A catalyst for preparing 2,5-dimethylfuran and a preparation method and application thereof

Abstract

The application discloses a catalyst for preparing 2,5-dimethylfuran and a preparation method and application thereof. The catalyst comprises Ni-Fe-C3N4 / X, wherein X is a carrier. The catalyst is used in a reaction for preparing 2,5-dimethylfuran, and has the characteristics of high efficient conversion of 5-hydroxymethylfurfural and high selectivity of the product 2,5-dimethylfuran under mild reaction conditions, and outstanding stability of the catalyst in cyclic use.

Description

Technical Field

[0001] This invention relates to the field of catalytic chemistry, specifically to a catalyst for the preparation of 2,5-dimethylfuran, its preparation method, and its application, particularly a catalyst for the catalytic conversion of 5-hydroxymethylfurfural to 2,5-dimethylfuran, its preparation method, and its application. Background Technology

[0002] With the advancement of science and technology and the development of society, human demand for traditional fossil energy sources such as coal, oil, and natural gas is increasing, leading to the depletion of fossil energy reserves on Earth. Furthermore, the combustion of fossil energy causes severe environmental pollution. Conversely, biomass, as a green and renewable energy source, is abundant on Earth, and its conversion and utilization process does not pollute the environment. Therefore, many scholars have focused on using biomass to supplement fossil energy. 2,5-Dimethylfuran (DMF), as an important product of biomass chemical conversion, has promising applications. It can be used as fuel, possessing a high energy density (31.5 MJ / L) and octane number (119). Compared with traditional bioethanol, DMF has significant advantages and is more suitable as a gasoline additive. Simultaneously, due to the presence of diene bonds on its furan ring, it can also undergo a Diels-Alder reaction (DA reaction) with monoolefins such as ethylene to directly synthesize bio-based p-xylene.

[0003] 2,5-Dimethylfuran is mainly prepared by hydrogenolysis of 5-hydroxymethylfurfural (HMF). When hydrogen is used as the hydrogen source, commonly used catalysts include supported noble metals such as ruthenium (Ru), platinum (Pt), and palladium (Pd), as well as transition metals such as nickel (Ni), copper (Cu), and cobalt (Co). For example, Shi et al. (Fuel, 2016, 163, 74-79) found that reduced graphene oxide supported platinum (Pt / rGO) has extremely high activity and selectivity. Using a microwave reduction method to prepare the catalyst, a 100% HMF conversion and a 73.2% DMF yield can be obtained at 120 °C and 3.0 MPa. Zu et al. reported (Applied Catalysis B: Environmental, 2014, 146, 244-248) that Ru / Co3O4 prepared by co-precipitation achieved a HMF conversion of over 99% and a DMF yield of 93.4% under H2 conditions of 130 °C and 0.7 MPa. The catalyst could be reused five times without loss of activity. The results indicate that Ru plays a hydrogenation role, while CoO... x It plays a role in adsorbing hydrogenation intermediates and subsequently breaking CO bonds. In the presence of noble metal catalysts, the production of DMF from HMF usually yields satisfactory results; however, the low reusability and high cost of noble metals severely hinder their commercial application.

[0004] In summary, existing technologies mainly suffer from problems such as low product selectivity or poor catalyst cycle stability, which pose significant challenges to practical industrial applications. Summary of the Invention

[0005] The technical problem this invention aims to solve is the low product selectivity or poor catalyst cycling stability found in existing technologies. This invention provides a catalyst for the catalytic conversion of 5-hydroxymethylfurfural to 2,5-dimethylfuran, its preparation method, and its application. This catalyst, used in the reaction to prepare 2,5-dimethylfuran, exhibits high efficiency in the conversion of 5-hydroxymethylfurfural under mild reaction conditions, high selectivity for the product 2,5-dimethylfuran, and outstanding stability during catalyst cycling.

[0006] The first aspect of the present invention provides a catalyst for preparing 2,5-dimethylfuran, wherein the catalyst comprises Ni-Fe-C3N4 / X; X is a support.

[0007] According to the present invention, the catalyst, based on the support mass, has a relative Ni content of 1 wt% to 20 wt%; and / or, a relative Fe content of 0.1 wt% to 5 wt%; and / or, a relative C3N4 content of 2 wt% to 50 wt%.

[0008] According to the present invention, preferably, the catalyst has a relative Ni content of 3 wt% to 10 wt% based on the support mass; and / or a relative Fe content of 0.2 wt% to 3 wt%; and / or a relative C3N4 content of 5 wt% to 30 wt%.

[0009] According to the present invention, the carrier is activated carbon. The activated carbon includes at least one of coconut shell activated carbon and wood-based activated carbon. The total specific surface area of ​​the activated carbon is 800–2000 m². 2 ·g -1 More preferably 1000-1800m 2 ·g -1 .

[0010] According to the present invention, the total specific surface area of ​​the catalyst is 500–1700 m². 2 ·g -1 Preferably 700-1250m 2 ·g -1 .

