Porous molybdenum disulfide catalyst and application thereof in hydrogenation of 5-hydroxymethylfurfural

Abstract

The invention relates to a porous molybdenum disulfide catalyst and application thereof in hydrogenation of 5-hydroxymethylfurfural. The catalyst is prepared according to the following method: dissolving a molybdenum source and a sulfur source, and uniformly stirring to obtain a first mixed solution; putting the first mixed solution into a silica gel solution, and uniformly stirring to obtain a second mixed solution; drying the second mixed solution to obtain a first precursor; grinding and roasting the first precursor to obtain a second precursor; and removing silicon from the second precursor, cleaning and drying to obtain the catalyst. The molybdenum source and the sulfur source are immersed into the silica gel, the first precursor is obtained in a uniform stirring mode, the silica gel serves as a template and also serves as a material for uniformly dispersing the molybdenum source and the sulfur source, and after full stirring is conducted in the mode, obtained molybdenum disulfide has a very good low-temperature hydrogenation effect and has very good reusability.

Description

Technical Field

[0001] The present application relates to a porous molybdenum disulfide catalyst and its application in the hydrogenation of 5-hydroxymethylfurfural. Background Art

[0002] With the gradual depletion of fossil energy, exploring and developing renewable energy to replace traditional fossil fuels has become an urgent task in the current scientific research field. Among numerous renewable energies, biomass energy is regarded as an ideal successor to fossil energy due to its rich sources, wide distribution, low cost, and being the only renewable resource containing organic carbon. As a renewable and important industrial raw material, 5-hydroxymethylfurfural can be produced in large quantities through the dehydration reaction of glucose or fructose. Through a series of chemical reactions such as hydrogenation, oxidation, etherification, and amination, 5-hydroxymethylfurfural can be derived into a series of high-value-added chemicals or fuels. Among them, furan compounds have attracted much attention due to their wide application fields. They can serve as fuel additives and key intermediates in the pharmaceutical industry. It is worth mentioning that 5-hydroxymethylfurfural is also the starting point for the synthesis of furan compounds. Through direct hydrogenation, 5-hydroxymethylfurfural can be converted into compounds such as 2,5-dimethylfuran. At present, the biomass-derived chemical 2,5-dimethylfuran (DMF) as a fuel substitute has received extensive research attention, and it exhibits many excellent properties comparable to gasoline. DMF not only has an energy density as high as 30 MJ / L and a high octane number of 119, but also its boiling point range is between 92 - 94 °C, and its solubility in water is extremely low, only 0.26 wt%, which can be perfectly miscible with gasoline and can also be used independently.

[0003] However, at present, there are still relatively few relevant technical research reports on directly preparing 2,5-dimethylfuran from 5-hydroxymethylfurfural by using a catalyst, especially a non-noble metal catalyst. Molybdenum disulfide (MoS₂) is a good hydrogenation reaction catalyst. The layered structure of molybdenum disulfide provides it with a large specific surface area, and there are a large number of unsaturated sulfur atoms and molybdenum atoms on its surface. These atoms, as active sites, can efficiently adsorb and activate reactants such as hydrogen, promoting the catalytic reaction. The catalytic effect of the single MoS₂ reported currently is not ideal, and it is necessary to dope noble metals to improve its performance. For example, noble metal Ir-doped molybdenum disulfide catalyst is used for the hydrogenation reaction of 5-hydroxymethylfurfural [Ji, J. et al. Chem. Eng. Sci. 291, 119896 (2024)]. Restricted by the high production cost, it is not conducive to industrial production. Therefore, it is necessary to explore and develop a molybdenum sulfide catalyst with high performance in the hydrogenation reaction of 5-hydroxymethylfurfural. Summary of the Invention

[0004] To solve the above problems, on the one hand, the present application proposes a porous molybdenum disulfide catalyst, which is prepared by the following method:

[0005] Dissolve the molybdenum source and sulfur source and stir evenly to obtain a first mixed solution;

[0006] Put the first mixed solution into the silica gel solution and stir evenly to obtain a second mixed solution;

[0007] Dry the second mixed solution to obtain a first precursor;

[0008] Grind and calcine the first precursor to obtain a second precursor;

[0009] After removing silicon from the second precursor, wash and dry to obtain the catalyst. In the present application, the molybdenum source and sulfur source are immersed in silica gel and stirred evenly to obtain the first precursor. Silica gel itself serves as both a template and a material for uniformly dispersing the molybdenum source and sulfur source. After sufficient stirring in this way, the obtained molybdenum disulfide has very good low-temperature hydrogenation effect and very good reusability.

[0010] Preferably, it includes the following steps: the molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:2.5 - 3.5;

[0011] The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

[0012] Preferably, the mass concentration of the silica gel solution is 25 - 30%;

[0013] The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is: 1:1.5 - 2.

[0014] Preferably, the stirring time of the first mixed solution is not less than 30 min;

[0015] The stirring time of the second mixed solution is not less than 2 h.

