Ni / Y type molecular sieve catalyst and preparation method and application thereof

Abstract

The invention discloses a Ni / Y type molecular sieve catalyst and a preparation method and application thereof. The catalyst comprises an active component and a carrier, the active component is a nickel element, and the carrier is a Y-type molecular sieve; the valence state of the nickel element in the Ni / Y type molecular sieve catalyst comprises metallic Ni and Ni < 2 + >, wherein the molar ratio of Ni0 to Ni < 2 + > is (0.5-3.0): 1. The catalyst provided by the invention is used in a reaction for preparing hydroxysuccinic acid, and has the characteristics of efficient conversion of furfural, high selectivity of the product hydroxysuccinic acid and the like under mild reaction conditions.

Description

Technical Field

[0001] This invention relates to the field of catalytic chemistry, specifically to a Ni / Y type molecular sieve catalyst, its preparation method, and its application. Background Technology

[0002] Hydroxysuccinic acid (HSA) can be used to treat various diseases and is also a key chemical intermediate in the food and pharmaceutical industries. Currently, the main production technologies for HSA are chemical synthesis and bio-fermentation (CN110241147B). The chemical synthesis method involves hydrating maleic acid obtained from the catalytic oxidation of benzene under high temperature and pressure to obtain HSA. This process has harsh reaction conditions and high production costs. To address the rapid depletion of fossil fuels, the search for renewable alternatives to sustain the production of chemicals and fuels has received increasing attention. Biomass is a promising renewable carbon source with the potential for large-scale conversion into chemicals and liquid transport fuels. Furfural, produced by the hydrolysis of hemicellulose acid from biomass resources, is a platform compound with significant growth potential. Furfural has a highly functionalized molecular structure and can be further converted into numerous fossil fuel alternatives and value-added chemicals with broad commercial applications. One application of furfural is the selective oxidation of furfural to synthesize downstream C4 chemicals, including C4 carboxylic acids such as maleic acid and hydroxysuccinic acid.

[0003] Developing novel, green, and energy-efficient bio-based hydroxysuccinic acid (HSA) preparation routes is of great significance for the industrial application of HSA. The production of HSA from furfural can be divided into two steps: furfural oxidation to maleic acid, followed by hydration of maleic acid to form HSA. Choi et al. (ACS Sustainable Chem. Eng. 2018, 6, 9596-9600) disclosed a new electrochemical oxidation method for producing maleic acid at room temperature and pressure in a water-based medium, without the need for an oxidant. PbO2, MnO2, and Pt, stable in acidic solution at strong oxidation potentials, serve as the anode for furfural oxidation. The use of an acidic medium promotes the opening of the furan ring during oxidation, which is crucial for the formation of maleic acid, achieving a maleic acid yield of 65.1%. Hwang et al. (J. Mater. Chem. A, 2023, 11, 16559-16569) further discovered that Bi doping (PbBiOx) in lead oxide can effectively regulate the reactivity of furfural, achieving a maleic acid yield of 57%. The direct oxidation of furfural to hydroxysuccinic acid has become a research focus due to its short process and high efficiency. Fukuoka et al. (ACS Catal. 2022, 12, 3534-3542) disclosed a method using TS-1 as a catalyst to oxidize furfural to hydroxysuccinic acid, with a maximum yield of only 9%.

[0004] Currently, research on the preparation of bio-based hydroxysuccinic acid is still in its early stages, with only a few studies finding it as a trace byproduct. Therefore, there is an urgent need to develop efficient and stable catalytic reaction systems to improve the yield of hydroxysuccinic acid. Summary of the Invention

[0005] The technical problem to be solved by this invention is the low catalytic efficiency and low yield of hydroxysuccinic acid in the existing technology for preparing hydroxysuccinic acid. This invention provides a Ni / Y type molecular sieve catalyst, its preparation method, and its application. This catalyst, when used in the reaction to prepare hydroxysuccinic acid, exhibits high efficiency in the conversion of furfural under mild reaction conditions and high selectivity for the product hydroxysuccinic acid.

[0006] The first aspect of the present invention provides a Ni / Y type molecular sieve catalyst, wherein the catalyst comprises an active component and a support, the active component being nickel and the support being a Y type molecular sieve;

[0007] The valence state of nickel in the Ni / Y type molecular sieve catalyst includes metallic Ni and Ni2+. 2+ Ni 0 and Ni 2+ The molar ratio is 0.5 to 3.0:1, preferably 0.8 to 2.0:1.

[0008] Furthermore, in the Ni / Y type molecular sieve catalyst, the relative Ni content is 0.5-5 wt%, preferably 0.6-4 wt%, based on the mass of the catalyst.

[0009] Furthermore, in the Ni / Y type molecular sieve catalyst, the Si / Al molar ratio is 4 to 10, preferably 5 to 8.

[0010] Furthermore, the total specific surface area of ​​the Ni / Y type molecular sieve catalyst is 490–765 m². 2 / g, preferably 585~710m 2 / g; pore volume is 0.15~0.55cm³ 3 / g, preferably 0.25~0.45cm 3 / g.

[0011] Furthermore, the average size of the nickel nanoparticles in the Ni / Y type molecular sieve catalyst is 5–15 nm, preferably 10–13 nm.

[0012] Furthermore, in the Ni / Y type molecular sieve catalyst, The / Lewis acid ratio is 0.1 to 1, preferably 0.15 to 0.5.