[0011] According to the present invention, the total acidity of the catalyst is 100–400 μmol·g. -1 Preferably, it is 130–300 μmol·g -1 .

[0012] A second aspect of the present invention provides a method for preparing the above-mentioned catalyst. The preparation method includes the following steps:

[0013] The catalyst is obtained by loading a nickel source, an iron source, C3N4 and / or a first nitrogen-containing precursor onto a support, followed by drying, calcination and reduction.

[0014] According to the present invention, the loading method is preferably an impregnation method, specifically: a nickel source and an iron source are prepared into a solution, mixed with C3N4 and / or a first nitrogen-containing precursor and a support, and then dried, calcined and reduced to obtain the catalyst.

[0015] According to the present invention, in the preparation method of the catalyst Ni-Fe-C3N4 / X, the drying, calcination, and reduction can be carried out using conventional methods. Preferably, the drying temperature is 50–90°C, and the drying time is 4–12 h. The calcination temperature is 300–650°C, preferably 350–600°C; the calcination time is 1–12 h, preferably 2–6 h; and the calcination atmosphere is a non-oxygen gas atmosphere. The non-oxygen gas includes at least one of nitrogen and argon. The reduction temperature is 300–650°C, preferably 350–600°C; the reduction time is 1–12 h, preferably 2–6 h; and the reduction atmosphere is hydrogen.

[0016] According to the present invention, in the method for preparing the catalyst Ni-Fe-C3N4 / X, the nickel source includes one or more of nickel nitrate, nickel acetate, nickel chloride, nickel acetylacetonate, and nickel sulfate, preferably at least one of nickel acetate and nickel acetylacetonate. The iron source includes at least one of ferric nitrate, ferric citrate, ferric acetylacetonate, ferrocene, ferroceneformic acid, acetylated ferrocene, tert-butylferrocene, and ferric chloride, preferably at least one of ferric acetylacetonate, ferrocene, and ferric acetate.

[0017] According to the present invention, in the method for preparing the catalyst Ni-Fe-C3N4 / X, the first nitrogen-containing precursor includes one or more of urea, cyanamide, dicyandiamide, and melamine, preferably at least one of urea and dicyandiamide. The first nitrogen-containing precursor is converted into the C3N4 component in the catalyst composition during the preparation method of the catalyst Ni-Fe-C3N4 / X.

[0018] According to the present invention, the method for synthesizing C3N4 includes the following steps: calcining a second nitrogen-containing precursor to obtain C3N4.

[0019] According to the present invention, the C3N4 obtained in the C3N4 synthesis method is a yellow powder.

[0020] According to the present invention, in the method for synthesizing C3N4, the second nitrogen-containing precursor includes one or more of urea, cyanamide, dicyandiamide, and melamine, preferably at least one of urea and melamine. The composition of the second nitrogen-containing precursor in the method for synthesizing C3N4 may be the same as or different from that of the first nitrogen-containing precursor in the Ni-Fe-C3N4 / X preparation method.

[0021] According to the present invention, in the method for synthesizing C3N4, the calcination temperature is 500–600°C, and the calcination time is 3–8 hours. The calcination atmosphere is a non-oxygen gas atmosphere; preferably, the non-oxygen gas includes at least one of nitrogen and argon.

[0022] The third aspect of the present invention provides the application of the above-described catalyst or the catalyst prepared by the above-described method in the reaction of 5-hydroxymethylfurfural to 2,5-dimethylfuran.

[0023] According to the present invention, the method of application includes: 5-hydroxymethylfurfural reacting in the presence of the above catalyst with hydrogen as the hydrogen source to obtain 2,5-dimethylfuran.

[0024] According to the present invention, preferably, 5-hydroxymethylfurfural is dissolved in an organic solvent. More 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.

[0025] According to the present invention, the mass ratio of 5-hydroxymethylfurfural to catalyst is 0.1 to 5.0:1, preferably 0.4 to 3.0:1.

[0026] According to the present invention, the mass ratio of the organic solvent to 5-hydroxymethylfurfural is 10 to 60:1, preferably 20 to 50:1.

[0027] According to the present invention, hydrogen gas is introduced into the reaction system to adjust the reaction pressure. The reaction pressure is 0.2 to 5 MPa, preferably 0.5 to 3 MPa.

[0028] According to the present invention, the reaction conditions are as follows: the reaction temperature is 100-200°C, preferably 110-180°C; and / or the reaction time is 6-64 h, preferably 8-36 h.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) In this invention, the catalyst comprises Ni-Fe-C3N4 / X; X is a support. The catalyst of this invention is modified with C3N4 and used in combination with Ni and Fe elements. It has the characteristics of high efficiency in the conversion of 5-hydroxymethylfurfural under mild reaction conditions, high selectivity for the product 2,5-dimethylfuran, and outstanding stability in the recycling of the catalyst.

