Catalyst for preparing 2, 5-dimethylfuran through fructose hydrodeoxygenation and preparation method

Abstract

The invention belongs to the technical field of chemical engineering, and provides a catalyst for preparing 2, 5-dimethylfuran through fructose hydrodeoxygenation and a preparation method, the catalyst for preparing 2, 5-dimethylfuran through fructose hydrodeoxygenation comprises a deoxygenation catalyst and a hydrogenation catalyst; the preparation method of the deoxidation catalyst comprises the following steps: grinding dried vinasse to obtain vinasse powder; adding vinasse powder into a sulfuric acid solution, fully stirring, washing, drying and grinding to obtain a deoxidation catalyst; the preparation method of the hydrogenation catalyst comprises the following steps: adding activated carbon into a nitric acid solution, fully stirring, washing, drying, grinding and roasting to obtain an activated carbon precursor; and adding the active carbon precursor into a metal salt solution, fully stirring until the active carbon precursor is dried, drying, grinding, and roasting in a nitrogen-introduced muffle furnace to obtain the hydrogenation catalyst. The reaction process and the preparation process are simple, a separation step is not needed, and the product selectivity is high.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry and provides a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose and a preparation method thereof. Background Art

[0002] As the only renewable carbon resource, biomass resources can not only be used to produce new fuels but also replace fossil resources as raw materials for the production of bulk chemicals, which is beneficial to the sustainable development of mankind. 2,5-Dimethylfuran is considered to be a promising biomass fuel. It has excellent combustion characteristics such as calorific value comparable to gasoline, high octane number, suitable ignition point, insoluble in water, easy to transport, and can be well adapted to existing automobile engines. It is considered to be a better biomass fuel than bioethanol. In addition, 2,5-dimethylfuran has a furan ring structure that can make full use of oxygen atoms in biomass resources and achieve higher atomic economy.

[0003] In the prior art, fructose is generally prepared into 2,5-dimethylfuran by a two-step method: (1) fructose is first dehydrated to produce 5-hydroxymethylfurfural, and (2) the separated and purified 5-hydroxymethylfurfural is hydrodeoxygenated to convert it into 2,5-dimethylfuran. Although a high yield of 2,5-dimethylfuran can be obtained through the above reaction, the separation and purification process is energy-intensive and the process is complicated. At the same time, 5-hydroxymethylfurfural is highly reactive, difficult to preserve, and is prone to other side reactions. Therefore, it is of great significance to develop a catalyst that uses fructose as a raw material to directly generate 2,5-dimethylfuran without the need for separation and purification steps. Summary of the invention

[0004] The purpose of the present invention is to provide a catalyst with simple reaction process and preparation process, no separation step required and high product selectivity for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose, in view of the current development status that the separation energy consumption is large and the process is complicated in preparing 2,5-dimethylfuran from fructose.

[0005] The technical solution provided by the present invention is as follows:

[0006] A method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose, wherein the catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose comprises a deoxygenation catalyst and a hydrogenation catalyst;

[0007] The preparation method of the deoxygenation catalyst comprises: grinding the dried vinasse to obtain vinasse powder; adding the vinasse powder to a sulfuric acid solution, stirring it fully, and washing it with deionized water until the pH value of the filtrate is neutral; drying and grinding the washed vinasse powder to obtain a deoxygenation catalyst;

[0008] The preparation method of the hydrogenation catalyst comprises: adding activated carbon to a nitric acid solution, stirring it fully, and then washing it with deionized water until the pH value of the filtrate is neutral; drying and grinding the washed activated carbon, and calcining it in a nitrogen muffle furnace to obtain an activated carbon precursor; adding the activated carbon precursor to a metal salt solution and stirring it fully, then placing it in a magnetic stirrer, stirring it under high temperature conditions until it is dry, and continuing to dry it to obtain activated carbon impregnated with a metal salt; grinding the activated carbon impregnated with a metal salt into powder, and calcining it in a nitrogen muffle furnace to obtain a hydrogenation catalyst.

