Preparation method and application of palladium / amphoteric chelate resin hydrogenation catalyst

Abstract

The invention belongs to the technical field of noble metal supported catalysts, and particularly relates to a preparation method and application of a palladium / amphoteric chelate resin hydrogenation catalyst. The preparation method comprises the following steps: heating and stirring primary amine resin, a phosphorous acid aqueous solution and hydrochloric acid, then adding formaldehyde and preserving heat to obtain functional resin; purifying the functional resin in an ion exchange column, and washing with water to obtain amphoteric chelate resin; the preparation method comprises the following steps: adding a palladium nitrate solution into amphoteric chelate resin, stirring, filtering and cleaning to obtain amphoteric chelate resin loaded with palladium ions, and then carrying out ascorbic acid liquid phase reduction and mixed hydrogen flow gas phase reduction to obtain the palladium / amphoteric chelate resin hydrogenation catalyst. According to the application, the prepared hydrogenation catalyst is used for preparing cyclopentanone through furfuryl alcohol hydrogenation. The invention designs a novel preparation method, and solves the problems of insufficient selectivity, catalytic activity and long-time use structural stability of an ion exchange resin-based catalyst obtained by the existing preparation method.

Description

Technical Field

[0001] The present invention belongs to the technical field of noble metal supported catalysts, and particularly relates to a preparation method and application of a palladium / amphoteric chelating resin hydrogenation catalyst. Background Art

[0002] Cyclopentanone is an organic compound with important application value. From the perspectives of chemical synthesis and industrial applications, it shows important application value in multiple fields such as cosmetics, medicine, energy, national defense, and materials. Due to the importance of cyclopentanone, the optimization and innovation of its preparation process have become the focus of common concern in the academic and industrial communities. Currently, the main method for preparing cyclopentanone is the pyrolysis of adipic acid. In addition, there are also methods such as the oxidation of cyclopentene, the cyclopentane method, and the catalytic oxidation of cyclopentanol. However, the raw materials used in traditional methods are mostly derivatives of fossil energy, which exacerbates the consumption of fossil energy and does not conform to the current development trend of the chemical industry with low VOCs. Therefore, the development of a synthetic process based on renewable resources, environmentally friendly, and with high atom economy is of great significance for the development of the cyclopentanone industry.

[0003] As a potential green synthesis route, the catalytic hydrogenation of furfuryl alcohol has attracted much attention due to its wide raw material sources, low cost, and efficient utilization of biomass resources. This process uses furfuryl alcohol as the starting material and realizes the efficient conversion of cyclopentanone through catalytic hydrogenation reaction. Not only is the energy utilization efficiency significantly improved, but it also conforms to the basic principles of green chemistry. Therefore, the research on the hydrogenation of furfuryl alcohol to prepare cyclopentanone not only has important scientific significance but also may provide a sustainable technical path for the industrial production of cyclopentanone.

[0004] The process for preparing cyclopentanone by hydrogenation of furfuryl alcohol mainly relies on copper, cobalt, nickel, palladium or platinum-based catalysts, such as molecular sieve catalysts, supported metal catalysts and ion exchange resin-based catalysts; among them, in non-polar or high-viscosity reaction media, molecular sieve catalysts are prone to mass transfer limitations, resulting in reduced reaction efficiency; some molecular sieve catalysts will cause irreversible deactivation of the catalyst when exposed to the aqueous phase environment for a long time, restricting their application scope. In addition, supported metal catalysts are prone to metal detachment during the reaction process, causing the catalyst to gradually deactivate. For example, the supported metal catalysts mentioned in patents such as CN118949983A, CN113649004A, CN117563600A, CN114605246A, etc. The supported metal catalysts prepared by the traditional impregnation method have problems such as uneven metal distribution and easy dissolution, resulting in obvious batch differences and affecting the consistency of catalytic performance. In contrast, ion exchange resin-based catalysts show certain advantages in catalytic applications, mainly reflected in the following aspects: (1) Ion exchange resins show good stability in aqueous phase, organic phase and two-phase systems and are ideal carriers; (2) When ion exchange resins are used as carriers, metal active components are combined with ion exchange resins by ion exchange or chelation, etc., effectively reducing the risk of metal ion detachment; (3) Ion exchange resins have good physical, chemical and mechanical stabilities, can be specifically resistant to acidic or alkaline environments, are beneficial to extending the service life of the catalyst, and reducing the operating cost during industrial production. At present, several patents have disclosed methods for preparing ion exchange resin-based catalysts with cation exchange resins and palladium nitrate, such as CN1457927A, CN1288782A, etc. When preparing ion exchange resin-based catalysts in such patents, acidic cation exchange resins are used to exchange ions with palladium ions, resulting in uneven metal loading, thus affecting the stability and service life of the catalyst. To solve the above problems, Chinese patent CN101486000A discloses a method of first forming a chelate with a chelating agent and a palladium salt, and then using the impregnation method to combine the palladium chelate with the ion exchange resin through van der Waals forces. This is a method of indirectly chelating with a third component. Although it improves the loading uniformity of palladium ions to a certain extent; however, some chelating agents used in this method, such as dimethylglyoxime and diphenylthiocarbazone, have poor water solubility, and there is a risk of gradual aggregation of the formed palladium chelate in the resin pores, affecting catalytic activity and long-term use stability. Based on the above problems, there is an urgent need to develop a new method for preparing resin catalysts to improve the selectivity, catalytic activity and long-term use structural stability of ion exchange resin-based catalysts, especially that the catalyst can be used for catalyzing the hydrogenation of furfuryl alcohol to prepare cyclopentanone. Summary of the Invention

