Ni-Silicalite-1 molecular sieve as well as preparation method and application thereof

Abstract

The invention discloses a Ni-Silicalite-1 molecular sieve as well as a preparation method and application of the Ni-Silicalite-1 molecular sieve. The Ni-Silicalite-1 molecular sieve has a long strip-shaped morphology, the length of the Ni-Silicalite-1 molecular sieve crystal is less than 15 [mu] m, the length-width ratio is 3-9, and the average thickness is 200-580 nm. The Ni-Silicalite-1 molecular sieve provided by the invention has the characteristics of high-efficiency conversion of 5-hydroxymethylfurfural under mild reaction conditions, high selectivity of the product 2, 5-tetrahydrofuran dimethyl carbinol, outstanding recycling stability of the catalyst and the like.

Description

Technical Field

[0001] The invention relates to the field of molecular sieves, and in particular to a Ni-Silicalite-1 molecular sieve and a preparation method thereof, and application thereof in catalytically converting 5-hydroxymethylfurfural to prepare 2,5-tetrahydrofuran dimethanol. Background Art

[0002] Molecular sieves are a type of crystalline nanoporous materials with large specific surface area, regular and diverse microporous channels, and adjustable pH. They are widely used in various industrial fields and show excellent catalytic activity and product selectivity. Molecular sieves have also been proven to be ideal carriers for highly dispersed fixed metal species such as nanoparticles (NPs), clusters, single atoms, and isolated ions. Molecular sieve-supported metal catalysts have attracted widespread attention from academia and industry due to their excellent activity and stability in various heterogeneous catalytic processes. Among non-precious metal-based molecular sieves, the development of nickel-based molecular sieves with high hydrogenation capacity is of great significance.

[0003] 2,5-Tetrahydrofuran dimethanol (THFDM), which has both tetrahydrofuran ring structure and symmetrical diol functional groups, can be widely used in adhesives, coatings, resins and polyesters, and is expected to show unique advantages in barrier properties, dyeability, and degradability, becoming a hot topic in academic and industrial research. 2,5-Tetrahydrofuran dimethanol (THFDM) is mainly prepared by hydrogenation of 5-hydroxymethylfurfural (HMF). When hydrogen is used as a hydrogen source, commonly used catalysts include loaded precious metals such as ruthenium (Ru), platinum (Pt) and palladium (Pd), as well as transition metals such as nickel (Ni) and copper (Cu). CN 103228626B reported that 5% Ru / C was used as a catalyst and methanol was used as a reaction solvent. After reacting at 5MPa hydrogen and 75°C for 1.5 hours, and then reacting at 9MPa hydrogen and 200°C for 14 hours, the yield of THFDM was only 30%. CN 113651780A reports a method for preparing 2,5-tetrahydrofuran dimethanol, using Pd / C as a catalyst and ethanol as a reaction solvent. Under the reaction conditions of 1MPa hydrogen and 90°C, the initial selectivity of THFDM is only 35%. As the pressure increases to 7.5-9MPa, the selectivity of THFDM increases to 99%. In the presence of precious metal catalysts, HMF can usually achieve a higher conversion efficiency in the production of THFDM, but the low reusability and high cost of precious metals seriously hinder their commercial application. Therefore, the use of non-precious metals has gradually attracted the attention of researchers. For example, the Klaus Hellgardt research group (RSC Adv., 2017, 7, 31401) used Raney Cu and Ni double-layer catalysts to realize a two-stage hydrogenation method. Under the reaction conditions of a flow rate of 0.05mL / min, 9MPa hydrogen and 90°C, the initial selectivity of THFDM can reach up to 98%, but the Raney Ni catalyst used in the second stage is gradually deactivated. In the presence of non-precious metal catalysts, the reaction pressure is usually high and the loss of active components is serious. In summary, the existing technology mainly has problems such as low THFDM selectivity, harsh reaction conditions or poor catalyst cycle stability, which brings great problems to practical industrial applications. Summary of the invention

[0004] The purpose of the present invention is to provide a Ni-Silicalite-1 molecular sieve and a preparation method and application thereof. The molecular sieve has a new crystal morphology and is in the shape of a thin long strip. The molecular sieve is used for catalytic conversion of 5-hydroxymethylfurfural to prepare 2,5-tetrahydrofuran dimethanol. The molecular sieve has the characteristics of efficient conversion of 5-hydroxymethylfurfural under mild reaction conditions and high selectivity of the product 2,5-tetrahydrofuran dimethanol, as well as outstanding stability in recycling use.

[0005] The first aspect of the present invention provides a Ni-Silicalite-1 molecular sieve, wherein the Ni-Silicalite-1 molecular sieve has an elongated strip morphology, the length of the Ni-Silicalite-1 molecular sieve crystal is less than 15 μm, the aspect ratio is 3 to 9, and the average thickness is 200 to 580 nm.

[0006] According to the present invention, preferably, the length of the Ni-Silicalite-1 molecular sieve crystal is 4 to 12 μm.

[0007] According to the present invention, based on the mass of Silicalite-1 calculated as SiO2, the content of Ni calculated as Ni is 1wt% to 20wt%; preferably, based on the mass of Silicalite-1 calculated as SiO2, the content of Ni calculated as Ni is 3wt% to 10wt%.

[0008] According to the present invention, the specific surface area of ​​the Ni-Silicalite-1 molecular sieve is 120 to 500 m 2 / g, preferably 150 to 400 m 2 / g; total pore volume is 0.04~0.30cm 3 / g, preferably 0.05 to 0.25 cm 3 / g.

[0009] According to the present invention, Ni in the Ni-Silicalite-1 molecular sieve represents the active component nickel, and the active component nickel includes metallic nickel and nickel oxide, wherein the molar ratio of metallic nickel to nickel oxide is represented by Ni / NiO.

[0010] According to the present invention, the molar ratio of Ni / NiO in the Ni-Silicalite-1 molecular sieve is 1.3-2.3:1, preferably 1.5-2.0:1.

[0011] The second aspect of the present invention provides a method for preparing a Ni-Silicalite-1 molecular sieve, comprising the following steps: mixing a template, an additive, water, and a silicon source, adding a nickel precursor dropwise, and then aging, crystallizing, calcining, and reducing to obtain the Ni-Silicalite-1 molecular sieve.

[0012] According to the present invention, preferably, the nickel precursor comprises a complexing agent and a nickel source.

[0013] According to the present invention, the crystallization equipment is preferably a crystallization kettle.