[0013] A second aspect of the present invention provides a method for preparing the above-mentioned Ni / Y type molecular sieve catalyst, the method comprising the following steps:

[0014] A Ni / Y type molecular sieve catalyst was prepared by loading nickel-containing metal salts onto a Y-type molecular sieve using a precipitation deposition method, followed by reduction treatment.

[0015] Furthermore, the preparation method of loading nickel-containing metal salts onto Y-type molecular sieves by precipitation deposition includes:

[0016] (1) Dissolve the nickel-containing metal salt in water and mix well to obtain solution A;

[0017] (2) Disperse Y-type molecular sieve in aqueous solution to obtain suspension B, and slowly add solution A to suspension B to obtain material C;

[0018] (3) Add the inorganic alkaline solution dropwise into material C, adjust the pH value to 10-11, obtain the precipitate, wash and dry it.

[0019] Furthermore, the nickel-containing metal salt includes one or more of nickel nitrate, nickel acetate, nickel chloride, nickel acetylacetonate, and nickel sulfate, preferably at least one of nickel nitrate and nickel acetate.

[0020] Furthermore, the Si / Al molar ratio of the Y-type molecular sieve is 4 to 10, preferably 5 to 8.

[0021] Furthermore, the total specific surface area of ​​the Y-type molecular sieve is 500–750 m². 2 / g, preferably 600-700m 2 / g; pore volume is 0.2–0.5 cm³ 3 / g, preferably 0.3-0.4cm 3 / g.

[0022] Furthermore, the mass ratio of the nickel-containing metal salt (calculated as elemental nickel) to the Y-type molecular sieve is 0.8 to 10:100, preferably 1.0 to 8:100.

[0023] Further, in step (1), the mass ratio of water in solution A to water in suspension B is 0.5 to 2:1, preferably 0.7 to 1.5.

[0024] Further, the inorganic base mentioned in step (3) includes one or more of sodium hydroxide, potassium hydroxide, and ammonia water, preferably at least one of sodium hydroxide and ammonia water.

[0025] Further, the concentration of the inorganic alkaline solution in step (3) is 0.05 to 1.0 mol / L, preferably 0.5 to 1.0 mol / L.

[0026] Furthermore, the drying conditions described in step (3) are: drying at 50–130°C for 2–12 hours.

[0027] Furthermore, the reduction temperature is 400–600°C, preferably 500–550°C.

[0028] Furthermore, the reducing atmosphere in the reduction process is hydrogen or a hydrogen / nitrogen mixture, wherein the volume percentage of hydrogen in the hydrogen / nitrogen mixture is 10-30%.

[0029] A third aspect of the present invention provides the application of the above-described catalyst in the preparation of hydroxysuccinic acid.

[0030] Furthermore, the reaction comprises mixing the substrate furfural, solvent, and oxidant under a hydrogen atmosphere and with the action of the catalyst described above, and then performing a one-step oxidation reaction to obtain hydroxysuccinic acid.

[0031] Furthermore, the reaction conditions include: a reaction temperature of 50–100°C, preferably 60–80°C; and / or a reaction time of 2–12 h, preferably 4–8 h.

[0032] Further, the oxidant is hydrogen peroxide, wherein the mass fraction of hydrogen peroxide in the hydrogen peroxide is 20-80 wt%, preferably 30-70 wt%.

[0033] Further, the solvent is water; the mass ratio of the solvent to the substrate furfural is 75-95:1, preferably 80-90:1.

[0034] Furthermore, the mass ratio of the catalyst to the substrate furfural is 0.2 to 1:1, preferably 0.5 to 1:1.

[0035] Furthermore, the molar ratio of the oxidant to the substrate furfural is 5–25:1, preferably 10–20:1.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] The catalyst provided by this invention is a Ni / Y type molecular sieve catalyst, which is used in the preparation of hydroxysuccinic acid. It has the characteristics of high efficiency in the conversion of furfural under mild reaction conditions, high selectivity of the product hydroxysuccinic acid, and outstanding stability of the catalyst in recycling. Attached Figure Description

[0038] Figure 1 The image shows the XRD pattern of the Y-type molecular sieve in Example 1.

[0039] Figure 2 The N2 adsorption-desorption isotherm diagram of the Y-type molecular sieve in Example 1;

[0040] Figure 3 The image shows the XRD pattern of the Ni / Y type molecular sieve catalyst in Example 1.

[0041] Figure 4 This is a TEM image of the Ni / Y type molecular sieve catalyst in Example 1;

[0042] Figure 5 XPS image of the Ni / Y type molecular sieve catalyst in Example 1;

[0043] Figure 6 The image shows the pyridine infrared spectrum of the Ni / Y type molecular sieve catalyst in Example 1.

[0044] Figure 7 The XRD pattern of the Y-NaOH catalyst in Comparative Example 1 is shown.

[0045] Figure 8 The N2 adsorption-desorption isotherm of the Y-NaOH catalyst in Comparative Example 1 is shown.

[0046] Figure 9 The image shows the pyridine infrared spectrum of the Y-NaOH catalyst in Comparative Example 1. Detailed Implementation

[0047] The technical solution of the present invention will be further illustrated below through embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0048] In this invention, the XRD measurement method for the product is as follows: the phase composition of the sample is analyzed using a Rigaku Ultima IV X-ray powder diffractometer (Japan), with a CuKα ray source. Nickel filter, 2θ scanning range 2°-50°, operating voltage 35kV, current 25mA, scanning rate 10° / min.