[0031] (2) In this invention, the catalyst preparation method involves adding C3N4 and / or a first nitrogen-containing precursor to modify the catalyst. The selection of iron sources (ferric acetylacetonate, ferrocene, and ferric acetate) and nickel sources (nickel acetate and nickel acetylacetonate) in the preparation method, in particular, combined with C3N4 and the support, results in a more uniform distribution of metal elements on the catalyst. The prepared catalyst exhibits high efficiency in the conversion of 5-hydroxymethylfurfural under mild reaction conditions, high selectivity for the product 2,5-dimethylfuran, and outstanding stability during catalyst recycling.

[0032] (3) In this invention, the catalyst is used in the preparation of 2,5-dimethylfuran from 5-hydroxymethylfurfural. Under mild reaction conditions, 5-hydroxymethylfurfural can be efficiently converted to 2,5-dimethylfuran, with significantly improved conversion rate and product selectivity. Simultaneously, the content of key impurities (e.g., 5-methylfurfural, 2,5-dimethyltetrahydrofuran) in the obtained product is extremely low, greatly reducing separation energy consumption. Furthermore, this invention uses Ni-Fe-C3N4 / C as the catalyst, which exhibits high stability; no significant change in catalyst performance was observed after four cycles of use. Attached Figure Description

[0033] Figure 1 The XRD pattern of the 5Ni-1Fe-20C3N4 / C catalyst in Example 1 is shown below.

[0034] Figure 2 The NH3-TPD diagram of the 5Ni-1Fe-20C3N4 / C catalyst in Example 1 is shown.

[0035] Figure 3 The XRD pattern of the 5Ni-1Fe-20C3N4 / C-Coal catalyst in Comparative Example 1 is shown.

[0036] Figure 4 The image shows the NH3-TPD of the 5Ni-1Fe-20C3N4 / C-Coal catalyst obtained in Comparative Example 1. Detailed Implementation

[0037] In this invention, the reaction product 2,5-dimethylfuran (DMF) was qualitatively analyzed by gas chromatography-mass spectrometry (GC-MS), and the conversion rate of the substrate 5-hydroxymethylfurfural (HMF) and the yield of the reaction product DMF were analyzed by gas chromatography (GC). The GC-MS system was an Agilent 7890A from Agilent Technologies, USA, with an HP-5 nonpolar capillary column (30m, 0.53mm). The gas chromatograph was an Agilent 7890B, with a flame ionization detector (FID) and an SE-54 capillary column (30m, 0.53mm).

[0038] 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.

[0039] 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.

[0040] In this invention, the NH3 temperature-programmed desorption (NH3-TPD) experiment was conducted on a TPD / TPR Altamira AMI-3300 instrument, and the total acid content was calculated by fitting and peaking the obtained spectrum.

[0041] In this invention, the N2 adsorption-desorption (BET) isotherm of the sample was determined using a NOVA 1200e Surface Area & Pore Size Analyzer, and its specific surface area was obtained using the BET method. Before sample testing, the sample needs to be vacuum-treated at 200°C for 4 hours to remove moisture and volatile impurities from the catalyst surface.

[0042] In this invention, the conversion formula for 5-hydroxymethylfurfural is:

[0043] HMF conversion % = (molar amount of HMF participating in the reaction) / (molar amount of HMF substrate) × 100%.

[0044] In this invention, the formula for calculating the DMF yield is as follows:

[0045] The yield % of product DMF = (molar amount of DMF produced in the reaction) / (molar amount of HMF, the substrate) × 100%.

[0046] In this invention, the formula for calculating the DMF selectivity of the product is:

[0047] Selectivity of product DMF % = (molar amount of DMF produced in the reaction) / (molar amount of HMF participating in the reaction) × 100%.

[0048] In this invention, the selectivity of the byproduct 5-methylfurfural is calculated using the following formula:

[0049] Selectivity of 5-methylfurfural % = (molar amount of 5-methylfurfural produced in the reaction) / (molar amount of HMF participating in the reaction) × 100%.

[0050] 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.

[0051] Example 1

[0052] Melamine was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0053] Under stirring conditions, 1.50 g of nickel acetate and 0.33 g of ferrocene were dissolved in 50 mL of aqueous solution, and then 2.0 g of C3N4 and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) were added. 2 g -1 The impregnated product was dried at 80°C for 8 hours, calcined at 400°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 5wt%, the relative content of Fe is 1wt%, and the relative content of C3N4 is 20wt%. The catalyst was named 5Ni-1Fe-20C3N4 / C.

[0054] BET test results show that the catalyst has a specific surface area of ​​1050 m². 2 g -1 The XRD pattern of the sample is as follows: Figure 1 As shown; the NH3-TPD of the sample is as follows Figure 2 As shown, the total acid content calculated from this is 191 μmol·g. -1 .

