 h to obtain hollow hierarchical β-zeolite; the hollow hierarchical β-zeolite is subjected to ion exchange in ammonium chloride aqueous solution, followed by washing, drying, and calcination at 500–600 °C for 3–5 h to obtain Hβ-zeolite; chloroplatinic acid is loaded onto Hβ-zeolite using an impregnation method, and then calcined at 450–550 °C for 3–5 h in air; finally, it is reduced by 1–3 times at 200–400 °C in a mixed atmosphere of hydrogen and argon. h, the Pt / Hβ catalyst was obtained.

[0011] In the above-mentioned method for preparing the Pt / Hβ catalyst, the preferred mass ratio of the activated β zeolite to sodium hydroxide, sodium aluminate, tetraethylammonium hydroxide, and deionized water is 1:0.5-0.6:0.3-0.4:2.0-4.0:40-60.

[0012] In the above-mentioned method for preparing the Pt / Hβ catalyst, the dissolution-recrystallization reaction is preferably carried out at 130–150 °C.

[0013] In the above-mentioned method for preparing Pt / Hβ catalyst, hollow hierarchical β zeolite is preferably subjected to ion exchange in a 1-2 mol / L ammonium chloride aqueous solution at 75-95 °C for 2-4 times, each time for 1-6 h.

[0014] In the above method for preparing the Pt / Hβ-x catalyst, the preferred volume ratio of hydrogen to argon is 1:9.

[0015] The beneficial effects of this invention are as follows:

[0016] This invention utilizes isopropanol as the reaction solvent and a Pt / Hβ catalyst to achieve a one-pot hydrogenolysis process for preparing cyclopentanol from furfural in a high-pressure reactor under a hydrogen atmosphere. The preparation process is simple, the raw materials are readily available, the reaction is environmentally friendly and pollution-free, and the catalytic system is relatively simple. The raw material conversion rate can reach 100%, and the cyclopentanol yield can reach a maximum of 95.66%. Furthermore, the Pt / Hβ catalyst exhibits good stability and can be recycled after washing and drying, saving resources and reducing costs. It has significant application value and is suitable for industrial production and application. Detailed Implementation

[0017] The technical solution of the present invention will be described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited to these embodiments.

[0018] The Pt / Hβ catalyst used in the following examples was prepared according to the following method:

[0019] 1 g of commercially available β-zeolite (produced by Tianjin Nanhua Catalyst Co., Ltd., a market-purchased commodity) was heated to 550 °C at a heating rate of 5 °C / min under air atmosphere and calcined at this temperature for 4 h to obtain activated β-zeolite. 0.55 g of sodium hydroxide, 0.35 g of sodium aluminate, 2.9 g of tetraethylammonium hydroxide, and 50 g of deionized water were mixed, and 1 g of activated β-molecular sieve was added. After stirring evenly, the mixture was transferred to a polytetrafluoroethylene-lined high-pressure reactor and subjected to a dissolution-recrystallization reaction at 140 °C for 3 h and 5 h, respectively. After the reaction was complete, the solid was washed with deionized water, dried at 100 °C for 12 h, and then heated to 550 °C at a heating rate of 5 °C / min under air atmosphere and calcined at this temperature for 4 h to obtain hollow hierarchical porous β-zeolite, which was designated as β-3 zeolite and β-5 zeolite based on the different reaction times. Hollow hierarchical porous β-zeolite was ion-exchanged in a 2 mol / L ammonium chloride aqueous solution at 85 °C for 2 h, and the ion-exchange was repeated 3 times. After the ion-exchange reaction was completed, the surface was washed with deionized water to remove residual ammonium salts and other impurities, then dried at 100 °C for 12 h, and finally calcined at 550 °C in air at a heating rate of 5 °C / min for 4 h to obtain Hβ zeolite, which was designated as Hβ-3 zeolite and Hβ-5 zeolite, respectively. 1 g of the obtained Hβ zeolite was poured into a 25 mL round-bottom flask, and 3.4649 mL of 0.02 g / mL H2PtCl6 (purchased from Maclean (Shanghai) Biochemical Technology Co., Ltd.) aqueous solution was added. The mixture was sonicated for 30 min, stirred at room temperature for 12 h, and the solvent was evaporated by rotary evaporation. After drying at 100 °C for 12 h, the temperature was increased to 550 °C at a rate of 5 °C / min under air atmosphere and calcined at this temperature for 4 h. Finally, the temperature was increased to 300 °C at a rate of 2 °C / min under a mixed atmosphere of hydrogen and argon (volume ratio 1:9) and reduced at this temperature for 2 h to obtain the Pt / Hβ catalyst. Based on the mass of the catalyst (100%), the Pt loading in the Pt / Hβ catalyst was 2.5%, and it was designated as 2.5Pt / Hβ-3 catalyst and 2.5Pt / Hβ-5 catalyst, respectively.