[0014] According to the present invention, in the preparation method of the Ni-Silicalite-1 molecular sieve, the molar ratio of the template, additive, water and silicon source in terms of SiO2 is 0.05-0.5: 0.02-0.40: 5-50: 1, preferably 0.1-0.4: 0.05-0.20: 10-40: 1, and further preferably 0.1-0.4: 0.10-0.15: 10-40: 1.

[0015] According to the present invention, in the preparation method of the Ni-Silicalite-1 molecular sieve, the mass ratio of nickel in the nickel precursor, calculated as Ni, to the silicon source, calculated as SiO2, is 0.02-0.20:1, preferably 0.03-0.15:1, and further preferably 0.09-0.15:1.

[0016] According to the present invention, in the method for preparing the Ni-Silicalite-1 molecular sieve, the molar ratio of nickel in the nickel precursor (calculated as Ni) to the complexing agent is 0.1 to 3.0:1, preferably 0.2 to 2.0:1.

[0017] According to the present invention, in the preparation method, the template, additives and water are first mixed and then mixed with the silicon source.

[0018] According to the present invention, in the method for preparing the Ni-Silicalite-1 molecular sieve, the template agent includes one or more of tetrapropylammonium hydroxide, tetrapropylchloride hydroxide and tetrapropylbromide hydroxide, preferably tetrapropylammonium hydroxide.

[0019] According to the present invention, in the preparation method of the Ni-Silicalite-1 molecular sieve, the additive includes one or more of urea, cyanamide, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol and glycerol, preferably urea.

[0020] According to the present invention, in the preparation method of the Ni-Silicalite-1 molecular sieve, the silicon source includes one or more of white carbon black, sodium silicate, tetraethyl orthosilicate, and silica sol, preferably tetraethyl orthosilicate.

[0021] According to the present invention, in the preparation method of the Ni-Silicalite-1 molecular sieve, the nickel source includes one or more of nickel nitrate, nickel acetate, nickel chloride, nickel acetylacetonate, and nickel sulfate, preferably nickel nitrate.

[0022] According to the present invention, in the preparation method of the Ni-Silicalite-1 molecular sieve, the complexing agent includes one or more of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, and ethylenediamine, preferably ethylenediamine.

[0023] According to the present invention, preferably, the nickel precursor exists in the form of a nickel precursor solution, that is, a nickel source and a complexing agent are dissolved in water to form a nickel precursor solution.

[0024] According to the present invention, the aging temperature is 20 to 100° C., preferably 30 to 80° C.; the aging time is 2 to 48 hours, preferably 6 to 24 hours.

[0025] According to the present invention, the crystallization temperature is 120-220° C., preferably 150-180° C.; the crystallization time is 2-9 days, preferably 3-7 days.

[0026] According to the present invention, the calcination temperature is 300-650° C.; the calcination time is 1-12 hours; and the calcination atmosphere is oxygen-containing gas.

[0027] According to the present invention, the reduction temperature is 450-1000° C., preferably 550-900° C.; the reduction time is 2-10 hours, preferably 3-6 hours; the reduction atmosphere is hydrogen or a hydrogen-argon mixture, wherein the volume fraction of hydrogen in the hydrogen-argon mixture is not less than 10%, preferably 10%-50%.

[0028] The third aspect of the present invention provides a Ni-Silicalite-1 molecular sieve composition, comprising the Ni-Silicalite-1 molecular sieve according to any of the aforementioned aspects or the Ni-Silicalite-1 molecular sieve prepared by the preparation method according to any of the aforementioned aspects, and a binder.

[0029] In a fourth aspect, the present invention provides an application of the Ni-Silicalite-1 molecular sieve according to any of the preceding aspects, the Ni-Silicalite-1 molecular sieve prepared by the preparation method according to any of the preceding aspects, or the Ni-Silicalite-1 molecular sieve composition as a catalyst for catalytic conversion of 5-hydroxymethylfurfural to prepare 2,5-tetrahydrofuran dimethanol.

[0030] According to the present invention, the application method comprises: 5-hydroxymethylfurfural reacts in the presence of the above catalyst with hydrogen as a hydrogen source to obtain 2,5-tetrahydrofuran dimethanol.

[0031] According to the present invention, preferably, 5-hydroxymethylfurfural is dissolved in an organic solvent. Further preferably, the organic solvent includes one or more of methanol, ethanol, n-butanol, tetrahydrofuran, 1,4-dioxane, and methyl isobutyl ketone, preferably at least one of n-butanol and tetrahydrofuran.

[0032] According to the present invention, the mass ratio of 5-hydroxymethylfurfural to catalyst is 0.2-10:1, preferably 0.5-5.0:1.

[0033] According to the present invention, the mass ratio of the organic solvent to 5-hydroxymethylfurfural is 20 to 300:1, preferably 30 to 200:1.

[0034] According to the present invention, hydrogen is charged into the reaction system to adjust the reaction pressure, which is 0.2 to 5 MPa, preferably 0.5 to 3 MPa.

[0035] According to the present invention, the reaction conditions are as follows: the reaction temperature is 115 to 220° C., preferably 120 to 200° C.; and / or the reaction time is 1 to 24 hours, preferably 2 to 8 hours.

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

[0037] (1) In the present invention, the Ni-Silicalite-1 molecular sieve has a special crystal morphology, a long strip morphology, and a thin thickness. Preferably, the molar ratio of metallic Ni to oxidized NiO in the molecular sieve is controlled, and it is used for catalytic conversion of 5-hydroxymethylfurfural to prepare 2,5-tetrahydrofuran dimethanol. It has the characteristics of efficient conversion of 5-hydroxymethylfurfural under mild reaction conditions and high selectivity of the product 2,5-tetrahydrofuran dimethanol, as well as outstanding stability in recycling use.