[0049] In this invention, an inductively coupled plasma atomic emission spectrometer (ICP) of model Varian 725-ES is used to dissolve the analytical sample in hydrofluoric acid to detect the content of metal elements.

[0050] In this invention, the acid content and type of the catalyst are determined using the pyridine adsorption infrared method (Nicolet Model 710 spectrometer). The specific operation steps are as follows: a) Sample pretreatment: The sample (approximately 30 mg) is compressed into a thin disc with a diameter of 13 mm and placed in the infrared sample cell; then, the sample is pretreated at 400°C under vacuum conditions for 1 hour. After the sample cell cools to room temperature, the infrared data of the sample is scanned as background. b) Pyridine adsorption: Pyridine vapor is introduced into the in-situ under room temperature and vacuum conditions until adsorption reaches equilibrium, with an adsorption time of 1 hour. c) Pyridine desorption: After adsorption, a vacuum is drawn at 150°C until the internal pressure no longer changes, with a desorption time of 40 minutes, and the infrared absorption spectra are scanned and recorded. The difference spectrum before and after pyridine adsorption is the obtained pyridine adsorption-infrared absorption spectrum. The acid content of the sample is semi-quantitatively calculated based on the spectrum.

[0051]

[0052] Where r and w are the diameter (cm) and mass (g) of the catalyst disc, respectively, and A is the integral absorbance value at the specified wavenumber peak based on the scanned pyridine adsorption-infrared absorption spectrum. IMEC is the integral molar extinction coefficient. L Version 2.22, IMEC B It is 1.67.

[0053] In this invention, N2 adsorption-desorption (BET) isotherms of the samples were measured using a NOVA 1200e Surface Area & Pore Size Analyzer, and the specific surface area and pore volume were obtained using the BET method. Before sample testing, the samples were vacuum-treated at 200°C for 4 hours to remove moisture and volatile impurities from the catalyst surface.

[0054] In this invention, the transmission electron microscope (TEM) used for the molecular sieve is a S-4800II field emission scanning electron microscope. The size of the nickel particles in the molecular sieve is obtained by statistically analyzing the sizes of approximately 30 nickel particles from the TEM images and then calculating the average value.

[0055] In this invention, the element binding energy on the catalyst surface was measured on a Thermo X-ray photoelectron spectrometer (ESCALAB-250), and the measured element signal was corrected using C1s = 284.6 eV as an internal standard.

[0056] In this invention, the reaction product hydroxysuccinic acid was qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS), and the conversion rate of the substrate furfural (FF) and the yield of the reaction product hydroxysuccinic acid were analyzed by gas chromatography (GC). The GC-MS system was an Agilent 7890A from Agilent Technologies, USA, with an INNOWAX gas chromatograph capillary column (60m, 0.32mm). The gas chromatograph was an Agilent 7890B, with a flame ionization detector (FID) and an INNOWAX gas chromatograph capillary column (60m, 0.32mm).

[0057] In this invention, the furfural conversion rate formula is:

[0058] The conversion rate of furfural (%) = (molar amount of furfural participating in the reaction) / (molar amount of furfural substrate) × 100%.

[0059] In this invention, the formula for calculating the yield of the product hydroxysuccinic acid is as follows:

[0060] The yield % of the product hydroxysuccinic acid = (molar amount of hydroxysuccinic acid produced in the reaction) / (molar amount of the reaction substrate furfural) × 100%.

[0061] In this invention, the formula for calculating the selectivity of the product hydroxysuccinic acid is as follows:

[0062] The selectivity % of the product hydroxysuccinic acid = (molar amount of hydroxysuccinic acid produced in the reaction) / (molar amount of furfural participating in the reaction) × 100%.

[0063] To facilitate understanding of the present invention, the following embodiments are provided. However, these embodiments are merely for the purpose of helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0064] Example 1

[0065] Y-type molecular sieves were selected as the support, with a Si / Al molar ratio of 7. XRD patterns are shown below. Figure 1 As shown, the N2 adsorption-desorption isotherm is as follows: Figure 2 As shown, its specific surface area, calculated using the BET method, is 663 m². 2 / g; pore volume is 0.36cm³ 3 / g.

[0066] The nickel source was nickel nitrate, with a nickel nitrate (calculated as nickel) to Y-type molecular sieve mass ratio of 1.6:100. The water mass ratio in solution A to suspension B was 1:1. The sodium hydroxide solution concentration was 0.5M, and the reduction temperature was 550℃. The specific synthesis was as follows: 0.05g of nickel nitrate was dissolved in 20g of aqueous solution and mixed thoroughly to obtain solution A; 1.00g of Y-type molecular sieve was dispersed in 20g of aqueous solution to obtain suspension B. Solution A was slowly added to suspension B. Then, sodium hydroxide solution (0.5mol / L) was added dropwise to the above solution to adjust the pH to 10-11. The mixed solution was continuously stirred at room temperature. The resulting precipitate was removed, centrifuged, washed with deionized water and ethanol until neutral, and then transferred to an oven to dry (60℃, 12 hours). Reduction was performed in a tube furnace under a hydrogen atmosphere at 550℃ for 3 hours to obtain the supported Ni / Y-type molecular sieve catalyst.