[0055] Example 2

[0056] Melamine was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0057] Under stirring conditions, 0.90 g of nickel acetate and 0.15 g of ferrocene were dissolved in 50 mL of aqueous solution, and then 2.5 g of C3N4 and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) were added. 2 g -1 The impregnated product was dried at 80°C for 8 hours, calcined at 400°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 3wt%, the relative content of Fe is 0.5wt%, and the relative content of C3N4 is 25wt%. The catalyst was named 3Ni-0.5Fe-25C3N4 / C.

[0058] BET test results show that the catalyst has a specific surface area of ​​963 m². 2 g -1 XRD of the sample and Figure 1 Similar; the NH3-TPD of the sample is similar to Figure 2 Similarly, the total acidity calculated from this is 184 μmol·g. -1 .

[0059] Example 3

[0060] Melamine was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0061] Under stirring conditions, 1.81 g of nickel acetate and 0.27 g of ferrocene were dissolved in 50 mL of aqueous solution, and then 1.5 g of C3N4 and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) were added. 2 g -1 The impregnated product was dried at 80°C for 8 hours, calcined at 400°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 6wt%, the relative content of Fe is 0.8wt%, and the relative content of C3N4 is 15wt%. The catalyst was named 6Ni-0.8Fe-15C3N4 / C.

[0062] BET test results show that the catalyst has a specific surface area of ​​927 m². 2 g -1 XRD of the sample and Figure 1 Similar; the NH3-TPD of the sample is similar to Figure 2 Similarly, the total acidity calculated from this is 176 μmol·g. -1 .

[0063] Example 4

[0064] Melamine was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0065] Under stirring conditions, 1.50 g of nickel acetate and 0.50 g of ferrocene were dissolved in 50 mL of aqueous solution, and then 2.5 g of C3N4 and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) were added. 2 g -1 The impregnated product was dried at 80°C for 8 hours, calcined at 400°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 5wt%, the relative content of Fe is 1.5wt%, and the relative content of C3N4 is 25wt%. The catalyst was named 5Ni-1.5Fe-25C3N4 / C.

[0066] BET test results show that the catalyst has a specific surface area of ​​1053 m². 2 g -1 XRD of the sample and Figure 1 Similar; the NH3-TPD of the sample is similar to Figure 2 Similarly, the total acidity calculated from this is 193 μmol·g. -1 .

[0067] Example 5

[0068] Urea was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0069] Under stirring conditions, 3.06 g of nickel acetylacetonate and 0.40 g of ferrocene were dissolved in 50 mL of aqueous solution, and then 3.0 g of C3N4 and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) were added. 2 g -1 The impregnated product was dried at 80°C for 8 hours, calcined at 400°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 7wt%, the relative content of Fe is 1.2wt%, and the relative content of C3N4 is 30wt%. The catalyst was named 7Ni-1.2Fe-30C3N4 / C.

[0070] BET test results show that the catalyst has a specific surface area of ​​1250 m². 2 g -1 XRD of the sample and Figure 1 Similar; the NH3-TPD of the sample is similar to Figure 2 Similarly, the total acidity calculated from this is 210 μmol·g. -1 .

[0071] Example 6

[0072] Urea was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0073] Under stirring conditions, 1.75 g of nickel acetylacetonate and 0.44 g of iron acetylacetonate were dissolved in 50 mL of aqueous solution, and 2.0 g of C3N4 and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) were added. 2 g -1 The impregnated product was dried at 80°C for 8 hours, calcined at 400°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 4wt%, the relative content of Fe is 0.7wt%, and the relative content of C3N4 is 20wt%. The catalyst was named 4Ni-0.7Fe-20C3N4 / C.

[0074] BET test results show that the catalyst has a specific surface area of ​​1033 m². 2 g -1 XRD of the sample and Figure 1 Similar; the NH3-TPD of the sample is similar to Figure 2 Similarly, the total acidity calculated from this is 237 μmol·g. -1 .

[0075] Example 7

[0076] Melamine was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0077] Under stirring conditions, 1.56 g of nickel nitrate and 0.43 g of ferric nitrate were dissolved in 50 mL of aqueous solution, and then 2.0 g of C3N4 and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) were added. 2 g -1The impregnated product was dried at 80°C for 8 hours, calcined at 400°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 5wt%, the relative content of Fe is 1wt%, and the relative content of C3N4 is 20wt%. The catalyst was named 5Ni-1Fe-20C3N4 / C.

[0078] BET test results show that the catalyst has a specific surface area of ​​1036 m². 2 g -1 The XRD pattern of the sample is similar to that of... Figure 1 Similar; the NH3-TPD of the sample is similar to Figure 2 Similarly, the total acidity calculated from this is 175 μmol·g. -1 .

[0079] Example 8

[0080] Under stirring conditions, 1.50 g of nickel acetate, 0.33 g of ferrocene, and 5.10 g of dicyandiamide were dissolved in 50 mL of aqueous solution, and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) was added. 2 g -1 The impregnated product was dried at 80°C for 8 hours, calcined at 550°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 5wt%, the relative content of Fe is 1.0wt%, and the relative content of C3N4 is 20wt%. The catalyst was named 5Ni-1Fe-20C3N4 / C.