[0016] Preferably, the second mixed solution is subjected to rotary evaporation and then vacuum drying;

[0017] The rotary evaporation temperature is 55 - 65 °C, the time is 1.5 - 2 h, and the vacuum degree is 60 - 80 kPa;

[0018] The temperature of vacuum drying is 75 - 85 °C, the drying time is 8 - 12 h, and the vacuum degree of vacuum drying is 80 - 90 kPa. The drying of the catalyst precursor in the present application can actually be regarded as two steps. The first step is rotary evaporation. The rotary evaporation process is a relatively slow process of fixing the molybdenum source and sulfur source into silica gel, and then obtaining particles by means of grinding and calcination. By adopting the method of slow solidification, subsequent calcination, and etching off the silicon source, a porous molybdenum disulfide catalyst with a stable structure is obtained.

[0019] Preferably, the roasting is carried out as follows:

[0020] The ground first precursor is placed in a tube furnace, the input gas flow is 5 - 15 vol% H2 / Ar, the temperature of the tube furnace is 300 - 350 °C, the reaction time is 2.5 - 3.5 h, and after the reaction, the tube furnace is allowed to cool naturally to room temperature and then the second precursor is collected.

[0021] Preferably, the desilication is carried out as follows:

[0022] The second precursor is placed in the inner liner of a polytetrafluoro reaction kettle and treated with a hydrofluoric acid solution at room temperature for 4 - 6 h, and the concentration of the hydrofluoric acid solution is 40 wt%.

[0023] The cleaning and drying after desilication are carried out as follows:

[0024] After cleaning with the hydrofluoric acid solution, it is then placed in a vacuum drying oven at 75 - 85 °C for drying, ground into powder, and the powder solid collected is the catalyst.

[0025] Preferably, it further includes the process of metal loading:

[0026] The catalyst and the soluble metal salt are placed in water and stirred to obtain a preliminary mixture;

[0027] The preliminary mixture is dried to obtain a preliminary loaded solid;

[0028] The preliminary loaded solid is reduced to obtain a loaded catalyst. This application uses inexpensive alkali metal salts and transition metal salts for loading, which can greatly reduce the production cost and has a certain effect of improving the catalytic performance of the original molybdenum disulfide catalyst.

[0029] Preferably, the preliminary mixture is obtained as follows:

[0030] The catalyst, a soluble metal salt of 0.05 - 0.5 wt% based on metal, and 4 - 6 times the mass of the catalyst of water are stirred at room temperature for 0.5 - 1 h, and the stirring rate is 500 - 800 r / min;

[0031] The drying of the preliminary mixture is carried out as follows:

[0032] The drying method is rotary evaporation, the rotary evaporation temperature is 55 - 65 °C, the time is 1.5 - 2 h, and the vacuum degree is 60 - 80 kPa;

[0033] The reduction of the preliminary loaded solid is carried out as follows:

[0034] The preliminarily loaded solid after grinding is placed in a tubular furnace. The input gas flow is 5-15 vol% H2 / Ar, the temperature of the tubular furnace is 300-350 °C, the reaction time is 2.5-3.5 h. After the reaction is completed, wait for the tubular furnace to cool naturally to room temperature and then collect the supported catalyst;

[0035] The metal salt is at least one of lithium carbonate, sodium carbonate, potassium carbonate, copper nitrate, ferrous nitrate, cobalt nitrate, nickel nitrate, manganese nitrate, chromium nitrate or a mixture of any two or more in any proportion. This application discloses a porous molybdenum disulfide catalyst and its modification strategy, aiming to efficiently directly hydrogenate 5-hydroxymethylfurfural to 2,5-dimethylfuran. The core of this invention is to develop a novel non-noble metal catalyst, which exhibits high selectivity and high conversion characteristics for 5-hydroxymethylfurfural. This reaction system uses pure hydrogen as the hydrogen source, not only with mild reaction conditions (i.e., low temperature and low pressure), but also with a simple and fast operation process, short reaction time, and low energy consumption. Particularly importantly, this catalyst shows excellent activity, can significantly improve the conversion rate of 5-hydroxymethylfurfural, indicating its broad and attractive prospects in industrial applications.

[0036] On the other hand, this application also discloses the application of a porous molybdenum disulfide catalyst in the hydrogenation of 5-hydroxymethylfurfural. The reaction temperature is: 30-100 °C; preferably, the reaction temperature is: 70-100 °C. In this application, in a high-pressure reaction kettle, the catalyst is fully mixed and contacted with the reaction substrate 5-hydroxymethylfurfural and hydrogen for reaction, achieving the preparation of the target product 2,5-dimethylfuran with high selectivity and high conversion rate. This process not only improves the purity of the product, but also significantly enhances the overall reaction efficiency, providing a new economical and environmentally friendly way for the industrial production of 2,5-dimethylfuran. The conversion rate of the catalyst of this application for catalyzing the hydrogenation reaction of 5-hydroxymethylfurfural at 100 °C is not less than 99%, and the selectivity of 2,5-dimethylfuran is not less than 85%. Even when reacting at a temperature of 30 °C, the conversion rate can reach not less than 85% and relatively high selectivity.

[0037] This application can bring the following beneficial effects:

[0038] 1. In this application, the molybdenum source and sulfur source are immersed in silica gel and evenly stirred to obtain a first precursor. Silica gel itself serves as both a template and a material for evenly dispersing the molybdenum source and sulfur source. After sufficient stirring by this method, the obtained molybdenum disulfide has very good low-temperature hydrogenation effects and very good reusability.