[0009] Furthermore, the mass ratio of the deoxygenation catalyst to the hydrogenation catalyst is 0~3:1~3.

[0010] Furthermore, the supported metal of the hydrogenation catalyst is one or two of Pt, Ni, W, Fe, Cu, Mo, and Co.

[0011] Furthermore, the concentration of the metal salt solution, calculated as the mass of metal ions, is 1-5% of the total mass of the activated carbon precursor.

[0012] Furthermore, activated carbon was added into the nitric acid solution and stirred at 70-90° C. on a magnetic stirrer for 3-5 h.

[0013] Furthermore, the calcination temperature in the muffle furnace with nitrogen is 350-450° C., and the calcination time is 2-4 hours.

[0014] Furthermore, the stirring until dry under high temperature conditions is: adding the activated carbon precursor to the metal salt solution and fully stirring with a glass rod, placing it in a magnetic stirrer, and drying at 70-90° C., and stirring with a glass rod regularly during the drying process until dry.

[0015] The present invention also provides a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose, which is prepared by the above method.

[0016] The present invention also provides an application of the catalyst in the preparation of 2,5-dimethylfuran. Biomass fructose is used as a raw material, the catalyst is added, and a deoxygenation reaction is carried out in a high-pressure reactor filled with nitrogen. After the deoxygenation reaction is completed, hydrogen is filled into the high-pressure reactor, and 2,5-dimethylfuran is obtained after the dehydrogenation reaction is completed.

[0017] Furthermore, the deoxygenation reaction temperature is 140-180°C, the deoxygenation reaction time is 1-3h, and the nitrogen pressure is 0.5-2MPa; the hydrogenation reaction temperature is 160-220°C, the hydrogenation reaction time is 4-12h, and the hydrogen pressure is 0.5-5.0MPa.

[0018] A method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose comprises:

[0019] 1. Preparation of deoxygenation catalyst (C-SO3H)

[0020] Wash the lees, put them in an oven, dry them for 48-72 hours, and grind them into lees powder in a pulverizer; add 85wt% sulfuric acid solution, and the mass ratio of lees powder to sulfuric acid solution is 1-2:5-8; after being fully mixed, quickly add the lees powder obtained in step a into the sulfuric acid solution, use a glass rod to stir until the sulfuric acid solution and the lees are evenly mixed, and stir at room temperature for 1.5 hours on a magnetic stirrer; wash the stirred sample with deionized water until the pH value of the filtrate is 7; put the washed sample into an oven at 80°C and dry it for 12 hours, and grind it into fine powder with a mortar to obtain a deoxygenation catalyst for fructose hydrodeoxygenation to prepare 2,5-dimethylfuran.

[0021] 2. Preparation of hydrogenation catalyst

[0022] (1) Activated carbon pretreatment

[0023] Commercial activated carbon was added to a 6 mol / L nitric acid solution, and stirred at 80°C for 4 h on a magnetic stirrer. The activated carbon treated in step a was washed with deionized water until the pH of the filtrate was 7; the washed activated carbon was placed in an oven at 80°C and dried for 12 h, and the dried sample was ground into fine powder with a mortar, and calcined in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400°C and a calcination time of 3 h to obtain an activated carbon precursor;

[0024] (2) Impregnation and drying of activated carbon powder and metal salt

[0025] Weigh a certain amount of H2PtCl6, Ni(NO3)2, Co(NO3)2, Fe(NO3)3, H 24 Mo7N6O 24 ·One or two of 24H2O; in the metal salt solution, the concentration is calculated based on the mass of metal ions in the metal salt, and the impregnation solution is prepared in a certain proportion. After sufficient dissolution is completed, a certain mass of activated carbon powder precursor is quickly added, and fully stirred with a glass rod. Then, it is placed in a magnetic stirrer and dried at 80°C. During the drying process, it is regularly stirred with a glass rod until dry, and then the sample is continued to be dried in a 100°C oven for 12-18h to obtain activated carbon impregnated with metal salts.