[0005] The object of the present invention is to provide a preparation method of a palladium / amphoteric chelating resin hydrogenation catalyst to solve the problems of insufficient selectivity, catalytic activity and structural stability during long-term use of the ion exchange resin-based catalyst obtained by the current preparation methods; the present invention also provides an application, and this catalyst can be used for the hydrogenation of furfuryl alcohol to prepare cyclopentanone.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: The preparation method of the palladium / amphoteric chelating resin hydrogenation catalyst described in the present invention includes the following steps: (1) Blend a primary amine resin, an aqueous phosphorous acid solution and hydrochloric acid, heat and stir, then add formaldehyde and keep warm, and obtain a functionalized resin after cooling and filtration; the primary amine resin is made by introducing a primary amino group into a polystyrene-divinylbenzene resin and is a commercially available product; (2) Load the functionalized resin into an ion exchange column, treat the resin with pure water and hydrochloric acid in sequence, and then wash with water to obtain an amphoteric chelating resin; (3) Add a palladium nitrate solution to the amphoteric chelating resin, stir and filter, and then wash the amphoteric chelating resin until there is no palladium ion in the washing water to obtain an amphoteric chelating resin loaded with palladium ions; (4) Perform liquid-phase reduction on the amphoteric chelating resin loaded with palladium ions using an aqueous ascorbic acid solution, and after standing, filtering, washing and drying, then perform gas-phase reduction on the amphoteric chelating resin loaded with palladium ions using a mixed hydrogen gas stream to obtain a palladium / amphoteric chelating resin hydrogenation catalyst.

[0007] Among them: In the step (1), the concentration of the aqueous phosphorous acid solution is 18-22 wt%, the concentration of hydrochloric acid is 36-38 wt%, the mass ratio of the aqueous phosphorous acid solution, hydrochloric acid to the primary amine resin is (1.25-1.45):(0.25-0.35):1, the concentration of formaldehyde is 33-42 wt%, and the mass ratio of formaldehyde to the primary amine resin is (0.25-0.3):1; the stirring temperature is 85-95 °C, and the heat preservation time is 10-15 h.

[0008] In the step (2), the purity of hydrochloric acid is 4-7 wt%, the mass ratio of pure water, hydrochloric acid to the functionalized resin is (7-12):4:1, and the feeding flow rates of pure water and hydrochloric acid are 2-4 BV / h; during water washing, when the pH value of the effluent is ≥ 3.0, the water washing is completed.

[0009] In the said step (2), the physicochemical indexes of the amphoteric chelating resin are as follows: particle size range 0.4 - 0.5 mm, coefficient of uniformity 1.19 - 1.21, water content 54.22 - 55.35%, wet apparent density 0.73 g / mL, wet true density 1.10 - 1.12 g / mL, attrition resistance of spherical beads 99%, weak acid group exchange capacity 2.23 - 2.40 mmol / g, weak base group exchange capacity 2.28 - 2.52 mmol / g.

[0010] In the said step (3), the concentration of the palladium nitrate solution is 0.75 - 0.85 wt%, and the mass ratio of the palladium nitrate solution to the amphoteric chelating resin is (1.75 - 5.0):1; the stirring temperature is 23 - 30 °C, and the stirring time is 4 - 6 h.

[0011] In the said step (3), the cleaning method of the amphoteric chelating resin loaded with palladium ions is to wash it with pure water multiple times and then filter it by suction or pass it through an ion exchange column.

[0012] In the said step (4), the concentration of the ascorbic acid aqueous solution is 9.5 - 10.5 wt%, the mass ratio of the ascorbic acid aqueous solution to the amphoteric chelating resin is (1 - 3):1, the standing time is 6 - 12 h, and the drying temperature is 60 - 70 °C.

[0013] In the said step (4), the volume ratio of hydrogen to nitrogen in the mixed hydrogen gas stream is 1:(7 - 9), the gas-phase reduction temperature is 220 - 250 °C, the gas-phase reduction time is 3 - 5 h; the palladium loading of the palladium / amphoteric chelating resin hydrogenation catalyst is 1.0 - 3.5 wt%.