[0039] 2. The drying of the catalyst precursor in this application can actually be regarded as two steps. The first step is rotary evaporation. During the rotary evaporation process, the molybdenum source and sulfur source are relatively slowly fixed into the silica gel, and then particles are obtained by grinding and roasting. By using this method of slow curing, subsequent roasting, and etching away the silicon source, a porous molybdenum disulfide catalyst with a stable structure is obtained.

[0040] 3. This application uses inexpensive alkali metal salts and transition metal salts for loading, which can greatly reduce the production cost and has a certain effect of improving the catalytic performance of the original molybdenum disulfide catalyst.

[0041] 4. The conversion rate of the catalyst of this application for catalytic hydrogenation of 5-hydroxymethylfurfural at 100 °C is not less than 95%, and the selectivity of 2,5-dimethylfuran is not less than 85%. Even when the reaction is carried out at a temperature of 30 °C, the conversion rate can reach not less than 85% and the selectivity is relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings described herein are used to provide a further understanding of this application, form a part of this application, and the schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0043] Figure 1 is the flow chart of catalytic direct hydrogenation of 5-hydroxymethylfurfural provided by this application.

[0044] Figure 2 is the schematic diagram of the synthesis of porous molybdenum sulfide provided by this application.

[0045] Figure 3 The mass spectrum of 2,5-dimethylfuran obtained by catalytic direct hydrogenation of 5-hydroxymethylfurfural provided by this application.

[0046] Figure 4 The X-ray diffraction pattern of the porous molybdenum disulfide catalyst used for catalytic direct hydrogenation of 5-hydroxymethylfurfural provided by this application.

[0047] Figure 5 The physical adsorption diagram of the porous molybdenum disulfide catalyst used for catalytic direct hydrogenation of 5-hydroxymethylfurfural provided by this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] To clearly illustrate the technical features of this solution, the following will elaborate on this application in detail through specific embodiments and in combination with its drawings.

[0049] As Figure 1-2 shown, this application discloses a porous molybdenum disulfide catalyst, which is prepared according to the following method:

[0050] S1 Dissolve the molybdenum source and sulfur source and stir evenly to obtain the first mixed solution;

[0051] The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:2.5 - 3.5;

[0052] The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

[0053] The stirring time of the first mixed solution is not less than 30 min;

[0054] S2 Put the first mixed solution into the silica gel solution and stir evenly to obtain the second mixed solution;

[0055] The mass concentration of the silica gel solution is 25 - 30%;

[0056] The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is: 1:1.5 - 2.

[0057] The stirring time of the second mixed solution is not less than 2 h.

[0058] S3 Dry the second mixed solution to obtain the first precursor;

[0059] Perform rotary evaporation on the second mixed solution and then perform vacuum drying;

[0060] The rotary evaporation temperature is 55 - 65 °C, the time is 1.5 - 2 h, and the vacuum degree is 60 - 80 kPa;

[0061] The temperature of vacuum drying is 75 - 85 °C, the drying time is 8 - 12 h, and the vacuum degree of vacuum drying is 80 - 90 kPa.

[0062] S4 Grind and calcine the first precursor to obtain the second precursor;

[0063] The calcination is carried out as follows:

[0064] Put the ground first precursor into a tubular furnace, the input gas flow is 5 - 15 vol% H2 / Ar, the temperature of the tubular furnace is 300 - 350 °C, the reaction time is 2.5 - 3.5 h, and after the reaction ends, wait for the tubular furnace to cool naturally to room temperature and then collect to obtain the second precursor.

[0065] S5 Remove silicon from the second precursor, wash and dry to obtain the catalyst.

[0066] Put the second precursor into the inner liner of a polytetrafluoroethylene reaction kettle, and treat it with a hydrofluoric acid solution at room temperature for 4 - 6 h, and the concentration of the hydrofluoric acid solution is 40 wt%;

[0067] The silicon removal, washing and drying are carried out as follows:

[0068] After cleaning with hydrofluoric acid solution, it is then placed in a vacuum drying oven at 75 - 85 °C for drying, ground into powder, and the collected powder solid is the catalyst.

[0069] Since the catalyst itself is actually porous molybdenum disulfide, it can be used for the loading of metals:

[0070] S61 Place the catalyst and the soluble metal salt in water and stir to obtain a preliminary mixture;

[0071] The preliminary mixture is obtained as follows:

[0072] Put the catalyst, 0.05 - 0.5 wt% of the soluble metal salt based on the metal, and 4 - 6 times the mass of the catalyst of water, stir at room temperature for 0.5 - 1 h, and the stirring rate is 500 - 800 r / min;

[0073] S62 Dry the preliminary mixture to obtain a preliminary loaded solid;

[0074] The drying method is rotary evaporation, the rotary evaporation temperature is 55 - 65 °C, the time is 1.5 - 2 h, and the vacuum degree is 60 - 80 kPa;

[0075] S63 Reduce the preliminary loaded solid to obtain a loaded catalyst.