[0026] (3) Calcination

[0027] The activated carbon impregnated with the metal salt was ground into powder and calcined in a nitrogen muffle furnace at a temperature of 400°C and a heating rate of 2°C / min. After reaching the preset calcination temperature, the temperature was maintained for 3 hours to obtain a hydrogenation catalyst.

[0028] The metal salt is H2PtCl6, Ni(NO3)2, Co(NO3)2, Fe(NO3)3, H 24 Mo7N6O 24 ·One or two of 24H2O; in the metal salt solution, the concentration is calculated based on the mass of metal ions in the metal salt.

[0029] When the catalyst of the present invention is used for preparing furan chemicals (2,5-dimethylfuran, 5-methylfurfural, 5-hydroxymethylfurfural, etc.) by hydrogenating and deoxygenating fructose, a high-pressure reactor with a mechanical stirring device is used, and the solvent is 50 mL; in the reaction system, the mass of fructose is 0.3 g, the concentration is 0.012 g / mL, the hydrogenation catalyst is 0.1 g, the deoxygenation catalyst is 0.1 g, the solvent is 1,4-dioxane and water, which are 22.5 mL and 2.5 mL respectively, so the mass concentration of the reactants is 0.01 g / mL; the hydrogenation reaction temperature is 180-220°C, preferably 180°C, the hydrogenation reaction time is 4-12 h, preferably 10 h; the reaction hydrogen pressure is 3 MPa; the mechanical stirring rate is 600 rpm; the reaction product is qualitatively analyzed by GC-MS, and quantitatively analyzed by GC and HPLC, and the product yield is calculated.

[0030] Beneficial Effects

[0031] The present invention provides a catalyst preparation method for preparing 2,5-dimethylfuran by hydrogenation deoxygenation of fructose, and 2,5-dimethylfuran is generated with high conversion rate and high selectivity through hydrogenation catalysis. The catalyst preparation method of the present invention is simple, activated carbon is used as a catalyst carrier, and the raw materials are green and environmentally friendly; the two-step reaction is coupled into one step, the reaction process is simple, and separation and purification are not required, thereby reducing energy consumption during the reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a GC spectrum of the product of preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose in Example 12. From the GC image, it can be seen that 2,5-dimethylfuran is the main product.

[0033] Figure 2 TEM image of 5Pt / C catalyst.

[0034] Figure 3 TEM image of 5Pt5Fe / C catalyst. DETAILED DESCRIPTION

[0035] The present invention is described in more detail below through specific examples. The provided embodiments are only used to illustrate the present invention, but do not limit the protection scope of the present invention in any way.

[0036] Example 1

[0037] Catalyst preparation: Commercial activated carbon was stirred in 6 mol / L nitric acid solution at 80°C for 4 h, washed with deionized water until the filtrate pH = 7; dried in an oven at 80°C for 12 h, calcined in a nitrogen muffle furnace with nitrogen at 400°C for 3 h, and ground into powder in a mortar. A certain mass of PtCl6⋅6H2O and Fe(NO3)2⋅9H2O were weighed and dissolved in deionized water, where the mass of PtCl6⋅6H2O was 0.1351 g, the mass of Fe(NO3)2⋅9H2O was 0.3617 g, and the volume of deionized water was 20 mL, resulting in a concentration of 0.6755×10 -2 g·mL -1 PtCl6⋅6H2O aqueous solution, the concentration is 1.8085×10 -2 g·mL -1 Fe(NO3)2⋅9H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80°C until dry, and then continue to dry the sample in a 100°C oven for 12 hours. Grind the dried sample into a fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400°C and a calcination time of 3 hours to obtain the prepared catalyst. The catalyst is named 5Pt5Fe / C, and the TEM image is shown in the figure. Figure 3 As shown in the TEM image, it can be seen that Pt and Fe are evenly dispersed on the carrier, and the main form of Fe is Fe2O3. Compared with the 5Pt / C catalyst, the metal particles of 5Pt5Fe / C are larger and easier to contact with the reactants, and the acidic Fe2O3 can further promote the formation of 2,5-dimethylfuran.