[0014] The application of the palladium / amphoteric chelating resin hydrogenation catalyst described in the present invention: Add furfuryl alcohol and water into a reaction kettle, then continue to add the palladium / amphoteric chelating resin hydrogenation catalyst, start stirring, introduce hydrogen for hydrogenation reaction, and cyclopentanone is obtained after filtration.

[0015] Among them: The ratio of the palladium / amphoteric chelating resin hydrogenation catalyst to furfuryl alcohol is (0.1 - 0.3):1, and the mass ratio of furfuryl alcohol to water is 1:(10 - 100).

[0016] The reaction kettle needs to be purged with hydrogen 5 - 10 times, the hydrogen pressure of the hydrogenation reaction is 1 - 3 MPa, the hydrogenation reaction temperature is 140 - 180 °C, the stirring speed is 160 - 180 rpm, and the hydrogenation reaction duration is 5 - 10 h.

[0017] The structural formula of the palladium / amphoteric chelating resin hydrogenation catalyst prepared by the present invention is as follows: .

[0018] The beneficial effects of the present invention are as follows: (1) The present invention modifies the existing primary amine resin with a polystyrene-divinylbenzene backbone. Based on the macroporous structure and capillary action of the polystyrene-divinylbenzene resin, aminomethylphosphonic acid groups (-NHCH 2 -PO 3 H 2 ) are selectively introduced into the macroporous structure, and an appropriate amount of primary amino groups (-CH 2 NH 2 ) are retained to prepare an amphoteric chelating resin. The two functional groups have a synergistic coordination effect: the protonated primary amino group (-NH 3 + ) can rapidly capture palladium ions. The simple structure of the primary amino group makes it easy to orient on both sides of the pore channels, forming a planar quadrilateral coordination cavity together with the aminomethylphosphonic acid groups. Since the electronic configuration of Pd 2+ is d 8 , and the typical coordination configuration is a parallelogram, this coordination cavity can minimize the repulsive force between the d-orbital electrons in Pd 2+ , improving the stability of the system.

[0019] (2) In the present invention, ascorbic acid is not only a reducing agent but also has the functions of not affecting the normal nucleation process of the hydrogenation catalyst and reducing the aggregation of palladium nanoparticles: the reduction mechanism of ascorbic acid is a two-step single-electron transfer process. Compared with conventional reducing agents such as NaBH 4 , the reduction rate of ascorbic acid is moderate, allowing Pd 0 atoms to nucleate uniformly in the pore channels of the amphoteric chelating resin; the weak coordination ability of ascorbic acid does not interfere with the interaction between the amphoteric chelating resin and palladium ions during the reduction process. Thus, the amphoteric chelating resin can fully exert the confinement effect of the aminomethylphosphonic acid groups and primary amino groups in its macroporous structure, control the particle size of the hydrogenation catalyst, limit the orientation and diffusion path of reactant molecules, and improve the selectivity of the target product. In addition, after participating in the reaction, the organic chain segments in the protonated ascorbic acid formed can be adsorbed around the newly formed palladium nanoparticles. Through its hydrophilic groups, hydrogen bond networks are formed with the organic chain segments in other ascorbic acids and water molecules, reducing the movement of water molecules and forming steric hindrance to prevent particle aggregation and ensure the catalytic activity of the hydrogenation catalyst.

[0020] Sodium borohydride and hydrazine hydrate are commonly used metal ion reducing agents. Strong reducing agents such as sodium borohydride or hydrazine hydrate can cause the movement and aggregation of palladium ions inside the amphoteric chelating resin carrier, affecting the dispersion of the metal on the macroporous structure within the amphoteric chelating resin. The reducing ability of ascorbic acid is weaker than that of sodium borohydride and hydrazine hydrate, and the reduction reaction is milder. Under the action of ascorbic acid, the palladium ions chelated on the resin can be slowly reduced, which is beneficial to the uniform dispersion of palladium inside the amphoteric chelating resin. After the liquid-phase reduction with ascorbic acid, zero-valent palladium is uniformly dispersed on the amphoteric chelating resin, and then the reduction with hydrogen at high temperature is used to ensure that all palladium ions are reduced to palladium metal.