[0038] (2) In the present invention, the Ni-Silicalite-1 molecular sieve is prepared by an in-situ synthesis crystallization method. Furthermore, the preparation method comprises the following steps: after mixing the template, additives, water, and silicon source, adding a nickel precursor, and then aging, crystallizing, calcining, and reducing to obtain the Ni-Silicalite-1 molecular sieve; the nickel precursor comprises a complexing agent and a Ni source. The Ni-Silicalite-1 molecular sieve prepared by the method is a thin long strip morphology, and the molar ratio of Ni / NiO in the Ni-Silicalite-1 molecular sieve is preferably controlled. Under mild reaction conditions, 5-hydroxymethylfurfural can be efficiently converted into 2,5-tetrahydrofuran dimethanol, and the substrate conversion rate and product selectivity are significantly improved. In addition, the prepared Ni-Silicalite-1 molecular sieve has good stability, and no significant changes are observed after four cycles. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a SEM image of the Ni-Silicalite-1 catalyst obtained in Example 1;

[0040] Figure 2 is the XRD pattern of the Ni-Silicalite-1 catalyst obtained in Example 1;

[0041] Figure 3This is the XPS graph of the Ni-Silicalite-1 catalyst obtained in Example 1;

[0042] Figure 4 The HMF conversion rate and THFDM selectivity under the recycling conditions of the Ni-Silicalite-1 catalyst obtained in Example 1;

[0043] Figure 5 This is the SEM image of the Ni-Silicalite-1 catalyst obtained in Comparative Example 1. DETAILED DESCRIPTION

[0044] In the present invention, the reaction product 2,5-tetrahydrofuran dimethanol (THFDM) is qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS), and the conversion rate of substrate 5-hydroxymethyl furfural (HMF) and the yield of the reaction product THFDM are analyzed by gas chromatography (GC). The gas chromatography-mass spectrometry instrument is Agilent 7890A of Agilent Corporation of the United States, the chromatographic column is HP-5 non-polar capillary column (30m, 0.53mm), the gas chromatograph is Agilent 7890B, the detector is a hydrogen flame ionization detector (FID), and the chromatographic column is SE-54 capillary column (30m, 0.53mm).

[0045] In the present invention, the XRD measurement method of the molecular sieve product is: using a Japanese Rigaku Ultima IV X-ray powder diffractometer to analyze the physical phase of the sample, and a CuKα ray source Nickel filter, 2θ scanning range 2°-50°, operating voltage 35 kV, current 25 mA, scanning rate 10° / min.

[0046] In the present invention, the inductively coupled plasma atomic emission spectrometer (ICP) model is Varian 725-ES, and the analysis sample is dissolved with hydrofluoric acid to detect the content of the metal element.

[0047] In the present invention, the physical adsorption instrument model is Micromeretic ASAP2020M, and the test conditions are: the measurement temperature is -169°C, the molecular sieve is vacuum pretreated at 300°C for 10 hours before the measurement, and the pore volume, specific surface area and other parameters are calculated by using the BET method and t-plot method.

[0048] In the present invention, the determination of the element binding energy on the catalyst surface is carried out on an X-ray photoelectron spectrometer (ESCA LAB-250) produced by Thermo Company, using C1s=284.6eV as an internal standard to calibrate the measured element signal.

[0049] In the present invention, the model of the molecular sieve scanning electron microscope (SEM) is S-4800II field emission scanning electron microscope. The average thickness of the molecular sieve is calculated by selecting the thickness of 10 molecular sieve crystals for statistics through the SEM image and then calculating the average value.

[0050] In the present invention, the 5-hydroxymethylfurfural conversion formula is:

[0051] HMF conversion rate % = (molar amount of HMF participating in the reaction) / (molar amount of HMF as the reaction substrate) × 100%.

[0052] In the present invention, the product THFDM selectivity calculation formula is:

[0053] The selectivity of the product THFDM (%) = (the molar amount of THFDM produced by the reaction) / (the molar amount of HMF reacted) × 100%.

[0054] In order to facilitate the understanding of the present invention, the present invention lists the following embodiments, but the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] Example 1

[0056] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, urea is used as additive, nickel source is nickel nitrate, and complexing agent is ethylenediamine. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.3:0.10:20:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.12:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 0.5.

[0057] The specific synthesis steps are as follows: weigh 29.3g of 25% tetrapropylammonium hydroxide aqueous solution, 0.72g of urea and 43.2g of deionized water, mix them evenly, slowly drop 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 2.69g of nickel nitrate and dissolve it in 10g of deionized water, add 1.77g of ethylenediamine and stir evenly to obtain solution B; slowly drop solution B into solution A, and continue aging at 80°C for 12 hours. The gel mixture obtained above is crystallized at 180°C for 4 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 800°C in a hydrogen atmosphere for 4 hours to obtain Ni-Silicalite-1 catalyst.

[0058] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 230 m 2 / g, and the total pore volume is 0.13cm 3 / g. Inductively coupled plasma atomic emission spectroscopy (ICP) was used to test that the relative content of Ni was 10wt% relative to Silicalite-1 (in terms of SiO2), and the catalyst was named 10Ni-Silicalite-1-A; the SEM of the sample was as follows Figure 1 As shown in Figure 2, the sample has a thin strip-like morphology, with a crystal length of 8 μm, an aspect ratio of 5.5, and an average thickness of 500 nm. The XRD characteristics of the sample are as follows: Figure 2 The XPS of the sample is shown as Figure 3 As shown in the figure, the binding energy at 852.9 eV corresponds to the metal element Ni (2p3 / 2 peak), and the binding energy at 855.4 eV corresponds to divalent nickel (2 + ), the molar ratio of metallic Ni to oxidized NiO was calculated by the ratio of the two peak areas (Ni / NiO ratio) and was 1.5.

[0059] Example 2

[0060] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, urea is used as additive, nickel source is nickel nitrate, and complexing agent is ethylenediamine. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.2:0.10:20:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.10:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 0.8.

[0061] The specific synthesis steps are as follows: weigh 19.5g of 25% tetrapropylammonium hydroxide aqueous solution, 0.72g of urea and 43.2g of deionized water, mix them evenly, slowly drop 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 2.24g of nickel nitrate and dissolve it in 10g of deionized water, add 0.92g of ethylenediamine and stir evenly to obtain solution B; slowly drop solution B into solution A, and continue aging at 70°C for 12 hours. The gel mixture obtained above is crystallized at 170°C for 6 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 800°C in a hydrogen atmosphere for 4 hours to obtain Ni-Silicalite-1 catalyst.

[0062] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 253 m 2 / g, with a total pore volume of 0.15 cm 3 / g. Inductively coupled plasma atomic emission spectroscopy (ICP) was used to test that the relative content of Ni was 8wt% relative to Silicalite-1 (in terms of SiO2), and the catalyst was named 8Ni-Silicalite-1; SEM and Figure 1Similarly, the sample has a thin strip morphology, with a crystal length of 8 μm, an aspect ratio of 5.2, and an average thickness of 520 nm; the XRD and Figure 2 The XPS and Figure 3 Similarly, the molar ratio of metallic Ni to oxidized NiO (Ni / NiO) is 1.7.