[0038] Experimental evaluation of high-pressure reactor: 0.15g of calcined 5Pt5Fe / C catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor, and the air in the reactor was replaced with H2 4 times, and the pressure was increased to 3MPa, and the reactor was sealed. The mechanical stirring was turned on (600rpm), and the reactor was heated to 180℃ in 50min. The reaction time was started, and the reaction time was 10h. The yield of 2,5-dimethylfuran was 30.5%. The reaction conditions and results are shown in Table 1.

[0039] Example 2

[0040] Catalyst preparation: Commercial activated carbon was stirred in 6 mol / L nitric acid solution at 80°C for 4 h, washed with deionized water until the filtrate pH = 7; dried in an oven at 80°C for 12 h, calcined in a nitrogen muffle furnace at 400°C for 3 h, and ground into powder in a mortar.24 Mo7N6O 24 ⋅24H2O is dissolved in deionized water, where the mass of PtCl6⋅6H2O is 0.1351g, H 24 Mo7N6O 24 The mass of ⋅24H2O is 0.0919 g, the volume of deionized water is 20 mL, and the concentration is 0.6755×10 -2 g·mL -1 The PtCl6⋅6H2O aqueous solution was obtained with a concentration of 0.4595×10 - 2 g·mL -1 H 24 Mo7N6O 24 ⋅24H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80℃ until it is dry, and then continue to dry the sample in a 100℃ oven for 12h. Grind the dried sample into fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400℃ and a calcination time of 3h to obtain the prepared catalyst. The catalyst is named 5Pt5Mo / C.

[0041] Experimental evaluation of high-pressure reactor: 0.15g of calcined 5Pt5Mo / C catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor, and the air in the reactor was replaced with H2 4 times, and the pressure was increased to 3MPa, and the reactor was sealed. The mechanical stirring was turned on (600rpm), and the reactor was heated to 180°C in 50min, and the timing reaction was started. The reaction time was 10h. The yield of 2,5-dimethylfuran was 16.3%. The reaction conditions and results are shown in Table 1.

[0042] Example 3

[0043] Catalyst preparation: Commercial activated carbon was stirred in 6 mol / L nitric acid solution at 80°C for 4 h, washed with deionized water until the filtrate pH = 7; dried in an oven at 80°C for 12 h, calcined in a nitrogen muffle furnace with nitrogen at 400°C for 3 h, and ground into powder in a mortar. Weigh a certain mass of PtCl6⋅6H2O and Co(NO3)2⋅6H2O and dissolve them in deionized water, where the mass of PtCl6⋅6H2O is 0.1351 g, the mass of Co(NO3)2⋅6H2O is 0.1235 g, and the volume of deionized water is 20 mL, to obtain a concentration of 0.6755×10 -2 g·mL -1 The PtCl6⋅6H2O aqueous solution was obtained with a concentration of 0.6175×10 -2g·mL -1 Co(NO3)2⋅6H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80℃ until it is dry, and then continue to dry the sample in a 100℃ oven for 12h. Grind the dried sample into a fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400℃ and a calcination time of 3h to obtain the prepared catalyst. The catalyst is named 5Pt5Co / C.

[0044] Experimental evaluation of high-pressure reactor: 0.15g of calcined 5Pt5Co / C catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor, and the air in the reactor was replaced with H2 4 times, and the pressure was increased to 3MPa, and the reactor was sealed. The mechanical stirring was turned on (600rpm), and the reactor was heated to 180°C in 50min, and the timing reaction was started. The reaction time was 10h. The yield of 2,5-dimethylfuran was 29.7%. The reaction conditions and results are shown in Table 1.