[0020] Example 1

[0021] 0.1869 g of furfural and 30 mL of isopropanol were placed in a 50 mL high-pressure reactor, followed by the addition of 0.1 g of 2.5Pt / Hβ-5 catalyst. The reactor was purged with N2 at room temperature, and then hydrogen gas was introduced into the reactor. The reaction was carried out for 3 h under a hydrogen atmosphere, at a pressure of 4 MPa, a temperature of 180 ℃, and a stirring rate of 600 rpm to ensure complete conversion of furfural. The reactor was then 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). -1Initial column temperature: 40 ℃, final column temperature: 250 ℃, heating rate: 10 ℃ / min, hold at 40 ℃ for 3 min, hold at 160 ℃ for 1 min, hold at 250 ℃ for 3 min. Detector temperature: 250 ℃. Furfural conversion rate: 100%, cyclopentanol yield: 95.66%.

[0022] The catalyst obtained by centrifugation was washed successively with ethanol and deionized water, then placed in a vacuum drying oven and dried at 50 °C for 24 h. It was then added to a high-pressure reactor and recycled a second time under the same conditions. The results showed that the furfural conversion rate was 100% and the cyclopentanol yield was 93.86%. A third recycling was performed using the same method, achieving a furfural conversion rate of 100% and a cyclopentanol yield of 90.12%.

[0023] Example 2

[0024] In this embodiment, the 2.5Pt / Hβ-5 catalyst in Example 1 was replaced with an equal mass of 2.5Pt / Hβ-3 catalyst, and the other steps were the same as in Example 1. The results showed that the furfural conversion rate was 100% and the cyclopentanol yield was 92.13%.

[0025] Example 3

[0026] In this embodiment, the amount of 2.5Pt / Hβ-5 catalyst added was 0.125 g, and the other steps were the same as in Example 1. The results showed that the furfural conversion rate was 100% and the cyclopentanol yield was 95.14%.

[0027] Example 4

[0028] In this embodiment, the amount of 2.5Pt / Hβ-5 catalyst added was 0.150 g, and the other steps were the same as in Example 1. The results showed that the furfural conversion rate was 100% and the cyclopentanol yield was 95.68%.

[0029] Example 5

[0030] In this embodiment, the reaction was carried out for 3 hours under a hydrogen atmosphere, at a pressure of 4.5 MPa, a temperature of 180 °C, and a stirring speed of 600 rpm. Other steps were the same as in Example 1. The results showed that the furfural conversion rate was 100%, and the cyclopentanol yield was 95.35%.

[0031] Example 6

[0032] In this embodiment, the reaction was carried out for 3 hours under a hydrogen atmosphere, at a pressure of 4.0 MPa, a temperature of 190 °C, and a stirring speed of 600 rpm. Other steps were the same as in Example 1. The results showed that the furfural conversion rate was 100%, and the cyclopentanol yield was 93.97%.