[0076] Place the ground preliminary loaded solid in a tubular furnace, the input gas flow is 5 - 15 vol% H2 / Ar, the temperature of the tubular furnace is 300 - 350 °C, the reaction time is 2.5 - 3.5 h, and after the reaction ends, wait for the tubular furnace to cool naturally to room temperature and then collect the loaded catalyst;

[0077] The metal salt is at least one or a mixture of two or more in any proportion of lithium carbonate, sodium carbonate, potassium carbonate, copper nitrate, ferrous nitrate, cobalt nitrate, nickel nitrate, manganese nitrate, chromium nitrate.

[0078] Apply the obtained catalyst in the hydrogenation of 5 - hydroxymethylfurfural, the reaction temperature is: 30 - 100 °C; preferably, the reaction temperature is: 70 - 100 °C.

[0079] As Figure 3As shown, during hydrogenation, 5-hydroxymethylfurfural is efficiently converted to 2,5-dimethylfuran with high purity hydrogen under the catalyst of porous molybdenum disulfide. The specific steps are as follows: 5-hydroxymethylfurfural is dissolved in tetrahydrofuran to prepare a reactant substrate solution with a molar concentration of 0.1 mol / L. Then, the catalyst is added. After being placed in a high-temperature and high-pressure reaction kettle, it is purged with pure hydrogen 3-5 times to expel air and then sealed. Then, it reacts at a set temperature and an initial hydrogen pressure of 2 MPa for 4-24 h. After cooling to room temperature, a liquid mixture is obtained by filtration, and a sample is taken for the following gas chromatography analysis: The liquid product after the reaction is subjected to off-line quantitative analysis by a gas chromatograph equipped with a thermal conductivity detector and a flame ionization detector, using nonane as the internal standard. The conversion rate of 5-hydroxymethylfurfural and the selectivity of 2,5-dimethylfuran are obtained.

[0080] For the preparation of the catalyst, the following examples are made:

[0081] Example 1:

[0082] S101 Dissolve the molybdenum source and the sulfur source and stir evenly to obtain a first mixed solution;

[0083] The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:2.5;

[0084] The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

[0085] The stirring time of the first mixed solution is 30 min;

[0086] S102 Put the first mixed solution into the silica gel solution and stir evenly to obtain a second mixed solution;

[0087] The mass concentration of the silica gel solution is 30%;

[0088] The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is: 1:1.5.

[0089] The stirring time of the second mixed solution is 2 h.

[0090] S103 Dry the second mixed solution to obtain a first precursor;

[0091] The second mixed solution is subjected to rotary evaporation and then vacuum drying;

[0092] The rotary evaporation temperature is 55 °C, the time is 2 h, and the vacuum degree is 80 kPa;

[0093] The temperature of vacuum drying is 75 °C, the drying time is 12 h, and the vacuum degree of vacuum drying is 90 kPa.

[0094] S104 Grind and calcine the first precursor to obtain a second precursor;

[0095] The ground first precursor is placed in a tube furnace. The input gas flow is 5 vol% H2 / Ar, the temperature of the tube furnace is 350 °C, the reaction time is 3.5 h. After the reaction, the tube furnace is allowed to cool naturally to room temperature, and then the second precursor is collected.

[0096] S105 The second precursor is desilicated, washed and dried to obtain the catalyst.

[0097] The second precursor is placed in the inner liner of a polytetrafluoro reaction kettle and treated with a hydrofluoric acid solution at room temperature for 4 h. The concentration of the hydrofluoric acid solution is 40 wt%.

[0098] The desilication, washing and drying are carried out as follows:

[0099] After washing with the hydrofluoric acid solution, it is then placed in a vacuum drying oven at 75 °C for drying for 3 h, ground into powder, and the collected powder solid is the catalyst, denoted as Catalyst No. 1. Based on the characterization of Catalyst No. 1, Figure 4 Figure 5 .

[0100] Example 2:

[0101] S201 Dissolve the molybdenum source and the sulfur source and stir evenly to obtain the first mixed solution;

[0102] The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:3.5;

[0103] The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

[0104] The stirring time of the first mixed solution is 30 min;

[0105] S202 Put the first mixed solution into the silica gel solution and stir evenly to obtain the second mixed solution;

[0106] The mass concentration of the silica gel solution is 25%;

[0107] The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is: 1:2.

[0108] The stirring time of the second mixed solution is 2 h.

[0109] S203 Dry the second mixed solution to obtain the first precursor;

[0110] The second mixed solution is rotary evaporated and then vacuum dried;

[0111] The rotary evaporation temperature is 65 °C, the time is 1.5 h, and the vacuum degree is 60 kPa;

[0112] The temperature of vacuum drying is 85 °C, the drying time is 8 h, and the vacuum degree of vacuum drying is 80 kPa.

[0113] S204 grinds and calcines the first precursor to obtain a second precursor;

[0114] The ground first precursor is placed in a tube furnace, the input gas flow is 15 vol% H2 / Ar, the temperature of the tube furnace is 350 °C, the reaction time is 2.5 h, and after the reaction is completed, the tube furnace is allowed to cool naturally to room temperature and then the second precursor is collected.

[0115] S205 desilicates the second precursor, then washes and dries it to obtain a catalyst.