[0045] Example 4

[0046] Catalyst preparation: Commercial activated carbon was stirred in 6 mol / L nitric acid solution at 80°C for 4 h, washed with deionized water until the filtrate pH = 7; dried in an oven at 80°C for 12 h, calcined in a nitrogen muffle furnace with nitrogen at 400°C for 3 h, and ground into powder in a mortar. A certain mass of PtCl6⋅6H2O and Ni(NO3)2⋅6H2O were weighed and dissolved in deionized water, where the mass of PtCl6⋅6H2O was 0.1351 g and the mass of Ni (NO3)2⋅6H2O was 0.1239 g, and the volume of deionized water was 20 mL, resulting in a concentration of 0.6755×10 -2 g·mL -1 The PtCl6⋅6H2O aqueous solution was obtained with a concentration of 0.6195×10 -2 g·mL -1 Ni(NO3)2 ⋅6H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80℃ until it is dry, and then continue to dry the sample in a 100℃ oven for 12h. Grind the dried sample into a fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400℃ and a calcination time of 3h to obtain the prepared catalyst. The catalyst is named 5Pt5Ni / C.

[0047] Experimental evaluation of high-pressure reactor: 0.15g of calcined 5Pt5Ni / C catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor. The air in the reactor was replaced with H2 4 times, and the pressure was increased to 3MPa. The reactor was sealed. Mechanical stirring (600rpm) was turned on, and the reactor was heated to 180°C in 50min, and the timing reaction was started. The reaction time was 10h. The yield of 2,5-dimethylfuran was 23.8%. The reaction conditions and results are shown in Table 1.

[0048] Table 1

[0049]

[0050] Reactants: fructose 0.3g; catalyst 0.15g; solvent: 1,4-dioxane 22.5mL + deionized water 2.5mL; reaction temperature: 180℃; H2 pressure: 3MPa; reaction time: 10h; stirring speed: 600rpm. The above data show that the effect of hydrogenation catalyst alone is not ideal and it is easy to produce mannitol, a direct hydrogenation product of fructose, so a deoxygenation catalyst is added for further optimization.

[0051] Example 5

[0052] Catalyst preparation: Grind the washed and dried vinasse into vinasse powder in a pulverizer; prepare a sulfuric acid solution of a certain concentration. Weigh a certain mass of vinasse powder and mix it evenly with the sulfuric acid solution, stir it at room temperature for 1.5 hours, wash it with deionized water until the filtrate pH = 7, put it in an oven at 80℃ and dry it for 12 hours, take it out after drying, and grind it into powder in a mortar to obtain the catalyst C-SO3H. Stir commercial activated carbon in a 6mol / L nitric acid solution at 80℃ for 4 hours, wash it with deionized water until the filtrate pH = 7; put it in an oven at 80℃ and dry it for 12 hours, calcine it in a nitrogen muffle furnace with nitrogen, the calcination temperature is 400℃, the calcination time is 3 hours, and grind it into powder in a mortar. Weigh a certain mass of PtCl6⋅6H2O and dissolve it in deionized water, where the mass of PtCl6⋅6H2O is 0.1351g and the volume of deionized water is 20mL, and the concentration is 0.6755×10 -2 g·mL -1 PtCl6⋅6H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80°C until it is dry, and then continue to dry the sample in a 100°C oven for 12 hours. Grind the dried sample into a fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400°C and a calcination time of 3 hours to obtain the prepared catalyst. The catalyst is named 5Pt / C, and the TEM image is as follows Figure 2As shown in the TEM image, it can be seen that Pt is uniformly dispersed on the support.

[0053] Experimental evaluation of high-pressure reactor: 0.1g of calcined 5Pt / C catalyst, 0.05g of C-SO3H catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor, and the air in the reactor was replaced with H2 4 times, and the pressure was increased to 3MPa, and the reactor was sealed. The mechanical stirring (600rpm) was turned on, and the reactor was heated to 160°C in 45min, and the timing reaction was started. The reaction time was 10h. The yield of 2,5-dimethylfuran was 22.3%. The reaction conditions and results are shown in Table 2.