[0063] Example 3

[0064] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, urea is used as additive, nickel source is nickel nitrate, and complexing agent is ethylenediamine. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.3:0.15:15:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.13:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 0.4.

[0065] The specific synthesis steps are as follows: weigh 29.3g of 25% tetrapropylammonium hydroxide aqueous solution, 1.08g of urea and 32.4g of deionized water, mix them evenly, slowly drop 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 2.91g of nickel nitrate and dissolve it in 10g of deionized water, add 2.39g of ethylenediamine and stir evenly to obtain solution B; slowly drop solution B into solution A, and continue aging at 80°C for 10 hours. The gel mixture obtained above is crystallized at 180°C for 5 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 800°C in a hydrogen atmosphere for 4 hours to obtain Ni-Silicalite-1 catalyst.

[0066] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 225 m 2 / g, and the total pore volume is 0.16cm 3 / g. Inductively coupled plasma atomic emission spectroscopy (ICP) was used to test that the relative content of Ni was 10wt% relative to Silicalite-1 (in terms of SiO2), and the catalyst was named 10Ni-Silicalite-1-B; SEM and Figure 1 Similarly, the sample has a thin strip morphology, with a crystal length of 8 μm, an aspect ratio of 6.0, and an average thickness of 510 nm; the XRD patterns of the sample are similar to those of Figure 2 The XPS and Figure 3 Similarly, the molar ratio of metallic Ni to oxidized NiO (Ni / NiO) is 1.6.

[0067] Example 4

[0068] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, urea is used as additive, nickel source is nickel nitrate, and complexing agent is ethylenediamine. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.3:0.12:15:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.09:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 0.5.

[0069] The specific synthesis steps are as follows: weigh 29.3g of 25% tetrapropylammonium hydroxide aqueous solution, 0.86g of urea and 32.4g of deionized water, mix them evenly, slowly drop 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 2.02g of nickel nitrate and dissolve it in 10g of deionized water, add 1.32g of ethylenediamine and stir evenly to obtain solution B; slowly drop solution B into solution A and age it at 60°C for 24 hours. The gel mixture obtained above is crystallized at 170°C for 6 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 850°C in a hydrogen atmosphere for 4 hours to obtain Ni-Silicalite-1 catalyst.

[0070] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 217 m 2 / g, with a total pore volume of 0.14 cm 3 / g. Inductively coupled plasma atomic emission spectroscopy (ICP) was used to test that the relative content of Ni was 7wt% relative to Silicalite-1 (in terms of SiO2). The catalyst was named 7Ni-Silicalite-1. The SEM and Figure 1 Similarly, the sample has a thin strip morphology, the crystal length is 8μm, the aspect ratio is 6.4, and the average thickness is 480nm; the XRD and Figure 2 The XPS and Figure 3 Similarly, the molar ratio of metallic Ni to oxidized NiO (Ni / NiO) is 1.8.

[0071] Embodiment 5-8

[0072] Tetrahydrofuran was used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF was 100, the mass ratio of HMF to catalyst was 1, the hydrogen pressure was 1.5 MPa, the reaction temperature was 130°C, and the reaction time was 5 h. 0.2 g of the catalyst in the above-mentioned Examples 1-4, 0.2 g of HMF and 20 g of tetrahydrofuran were added to a stirred autoclave, and 1.5 MPa of hydrogen was filled. The heating jacket was heated to a preset temperature using a programmed temperature increase, and then stirred using a magnetic stirrer. The reaction was carried out at 130°C for 5 h, and the HMF conversion rate and the product THFDM selectivity were calculated by gas phase analysis of the reaction liquid, as shown in Table 1.

[0073] Table 1 Catalytic evaluation results of catalysts of Examples 1-4

[0074]

[0075] Example 9

[0076] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 120, the mass ratio of HMF to catalyst is 0.8, the hydrogen pressure is 1.2MPa, the reaction temperature is 130°C, and the reaction time is 4h. 0.2g of the catalyst in the above-mentioned Example 1, 0.16g of HMF and 19.2g of tetrahydrofuran are added to a stirred autoclave, and 1.2MPa of hydrogen is filled. The programmed temperature heating jacket is raised to the preset temperature, and magnetic stirring is used and then stirred. The reaction is carried out at 130°C for 4h, and the HMF conversion is completely calculated by the gas phase analysis of the reaction liquid (conversion rate>99%), and the product THFDM selectivity is 91.7%.

[0077] Example 10

[0078] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 150, the mass ratio of HMF to catalyst is 1.0, the hydrogen pressure is 2.5MPa, the reaction temperature is 120°C, and the reaction time is 8h. 0.2g of the catalyst in Example 1, 0.2g of HMF and 30.0g of tetrahydrofuran are added to a stirred autoclave, and 2.5MPa of hydrogen is filled. The programmed temperature heating jacket is raised to a preset temperature, and magnetic stirring is used and then stirred. The reaction is carried out at 120°C for 8h, and the HMF conversion is completely calculated by gas phase analysis of the reaction liquid, and the product THFDM selectivity is 90.5%.

[0079] Embodiment 11

[0080] Tetrahydrofuran was used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF was 80, the mass ratio of HMF to catalyst was 1.3, the hydrogen pressure was 1.2 MPa, the reaction temperature was 160°C, and the reaction time was 3 h. 0.2 g of the catalyst in Example 1, 0.26 g of HMF and 20.8 g of tetrahydrofuran were added to a stirred autoclave, and 1.2 MPa of hydrogen was added. The temperature was raised to a preset temperature using a programmed heating jacket, and then stirred using magnetic stirring. The reaction was carried out at 160°C for 3 h, and the HMF conversion was completely calculated by gas phase analysis of the reaction liquid, and the product THFDM selectivity was 90.6%.

[0081] Example 12

[0082] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 110, the mass ratio of HMF to catalyst is 2.0, the hydrogen pressure is 2.0MPa, the reaction temperature is 150°C, and the reaction time is 4h. 0.2g of the catalyst in Example 2, 0.40g of HMF and 44.0g of tetrahydrofuran are added to a stirred autoclave, and 2.0MPa of hydrogen is filled. The programmed temperature heating jacket is raised to a preset temperature, and magnetic stirring is used and then stirred. The reaction is carried out at 150°C for 4h, and the HMF conversion is completely calculated by gas phase analysis of the reaction liquid, and the product THFDM selectivity is 90.9%.