[0067] The relative Ni content in the sample was determined to be 0.7 wt% using inductively coupled plasma atomic emission spectrometry (ICP). The XRD pattern of the sample is shown below. Figure 3 As shown. The N2 adsorption-desorption isotherm of the sample and Figure 8 Similarly, using the BET method, the specific surface area of ​​the sample was calculated to be 649 m². 2 / g; pore volume is 0.35cm³ 3 / g. TEM images of the sample are shown below. Figure 4 As shown, the Ni nanoparticle size is 11.8 nm. The XPS of the sample is as follows. Figure 5 As shown, the molar ratio (Ni / NiO ratio) of metallic Ni to oxidized NiO in the catalyst is 1:1. The pyridine infrared spectroscopy is shown below. Figure 6 In the catalyst The / Lewis acid ratio is 0.21.

[0068] Example 2

[0069] Y-type molecular sieves were selected as the support, with a Si / Al molar ratio of 6. XRD and Figure 1 Similarly, the N2 adsorption-desorption isotherm is similar to... Figure 2 Similarly, using the BET method, its specific surface area is calculated to be 687 m². 2 / g; pore volume is 0.38cm³ 3 / g.

[0070] The nickel source was nickel nitrate, with a nickel nitrate (calculated as nickel) to Y-type molecular sieve mass ratio of 3:100. The water mass ratio in solution A to solution B was 1:1.5. The sodium hydroxide solution concentration was 0.7M, and the reduction temperature was 550℃. The specific synthesis was as follows: 0.09g of nickel nitrate was dissolved in 20g of aqueous solution and mixed thoroughly to obtain solution A. 1.00g of Y-type molecular sieve was dispersed in 30g of aqueous solution to obtain suspension B. Solution A was slowly added to suspension B. Then, sodium hydroxide solution (0.7mol / L) was added dropwise to the above solution to adjust the pH to 10-11. The mixed solution was continuously stirred at room temperature. The resulting precipitate was removed, centrifuged, washed with deionized water and ethanol until neutral, and then transferred to an oven to dry (60℃, 12 hours). Reduction was performed in a tube furnace under a hydrogen atmosphere at 550℃ for 3 hours to obtain the supported Ni / Y-type molecular sieve catalyst.

[0071] The relative Ni content in the sample was determined to be 1.1 wt% using inductively coupled plasma atomic emission spectrometry (ICP). The XRD pattern of the sample and... Figure 3 Similar to the N2 adsorption-desorption isotherm of the sample. Figure 8 Similarly, using the BET method, the specific surface area of ​​the sample was calculated to be 663 m². 2 ·g -1 The pore volume is 0.37 cm³. -3 g -1 TEM of the sample and Figure 4 Similarly, the Ni nanoparticles have a size of 12.2 nm. The XPS of the sample is similar to... Figure 5 Similarly, the molar ratio (Ni / NiO ratio) of metallic Ni to oxidized NiO in the catalyst is 0.9:1. Pyridine infrared spectroscopy and... Figure 6 Similarly, in catalysts The / Lewis acid ratio is 0.18.

[0072] Example 3

[0073] Y-type molecular sieves were selected as the support, with a Si / Al molar ratio of 8. XRD and Figure 1 Similarly, the N2 adsorption-desorption isotherm is similar to... Figure 2 Similarly, using the BET method, its specific surface area is calculated to be 675 m². 2 / g; pore volume is 0.33cm³ 3 / g.

[0074] The nickel source was nickel acetate, with a nickel acetate-to-Y-type molecular sieve mass ratio of 7:100. The water-to-water mass ratio in solution A was 1:1. The sodium hydroxide solution concentration was 0.8 M, and the reduction temperature was 550 °C. The specific synthesis was as follows: 0.21 g of nickel acetate was dissolved in 20 g of aqueous solution and mixed thoroughly to obtain solution A. 1.00 g of Y-type molecular sieve was dispersed in 20 g of aqueous solution to obtain suspension B. Solution A was slowly added to suspension B. Then, sodium hydroxide solution (0.8 mol / L) was added dropwise to the above solution to adjust the pH to 10-11. The mixture was continuously stirred at room temperature. The resulting precipitate was removed, centrifuged, washed with deionized water and ethanol until neutral, and then transferred to an oven to dry (60 °C, 12 hours). Reduction was performed in a tube furnace under a hydrogen atmosphere at 550 °C for 3 hours to obtain the supported Ni / Y-type molecular sieve catalyst.

[0075] The relative Ni content in the sample was determined to be 2.6 wt% using inductively coupled plasma atomic emission spectrometry (ICP). The XRD pattern of the sample and... Figure 3 Similar to the N2 adsorption-desorption isotherm of the sample. Figure 8 Similarly, using the BET method, the specific surface area of ​​the sample was calculated to be 661 m². 2 / g; pore volume is 0.32cm³ 3 / g. TEM of the sample and Figure 4 Similarly, the Ni nanoparticles have a size of 12.7 nm. The XPS of the sample is similar to... Figure 5 Similarly, the molar ratio (Ni / NiO ratio) of metallic Ni to oxidized NiO in the catalyst is 1.3:1. Pyridine infrared spectroscopy and... Figure 6 Similarly, in catalysts The / Lewis acid ratio is 0.34.

[0076] Example 4

[0077] Y-type molecular sieves were selected as the support, with a Si / Al molar ratio of 5. XRD and Figure 1 Similarly, the N2 adsorption-desorption isotherm is similar to... Figure 2 Similarly, using the BET method, its specific surface area is calculated to be 672 m². 2 / g; pore volume is 0.34cm³ 3 / g.