[0054] Example 6

[0055] Catalyst preparation: Wash and dry the vinasse and grind it into vinasse powder in a pulverizer; prepare a sulfuric acid solution of a certain concentration. Weigh a certain mass of vinasse powder and mix it evenly with the sulfuric acid solution, stir it at room temperature for 1.5 hours, wash it with deionized water until the filtrate pH = 7, put it in an oven at 80℃ and dry it for 12 hours. After drying, take it out and grind it into powder in a mortar to obtain the catalyst C-SO3H. Stir commercial activated carbon in a 6mol / L nitric acid solution at 80℃ for 4 hours, wash it with deionized water until the filtrate pH = 7; put it in an oven at 80℃ and dry it for 12 hours, and calcine it in a nitrogen muffle furnace with nitrogen gas. The calcination temperature is 400℃ and the calcination time is 3 hours, and then grind it into powder in a mortar. Weigh a certain amount of PtCl6⋅6H2O and dissolve it in deionized water, where the mass of PtCl6⋅6H2O is 0.1351g, the mass of Fe(NO3)2⋅9H2O is 0.3617g, and the volume of deionized water is 20mL, to obtain a concentration of 0.6755×10 -2 g·mL -1 PtCl6⋅6H2O aqueous solution, the concentration is 1.8085×10 -2 g·mL -1 Fe(NO3)2 ⋅9H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80℃ until it is dry, and then continue to dry the sample in a 100℃ oven for 12h. Grind the dried sample into fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400℃ and a calcination time of 3h to obtain the prepared catalyst. The catalyst is named 5Pt5Fe / C.

[0056] Experimental evaluation of high-pressure reactor: 0.1g of calcined 5Pt5Fe / C catalyst, 0.05g of C-SO3H catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor, and the air in the reactor was replaced with H2 4 times, and the pressure was increased to 3MPa, and the reactor was sealed. The mechanical stirring was turned on (600rpm), and the reactor was heated to 160°C in 45min, and the timing reaction was started. The reaction time was 10h. The yield of 2,5-dimethylfuran was 45.8%. The reaction conditions and results are shown in Table 2.

[0057] Example 7

[0058] Catalyst preparation: Grind the washed and dried vinasse into vinasse powder in a pulverizer; prepare a sulfuric acid solution of a certain concentration. Weigh a certain mass of vinasse powder and mix it evenly with the sulfuric acid solution, stir it at room temperature for 1.5 hours, wash it with deionized water until the filtrate pH = 7, dry it in an oven at 80°C for 12 hours, take it out after drying, and grind it into powder in a mortar to obtain the catalyst C-SO3H. Stir commercial activated carbon in a 6 mol / L nitric acid solution at 80°C for 4 hours, wash it with deionized water until the filtrate pH = 7; dry it in an oven at 80°C for 12 hours, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400°C for 3 hours, and grind it into powder in a mortar. Weigh a certain mass of PtCl6⋅6H2O, H 24 Mo7N6O 24 ⋅24H2O is dissolved in deionized water, where the mass of PtCl6⋅6H2O is 0.1351g, H 24 Mo7N6O 24 The mass of ⋅24H2O is 0.0919 g, the volume of deionized water is 20 mL, and the concentration is 0.6755×10 -2 g·mL -1 The PtCl6⋅6H2O aqueous solution was obtained with a concentration of 0.4595×10 -2 g·mL -1 H 24 Mo7N6O 24 ⋅24H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80℃ until it is dry, and then continue to dry the sample in a 100℃ oven for 12h. Grind the dried sample into fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400℃ and a calcination time of 3h to obtain the prepared catalyst. The catalyst is named 5Pt5Mo / C.

[0059] Experimental evaluation of high-pressure reactor: 0.1g of calcined 5Pt5Mo / C catalyst, 0.05g of C-SO3H catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor, and the air in the reactor was replaced with H2 for 4 times, and the pressure was increased to 3MPa, and the reactor was sealed. The mechanical stirring was turned on (600rpm), and the reactor was heated to 160°C in 45min, and the timing reaction was started. The reaction time was 10h. The yield of 2,5-dimethylfuran was 31.6%. The reaction conditions and results are shown in Table 2.