[0083] Example 13

[0084] Tetrahydrofuran was used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF was 100, the mass ratio of HMF to catalyst was 1.0, the hydrogen pressure was 1.4 MPa, the reaction temperature was 140°C, and the reaction time was 4 h. 0.2 g of the catalyst in Example 2, 0.20 g of HMF and 20.0 g of tetrahydrofuran were added to a stirred autoclave, and 1.4 MPa of hydrogen was added. The temperature was raised to a preset temperature using a programmed heating jacket, and then stirred using magnetic stirring. The reaction was carried out at 140°C for 5 h, and the HMF conversion was completely calculated by gas phase analysis of the reaction liquid, and the product THFDM selectivity was 90.4%.

[0085] Embodiment 14

[0086] Tetrahydrofuran was used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF was 80, the mass ratio of HMF to catalyst was 1.5, the hydrogen pressure was 1.7 MPa, the reaction temperature was 130°C, and the reaction time was 5 h. 0.2 g of the catalyst in Example 3, 0.30 g of HMF and 24.0 g of tetrahydrofuran were added to a stirred autoclave, and 1.7 MPa of hydrogen was added. The temperature was raised to a preset temperature using a programmed heating jacket, and then stirred using magnetic stirring. The reaction was carried out at 130°C for 5 h, and the HMF conversion was completely calculated by gas phase analysis of the reaction liquid, and the product THFDM selectivity was 89.6%.

[0087] Embodiment 15

[0088] n-Butanol was used as the reaction solvent, the mass ratio of n-butanol to HMF was 120, the mass ratio of HMF to catalyst was 0.6, the hydrogen pressure was 1.5MPa, the reaction temperature was 140°C, and the reaction time was 5h. 0.2g of the catalyst in Example 3, 0.12g of HMF and 14.4g of n-butanol were added to a stirred autoclave, and 1.5MPa of hydrogen was added. The programmed temperature heating jacket was raised to a preset temperature, and magnetic stirring was used and then stirred. The reaction was carried out at 140°C for 5h, and the HMF conversion was completely calculated by gas phase analysis of the reaction liquid, and the product THFDM selectivity was 91.1%.

[0089] Example 16

[0090] n-Butanol was used as the reaction solvent, the mass ratio of n-butanol to HMF was 150, the mass ratio of HMF to catalyst was 2.0, the hydrogen pressure was 2.5 MPa, the reaction temperature was 150°C, and the reaction time was 4 h. 0.2 g of the catalyst in Example 3, 0.40 g of HMF and 60.0 g of n-butanol were added to a stirred autoclave, and 2.5 MPa of hydrogen was added. The programmed temperature heating jacket was raised to a preset temperature, and magnetic stirring was used and then stirred. The reaction was carried out at 150°C for 4 h, and the HMF conversion was completely calculated by gas phase analysis of the reaction liquid, and the product THFDM selectivity was 90.2%.

[0091] In order to more intuitively describe the reaction conditions and results of the above Examples 9-16, various parameters and results are listed in Table 2.

[0092] Table 2 Catalytic performance results of Examples 9-16

[0093]

[0094] Embodiment 17

[0095] Tetrahydrofuran was used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF was 120, the mass ratio of HMF to catalyst was 0.8, the hydrogen pressure was 1.2 MPa, the reaction temperature was 130°C, and the reaction time was 4 h. 0.2 g of the catalyst in Example 1 above, 0.16 g of HMF and 19.2 g of tetrahydrofuran were added to a stirred high-pressure reactor, and 1.2 MPa of hydrogen was filled in. The temperature was raised to the preset temperature using a programmed heating jacket, and then stirred using a magnetic stirrer. The reaction was carried out at 130°C for 4 hours, and the HMF conversion rate and product THFDM selectivity were calculated by gas phase analysis of the reaction liquid. The used catalyst was washed and dried and then put into the next reaction. A total of 4 reactions were repeated, and the results are as follows Figure 4 The results show that after 4 reactions, HMF is completely converted (conversion rate>99%), and THFDM selectivity is maintained at 89.8%, indicating that the catalyst of the present invention has good cycle stability.

[0096] Embodiment 18

[0097] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, urea is used as additive, nickel source is nickel nitrate, and complexing agent is ethylenediamine. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.2:0.03:20:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.17:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 0.8.

[0098] The specific synthesis steps are as follows: weigh 19.5g of 25% tetrapropylammonium hydroxide aqueous solution, 0.22g of urea and 43.2g of deionized water, mix them evenly, slowly drop 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 3.81g of nickel nitrate and dissolve it in 10g of deionized water, add 1.56g of ethylenediamine and stir evenly to obtain solution B; slowly drop solution B into solution A, and continue aging at 90°C for 12 hours. The gel mixture obtained above is crystallized at 160°C for 6 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 800°C in a hydrogen atmosphere for 4 hours to obtain Ni-Silicalite-1 catalyst.

[0099] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 247 m 2 / g, with a total pore volume of 0.18 cm 3 / g. Inductively coupled plasma atomic emission spectroscopy (ICP) was used to test that the relative content of Ni was 14wt% relative to Silicalite-1 (in terms of SiO2). The catalyst was named 14Ni-Silicalite-1. The SEM and Figure 1 Similarly, the sample has a thin strip morphology, the crystal length is 9μm, the aspect ratio is 6.5, and the average thickness is 470nm; the XRD and Figure 2 The XPS and Figure 3 Similarly, the molar ratio of metallic Ni to oxidized NiO (Ni / NiO) is 1.3.

[0100] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 100, the mass ratio of HMF to catalyst is 1, the hydrogen pressure is 1.5MPa, the reaction temperature is 130°C, and the reaction time is 5h. 0.2g of the catalyst of the above embodiment, 0.2gHMF and 20g of tetrahydrofuran are added to a stirred autoclave, and 1.5MPa of hydrogen is filled. The program temperature heating jacket is raised to the preset temperature, and magnetic stirring is used and then stirred. React at 130°C for 5h, and the reaction liquid gas phase analysis calculates that HMF is completely converted, and the product THFDM selectivity is 87.7%. The used catalyst is washed and dried and then put into the next reaction, and the reaction is circulated 4 times. The results show that after 4 reactions, HMF is completely converted and the THFDM selectivity remains at 85.5%.

[0101] Embodiment 19

[0102] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, urea is used as additive, nickel source is nickel nitrate, and complexing agent is ethylenediamine. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.3:0.35:15:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.15:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 2.5.