[0078] The nickel source was nickel acetate, with a nickel acetate (calculated as nickel) to Y-type molecular sieve mass ratio of 5:100. The water mass ratio in solution A to solution B was 0.8:1. The ammonia concentration was 1.0 M, and the reduction temperature was 550 °C. The specific synthesis was as follows: 0.15 g of nickel acetate was dissolved in 20 g of aqueous solution and mixed thoroughly to obtain solution A. 1.00 g of Y-type molecular sieve was dispersed in 20 g of aqueous solution to obtain suspension B. Solution A was slowly added to suspension B. Then, sodium hydroxide solution (1.0 mol / L) was added dropwise to the above solution to adjust the pH to 10-11. The mixed solution was continuously stirred at room temperature. The resulting precipitate was removed, centrifuged, washed with deionized water and ethanol until neutral, and then transferred to an oven to dry (60 °C, 12 hours). Reduction was performed in a tube furnace under a hydrogen atmosphere at 550 °C for 3 hours to obtain the supported Ni / Y-type molecular sieve catalyst.

[0079] The relative Ni content in the sample was determined to be 1.7 wt% using inductively coupled plasma atomic emission spectrometry (ICP). The XRD pattern of the sample... Figure 3 Similar to the N2 adsorption-desorption isotherm of the sample. Figure 8 Similarly, using the BET method, the specific surface area of ​​the sample was calculated to be 653 m². 2 / g; pore volume is 0.31cm³ 3 / g. TEM of the sample and Figure 4 Similarly, the Ni nanoparticles have a size of 10.9 nm. The XPS of the sample is similar to... Figure 5 Similarly, the molar ratio (Ni / NiO ratio) of metallic Ni to oxidized NiO in the catalyst is 1.1:1. Pyridine infrared spectroscopy and... Figure 6 Similarly, in catalysts The / Lewis acid ratio is 0.27.

[0080] Comparative Example 1

[0081] Y-type molecular sieves were selected as the support, with a Si / Al molar ratio of 7. XRD patterns are shown below. Figure 1 As shown, the N2 adsorption-desorption isotherm is as follows: Figure 2 As shown, its specific surface area, calculated using the BET method, is 663 m². 2 / g; pore volume is 0.36cm³ 3 / g.

[0082] Without an external nickel source, the sodium hydroxide solution concentration was 0.5 M, and the calcination temperature was 550 °C. The specific synthesis was as follows: 1.00 g of Y-type molecular sieve was dispersed in 40 mL of aqueous solution to obtain solution A. Then, sodium hydroxide solution (0.5 mol / L) was added dropwise to solution A to adjust the pH to 10-11. The mixture was continuously stirred at room temperature. The resulting precipitate was removed, centrifuged, washed with deionized water and ethanol until neutral, and then transferred to an oven to dry (60 °C, 12 hours). Calcined in a tube furnace under a hydrogen atmosphere at 550 °C for 3 hours, the Y-NaOH catalyst was obtained.

[0083] XRD of the sample Figure 7 As shown. The N2 adsorption-desorption isotherm of the sample is as follows. Figure 8 As shown, the specific surface area of ​​the sample, calculated using the BET method, is 650 m². 2 / g; pore volume is 0.42cm³ 3 / g. Pyridine infrared spectroscopy Figure 9 As shown, in the catalyst The / Lewis acid ratio is 0.14.

[0084] Comparative Example 2

[0085] Y-type molecular sieves were selected as the support, with a Si / Al molar ratio of 7. XRD patterns are shown below. Figure 1 As shown, the N2 adsorption-desorption isotherm is as follows: Figure 2 As shown, its specific surface area, calculated using the BET method, is 663 m². 2 / g; pore volume is 0.36cm³ 3 / g.

[0086] The mass ratio of cobalt nitrate (calculated as cobalt) to Y-type molecular sieve was 1.6:100, the mass ratio of water in solution A to water in suspension B was 1:1, the sodium hydroxide solution concentration was 0.5M, and the reduction temperature was 550℃. The specific synthesis was as follows: 0.05g of cobalt nitrate was dissolved in 20g of aqueous solution and mixed thoroughly to obtain solution A; 1.00g of Y-type molecular sieve was dispersed in 20g of aqueous solution to obtain suspension B, and solution A was slowly added to suspension B. Then, sodium hydroxide solution (0.5mol / L) was added dropwise to the above solution to adjust the pH to 10-11. The mixed solution was continuously stirred at room temperature. The resulting precipitate was removed, centrifuged, washed with deionized water and ethanol until neutral, and transferred to an oven to dry (60℃, 12 hours). Reduction was performed in a tube furnace under a hydrogen atmosphere at 550℃ for 3 hours to obtain the supported Ni / Y-type molecular sieve catalyst.

[0087] The relative Co content in the sample was determined to be 0.8 wt% using inductively coupled plasma atomic emission spectrometry (ICP), and the specific surface area of ​​the sample was 655 m². 2 / g; pore volume is 0.36cm³ 3 / g. TEM results for the sample showed that the Co nanoparticle size was 21 nm. Pyridine infrared spectroscopy results showed that the catalyst contained... The / Lewis acid ratio is 0.12.

[0088] Comparative Example 3

[0089] Using ZSM-5 molecular sieve as the support, with a Si / Al molar ratio of 25, N2 adsorption-desorption isotherm results show that, calculated using the BET method, its specific surface area is 327 m². 2 / g; pore volume is 0.30cm³ 3 / g, in catalyst The ratio of Lewis acid is 1.05.