[0021] (3) The preparation process of this catalyst is simple. After reduction treatment, it can highly selectively catalyze the hydrogenation of furfuryl alcohol to cyclopentanone under low hydrogen pressure conditions. The yield of the present invention is significantly higher than that of the palladium-loaded catalyst prepared from commercially available chelating resin, and it has good stability in recycling. The resin skeleton of the palladium / amphoteric chelating resin hydrogenation catalyst of the present invention is attached with abundant phosphonic acid groups, which can provide a complete acidic environment instead of hydrochloric acid in the traditional process, avoiding the corrosion of the equipment caused by directly adding hydrochloric acid. In addition, the catalyst of the present invention is used in the aqueous phase, and no other reaction aids need to be added during the reaction process, and no difficult-to-treat waste liquid will be formed, which is environmentally friendly and conducive to large-scale industrial production. The experimental results show that the present invention realizes the efficient conversion of furfuryl alcohol to cyclopentanone by using a novel hydrogenation catalyst, which not only improves the added value of biomass resources but also conforms to the basic principles of green chemistry. Further, the present invention provides a novel amphoteric chelating resin. This resin has stable physical and chemical properties, and the functional groups are easy to regulate, and it can stably load other metal ions as needed, expanding its application range. Therefore, the catalyst and the application technical route provided by the present invention have important application value in the industrial production of cyclopentanone. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the gas chromatogram of the solution containing cyclopentanone in Example 1; Figure 2 It is the gas chromatogram of the solution containing cyclopentanone in Example 2; Figure 3 It is the gas chromatogram of the solution containing cyclopentanone in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention will be specifically described and illustrated below with reference to the examples.

[0024] Example 1 Prepare a palladium / amphoteric chelating resin hydrogenation catalyst: (1) Accurately weigh 35 g of primary amine resin and add it to a three-necked flask. Add 43.8 g of 20 wt% phosphorous acid aqueous solution and 10 g of 38 wt% hydrochloric acid. Heat it to 90 °C under mechanical stirring, and then slowly add 8.8 g of 37 wt% formaldehyde. After keeping the temperature for 15 h, cool it naturally to room temperature, and filter out the functionalized resin. The primary amine resin is produced by Shandong Decuan Chemical Technology Co., Ltd., with the brand D303.

[0025] (2) Load the functionalized resin into an ion exchange column, and adopt the way of flowing in from the top and out from the bottom. According to the mass ratio of pure water, dilute hydrochloric acid to the functionalized resin of 8:4:1, treat the functionalized resin with pure water and 5 wt% hydrochloric acid in turn, and the feeding flow rate of pure water and dilute hydrochloric acid is 3 BV / h; then wash the functionalized resin with pure water until the pH value of the effluent is ≥ 3.0 to obtain the amphoteric chelating resin.

[0026] The physical and chemical indexes of the amphoteric chelating resin are as follows: particle size range 0.4 - 0.5 mm, uniformity coefficient 1.21, water content 55.35%, wet apparent density 0.73 g / mL, wet true density 1.11 g / mL, attrition resistance rate of spherical particles 99%, weak acid group exchange capacity 2.35 mmol / g, weak base group exchange capacity 2.52 mmol / g.

[0027] (3) Weigh 50 g of the amphoteric chelating resin and add it to a 250 mL three-necked round-bottom flask. Add 120 g of 0.8 wt% palladium nitrate solution, stir mechanically at 25 °C for 4 h, then filter out the solution, load the amphoteric chelating resin into an ion exchange column, and wash it with pure water until there is no palladium ion in the effluent to obtain the amphoteric chelating resin loaded with palladium ions.

[0028] (4) Add the amphoteric chelating resin loaded with palladium ions to a 250 mL beaker, add 50 g of 10 wt% ascorbic acid aqueous solution, let it stand at room temperature for 6 h, then filter and wash it 3 times with pure water. Then dry it in a vacuum drying oven at 60 °C, and then load it into a fixed bed. Carry out gas-phase reduction of the resin catalyst for 3 h in a mixed hydrogen stream (the volume ratio of hydrogen to nitrogen is 1:9) at 220 °C, and naturally cool it to obtain the palladium / amphoteric chelating resin hydrogenation catalyst. Use XRF to characterize the palladium / amphoteric chelating resin hydrogenation catalyst, and the measured palladium loading is 1.8 wt%.

[0029] Catalyze the hydrogenation of furfuryl alcohol to prepare cyclopentanone: Weigh 1.0 g of furfuryl alcohol and 19 mL of deionized water, mix them and transfer them to a high-pressure reactor. Then, add 0.2 g of the palladium / amphoteric chelating resin hydrogenation catalyst.

[0030] The autoclave was purged with hydrogen five times. After the purging was completed, hydrogen was introduced and the autoclave was pressurized to 1.4 MPa. The magnetic stirring device was started, the rotation speed was set at 180 rpm, and at the same time, the reaction system was heated to 160 °C at a heating rate of 5 °C / min and reacted for 5 h.

[0031] After the reaction was completed, the system was naturally cooled to room temperature. The resin catalyst in the reaction solution was filtered, and finally a solution containing cyclopentanone was obtained. The conversion rate of furfuryl alcohol and the selectivity of cyclopentanone were detected by a gas chromatograph. By detecting the solution containing cyclopentanone, as Figure 1 shown: the conversion rate of furfuryl alcohol was 98.280%, and the selectivity of cyclopentanone was 98.840%. The solution containing cyclopentanone was concentrated and crystallized to obtain cyclopentanone crystals, and the yield was calculated to be 97.140%.