[0103] The specific synthesis steps are as follows: weigh 29.3g of 25% tetrapropylammonium hydroxide aqueous solution, 2.52g of urea and 32.4g of deionized water, mix them evenly, slowly drop 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 3.36g of nickel nitrate and dissolve it in 10g of deionized water, add 0.44g of ethylenediamine and stir evenly to obtain solution B; slowly drop solution B into solution A, and continue aging at 80°C for 10 hours. The gel mixture obtained above is crystallized at 180°C for 5 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 950°C in a hydrogen atmosphere for 4 hours to obtain Ni-Silicalite-1 catalyst.

[0104] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 235 m 2 / g, with a total pore volume of 0.17 cm3 / g. Inductively coupled plasma atomic emission spectroscopy (ICP) was used to test that the relative content of Ni was 12wt% relative to Silicalite-1 (in terms of SiO2). The catalyst was named 12Ni-Silicalite-1. The SEM and Figure 1 Similarly, the sample has a thin strip morphology, with a crystal length of 7 μm, an aspect ratio of 6.3, and an average thickness of 580 nm; the XRD patterns of the sample are similar to those of Figure 2 The XPS and Figure 3 Similarly, the molar ratio of metallic Ni to oxidized NiO (Ni / NiO) is 1.4.

[0105] n-Butanol was used as the reaction solvent, the mass ratio of n-butanol to HMF was 150, the mass ratio of HMF to catalyst was 2.0, the hydrogen pressure was 2.5MPa, the reaction temperature was 150°C, and the reaction time was 4h. 0.2g of the catalyst in the above embodiment, 0.40g of HMF and 60.0g of n-butanol were added to a stirred autoclave, and 2.5MPa of hydrogen was filled. The programmed temperature heating jacket was raised to a preset temperature, and magnetic stirring was used and then stirred. The reaction was carried out at 150°C for 4h, and the HMF conversion was completely calculated by gas phase analysis of the reaction liquid, and the product THFDM selectivity was 86.9%. The used catalyst was washed and dried and then put into the next reaction, and the reaction was circulated 4 times. The results show that after 4 reactions, HMF conversion is complete, and the THFDM selectivity remains at 84.7%.

[0106] Embodiment 20

[0107] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, glycerol is used as additive, nickel source is nickel nitrate, and complexing agent is disodium ethylenediaminetetraacetate. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.3:0.10:20:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.12:1. The molar ratio of nickel nitrate (calculated as Ni mole) to disodium ethylenediaminetetraacetate is 0.5.

[0108] The specific synthesis steps are as follows: weigh 29.3g of 25% tetrapropylammonium hydroxide aqueous solution, 1.1g of glycerol and 43.2g of deionized water, mix them evenly, slowly drop 25g of ethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 2.63g of nickel nitrate and dissolve it in 10g of deionized water, add 9.68g of disodium ethylenediaminetetraacetate and stir evenly to obtain solution B; slowly drop solution B into solution A, and continue aging at 80°C for 12 hours. The gel mixture obtained above is crystallized at 180°C for 4 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 800°C in a hydrogen atmosphere for 4 hours to obtain Ni-Silicalite-1 catalyst.

[0109] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 251 m 2 / g, with a total pore volume of 0.15 cm 3 / g. Inductively coupled plasma atomic emission spectroscopy (ICP) was used to test that the relative content of Ni was 10wt% relative to Silicalite-1 (in terms of SiO2), and the catalyst was named 10Ni-Silicalite-1-C; SEM and Figure 1 Similarly, the sample has a thin strip morphology, with a crystal length of 13μm, an aspect ratio of 7.2, and an average thickness of 410nm; the XRD and Figure 2 The XPS and Figure 3 Similarly, the binding energy at 852.9 eV corresponds to the metal element Ni (2p 3 / 2 The peak with a binding energy of 855.4 eV corresponds to divalent nickel (2 + ), the molar ratio of metallic Ni to oxidized NiO was calculated by the ratio of the two peak areas (Ni / NiO ratio) and was 2.1.

[0110] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 100, the mass ratio of HMF to catalyst is 1, the hydrogen pressure is 1.5MPa, the reaction temperature is 130°C, and the reaction time is 5h. 0.2g of the catalyst in the above embodiment, 0.2gHMF and 20g of tetrahydrofuran are added to a stirred autoclave, and 1.5MPa of hydrogen is filled. The program temperature heating jacket is raised to the preset temperature, and magnetic stirring is used and then stirred. React at 130°C for 5h, and the reaction liquid gas phase analysis calculates that HMF is completely converted, and the product THFDM selectivity is 87.3%. The used catalyst is washed and dried and then put into the next reaction, and the reaction is circulated 4 times. The results show that after 4 reactions, HMF is completely converted and the THFDM selectivity remains at 85.2%.

[0111] Comparative Example 1

[0112] TEOS is used as silicon source, tetrapropylammonium hydroxide (TPAOH) as template, nickel source as nickel nitrate, and complexing agent as ethylenediamine. The molar ratio of template, water and TEOS (calculated as SiO2) is 0.3:20:1, the mass ratio of nickel nitrate (calculated as Ni mass) and silica sol (calculated as SiO2 mass) is 0.12:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 0.5.

[0113] The specific synthesis steps are as follows: weigh 29.3g of 25% tetrapropylammonium hydroxide aqueous solution and mix it evenly with 43.2g of deionized water, slowly add 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 2.69g of nickel nitrate and dissolve it in 10g of deionized water, add 1.77g of ethylenediamine and stir evenly to obtain solution B; slowly add solution B dropwise to solution A, and continue aging at 80°C for 12 hours. The gel mixture obtained above is crystallized at 180°C for 4 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 800°C in a hydrogen atmosphere for 4 hours to obtain Ni-Silicalite-1 catalyst.

[0114] The inductively coupled plasma atomic emission spectroscopy (ICP) test showed that the relative content of Ni was 10 wt% relative to Silicalite-1 (in terms of SiO2). The catalyst was named D-10Ni-Silicalite-1. Figure 5 As shown (short fat type), the crystal length is 200nm, the aspect ratio is 1.6, and the average thickness is 130nm. Using the BET method and t-plot method, the specific surface area of ​​the sample is 309m 2 / g, with a total pore volume of 0.28 cm 3 / g. XRD and Figure 2 The XPS calculation of the sample showed that the molar ratio of metallic Ni to oxidized NiO (Ni / NiO ratio) was 1.1.