[0116] The second precursor is placed in the inner liner of a polytetrafluoro reaction kettle and treated with a hydrofluoric acid solution at room temperature for 6 h, and the concentration of the hydrofluoric acid solution is 40 wt%;

[0117] The desilication, washing and drying are carried out as follows:

[0118] After washing with the hydrofluoric acid solution, it is then placed in a vacuum drying oven at 85 °C and dried for 3 h, ground into powder, and the collected powder solid is the catalyst, denoted as catalyst No. 2.

[0119] Example 3

[0120] After obtaining catalyst No. 1, catalyst No. 1 is subjected to metal loading.

[0121] S301 places the catalyst and the soluble metal salt in water and stirs to obtain a preliminary mixture;

[0122] The catalyst, potassium carbonate at 0.05 wt% based on metal, and water with a mass 4 times that of the catalyst are stirred at room temperature for 0.5 h, and the stirring rate is 800 r / min;

[0123] S302 dries the preliminary mixture to obtain a preliminary loaded solid;

[0124] The drying of the preliminary mixture is carried out as follows:

[0125] The drying method is rotary evaporation, the rotary evaporation temperature is 55 °C, the time is 2 h, and the vacuum degree is 80 kPa;

[0126] S303 reduces the preliminary loaded solid to obtain a loaded catalyst.

[0127] The ground preliminary loaded solid is placed in a tube furnace, the input gas flow is 5 vol% H2 / Ar, the temperature of the tube furnace is 300 °C, the reaction time is 3.5 h, and after the reaction is completed, the tube furnace is allowed to cool naturally to room temperature and then the loaded catalyst is collected, denoted as catalyst No. 3.

[0128] Example 4

[0129] After obtaining the No. 1 catalyst, the No. 1 catalyst is subjected to metal loading.

[0130] S401 Place the catalyst and the soluble metal salt in water and stir to obtain a preliminary mixture;

[0131] Place the catalyst, potassium carbonate at 0.5 wt% based on the metal, and water at 6 times the mass of the catalyst, and stir at room temperature for 1 h with a stirring rate of 500 r / min;

[0132] S402 Dry the preliminary mixture to obtain a preliminarily loaded solid;

[0133] The drying of the preliminary mixture is carried out as follows:

[0134] The drying method is rotary evaporation, the rotary evaporation temperature is 65 °C, the time is 1.5 h, and the vacuum degree is 60 kPa;

[0135] S403 Reduce the preliminarily loaded solid to obtain a loaded catalyst.

[0136] Place the ground preliminarily loaded solid in a tubular furnace, the input gas flow is 15 vol% H2 / Ar, the temperature of the tubular furnace is 350 °C, the reaction time is 2.5 h, and after the reaction ends, wait for the tubular furnace to cool naturally to room temperature and then collect the obtained loaded catalyst, denoted as the No. 4 catalyst.

[0137] Example 5

[0138] After obtaining the No. 1 catalyst, the No. 1 catalyst is subjected to metal loading.

[0139] S501 Place the catalyst and the soluble metal salt in water and stir to obtain a preliminary mixture;

[0140] Place the catalyst, cobalt nitrate at 0.05 wt% based on the metal, and water at 4 times the mass of the catalyst, and stir at room temperature for 0.5 h with a stirring rate of 800 r / min;

[0141] S502 Dry the preliminary mixture to obtain a preliminarily loaded solid;

[0142] The drying of the preliminary mixture is carried out as follows:

[0143] The drying method is rotary evaporation, the rotary evaporation temperature is 55 °C, the time is 2 h, and the vacuum degree is 80 kPa;

[0144] S503 Reduce the preliminarily loaded solid to obtain a loaded catalyst.

[0145] The preliminarily loaded solid after grinding was placed in a tubular furnace. The input gas flow was 5 vol% H2 / Ar, the temperature of the tubular furnace was 300 °C, the reaction time was 3.5 h. After the reaction ended, the tubular furnace was allowed to cool naturally to room temperature, and the loaded catalyst was collected and denoted as Catalyst No. 5.

[0146] Example 6

[0147] After obtaining Catalyst No. 1, Catalyst No. 1 was subjected to metal loading.

[0148] S601 The catalyst and the soluble metal salt were placed in water and stirred to obtain a preliminary mixture;

[0149] The catalyst, cobalt nitrate at 0.5 wt% based on metal, and water with a mass 6 times that of the catalyst were stirred at room temperature for 1 h, and the stirring rate was 500 r / min;

[0150] S602 The preliminary mixture was dried to obtain a preliminarily loaded solid;

[0151] The drying of the preliminary mixture was carried out as follows:

[0152] The drying method was rotary evaporation. The rotary evaporation temperature was 65 °C, the time was 1.5 h, and the vacuum degree was 60 kPa;

[0153] S603 The preliminarily loaded solid was reduced to obtain a loaded catalyst.

[0154] The ground preliminarily loaded solid was placed in a tubular furnace. The input gas flow was 15 vol% H2 / Ar, and the loaded catalyst was collected and denoted as Catalyst No. 6.

[0155] To characterize the effectiveness of the catalyst of the present application, the following comparative examples were made:

[0156] Comparative Example 1:

[0157] D101 The molybdenum source and the sulfur source were dissolved and stirred evenly to obtain a first mixture;

[0158] The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source was 1:2.5;

[0159] The molybdenum source was ammonium molybdate tetrahydrate, and the sulfur source was thiourea.