[0081] BET test results show that the catalyst has a specific surface area of ​​1053 m². 2 g -1 XRD of the sample and Figure 1 Similar; the NH3-TPD of the sample is similar to Figure 2 Similarly, the total acidity calculated from this is 147 μmol·g. -1 .

[0082] Example 9

[0083] Under stirring conditions, 1.56 g of nickel nitrate, 0.43 g of ferric nitrate, and 5.10 g of dicyandiamide were dissolved in 50 mL of aqueous solution, and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) was added. 2 g -1The impregnated product was dried at 80°C for 8 hours, calcined at 550°C under a nitrogen atmosphere for 4 hours, and reduced at 450°C under a hydrogen atmosphere for 2 hours to obtain the Ni-Fe-C3N4 / C catalyst, wherein the relative content of Ni is 5wt%, the relative content of Fe is 1.0wt%, and the relative content of C3N4 is 20wt%. The catalyst was named 5Ni-1Fe-20C3N4 / C.

[0084] BET test results show that the catalyst has a specific surface area of ​​1077 m². 2 g -1 XRD of the sample and Figure 1 Similar; the NH3-TPD of the sample is similar to Figure 2 Similarly, the total acidity calculated from this is 162 μmol·g. -1 .

[0085] Examples 10-18

[0086] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 30, a mass ratio of HMF to catalyst of 0.5, a hydrogen pressure of 0.8 MPa, a reaction temperature of 130 °C, and a reaction time of 12 h.

[0087] 1.0 g of the catalyst from Examples 1-9 above, 0.5 g of HMF, and 15 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.8 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 130 °C for 12 h. The HMF conversion rate and the selectivity of the product DMF and the key byproduct 5-methylfurfural were calculated by gas phase analysis of the reaction liquid, as shown in Table 1.

[0088] Table 1 Catalytic evaluation results of catalysts in Examples 1-9

[0089]

[0090] Example 19

[0091] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 20, a mass ratio of HMF to catalyst of 0.8, a hydrogen pressure of 0.5 MPa, a reaction temperature of 120 °C, and a reaction time of 18 h.

[0092] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1 above, 0.8 g of HMF, and 16 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.5 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 120 °C for 18 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 90.8%, and the selectivity of the key byproduct 5-methylfurfural was 0.3%.

[0093] Example 20

[0094] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 25, a mass ratio of HMF to catalyst of 1.0, a hydrogen pressure of 0.7 MPa, a reaction temperature of 130 °C, and a reaction time of 10 h.

[0095] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1 above, 1.0 g of HMF, and 25 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.7 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 130 °C for 10 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 92.1%, and the selectivity of the key byproduct 5-methylfurfural was 0.2%.

[0096] Example 21

[0097] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 30, a mass ratio of HMF to catalyst of 1.2, a hydrogen pressure of 1.1 MPa, a reaction temperature of 140 °C, and a reaction time of 12 h.

[0098] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1 above, 1.2 g of HMF, and 36 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 1.1 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 140 °C for 12 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 93.3%, and the selectivity of the key byproduct 5-methylfurfural was 0.4%.

[0099] Example 22

[0100] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 40, a mass ratio of HMF to catalyst of 0.4, a hydrogen pressure of 1.2 MPa, a reaction temperature of 130 °C, and a reaction time of 12 h.

[0101] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1 above, 0.4 g of HMF, and 12 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 1.2 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 130 °C for 12 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 91.7%, and the selectivity of the key byproduct 5-methylfurfural was 0.3%.

[0102] Example 23

[0103] n-Butanol was used as the reaction solvent, with a mass ratio of n-butanol to HMF of 36, a mass ratio of HMF to catalyst of 0.5, a hydrogen pressure of 0.8 MPa, a reaction temperature of 130 °C, and a reaction time of 12 h.

[0104] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1 above, 0.5 g of HMF, and 18 g of n-butanol were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.8 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 130 °C for 12 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 90.2%, and the selectivity of the key byproduct 5-methylfurfural was 0.2%.

[0105] Example 24

[0106] n-Butanol was used as the reaction solvent, the mass ratio of n-butanol to HMF was 20, the mass ratio of HMF to catalyst was 0.8, the hydrogen pressure was 1.0 MPa, the reaction temperature was 140℃, and the reaction time was 12 h.

[0107] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1 above, 0.8 g of HMF, and 16 g of n-butanol were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 1.0 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 140 °C for 12 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 92.6%, and the selectivity of the key byproduct 5-methylfurfural was 0.2%.

[0108] Example 25

[0109] n-Butanol was used as the reaction solvent, the mass ratio of n-butanol to HMF was 26, the mass ratio of HMF to catalyst was 1.0, the hydrogen pressure was 1.2 MPa, the reaction temperature was 140℃, and the reaction time was 16 h.