[0090] The nickel source was nickel nitrate, with a nickel nitrate (calculated as nickel) to ZSM-5 molecular sieve mass ratio of 1.6:100. The mass ratio of water in solution A to water in suspension B was 1:1. The sodium hydroxide solution concentration was 0.5M, and the reduction temperature was 550℃. The specific synthesis was as follows: 0.05g of nickel nitrate was dissolved in 20g of aqueous solution and mixed thoroughly to obtain solution A; 1.00g of ZSM-5 molecular sieve was dispersed in 20g of aqueous solution to obtain suspension B. Solution A was slowly added to suspension B. Then, sodium hydroxide solution (0.5mol / L) was added dropwise to the above solution to adjust the pH to 10-11. The mixed solution was continuously stirred at room temperature. The resulting precipitate was removed, centrifuged, washed with deionized water and ethanol until neutral, and then transferred to an oven to dry (60℃, 12 hours). Reduction was performed in a tube furnace under a hydrogen atmosphere at 550℃ for 3 hours to obtain the supported Ni / ZSM-5 molecular sieve catalyst.

[0091] The relative Ni content in the sample was determined to be 0.6 wt% using inductively coupled plasma atomic emission spectrometry (ICP). The specific surface area of ​​the sample was 314 m². 2 / g; pore volume is 0.29cm³ 3 / g. The Ni nanoparticle size is 11.3 nm. The molar ratio (Ni / NiO ratio) of metallic Ni to oxidized NiO in the catalyst is 1.1:1. In the catalyst... The / Lewis acid ratio is 1.12.

[0092] Examples 5-11

[0093] Water was used as the reaction solvent, with a water to furfural mass ratio of 85:1, a catalyst to substrate furfural mass ratio of 0.6:1, hydrogen peroxide mass fraction of 30wt% in hydrogen peroxide, a hydrogen peroxide to furfural molar ratio of 15:1, a reaction temperature of 70℃, and a reaction time of 6h.

[0094] 1.0 g of furfural was dissolved in 85 g of aqueous solution and added to a glass reaction tube. 0.6 g of catalyst from Examples 1-4 and Comparative Examples 1-3 were added, along with a magnetic stir bar. A glass tee connector was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 17.7 g of 30 wt% hydrogen peroxide solution was added to the other port of the glass tee connector, and the knob was rotated to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 70°C for 6 hours. Gas phase analysis of the reaction liquid showed furfural conversion and hydroxysuccinic acid yield, as shown in Table 1.

[0095] Table 1. Catalytic evaluation results of catalysts in Examples 1-4 and Comparative Examples 1-3

[0096] catalyst Furfural conversion rate (%) Hydroxysuccinic acid yield (%) Example 1 >99.9 90.1 Example 2 >99.9 89.6 Example 3 >99.9 89.8 Example 4 >99.9 89.3 Comparative Example 1 80.7 5.6 Comparative Example 2 >99.9 35.2 Comparative Example 3 >99.9 62.5

[0097] Example 12

[0098] Water was used as the reaction solvent, with a water to furfural mass ratio of 80:1, a catalyst to substrate furfural mass ratio of 0.5:1, hydrogen peroxide mass fraction of 70 wt%, a hydrogen peroxide to furfural molar ratio of 10:1, a reaction temperature of 60℃, and a reaction time of 5 h.

[0099] 1.0 g of furfural was dissolved in 80 g of aqueous solution and added to a glass reaction tube. 0.5 g of the supported Ni / Y catalyst from Example 1 was added, along with a magnetic stir bar. A glass tee was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 5.1 g of 70 wt% hydrogen peroxide solution was added to the other port of the glass tee, and the knob was turned to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 60°C for 5 hours. Gas phase analysis of the reaction liquid showed complete furfural conversion and a hydroxysuccinic acid yield of 89.5%.

[0100] Example 13

[0101] Water was used as the reaction solvent, with a water to furfural mass ratio of 80:1, a catalyst to substrate furfural mass ratio of 0.5:1, hydrogen peroxide mass fraction of 50wt%, and a hydrogen peroxide to furfural molar ratio of 12:1. The reaction temperature was 70℃, and the reaction time was 4h.

[0102] 1.0 g of furfural was dissolved in 80 g of aqueous solution and added to a glass reaction tube. 0.5 g of the supported Ni / Y catalyst from Example 1 was added, along with a magnetic stir bar. A glass tee was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 8.5 g of 50 wt% hydrogen peroxide solution was added to the other port of the glass tee, and the knob was turned to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 70°C for 4 hours. Gas phase analysis of the reaction liquid showed complete furfural conversion and a hydroxysuccinic acid yield of 89.4%.

[0103] Example 14

[0104] Water was used as the reaction solvent, with a water to furfural mass ratio of 85:1, a catalyst to substrate furfural mass ratio of 0.6:1, hydrogen peroxide mass fraction of 60wt%, a hydrogen peroxide to furfural molar ratio of 18:1, a reaction temperature of 65℃, and a reaction time of 5h.

[0105] 1.0 g of furfural was dissolved in 85 g of aqueous solution and added to a glass reaction tube. 0.6 g of the supported Ni / Y catalyst from Example 1 was added, along with a magnetic stir bar. A glass tee connector was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 10.6 g of 70 wt% hydrogen peroxide solution was added to the other port of the glass tee connector, and the knob was turned to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 65°C for 5 hours. Gas phase analysis of the reaction liquid showed complete furfural conversion and a hydroxysuccinic acid yield of 88.7%.