[0033] Example 7

[0034] In this embodiment, the reaction was carried out for 4 hours under a hydrogen atmosphere, at a pressure of 4.0 MPa, a temperature of 180 °C, and a stirring speed of 600 rpm. Other steps were the same as in Example 1. The results showed that the furfural conversion rate was 100%, and the cyclopentanol yield was 92.66%.

Claims

1. A process for the one-pot preparation of cyclopentanol from furfural, characterized in that: The furaldehyde and isopropyl alcohol are placed in a high-pressure reaction kettle, a Pt / Hβ catalyst is added, and stirring reaction is carried out at 4-4.5 MPa hydrogen atmosphere and 180-190 ℃ for 3-4 hours; after the reaction is completed, the catalyst is separated by centrifugation, and cyclopentanol is obtained; The mass ratio of the furaldehyde to the Pt / Hβ catalyst is 1:0.3-1.0; and the loading amount of Pt in the Pt / Hβ catalyst is 1.5%-3.5% based on 100% of the mass of the catalyst. The preparation method of the Pt / Hβ catalyst is as follows: commercially available β zeolite is calcined at 500-600 ℃ in air atmosphere for 3-5 hours to obtain activated β zeolite; sodium hydroxide, sodium aluminate, tetraethylammonium hydroxide and deionized water are mixed, and the activated β zeolite is added to carry out a dissolution-recrystallization reaction at 120-160 ℃ for 3-5 hours; after the reaction is completed, washing, drying and calcination at 500-600 ℃ for 3-5 hours are carried out, and hollow multi-level pore β zeolite is obtained; the hollow multi-level pore β zeolite is subjected to ion exchange in an ammonium chloride aqueous solution, and then washing, drying and calcination at 500-600 ℃ for 3-5 hours are carried out to obtain Hβ zeolite; the Hβ zeolite is used as a carrier, and an impregnation method is used to load chloroplatinic acid, and then calcination at 450-550 ℃ in air atmosphere for 3-5 hours is carried out, and finally reduction at 200-400 ℃ in a mixed gas atmosphere of hydrogen and argon for 1-3 hours is carried out to obtain the Pt / Hβ catalyst.

2. The process for the one-pot preparation of cyclopentanol from furfural according to claim 1, characterized in that: The loading amount of Pt in the Pt / Hβ catalyst is 2%-3% based on 100% of the mass of the catalyst.

3. The process for the one-pot preparation of cyclopentanol from furfural according to claim 1 or 2, characterized in that: The mass ratio of the furaldehyde to the Pt / Hβ catalyst is 1:0.5-0.

8.

4. The process for the one-pot preparation of cyclopentanol from furfural according to claim 1, characterized in that: In the preparation method of the Pt / Hβ catalyst, the mass ratio of the activated β zeolite to sodium hydroxide, sodium aluminate, tetraethylammonium hydroxide, deionized water is 1:0.5-0.6:0.3-0.4:2.0-4.0:40-60.

5. The process for the one-pot preparation of cyclopentanol from furfural according to claim 1, characterized in that: In the preparation method of the Pt / Hβ catalyst, the dissolution-recrystallization reaction is carried out at 130-150 ℃.

6. The process for the one-pot preparation of cyclopentanol from furfural according to claim 1, characterized by: In the preparation method of the Pt / Hβ catalyst, the hollow multi-level pore β zeolite is ion exchanged in 1-2 mol / L ammonium chloride aqueous solution at 75-95 ℃ for 2-4 times, and each time is 1-6 hours.

7. The process for the one-pot preparation of cyclopentanol from furfural according to claim 1, characterized by: In the preparation method of the Pt / Hβ catalyst, the volume ratio of hydrogen to argon is 1:

9.

8. The process for the one-pot preparation of cyclopentanol from furfural according to claim 1, characterized by: The catalyst obtained after centrifugal separation is washed with ethanol and deionized water, and then vacuum dried at 40-60 ℃ for 20-24 hours for repeated use.