[0032] Example 2 Preparation of palladium / amphoteric chelating resin hydrogenation catalyst: (1) Accurately weigh 35 g of primary amine resin and add it to a three-necked flask, 50.8 g of 18 wt% phosphorous acid aqueous solution and 12.2 g of 36 wt% hydrochloric acid. Heat it to 95 °C under mechanical stirring, and then slowly add 10 g of 42 wt% formaldehyde. After keeping warm for 11 h, naturally cool it to room temperature, and filter out the functionalized resin. The primary amine resin is produced by Shandong Decuan Chemical Technology Co., Ltd., with the brand D303.

[0033] (2) Load the functionalized resin into an ion exchange column, and adopt the up-in and down-out method. According to the mass ratio of pure water, dilute hydrochloric acid to functionalized resin of 12:4:1, treat the functionalized resin with pure water and 4 wt% hydrochloric acid in turn, and the feeding flow rate of pure water and dilute hydrochloric acid is 4 BV / h; then wash the functionalized resin with pure water until the pH value of the effluent is ≥ 3.0 to obtain amphoteric chelating resin.

[0034] The physical and chemical indexes of this resin: particle size range 0.4 - 0.5 mm, uniformity coefficient 1.19, water content 54.86%, wet apparent density 0.73 g / mL, wet true density 1.12 g / mL, attrition resistance of spherical particles 99%, weak acid group exchange capacity 2.23 mmol / g, weak base group exchange capacity 2.38 mmol / g.

[0035] (3) Weigh 20 g of amphoteric chelating resin and add it to a 500 mL three-necked round-bottom flask, add 100 g of 0.75 wt% palladium nitrate solution, stir mechanically at 23 °C for 6 h, then filter out the solution, load the amphoteric chelating resin-2 into an ion exchange column, and wash it with pure water until there is no palladium ion in the effluent, that is, the amphoteric chelating resin loaded with palladium ions is obtained.

[0036] (4) Add the palladium-loaded amphoteric chelating resin to a 250 mL beaker, add 60 g of 9.5 wt% ascorbic acid aqueous solution, let it stand at room temperature for 8 h, then filter and wash it 3 times with pure water. Then dry it in a vacuum drying oven at 70 °C, and then load it into a fixed bed. Carry out gas-phase reduction of the resin catalyst for 5 h in a mixed hydrogen stream (the volume ratio of hydrogen to nitrogen is 1:8) at 230 °C, and obtain the palladium / amphoteric chelating resin hydrogenation catalyst after natural cooling. Use XRF to characterize the palladium / amphoteric chelating resin hydrogenation catalyst, and the measured palladium loading is 3.5 wt%.

[0037] Catalytic hydrogenation of furfuryl alcohol to prepare cyclopentanone: Weigh 1.0 g of furfuryl alcohol and 10 mL of deionized water, mix them and transfer them to a high-pressure reactor. Then, add 0.1 g of palladium / amphoteric chelating resin hydrogenation catalyst.

[0038] Use hydrogen to replace the high-pressure reactor 10 times. After the replacement is completed, introduce hydrogen and pressurize the high-pressure reactor to 1.0 MPa. Start the magnetic stirring device, set the rotation speed to 170 rpm, and at the same time heat the reaction system to 180 °C at a heating rate of 5 °C / min and react for 8 h.

[0039] After the reaction is completed, naturally cool the system to room temperature, filter the resin catalyst in the reaction solution, and finally obtain a solution containing cyclopentanone. Use a gas chromatograph to detect the conversion rate of furfuryl alcohol and the selectivity of cyclopentanone. By detecting the solution containing cyclopentanone, as Figure 2 shown: the conversion rate of furfuryl alcohol is 98.202%, and the selectivity of cyclopentanone is 98.923%. The solution containing cyclopentanone is concentrated and crystallized to obtain cyclopentanone crystals, and the calculated yield is 97.144%.

[0040] Example 3 Preparation of palladium / amphoteric chelating resin hydrogenation catalyst: (1) Accurately weigh 35 g of primary amine resin and add it to a three-necked flask. Add 45 g of 22 wt% phosphorous acid aqueous solution and 8.8 g of 37 wt% hydrochloric acid. Heat it to 85 °C under mechanical stirring, and then slowly add 10.5 g of 33 wt% formaldehyde. After keeping warm for 10 h, naturally cool it to room temperature and filter out the functionalized resin. The primary amine resin is produced by Shandong Decheng Chemical Technology Co., Ltd., and the brand is D303.