[0106] Example 15

[0107] Water was used as the reaction solvent, with a water to furfural mass ratio of 85:1, a catalyst to substrate furfural mass ratio of 0.7:1, hydrogen peroxide mass fraction of 40wt%, a hydrogen peroxide to furfural molar ratio of 20:1, a reaction temperature of 80℃, and a reaction time of 4h.

[0108] 1.0 g of furfural was dissolved in 85 g of aqueous solution and added to a glass reaction tube. 0.7 g of the supported Ni / Y catalyst from Example 1 was added, along with a magnetic stir bar. A glass tee connector was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 17.7 g of 40 wt% hydrogen peroxide solution was added to the other port of the glass tee connector, and the knob was turned to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 80°C for 4 hours. Gas phase analysis of the reaction liquid showed complete furfural conversion and a hydroxysuccinic acid yield of 88.9%.

[0109] Example 16

[0110] Water was used as the reaction solvent, with a water to furfural mass ratio of 90:1, a catalyst to substrate furfural mass ratio of 0.9:1, hydrogen peroxide mass fraction of 30wt%, and a hydrogen peroxide to furfural molar ratio of 15:1. The reaction temperature was 75℃, and the reaction time was 4h.

[0111] 1.0 g of furfural was dissolved in 90 g of aqueous solution and added to a glass reaction tube. 0.9 g of the supported Ni / Y catalyst from Example 1 was added, along with a magnetic stir bar. A glass tee was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 17.7 g of 30 wt% hydrogen peroxide solution was added to the other port of the glass tee, and the knob was turned to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 75°C for 4 hours. Gas phase analysis of the reaction liquid showed complete furfural conversion and a hydroxysuccinic acid yield of 88.6%.

[0112] Example 17

[0113] Water was used as the reaction solvent, with a water-to-furfural mass ratio of 90:1, a catalyst-to-substrate-furfural mass ratio of 1:1, a hydrogen peroxide mass fraction of 50 wt%, a hydrogen peroxide-to-furfural molar ratio of 14:1, a reaction temperature of 72℃, and a reaction time of 5 h.

[0114] 1.0 g of furfural was dissolved in 90 g of aqueous solution and added to a glass reaction tube. 1.0 g of the supported Ni / Y catalyst from Example 1 was added, along with a magnetic stir bar. A glass tee connector was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 9.9 g of 50 wt% hydrogen peroxide solution was added to the other port of the glass tee connector, and the knob was turned to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 72°C for 5 hours. Gas phase analysis of the reaction liquid showed complete furfural conversion and a hydroxysuccinic acid yield of 89.2%.

[0115] Example 18

[0116] Water was used as the reaction solvent, with a water to furfural mass ratio of 88:1, a catalyst to furfural mass ratio of 0.8:1, hydrogen peroxide mass fraction of 40wt%, a hydrogen peroxide to furfural molar ratio of 10:1, a reaction temperature of 68℃, and a reaction time of 6h.

[0117] 1.0 g of furfural was dissolved in 88 g of aqueous solution and added to a glass reaction tube. 0.8 g of the supported Ni / Y catalyst from Example 1 was added, along with a magnetic stir bar. A glass tee connector was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 8.9 g of 40 wt% hydrogen peroxide solution was added to the other port of the glass tee connector, and the knob was turned to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 68°C for 6 hours. Gas phase analysis of the reaction liquid showed complete furfural conversion and a hydroxysuccinic acid yield of 89.3%.

[0118] Example 19

[0119] Water was used as the reaction solvent, with a water to furfural mass ratio of 86:1, a catalyst to substrate furfural mass ratio of 0.6:1, hydrogen peroxide mass fraction of 60wt%, a hydrogen peroxide to furfural molar ratio of 20:1, a reaction temperature of 65℃, and a reaction time of 7h.

[0120] 1.0 g of furfural was dissolved in 86 g of aqueous solution and added to a glass reaction tube. 0.6 g of the supported Ni / Y catalyst from Example 1 was added, along with a magnetic stir bar. A glass tee was connected to the reaction tube opening, with one port connected to a gas collection bag. The reaction tube was connected to a vacuum pump to evacuate the gas environment inside, and then kept sealed. 11.8 g of 60 wt% hydrogen peroxide solution was added to the other port of the glass tee, and the knob was turned to maintain a sealed state. The reaction tube was placed in a thermostatic magnetic stirring bath and reacted at 65°C for 7 hours. Gas phase analysis of the reaction liquid showed complete furfural conversion and a hydroxysuccinic acid yield of 88.5%.

[0121] To more intuitively describe the reaction conditions and results of Examples 12-19 above, the parameters and results are listed in Table 2.

[0122] Table 2 Catalytic performance results of Examples 12-19

[0123]

[0124] Example 20

[0125] Water was used as the reaction solvent, with a water to furfural mass ratio of 80:1, a catalyst to substrate furfural mass ratio of 0.5:1, hydrogen peroxide mass fraction of 70 wt%, a hydrogen peroxide to furfural molar ratio of 10:1, a reaction temperature of 60℃, and a reaction time of 5 h.

[0126] Dissolve 1.0 g of furfural in 80 g of aqueous solution and add it to a glass reaction tube. Add 0.5 g of the supported Ni / Y catalyst from Example 1 above, and add a magnetic stir bar. Connect a glass tee connector to the inlet of the reaction tube, with one port connected to a gas collection bag. Connect the reaction tube to a vacuum pump to evacuate the gas environment inside the tube and then maintain a sealed state. Add 5.1 g of 70 wt% hydrogen peroxide aqueous solution to the other port of the glass tee connector, and then turn the knob to maintain a sealed state. Place the reaction tube in a thermostatic magnetic stirring bath and react at 60°C for 5 hours. Perform gas phase analysis on the reaction liquid.