[0115] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 100, the mass ratio of HMF to catalyst is 1, the hydrogen pressure is 1.5MPa, the reaction temperature is 130°C, and the reaction time is 5h. 0.2g of the catalyst in the above comparative example, 0.2g of HMF and 20g of tetrahydrofuran are added to a stirred autoclave, and 1.5MPa of hydrogen is filled. The programmed temperature heating jacket is raised to a preset temperature, and magnetic stirring is used and then stirred. The reaction is carried out at 130°C for 5h, and the reaction liquid is analyzed and calculated. The results show that the HMF conversion rate is 92% and the product THFDM selectivity is 58.2%.

[0116] Comparative Example 2

[0117] First, the Silicalite-1 molecular sieve was synthesized, and the specific synthesis steps were as follows: 32.5g of 25% tetrapropylammonium hydroxide aqueous solution, 0.72g of urea, 1.77g of ethylenediamine and 36g of deionized water were weighed and mixed evenly, and 25g of ethyl orthosilicate was slowly added dropwise, and stirred evenly at 50°C to obtain a mixed solution. The gel mixture obtained above was crystallized at 160°C for 72 hours, and after the crystallization was completed, it was washed, centrifuged and dried, and then calcined at 550°C for 6 hours to obtain the Silicalite-1 molecular sieve.

[0118] The Ni / Silicalite-1 catalyst was prepared by an impregnation method. The specific synthesis steps were as follows: 1.79 g of nickel nitrate was weighed and dissolved in 10 g of deionized water, 7.2 g of Silicalite-1 molecular sieve was added to the above solution, and the mixture was stirred until the solid reached an initial wet state, and then placed in a 50°C oven, dried, and then calcined at 550°C for 6 hours, and reduced in a hydrogen atmosphere at 800°C for 4 hours to obtain the Ni / Silicalite-1 catalyst.

[0119] The inductively coupled plasma atomic emission spectrometry (ICP) test showed that the relative content of Ni was 8 wt% relative to Silicalite-1 (in terms of SiO2). The catalyst was named D-8Ni-Silicalite-1. The specific surface area of ​​the sample was calculated by the BET method and t-plot method to be 346 m 2 / g, with a total pore volume of 0.24 cm 3 / g. XRD and Figure 2 The XPS calculation of the sample showed that the molar ratio of metallic Ni to oxidized NiO (Ni / NiO ratio) was 2.5. The sample morphology was nanoneedle-like, with a crystal length of 1.2 μm, an aspect ratio of 10, and an average thickness of 70 nm.

[0120] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 100, the mass ratio of HMF to catalyst is 1, the hydrogen pressure is 1.5MPa, the reaction temperature is 130°C, and the reaction time is 5h. 0.2g of the catalyst in the above comparative example, 0.2g of HMF and 20g of tetrahydrofuran are added to a stirred autoclave, and 1.5MPa of hydrogen is filled. The programmed temperature heating jacket is raised to the preset temperature, and magnetic stirring is used and then stirred. The reaction is carried out at 130°C for 5h, and the reaction liquid is analyzed and calculated. The results show that the HMF conversion rate is 75% and the product THFDM selectivity is 65.3%.

[0121] Comparative Example 3

[0122] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, urea is used as additive, nickel source is nickel nitrate, and complexing agent is ethylenediamine. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.3:0.10:20:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.12:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 0.05.

[0123] The specific synthesis steps are as follows: weigh 29.3g of 25% tetrapropylammonium hydroxide aqueous solution, 0.72g of urea and 43.2g of deionized water, mix them evenly, slowly drop 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 2.69g of nickel nitrate and dissolve it in 10g of deionized water, add 17.69g of ethylenediamine and stir evenly to obtain solution B; slowly drop solution B into solution A, and continue aging at 80°C for 12 hours. The gel mixture obtained above is crystallized at 180°C for 4 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 800°C in a hydrogen atmosphere for 4 hours to obtain a catalyst.

[0124] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 196 m 2 / g, with a total pore volume of 0.10 cm 3 / g. Inductively coupled plasma atomic emission spectroscopy (ICP) test shows that the relative content of Ni is 8wt% relative to SiO2, and the catalyst is named 8Ni-SiO2; the XRD results of the sample show that the catalyst is in an amorphous state. The XPS results of the sample show that the binding energy is located at 852.9eV, which corresponds to the metal element Ni (2p 3 / 2 The peak with a binding energy of 855.4 eV corresponds to divalent nickel (2 + ), the molar ratio of metallic Ni to oxidized NiO was calculated by the ratio of the two peak areas (Ni / NiO ratio) and was 2.4.

[0125] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 100, the mass ratio of HMF to catalyst is 1, the hydrogen pressure is 1.5MPa, the reaction temperature is 130°C, and the reaction time is 5h. 0.2g of the catalyst in the above comparative example, 0.2g of HMF and 20g of tetrahydrofuran are added to a stirred autoclave, and 1.5MPa of hydrogen is filled. The programmed temperature heating jacket is raised to the preset temperature, and magnetic stirring is used and then stirred. The reaction is carried out at 130°C for 5h, and the reaction liquid is analyzed and calculated. The results show that HMF is completely converted (conversion rate>99%), and the product THFDM selectivity is 72.1%.

[0126] Comparative Example 4

[0127] Tetraethyl orthosilicate (TEOS) is used as silicon source, tetrapropylammonium hydroxide (TPAOH) is used as template, urea is used as additive, nickel source is nickel nitrate, and complexing agent is ethylenediamine. The molar ratio of template, additive, water to tetraethyl orthosilicate (calculated as SiO2) is 0.3:1.00:20:1, the mass ratio of nickel nitrate (calculated as Ni mass) to tetraethyl orthosilicate (calculated as SiO2 mass) is 0.12:1. The molar ratio of nickel nitrate (calculated as Ni mole) to ethylenediamine is 0.5.

[0128] The specific synthesis steps are as follows: weigh 29.3g of 25% tetrapropylammonium hydroxide aqueous solution, 7.2g of urea and 43.2g of deionized water, mix them evenly, slowly drop 25g of tetraethyl orthosilicate, and stir evenly at 50°C to obtain solution A; weigh 2.69g of nickel nitrate and dissolve it in 10g of deionized water, add 1.77g of ethylenediamine and stir evenly to obtain solution B; slowly drop solution B into solution A, and continue aging at 80°C for 12 hours. The gel mixture obtained above is crystallized at 180°C for 4 days, washed, centrifuged and dried after crystallization, calcined at 550°C for 6 hours, and reduced at 800°C in a hydrogen atmosphere for 4 hours to obtain a catalyst.