[0160] The stirring time of the first mixture was 30 min;

[0161] D102 The ball-milled all-silica molecular sieve S-1 was added to the first mixture and stirred evenly to obtain a second mixture;

[0162] The mass ratio of molybdenum in the molybdenum source to silicon in the molecular sieve S-1 was: 1:3.

[0163] The ball milling time is 5 h.

[0164] The stirring time of the second mixed solution is 2 h.

[0165] D103 dries the second mixed solution to obtain the first precursor;

[0166] The second mixed solution is subjected to rotary evaporation and then vacuum drying;

[0167] The rotary evaporation temperature is 55 °C, the time is 2 h, and the vacuum degree is 80 kPa;

[0168] The temperature of the vacuum drying is 75 °C, the drying time is 12 h, and the vacuum degree of the vacuum drying is 90 kPa.

[0169] D104 grinds and calcines the first precursor to obtain the second precursor;

[0170] The ground first precursor is placed in a tubular furnace, the input gas flow is 5 vol% H2 / Ar, the temperature of the tubular furnace is 350 °C, the reaction time is 3.5 h, and after the reaction is completed, the second precursor is collected after the tubular furnace is naturally cooled to room temperature.

[0171] D105 desilicates the second precursor, cleans and dries it to obtain the catalyst.

[0172] The second precursor is placed in the inner liner of a polytetrafluoro reaction kettle and treated with a hydrofluoric acid solution at room temperature for 4 h, and the concentration of the hydrofluoric acid solution is 40 wt%;

[0173] The desilication, cleaning and drying are carried out as follows:

[0174] After cleaning with the hydrofluoric acid solution, it is then placed in a vacuum drying oven at 75 °C and dried for 3 h, ground into powder, and the collected powder solid is the catalyst, denoted as catalyst No. 7.

[0175] Comparative Example 2:

[0176] D201 dissolves and stirs evenly the molybdenum source and the sulfur source to obtain the first mixed solution;

[0177] The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:2.5;

[0178] The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

[0179] The stirring time of the first mixed solution is 30 min;

[0180] D202 puts the first mixed solution into the silica gel solution and stirs evenly to obtain the second mixed solution;

[0181] The mass concentration of the silica gel solution is 30%;

[0182] The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is: 1:5.

[0183] The stirring time of the second mixed solution is 2 h.

[0184] D203 dries the second mixed solution to obtain a first precursor;

[0185] The second mixed solution is rotary evaporated and then vacuum dried;

[0186] The rotary evaporation temperature is 55 °C, the time is 2 h, and the vacuum degree is 80 kPa;

[0187] The temperature of the vacuum drying is 75 °C, the drying time is 12 h, and the vacuum degree of the vacuum drying is 90 kPa.

[0188] D204 grinds and roasts the first precursor to obtain a second precursor;

[0189] The ground first precursor is placed in a tubular furnace, the input gas flow is 5 vol% H2 / Ar, the temperature of the tubular furnace is 350 °C, the reaction time is 3.5 h, and after the reaction is completed, the second precursor is collected after the tubular furnace is naturally cooled to room temperature.

[0190] D205 desilicates the second precursor, cleans and dries it to obtain a catalyst.

[0191] The second precursor is placed in the inner liner of a polytetrafluoroethylene reaction kettle and treated with a hydrofluoric acid solution at room temperature for 4 h, and the concentration of the hydrofluoric acid solution is 40 wt%;

[0192] Desilication, cleaning and drying are carried out as follows:

[0193] After cleaning with the hydrofluoric acid solution, it is then placed in a vacuum drying oven at 75 °C and dried for 3 h, ground into a powder, and the collected powder solid is the catalyst, denoted as catalyst No. 8.

[0194] Comparative Example 3:

[0195] D301 dissolves and stirs evenly the molybdenum source and the sulfur source to obtain a first mixed solution;

[0196] The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:2.5;

[0197] The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

[0198] The stirring time of the first mixed solution is 30 min;

[0199] D302 puts the first mixed solution into the silica gel solution and stirs evenly to obtain a second mixed solution;

[0200] The mass concentration of the silica gel solution is 30%;

[0201] The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is: 1:1.

[0202] The stirring time of the second mixed solution is 2 h.

[0203] D303 dries the second mixed solution to obtain a first precursor;

[0204] The second mixed solution is rotary evaporated and then vacuum dried;

[0205] The rotary evaporation temperature is 55 °C, the time is 2 h, and the vacuum degree is 80 kPa;

[0206] The temperature of the vacuum drying is 75 °C, the drying time is 12 h, and the vacuum degree of the vacuum drying is 90 kPa.

[0207] D304 grinds and calcines the first precursor to obtain a second precursor;

[0208] The ground first precursor is placed in a tube furnace, the input gas flow is 5 vol% H2 / Ar, the temperature of the tube furnace is 350 °C, the reaction time is 3.5 h, and after the reaction is completed, the tube furnace is allowed to cool naturally to room temperature and then the second precursor is collected.

[0209] D305 desilicates the second precursor, cleans and dries it to obtain a catalyst.