[0110] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1 above, 1.0 g of HMF, and 26 g of n-butanol were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 1.2 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 140 °C for 16 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 90.4%, and the selectivity of the key byproduct 5-methylfurfural was 0.2%.

[0111] Example 26

[0112] n-Butanol was used as the reaction solvent, with a mass ratio of n-butanol to HMF of 40, a mass ratio of HMF to catalyst of 1.2, a hydrogen pressure of 0.7 MPa, a reaction temperature of 150 °C, and a reaction time of 14 h.

[0113] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1 above, 1.2 g of HMF, and 48 g of n-butanol were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.7 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 150 °C for 14 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 90.9%, and the selectivity of the key byproduct 5-methylfurfural was 0.3%.

[0114] To more intuitively describe the reaction conditions and results of Examples 19-26 above, the parameters and results are listed in Table 2.

[0115] Table 2 Catalytic performance results of Examples 19-26

[0116]

[0117]

[0118] Example 27

[0119] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 30, a mass ratio of HMF to catalyst of 0.5, a hydrogen pressure of 0.8 MPa, a reaction temperature of 130 °C, and a reaction time of 12 h.

[0120] 1.0 g of the 5Ni-1Fe-20C3N4 / C catalyst from Example 1, 0.5 g of HMF, and 15 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.8 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and then stirred magnetically. The reaction was carried out at 130 °C for 12 h. Gas phase analysis of the reaction liquid was used to calculate the HMF conversion and the selectivity of the product DMF and the key byproduct 2-methylfurfural. The used catalyst was washed, dried, and then used in the next reaction cycle, for a total of 4 cycles. The results are shown in Table 3. The results show that after 4 reactions, the HMF conversion remained above 99%, the DMF selectivity remained above 90%, and the selectivity of the key byproduct 5-methylfurfural was below 0.6%, indicating that the 5Ni-1Fe-20C3N4 / C catalyst has good cycle stability.

[0121] Table 3 Catalyst Recycling Data

[0122]

[0123] Comparative Example 1

[0124] Melamine was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0125] Under stirring conditions, 1.50 g of nickel acetate and 0.33 g of ferrocene were dissolved in 50 mL of aqueous solution, and then 2.0 g of C3N4 and 10.0 g of coal-based activated carbon (with a specific surface area of ​​600 m²) were added. 2 g -1 The impregnated product was dried at 80°C for 8 hours and calcined at 400°C under a nitrogen atmosphere for 4 hours to obtain the Ni-Fe-C3N4 / C-Coal catalyst, wherein the relative content of Ni was 5wt%, the relative content of Fe was 1wt%, and the relative content of C3N4 was 20wt%. The catalyst was named 5Ni-1Fe-20C3N4 / C-Coal.

[0126] BET test results show that the catalyst has a specific surface area of ​​320 m². 2 g -1 The XRD pattern of the sample is as follows: Figure 3 As shown; the NH3-TPD of the sample is as follows Figure 4 As shown, the total acid content calculated from this is 283 μmol·g. -1 .

[0127] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 20, a mass ratio of HMF to catalyst of 0.8, a hydrogen pressure of 0.5 MPa, a reaction temperature of 120 °C, and a reaction time of 18 h.

[0128] 1.0 g of the 5Ni-1Fe-20C3N4 / C-Coal catalyst from Comparative Example 1, 0.8 g of HMF, and 16 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.5 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and the reactor was stirred magnetically. The reaction was carried out at 120 °C for 18 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 77.2%, and the selectivity of the key byproduct 5-methylfurfural was 6.4%.

[0129] Comparative Example 2

[0130] Melamine was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0131] Under stirring conditions, 1.50 g of nickel acetate and 0.32 g of cobalt dicene were dissolved in 50 mL of aqueous solution, and then 2.0 g of C3N4 and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) were added. 2 g -1 The impregnated product was dried at 80°C for 8 hours and calcined at 400°C under a nitrogen atmosphere for 4 hours to obtain the Ni-Co-C3N4 / C catalyst, wherein the relative content of Ni is 5wt%, the relative content of Co is 1wt%, and the relative content of C3N4 is 20wt%. The catalyst was named 5Ni-1Co-20C3N4 / C.

[0132] BET test results show that the catalyst has a specific surface area of ​​1029 m². 2 g -1 The total acid content of the sample was 183 μmol·g. -1 .

[0133] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 20, a mass ratio of HMF to catalyst of 0.8, a hydrogen pressure of 0.5 MPa, a reaction temperature of 120 °C, and a reaction time of 18 h.

[0134] 1.0 g of the 5Ni-1Co-20C3N4 / C catalyst from Comparative Example 2, 0.8 g of HMF, and 16 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.5 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and the reactor was stirred magnetically. The reaction was carried out at 120 °C for 18 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 85.2%, and the selectivity of the key byproduct 5-methylfurfural was 7.3%.