[0129] The specific surface area of ​​the sample was calculated by BET method and t-plot method to be 253 m 2 / g, with a total pore volume of 0.17 cm 3 / g. Using inductively coupled plasma atomic emission spectroscopy (ICP) testing, the relative content of Ni relative to SiO2 is 10wt%, and the catalyst is named 10Ni-SiO2; the XRD results of the sample show that the catalyst is in an amorphous state. The XPS results of the sample show that the binding energy is located at 852.9eV, which corresponds to the metal element Ni (2p 3 / 2 The peak with a binding energy of 855.4 eV corresponds to divalent nickel (2 + ), the molar ratio of metallic Ni to oxidized NiO was calculated by the ratio of the two peak areas (Ni / NiO ratio) and was 0.9.

[0130] Tetrahydrofuran is used as the reaction solvent, the mass ratio of tetrahydrofuran to HMF is 100, the mass ratio of HMF to catalyst is 1, the hydrogen pressure is 1.5MPa, the reaction temperature is 130°C, and the reaction time is 5h. 0.2g of the catalyst in the above comparative example, 0.2g of HMF and 20g of tetrahydrofuran are added to a stirred autoclave, and 1.5MPa of hydrogen is filled. The programmed temperature heating jacket is raised to a preset temperature, and magnetic stirring is used and then stirred. The reaction is carried out at 130°C for 5h, and the reaction liquid is analyzed and calculated. The results show that the HMF conversion rate is 83.9% and the product THFDM selectivity is 63.7%.

[0131] The above describes the specific implementation of the present invention in detail, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the various technical features being combined in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A Ni-Silicalite-1 molecular sieve, characterized in that: The Ni-Silicalite-1 molecular sieve has a long strip shape, the length of the Ni-Silicalite-1 molecular sieve crystal is less than 15 μm, the aspect ratio is 3 to 9, and the average thickness is 200 to 580 nm.

2. The Ni-Silicalite-1 molecular sieve according to claim 1, characterized in that: The length of the Ni-Silicalite-1 molecular sieve crystal is 4 to 12 μm.

3. The Ni-Silicalite-1 molecular sieve according to claim 1, characterized in that: The specific surface area of ​​the Ni-Silicalite-1 molecular sieve is 120 to 500 m 2 / g, preferably 150 to 400 m 2 / g; total pore volume is 0.04~0.30cm 3 / g, preferably 0.05 to 0.25 cm 3 / g.

4. The Ni-Silicalite-1 molecular sieve according to claim 1, characterized in that The molar ratio of Ni / NiO in the Ni-Silicalite-1 molecular sieve is 1.3-2.3:1, preferably 1.5-2.0:

1.

5. The Ni-Silicalite-1 molecular sieve according to claim 1, characterized in that: Based on the mass of Silicalite-1 calculated as SiO2, the content of Ni calculated as Ni is 1wt% to 20wt%; preferably, based on the mass of Silicalite-1 calculated as SiO2, the content of Ni calculated as Ni is 3wt% to 10wt%.

6. A method for preparing a Ni-Silicalite-1 molecular sieve, comprising the following steps: mixing a template, an additive, water, and a silicon source, adding a nickel precursor dropwise, and then aging, crystallizing, calcining, and reducing to obtain the Ni-Silicalite-1 molecular sieve.

7. The method for preparing Ni-Silicalite-1 molecular sieve according to claim 6, characterized in that: The nickel precursor includes a complexing agent and a nickel source.

8. The method for preparing Ni-Silicalite-1 molecular sieve according to claim 6, characterized in that: The molar ratio of the template, additive, water and silicon source in terms of SiO2 is 0.05-0.5:0.02-0.40:5-50:1, preferably 0.1-0.4:0.05-0.20:10-40:1; And / or, the mass ratio of nickel in the nickel precursor, calculated as Ni, to the silicon source, calculated as SiO2, is 0.02 to 0.20:1, preferably 0.03 to 0.15:

1.

9. The method for preparing Ni-Silicalite-1 molecular sieve according to claim 7, characterized in that: The molar ratio of nickel in the nickel precursor (calculated as Ni) to the complexing agent is 0.1 to 3.0:1, preferably 0.2 to 2.0:

1.

10. The method for preparing Ni-Silicalite-1 molecular sieve according to claim 6 or 7, characterized in that: The template agent includes one or more of tetrapropylammonium hydroxide, tetrapropylchloride hydroxide and tetrapropylbromide hydroxide, preferably tetrapropylammonium hydroxide; and / or, the additive comprises one or more of urea, cyanamide, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol and glycerol, preferably urea; And / or, the silicon source includes one or more of white carbon black, sodium silicate, tetraethyl orthosilicate, and silica sol, preferably tetraethyl orthosilicate; And / or, the nickel source comprises one or more of nickel nitrate, nickel acetate, nickel chloride, nickel acetylacetonate, and nickel sulfate, preferably nickel nitrate; And / or, the complexing agent includes one or more of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, and ethylenediamine, preferably ethylenediamine.

11. The method for preparing Ni-Silicalite-1 molecular sieve according to claim 6, characterized in that: The aging temperature is 20 to 100° C., preferably 30 to 80° C.; the aging time is 2 to 48 hours, preferably 4 to 24 hours; And / or, the crystallization temperature is 120-220° C., preferably 150-180° C.; the crystallization time is 2-9 days, preferably 3-7 days; And / or, the calcination temperature is 300-650°C; the calcination time is 1-12 hours; the calcination atmosphere is oxygen-containing gas; And / or, the reduction temperature is 450-1000° C., preferably 550-900° C.; the reduction time is 2-10 hours, preferably 3-6 hours; the reduction atmosphere is hydrogen or a hydrogen-argon mixture.

12. A Ni-Silicalite-1 molecular sieve composition, comprising the Ni-Silicalite-1 molecular sieve according to any one of claims 1 to 5 or the Ni-Silicalite-1 molecular sieve prepared by the preparation method according to any one of claims 6 to 11, and a binder.

13. Use of the Ni-Silicalite-1 molecular sieve according to any one of claims 1 to 5 or the Ni-Silicalite-1 molecular sieve prepared by the preparation method of the Ni-Silicalite-1 molecular sieve according to any one of claims 6 to 11, or the Ni-Silicalite-1 molecular sieve composition according to claim 12 in the catalytic conversion of 5-hydroxymethylfurfural to prepare 2,5-tetrahydrofuran dimethanol.

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