[0210] The second precursor is placed in the inner liner of a polytetrafluoroethylene reaction kettle and treated with a hydrofluoric acid solution at room temperature for 4 h, and the concentration of the hydrofluoric acid solution is 40 wt%;

[0211] The desilication, cleaning and drying are carried out as follows:

[0212] After cleaning with the hydrofluoric acid solution, it is then placed in a vacuum drying oven at 75 °C and dried for 3 h, ground into powder, and the powder solid collected is the catalyst, denoted as catalyst No. 9.

[0213] Comparative Example 4:

[0214] D401 dissolves the molybdenum source and the sulfur source and stirs them evenly to obtain a first mixed solution;

[0215] The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:2.5;

[0216] The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

[0217] The stirring time of the first mixed solution is 30 min;

[0218] D402 puts the first mixed solution into the silica gel solution and stirs evenly to obtain a second mixed solution;

[0219] The mass concentration of the silica gel solution is 30%.

[0220] The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is 1:1.5.

[0221] The stirring time of the second mixed solution is 2 h.

[0222] D403 dries the second mixed solution to obtain a first precursor.

[0223] The second mixed solution is dried in vacuum.

[0224] The temperature of vacuum drying is 75 °C, the drying time is 12 h, and the vacuum degree of vacuum drying is 90 kPa.

[0225] D404 grinds and calcines the first precursor to obtain a second precursor.

[0226] The ground first precursor is placed in a tubular furnace, the input gas flow is 5 vol% H2 / Ar, the temperature of the tubular furnace is 350 °C, the reaction time is 3.5 h, and after the reaction is completed, the second precursor is collected after the tubular furnace is naturally cooled to room temperature.

[0227] D405 desilicates the second precursor, cleans and dries it to obtain a catalyst.

[0228] The second precursor is placed in the inner liner of a polytetrafluoroethylene reaction kettle and treated with a hydrofluoric acid solution at room temperature for 4 h, and the concentration of the hydrofluoric acid solution is 40 wt%.

[0229] Desilication, cleaning and drying are carried out as follows:

[0230] After cleaning with the hydrofluoric acid solution, it is then placed in a vacuum drying oven at 75 °C and dried for 3 h, ground into powder, and the powder solid collected is the catalyst, denoted as catalyst No. 10.

[0231] Comparative example 5:

[0232] D501 dissolves the molybdenum source and the sulfur source and stirs them evenly to obtain a first mixed solution.

[0233] The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:2.5.

[0234] The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

[0235] The stirring time of the first mixed solution is 30 min.

[0236] D502 puts the first mixed solution into the silica gel solution and stirs it evenly to obtain a second mixed solution.

[0237] The mass concentration of the silica gel solution is 30%.

[0238] The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is 1:1.5.

[0239] The stirring time of the second mixed solution is 2 h.

[0240] D503 After desilicifying the second mixed solution and cleaning, a first precursor is obtained.

[0241] Place the second mixed solution in the inner liner of a polytetrafluoroethylene reaction kettle, and treat it with a hydrofluoric acid solution at room temperature for 4 h. The concentration of the hydrofluoric acid solution is 40 wt%.

[0242] The desilicification and cleaning are carried out as follows:

[0243] After cleaning with the hydrofluoric acid solution, centrifuge with anhydrous ethanol and deionized water crosswise 3 times respectively with a centrifuge, and then place it in a vacuum drying oven to dry for 12 h to obtain a second precursor.

[0244] The temperature of the vacuum drying is 75 °C, the drying time is 12 h, and the vacuum degree of the vacuum drying is 90 kPa.

[0245] D504 Grind and calcine the second precursor to obtain a catalyst.

[0246] Place the ground second precursor in a tubular furnace, the input gas flow is 5 vol% H2 / Ar, the temperature of the tubular furnace is 350 °C, the reaction time is 3.5 h. After the reaction ends, wait for the tubular furnace to cool naturally to room temperature and then collect the obtained powder solid, which is the catalyst, denoted as catalyst No. 11.

[0247] For the above catalyst, a catalytic hydrogenation experiment of 5-hydroxymethylfurfural is carried out. The liquid-phase product after the reaction is analyzed quantitatively offline by a gas chromatograph equipped with a thermal conductivity detector and a flame ionization detector, using nonane as an internal standard. The results of the specific hydrogenation experiment are as follows:

[0248] Table 1: Catalytic reaction effects of the catalysts obtained in the examples and comparative examples on 5-hydroxymethylfurfural

[0249]

[0250]

[0251] As can be seen from the results in Table 1, at a substrate concentration of 1 mol / L, the highest conversion rate of 5-hydroxymethylfurfural by the porous molybdenum disulfide described in the present application is 95.2% (reaction temperature is 100 °C), and the conversion rate can also reach 86.4% at a low temperature of 30 °C. For the comparative catalyst 8, even at a high temperature of 150 °C, the conversion rate can only reach 86.1% and the selectivity is 85.2%. When the temperature is lower than 100 °C, the effect of the comparative catalyst decreases significantly. The modified molybdenum disulfide has a good effect on improving the selectivity of the product 2,5-dimethylfuran, and the selectivity and conversion rate of the catalyst modified by the transition metal Co for 2,5-dimethylfuran are not less than 99%.