[0041] (2) Load the functionalized resin into an ion exchange column, and adopt the way of flowing in from the top and out from the bottom. According to the mass ratio of pure water, dilute hydrochloric acid to the functionalized resin of 7:4:1, treat the functionalized resin with pure water and 7 wt% hydrochloric acid in turn, and the flow rate of pure water and dilute hydrochloric acid is 2 BV / h; then wash the functionalized resin with pure water until the pH value of the effluent is ≥ 3.0 to obtain the amphoteric chelating resin.

[0042] The physical and chemical indexes of the amphoteric chelating resin are as follows: particle size range 0.4 - 0.5 mm, coefficient of uniformity 1.21, water content 54.22%, wet apparent density 0.73 g / mL, wet true density 1.1 g / mL, attrition resistant roundness 99%, weak acid group exchange capacity 2.40 mmol / g, weak base group exchange capacity 2.28 mmol / g.

[0043] (3) Weigh 40 g of the amphoteric chelating resin and add it to a 500 mL three - necked round - bottom flask. Then add 70 g of a 0.85 wt% palladium nitrate solution. Stir mechanically at 30 °C for 5 h. Subsequently, filter off the solution, load the amphoteric chelating resin into an ion - exchange column, and wash it with pure water until there is no palladium ion in the effluent, thus obtaining the amphoteric chelating resin loaded with palladium ions.

[0044] (4) Add the amphoteric chelating resin loaded with palladium ions to a 250 mL beaker, add 80 g of a 10.5 wt% ascorbic acid aqueous solution, let it stand at room temperature for 12 h, then filter and wash it 3 times with pure water. Then dry it in a vacuum drying oven at 65 °C, and then load it into a fixed bed. Carry out gas - phase reduction of the resin catalyst in a mixed hydrogen stream (volume ratio of hydrogen to nitrogen is 1:7) at 250 °C for 3.5 h. After natural cooling, obtain the palladium / amphoteric chelating resin hydrogenation catalyst. Use XRF to characterize the palladium / amphoteric chelating resin hydrogenation catalyst, and the measured palladium loading is 1.0 wt%.

[0045] Catalyze the hydrogenation of furfuryl alcohol to prepare cyclopentanone: Weigh 1.0 g of furfuryl alcohol and 100 mL of deionized water, mix them and transfer them to a high - pressure reactor. Subsequently, add 0.3 g of the palladium / amphoteric chelating resin hydrogenation catalyst.

[0046] Use hydrogen to replace the gas in the high - pressure reactor 8 times. After the replacement is completed, introduce hydrogen and pressurize the high - pressure reactor to 3.0 MPa. Start the magnetic stirring device, set the rotation speed to 160 rpm, and at the same time heat the reaction system to 140 °C at a heating rate of 5 °C / min and react for 10 h.

[0047] After the reaction is completed, let the system cool naturally to room temperature, filter the resin catalyst in the reaction solution, and finally obtain a solution containing cyclopentanone. Use a gas chromatograph to detect the conversion rate of furfuryl alcohol and the selectivity of cyclopentanone. By detecting the solution containing cyclopentanone, according to Figure 3 It can be obtained that: the conversion rate of furfuryl alcohol is 99.024%, and the selectivity of cyclopentanone is 99.012%. The solution containing cyclopentanone is concentrated and crystallized to obtain cyclopentanone crystals, and the calculated yield is 98.046%.

[0048] Comparative Example 1 Prepare a comparative resin - based hydrogenation catalyst: Replace the functionalized resin in Example 1 with a commercially available chelating resin (produced by Shandong Decuan Chemical Technology Co., Ltd., grade D467). The remaining steps and raw materials are the same as those in Example 1 to obtain a comparative resin-based hydrogenation catalyst. Using XRF characterization technology, the palladium loading on the comparative resin-based hydrogenation catalyst is measured to be 0.56 wt%.

[0049] Catalytic hydrogenation of furfuryl alcohol to prepare cyclopentanone: The steps are the same as those in Example 1 to obtain a solution containing cyclopentanone. The conversion rate of furfuryl alcohol and the selectivity of cyclopentanone are detected by a gas chromatograph. By detecting the solution containing cyclopentanone, it can be obtained that the conversion rate of furfuryl alcohol is 91.236%, and the selectivity of cyclopentanone is 65.041%.

[0050] Comparative Example 2 Preparation of a comparative resin-based hydrogenation catalyst: Replace the functionalized resin in Example 1 with a primary amine resin (produced by Shandong Decuan Chemical Technology Co., Ltd., grade D303). The remaining steps and raw materials are the same as those in Example 1 to obtain a comparative resin-based hydrogenation catalyst. Using XRF characterization technology, the palladium loading on the comparative resin-based hydrogenation catalyst is measured to be 0.21 wt%.