[0127] The used catalyst was washed, dried, and then fed into the next reaction. This cycle was repeated four times, and the results are shown in Table 3. The results show that furfural was completely converted after all four reactions, and the yield of hydroxysuccinic acid remained above 87%, indicating that the catalyst of this invention has good cycle stability.

[0128] Table 3 Catalyst Recycling Data

[0129] Number of times used Furfural conversion rate (%) Hydroxysuccinic acid yield (%) 1 time >99.9 89.5 2 times >99.9 89.3 3 times >99.9 88.3 4 times >99.9 87.5

[0130] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A Ni / Y type molecular sieve catalyst, wherein, The catalyst comprises an active component and a support, wherein the active component is nickel and the support is a Y-type molecular sieve. The valence state of nickel in the Ni / Y type molecular sieve catalyst includes metallic Ni and Ni2+. 2+ Ni 0 and Ni 2+ The molar ratio is 0.5 to 3.0:

1.

2. The catalyst according to claim 1, characterized in that, In the Ni / Y type molecular sieve catalyst, the relative Ni content is 0.5-5 wt%, based on the mass of the catalyst.

3. The catalyst according to claim 1, characterized in that, In the Ni / Y type molecular sieve catalyst, the Si / Al molar ratio is 4 to 10; And / or, the total specific surface area of ​​the Ni / Y type molecular sieve catalyst is 490–765 m². 2 / g, preferably 585~710m 2 / g; pore volume is 0.15~0.55cm³ 3 / g, preferably 0.25~0.45cm 3 / g.

4. The catalyst according to claim 1, characterized in that, The average size of the nickel nanoparticles in the Ni / Y type molecular sieve catalyst is 5-15 nm. And / or, in the Ni / Y type molecular sieve catalyst, The / Lewis acid ratio is 0.1 to 1.

5. A method for preparing the catalyst according to any one of claims 1-4, the method comprising the following steps: A Ni / Y type molecular sieve catalyst was prepared by loading nickel-containing metal salts onto a Y-type molecular sieve using a precipitation deposition method, followed by reduction treatment.

6. The preparation method according to claim 5, characterized in that, The precipitation-deposition method for preparing nickel-containing metal salts loaded onto Y-type molecular sieves includes: (1) Dissolve the nickel-containing metal salt in water and mix well to obtain solution A; (2) Disperse Y-type molecular sieve in aqueous solution to obtain suspension B, and slowly add solution A to suspension B to obtain material C; (3) Add the inorganic alkaline solution dropwise into material C, adjust the pH value to 10-11, obtain the precipitate, wash and dry it.

7. The preparation method according to claim 5 or 6, characterized in that, The nickel-containing metal salt includes one or more of nickel nitrate, nickel acetate, nickel chloride, nickel acetylacetonate, and nickel sulfate; And / or, the Si / Al molar ratio of the Y-type molecular sieve is 4 to 10; And / or, the total specific surface area of ​​the Y-type molecular sieve is 500–750 m². 2 / g, preferably 600-700m 2 / g; The pore volume is 0.2–0.5 cm³. 3 / g, preferably 0.3-0.4cm 3 / g.

8. The preparation method according to claim 5 or 6, characterized in that, The nickel-containing metal salt, calculated as elemental nickel, has a mass ratio of 0.8 to 10:100 with the Y-type molecular sieve.

9. The preparation method according to claim 6, characterized in that, The mass ratio of water in solution A in step (1) to water in suspension B in step (2) is 0.5 to 2:1; And / or, the inorganic base mentioned in step (3) includes one or more of sodium hydroxide, potassium hydroxide, and ammonia water; And / or, the concentration of the inorganic alkaline solution in step (3) is 0.05–1.0 mol / L; And / or, the drying conditions described in step (3) are: drying at 50 to 130°C for 2 to 12 hours.

10. The preparation method according to claim 6, characterized in that, The reducing atmosphere in the reduction process is hydrogen or a hydrogen / nitrogen mixture, wherein the volume percentage of hydrogen in the hydrogen / nitrogen mixture is 10-30%.

11. The use of the catalyst according to any one of claims 1-4 in the reaction for the preparation of hydroxysuccinic acid.

12. The application according to claim 11, characterized in that, The reaction comprises mixing the substrate furfural, solvent and oxidant under a hydrogen atmosphere and with the action of the catalyst according to any one of claims 1-4, and then performing a one-step oxidation reaction to obtain hydroxysuccinic acid.

13. The application according to claim 11, characterized in that, The reaction conditions include: a reaction temperature of 50–100°C; And / or, the reaction time is 2 to 12 hours.

14. The application according to claim 11, characterized in that, The oxidant is hydrogen peroxide, wherein the mass fraction of hydrogen peroxide in the hydrogen peroxide is 20-80 wt%. And / or, the solvent is water; the mass ratio of the solvent to the substrate furfural is 75-95:1, preferably 80-90:1; And / or, the mass ratio of the catalyst to the substrate furfural is 0.2 to 1:1, preferably 0.5 to 1:1; And / or, the molar ratio of the oxidant to the substrate furfural is 5 to 25:1, preferably 10 to 20:1.

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