[0135] Comparative Example 3

[0136] Melamine was calcined at 550°C for 4 hours under a nitrogen atmosphere, and the resulting yellow powder was N-doped carbon C3N4. C3N4 has a specific surface area of ​​23 m². 2 g -1 .

[0137] Under stirring conditions, 1.50 g of nickel acetate and 0.33 g of ferrocene were dissolved in 50 mL of aqueous solution, and 2.0 g of C3N4 was added for impregnation. The impregnated product was dried at 80 °C for 8 hours and calcined at 400 °C under a nitrogen atmosphere for 4 hours to obtain the Ni-Fe-C3N4 catalyst.

[0138] BET test results show that the catalyst has a specific surface area of ​​15 m². 2 g -1 The total acid content was 203 μmol·g. -1 .

[0139] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 20, a mass ratio of HMF to catalyst of 0.8, a hydrogen pressure of 0.5 MPa, a reaction temperature of 120 °C, and a reaction time of 18 h.

[0140] 1.0 g of the above catalyst, 0.8 g of HMF, and 16 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.5 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and the reactor was stirred magnetically. The reaction was carried out at 120 °C for 18 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 56.3%, and the selectivity of the key byproduct 5-methylfurfural was 13.7%.

[0141] Comparative Example 4

[0142] Under stirring conditions, 1.50 g of nickel acetate and 0.33 g of ferrocene were dissolved in 50 mL of aqueous solution, and 10.0 g of coconut shell activated carbon (specific surface area of ​​1700 m²) was added. 2 g -1The impregnated product was dried at 80°C for 8 hours and calcined at 400°C under a nitrogen atmosphere for 4 hours to obtain the Ni-Fe / C catalyst, wherein the relative content of Ni was 5wt% and the relative content of Fe was 1wt%, and the catalyst was named 5Ni-1Fe / C.

[0143] BET test results show that the catalyst has a specific surface area of ​​1120 m². 2 g -1 The total acid content of the sample was 223 μmol·g. -1 .

[0144] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 20, a mass ratio of HMF to catalyst of 0.8, a hydrogen pressure of 0.5 MPa, a reaction temperature of 120 °C, and a reaction time of 18 h.

[0145] 1.0 g of the above-mentioned 5Ni-1Fe / C catalyst, 0.8 g of HMF, and 16 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.5 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and the reactor was stirred magnetically. The reaction was carried out at 120 °C for 18 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 82.5%, and the selectivity of the key byproduct 5-methylfurfural was 2.3%.

[0146] Comparative Example 5

[0147] According to Chinese Patent (CN111346662A), nitrogen-doped activated carbon was synthesized using the following steps: Preparation of nitrogen-doped activated carbon: 1.8 mL of formaldehyde solution (mass fraction 37-40%) was diluted to 10-12 mL, the pH was adjusted to 9.5 with triethanolamine, 1 g of melamine was added, and the solution was dissolved by stirring in a water bath at 60°C. This solution was then added to 10 g of coconut shell activated carbon, kept at 60°C for 10 h, dried at 125°C, and calcined at 850°C for 2 h under nitrogen protection in an atmosphere furnace with a heating rate of 2-5°C / min to obtain nitrogen-doped activated carbon with a specific surface area of ​​1050 m². 2 g -1 .

[0148] Under stirring conditions, 1.50 g of nickel acetate and 0.33 g of ferrocene were dissolved in 50 mL of aqueous solution, and 10.0 g of the above nitrogen-doped activated carbon was added for impregnation. The impregnated product was dried at 80 °C for 8 hours and calcined at 400 °C under a nitrogen atmosphere for 4 hours to obtain the Ni-Fe / NC catalyst, wherein the relative content of Ni is 5 wt% and the relative content of Fe is 1 wt%. The catalyst was named 5Ni-1Fe / NC.

[0149] BET test results show that the catalyst has a specific surface area of ​​870 m². 2 g-1 The total acid content of the sample was 235 μmol·g. -1 .

[0150] Tetrahydrofuran was used as the reaction solvent, with a mass ratio of tetrahydrofuran to HMF of 20, a mass ratio of HMF to catalyst of 0.8, a hydrogen pressure of 0.5 MPa, a reaction temperature of 120 °C, and a reaction time of 18 h.

[0151] 1.0 g of the 5Ni-1Fe / NC catalyst from Comparative Example 5, 0.8 g of HMF, and 16 g of tetrahydrofuran were added to a high-pressure reactor equipped with a stirrer, and hydrogen gas was introduced at 0.5 MPa. The temperature was raised to the preset temperature using a programmed heating mantle, and the reactor was stirred magnetically. The reaction was carried out at 120 °C for 18 h. Gas phase analysis of the reaction liquid showed that the HMF conversion was >99%, the DMF selectivity was 78.9.2%, and the selectivity of the key byproduct 5-methylfurfural was 5.1%.