[0051] Catalytic hydrogenation of furfuryl alcohol to prepare cyclopentanone: The steps are the same as those in Example 1 to obtain a solution containing cyclopentanone. The conversion rate of furfuryl alcohol and the selectivity of cyclopentanone are detected by a gas chromatograph. By detecting the solution containing cyclopentanone, it can be obtained that the conversion rate of furfuryl alcohol is 90.103%, and the selectivity of cyclopentanone is 67.194%.

[0052] Comparative Example 3 Preparation of a comparative resin-based hydrogenation catalyst: Replace the amphoteric chelating resin in Example 1 with a commercially available chelating resin (produced by Shandong Decuan Chemical Technology Co., Ltd., grade D467). The remaining steps and raw materials are the same as those in Example 1 to obtain a comparative resin-based hydrogenation catalyst. Using XRF characterization technology, the palladium loading on the comparative resin-based hydrogenation catalyst is measured to be 0.37 wt%.

[0053] Catalytic hydrogenation of furfuryl alcohol to prepare cyclopentanone: The steps are the same as those in Example 1 to obtain a solution containing cyclopentanone. The conversion rate of furfuryl alcohol and the selectivity of cyclopentanone are detected by a gas chromatograph. By detecting the solution containing cyclopentanone, it can be obtained that the conversion rate of furfuryl alcohol is 90.569%, and the selectivity of cyclopentanone is 67.776%.

[0054] Comparative Example 4 Replace the aqueous solution of phosphorous acid with iminodiacetic acid or nitrilotriacetic acid. After detection, the palladium loading is <0.1%, and a qualified palladium / amphoteric chelating resin hydrogenation catalyst cannot be prepared. Therefore, no subsequent tests are carried out.

[0055] Test Example 1 Use the palladium / amphoteric chelating resin hydrogenation catalyst prepared in Example 1 to catalyze the hydrogenation of furfuryl alcohol to prepare cyclopentanone. Set different hydrogenation reaction times. The specific catalytic hydrogenation reaction steps are the same as those in Example 1. Test the effects of the reaction time on the conversion rate of furfuryl alcohol and the selectivity of cyclopentanone. The specific results are shown in Table 1.

[0056]

[0057] As can be seen from Table 1, the reaction time defined in the present invention is 5 - 10 h. Within this time range, the yield of cyclopentanone can be guaranteed at a relatively high level. Too short or too long reaction time will lead to an increase in the yield of by-products 2-cyclopentenone or cyclopentanol, resulting in a decrease in the yield of cyclopentanone.

[0058] Test Example 2 Use the palladium / amphoteric chelating resin hydrogenation catalyst prepared in Example 1 to catalyze the hydrogenation of furfuryl alcohol to prepare cyclopentanone. Set different hydrogenation reaction pressures. The specific catalytic hydrogenation reaction steps are the same as those in Example 1. Test the effects of the hydrogenation reaction pressure on the conversion rate of furfuryl alcohol and the selectivity of cyclopentanone. The specific results are shown in Table 2.

[0059]

[0060] As can be seen from Table 2, the reaction pressure defined in the present invention is 1 - 3 MPa. Within this pressure range, the conversion rate of furfuryl alcohol and the yield of cyclopentanone can be guaranteed at a relatively high level. When the pressure is less than this range, the effects of the present invention cannot be achieved.

[0061] Test Example 3 Use the palladium / amphoteric chelating resin hydrogenation catalyst prepared in Example 1 to catalyze the hydrogenation of furfuryl alcohol to prepare cyclopentanone. Set different hydrogenation reaction temperatures. The specific catalytic hydrogenation reaction steps are the same as those in Example 1. Test the effects of the hydrogenation reaction temperature on the conversion rate of furfuryl alcohol and the selectivity of cyclopentanone. The specific results are shown in Table 3.

[0062]

[0063] As can be seen from Table 3, the reaction temperature defined in the present invention is 140 - 180 °C. Within this temperature range, the selectivity of cyclopentanone can be guaranteed at a relatively high level. Too high or too low temperature cannot achieve the best effect.

[0064] Test Example 4 The reaction solutions in Examples 1 to 3 were filtered to obtain a palladium / amphoteric chelating resin hydrogenation catalyst, and the palladium / amphoteric chelating resin hydrogenation catalyst was recycled; the same was true for Comparative Examples 1 to 3, and the recycling results are shown in Table 4.

[0065]

[0066] " / " means that the yield was less than 40.000% after 5 recycles, and it no longer had the value of industrial application, so the test was no longer continued. It can be seen from Table 4 that the catalytic activities of the catalysts in Examples 1 to 3 did not decrease significantly after 20 recycles.