[0252] In order to verify whether there are differences in the recycling performance of the above catalysts, after 5 catalytic reactions, their catalytic efficiency was recorded:

[0253] Table 2: Catalytic reaction effects of the catalysts obtained in the examples and comparative examples after being recycled 5 times for 5-hydroxymethylfurfural

[0254]

[0255]

[0256] As can be seen from the results in Table 2, at a substrate concentration of 1 mol / L, the highest conversion rate of 5-hydroxymethylfurfural by the porous molybdenum disulfide described in the present application after 5 reactions is 93.2% (reaction temperature is 100 °C). After 5 reactions, the catalytic effects of the catalyst and the modified catalyst do not decrease significantly, while the conversion rate and selectivity of the comparative catalyst decrease significantly after 5 reactions.

[0257] The above are only examples of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A porous molybdenum disulfide catalyst, characterized in that: It is prepared by the following method: Dissolve the molybdenum source and sulfur source and stir evenly to obtain the first mixed solution; Put the first mixed solution into the silica gel solution and stir evenly to obtain the second mixed solution; Dry the second mixed solution to obtain the first precursor; Grind and calcine the first precursor to obtain the second precursor; Desilicate the second precursor, then wash and dry it to obtain the catalyst.

2. The porous molybdenum disulfide catalyst according to claim 1, wherein: It includes the following steps: The molar ratio of molybdenum element in the molybdenum source to sulfur element in the sulfur source is 1:2.5 - 3.5; The molybdenum source is ammonium molybdate tetrahydrate, and the sulfur source is thiourea.

3. A porous molybdenum disulfide catalyst according to claim 1, characterized in that: The mass concentration of the silica gel solution is 25 - 30%; The mass ratio of the molybdenum source to silicon dioxide in the silica gel solution is: 1:1.5 - 2.

4. A porous molybdenum disulfide catalyst according to claim 1, characterized in that: The stirring time of the first mixed solution is not less than 30 min; The stirring time of the second mixed solution is not less than 2 h.

5. A porous molybdenum disulfide catalyst as described in claim 1, characterized in that: Perform rotary evaporation on the second mixed solution and then perform vacuum drying; The rotary evaporation temperature is 55 - 65 °C, the time is 1.5 - 2 h, and the vacuum degree is 60 - 80 kPa; The temperature of vacuum drying is 75 - 85 °C, the drying time is 8 - 12 h, and the vacuum degree of vacuum drying is 80 - 90 kPa.

6. The porous molybdenum disulfide catalyst according to claim 1, wherein: The calcination is carried out as follows: Place the ground first precursor in a tubular furnace, the input gas flow is 5 - 15 vol% H2 / Ar, the temperature of the tubular furnace is 300 - 350 °C, the reaction time is 2.5 - 3.5 h, and after the reaction ends, wait for the tubular furnace to cool naturally to room temperature and then collect the second precursor.

7. A porous molybdenum disulfide catalyst according to claim 1, characterized in that: Desilication is carried out as follows: Place the second precursor in the inner liner of a polytetrafluoroethylene reaction kettle and treat it with a hydrofluoric acid solution at room temperature for 4 - 6 h, and the concentration of the hydrofluoric acid solution is 40 wt%; The washing and drying after desilication are carried out as follows: After washing with the hydrofluoric acid solution, put it into a vacuum drying oven at 75 - 85 °C to dry, grind it into powder, and collect the powder solid, which is the catalyst.

8. A porous molybdenum disulfide catalyst as described in claim 1, characterized in that: It also includes the process of metal loading: Place the catalyst and soluble metal salt in water and stir to obtain a preliminary mixed solution; Dry the preliminary mixed solution to obtain a preliminary loaded solid; Reduce the preliminary loaded solid to obtain a loaded catalyst.

9. A porous molybdenum disulfide catalyst as described in claim 8, characterized in that: The preliminary mixed solution is obtained as follows: The catalyst, 0.05 - 0.5 wt% of soluble metal salt based on metal, 4 - 6 times the mass of the catalyst of water, are stirred at room temperature for 0.5 - 1 h, and the stirring rate is 500 - 800 r / min; The drying of the preliminary mixed solution is carried out as follows: The drying method is rotary evaporation, the rotary evaporation temperature is 55 - 65 °C, the time is 1.5 - 2 h, and the vacuum degree is 60 - 80 kPa; The reduction of the preliminary loaded solid is carried out as follows: The preliminarily loaded solid after grinding is placed in a tubular furnace. The input gas flow is 5 - 15 vol% H2 / Ar, the temperature of the tubular furnace is 300 - 350 °C, the reaction time is 2.5 - 3.5 h. After the reaction is completed, the tubular furnace is allowed to cool naturally to room temperature, and then the loaded catalyst is collected. The metal salt is at least one or a mixture of two or more of lithium carbonate, sodium carbonate, potassium carbonate, copper nitrate, ferrous nitrate, cobalt nitrate, nickel nitrate, manganese nitrate, and chromium nitrate in any proportion.

10. Use of a porous molybdenum disulfide catalyst as described in claim 1 in the hydrogenation of 5-hydroxymethylfurfural, characterized in that: The reaction temperature is: 30 - 100 °C; preferably, the reaction temperature is: 70 - 100 °C.

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