[0152] 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 inventive concept, 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 method of making 2,5-dimethylfuran comprising: 5-hydroxymethylfurfural reacts in the presence of a catalyst to obtain 2,5-dimethylfuran, the catalyst comprising Ni-Fe-C3N4 / X; X is a carrier; the carrier is activated carbon; the relative content of Ni is 1wt%-20wt%, the relative content of Fe is 0.1wt%-5wt%, and the relative content of C3N4 is 2wt%-50wt% based on the mass of the carrier; the total specific surface area of the activated carbon is 800-2000 m 2 •g -1 ; The reaction temperature is 120-150 DEG C; and the reaction pressure is 0.2-5 MPa.

2. The method of claim 1, wherein, The 5-hydroxymethylfurfural is dissolved in an organic solvent, and the organic solvent includes one or more of methanol, ethanol, n-butanol, tetrahydrofuran, 1,4-dioxane, and methyl isobutyl ketone.

3. The method of claim 2, wherein, The organic solvent is at least one of n-butanol and tetrahydrofuran.

4. The method of claim 1, wherein, The mass ratio of the 5-hydroxymethylfurfural to the catalyst is 0.1-5.0:

1.

5. The method of claim 4, wherein, The mass ratio of the 5-hydroxymethylfurfural to the catalyst is 0.4-3.0:

1.

6. The method of claim 2, wherein, The mass ratio of the organic solvent to the 5-hydroxymethylfurfural is 10-60:

1.

7. The method of claim 6, wherein, The mass ratio of the organic solvent to the 5-hydroxymethylfurfural is 20-50:

1.

8. The method of claim 1, wherein, The reaction system is filled with hydrogen to adjust the reaction pressure.

9. The method of claim 1 wherein, The reaction time is 6-64 hours.

10. The method of claim 1, wherein, The reaction pressure is 0.2-3 MPa; and / or the reaction time is 8-36 hours.

11. The method of claim 1 wherein, The reaction pressure is 0.5-1.2 MPa.

12. The method of claim 1, wherein, The relative content of Ni in the catalyst is 3wt%-10wt% based on the mass of the carrier; The relative content of Fe is 0.2wt%-3wt%; The relative content of C3N4 is 5wt%-30wt%.

13. The method of claim 1 wherein, The carrier includes at least one of coconut shell activated carbon and wood activated carbon.

14. The method of claim 13, wherein, The total specific surface area of the activated carbon is 1000 to 1800 m 2 •g -1 .

15. The method of claim 1 wherein, The total specific surface area of the catalyst is 500 to 1700 m 2 •g -1 ; and / or the total acid amount of the catalyst is 100-400 µmol•g -1 .

16. The method of claim 15, wherein, The total specific surface area of the catalyst is 700 to 1250 m 2 •g -1 ; and / or the total acid amount of the catalyst is 130-300 pmol-g -1 .

17. The method of claim 1 wherein, The preparation method of the catalyst includes the following steps: The nickel source, the iron source, C3N4 and / or a first nitrogen-containing precursor are loaded on the carrier, and then dried, calcined and reduced to obtain the catalyst.

18. The method of claim 17, wherein, The drying temperature is 50-90 DEG C, and the drying time is 4-12 hours; The calcination temperature is 300-650 DEG C; the calcination time is 1-12 hours; and the calcination atmosphere is a non-oxygen gas atmosphere; The reduction temperature is 300-650 DEG C; the reduction time is 1-12 hours; and the reduction atmosphere is hydrogen; The nickel source includes one or more of nickel nitrate, nickel acetate, nickel chloride, nickel acetylacetate, and nickel sulfate; The iron source includes at least one of iron nitrate, iron citrate, iron acetylacetate, ferrocene, ferrocene formate, acetylferrocene, t-butyl ferrocene, and iron chloride; The first nitrogen-containing precursor includes one or more of urea, monocyamide, dicyamide, and melamine.

19. The method of claim 18, wherein, The calcination temperature is 350-600 DEG C; the calcination time is 2-6 hours; and the calcination atmosphere includes at least one of nitrogen and argon; The reduction temperature is 350-600 DEG C; and the reduction time is 2-6 hours; The nickel source is at least one of nickel acetate and nickel acetylacetate; The iron source is at least one of iron acetylacetate, ferrocene, and iron acetate; The first nitrogen-containing precursor is at least one of urea and dicyamide.

20. The method of claim 17, wherein, The synthesis method of the C3N4 includes the following step: the second nitrogen-containing precursor is calcined to obtain the C3N4.

21. The method of claim 20, wherein, The second nitrogen-containing precursor includes one or more of urea, monocyamide, dicyamide, and melamine; The calcination temperature is 500-600 DEG C; The calcination time is 3-8 hours; And / or, the atmosphere for the calcination is a non-oxygen gas atmosphere.

22. The preparation method according to claim 21, characterized in that, In the method for synthesizing the C3N4, the second nitrogen-containing precursor is at least one of urea and melamine. And / or, the atmosphere for the calcination is at least one of nitrogen and argon.

Images