Claims

1. A method for preparing a palladium / amphoteric chelate resin hydrogenation catalyst comprises the following steps: (1) mixing a primary amine resin, a phosphorous acid aqueous solution and hydrochloric acid, heating and stirring, then adding formaldehyde and keeping the temperature, cooling and filtering to obtain a functionalized resin; (2) The functionalized resin is loaded into an ion exchange column, and the resin is treated with pure water and hydrochloric acid in sequence, and then washed with water to obtain an amphoteric chelating resin; (3) adding palladium nitrate solution to the amphoteric chelate resin, stirring and filtering, and washing the amphoteric chelate resin until no palladium ions are present in the washed water, thereby obtaining an amphoteric chelate resin loaded with palladium ions; (4) Using an ascorbic acid aqueous solution to carry out liquid phase reduction of the amphoteric chelating resin loaded with palladium ions, after standing, filtering, washing and drying, using a mixed hydrogen gas flow to carry out gas phase reduction of the amphoteric chelating resin loaded with palladium ions to obtain a palladium / amphoteric chelating resin hydrogenation catalyst.

2. The preparation method of palladium / amphoteric chelate resin hydrogenation catalyst according to claim 1, characterized in that, In step (1), the concentration of the phosphorous acid aqueous solution is 18-22wt%, the concentration of the hydrochloric acid is 36-38wt%, the mass ratio of the phosphorous acid aqueous solution, the hydrochloric acid and the primary amine resin is (1.25-1.45):(0.25-0.35):1, the concentration of formaldehyde is 33-42wt%, and the mass ratio of formaldehyde to the primary amine resin is (0.25-0.3):1; the stirring temperature is 85-95°C, and the insulation time is 10-15h.

3. The preparation method of palladium / amphoteric chelate resin hydrogenation catalyst according to claim 1, characterized in that, In step (2), the concentration of hydrochloric acid is 4-7wt%, the mass ratio of pure water, hydrochloric acid and functionalized resin is (7-12):4:1, and the flow rate of pure water and hydrochloric acid is 2-4BV / h; during water washing, when the pH value of the outlet water is ≥3.0, the water washing is completed.

4. The preparation method of palladium / amphoteric chelate resin hydrogenation catalyst according to claim 1, characterized in that, In step (2), the physical and chemical indicators of the amphoteric chelating resin are: particle size range 0.4~0.5mm, uniformity coefficient 1.19~1.21, water content 54.22~55.35%, wet true density 1.10~1.12g / mL, weak acid group exchange capacity 2.23~2.40mmol / g, weak base group exchange capacity 2.28~2.52mmol / g.

5. The preparation method of palladium / amphoteric chelate resin hydrogenation catalyst according to claim 1, characterized in that, In step (3), the concentration of the palladium nitrate solution is 0.75-0.85wt%, and the mass ratio of the palladium nitrate solution to the amphoteric chelating resin is (1.75-5.0):1; the stirring temperature is 23-30°C, and the stirring time is 4-6h.

6. The preparation method of palladium / amphoteric chelate resin hydrogenation catalyst according to claim 1, characterized in that, In step (4), the concentration of the ascorbic acid aqueous solution is 9.5-10.5 wt %, the mass ratio of the ascorbic acid aqueous solution to the amphoteric chelating resin is (1-3):1, the standing time is 6-12 h, and the drying temperature is 60-70 ° C.

7. The preparation method of palladium / amphoteric chelate resin hydrogenation catalyst according to claim 1, characterized in that, In step (4), the volume ratio of hydrogen to nitrogen in the mixed hydrogen gas flow is 1:(7-9), the gas phase reduction temperature is 220-250° C., and the gas phase reduction time is 3-5 h; and the palladium content of the palladium / amphoteric chelating resin hydrogenation catalyst is 1.0-3.5 wt %.

8. Use of a palladium / amphoteric chelate resin hydrogenation catalyst prepared by the preparation method of the palladium / amphoteric chelate resin hydrogenation catalyst according to any one of claims 1 to 7, characterized in that: Furfuryl alcohol and water are added to a reaction kettle, and a palladium / amphoteric chelate resin hydrogenation catalyst is continuously added. Stirring is started, and hydrogen is introduced for hydrogenation reaction. Cyclopentanone is obtained after filtering.

9. The use of the palladium / amphoteric chelate resin hydrogenation catalyst according to claim 8, characterized in that: The ratio of palladium / amphoteric chelating resin hydrogenation catalyst to furfuryl alcohol is (0.1~0.3):1, and the mass ratio of furfuryl alcohol to water is 1:(10~100).

10. The use of the palladium / amphoteric chelate resin hydrogenation catalyst according to claim 8, characterized in that: The reactor needs to be purged with hydrogen 5 to 10 times, the hydrogenation reaction pressure is 1 to 3 MPa, the hydrogenation reaction temperature is 140 to 180°C, the stirring speed is 160 to 180 rpm, and the hydrogenation reaction time is 5 to 10 hours.

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