[0060] Example 8

[0061] Catalyst preparation: Wash and dry the vinasse and grind it into vinasse powder in a pulverizer; prepare a sulfuric acid solution of a certain concentration. Weigh a certain mass of vinasse powder and mix it evenly with the sulfuric acid solution, stir it at room temperature for 1.5 hours, wash it with deionized water until the filtrate pH = 7, put it in an oven at 80℃ and dry it for 12 hours. After drying, take it out and grind it into powder in a mortar to obtain the catalyst C-SO3H. Stir commercial activated carbon in a 6mol / L nitric acid solution at 80℃ for 4 hours, wash it with deionized water until the filtrate pH = 7; put it in an oven at 80℃ and dry it for 12 hours, and calcine it in a nitrogen muffle furnace with nitrogen gas. The calcination temperature is 400℃ and the calcination time is 3 hours, and then grind it into powder in a mortar. Weigh a certain mass of PtCl6⋅6H2O and Co(NO3)2⋅6H2O and dissolve them in deionized water, where the mass of PtCl6⋅6H2O is 0.1351g, the mass of Co(NO3)2⋅6H2O is 0.1235g, and the volume of deionized water is 20mL. The concentration is 0.6755×10 -2 g·mL -1 The PtCl6⋅6H2O aqueous solution was obtained with a concentration of 0.6175×10 -2 g·mL -1 Co(NO3)2 ⋅6H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80℃ until it is dry, and then continue to dry the sample in a 100℃ oven for 12h. Grind the dried sample into a fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400℃ and a calcination time of 3h to obtain the prepared catalyst. The catalyst is named 5Pt5Co / C.

[0062] Experimental evaluation of high-pressure reactor: 0.1g of calcined 5Pt5Co / C catalyst, 0.05g of C-SO3H catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor, and the air in the reactor was replaced with H2 for 4 times, and the pressure was increased to 3MPa, and the reactor was sealed. The mechanical stirring was turned on (600rpm), and the reactor was heated to 160°C in 45min, and the timing reaction was started. The reaction time was 10h. The yield of 2,5-dimethylfuran was 37.5%. The reaction conditions and results are shown in Table 2.

[0063] Example 9

[0064] Catalyst preparation: Wash and dry the vinasse and grind it into vinasse powder in a pulverizer; prepare a sulfuric acid solution of a certain concentration. Weigh a certain mass of vinasse powder and mix it evenly with the sulfuric acid solution, stir it at room temperature for 1.5 hours, wash it with deionized water until the filtrate pH = 7, put it in an oven at 80℃ and dry it for 12 hours. After drying, take it out and grind it into powder in a mortar to obtain the catalyst C-SO3H. Stir commercial activated carbon in a 6mol / L nitric acid solution at 80℃ for 4 hours, wash it with deionized water until the filtrate pH = 7; put it in an oven at 80℃ and dry it for 12 hours, and calcine it in a nitrogen muffle furnace with nitrogen gas. The calcination temperature is 400℃ and the calcination time is 3 hours, and then grind it into powder in a mortar. Weigh a certain mass of PtCl6⋅6H2O and Ni(NO3)2⋅6H2O and dissolve them in deionized water. The mass of PtCl6⋅6H2O is 0.1351 g, the mass of Ni (NO3)2⋅6H2O is 0.1239 g, and the volume of deionized water is 20 mL. The concentration is 0.6755×10 -2 g·mL -1 The PtCl6⋅6H2O aqueous solution was obtained with a concentration of 0.6195×10 -2 g·mL -1 Ni(NO3)2 ⋅6H2O aqueous solution. Stir the metal solution with a glass rod until it is fully dissolved, weigh 1g of activated carbon powder and add it to the metal salt solution, stir it in a magnetic stirrer at 80℃ until it is dry, and then continue to dry the sample in a 100℃ oven for 12h. Grind the dried sample into a fine powder with a mortar, and calcine it in a nitrogen muffle furnace with nitrogen at a calcination temperature of 400℃ and a calcination time of 3h to obtain the prepared catalyst. The catalyst is named 5Pt5Ni / C.

[0065] Experimental evaluation of high-pressure reactor: 0.1g of calcined 5Pt5Ni / C catalyst, 0.05g of C-SO3H catalyst, 0.3g of fructose, 22.5mL of 1,4-dioxane, and 2.5mL of deionized water were placed in a 50mL high-pressure reactor, and the air in the reactor was replaced with H2 4 times, and the pressure was increased to 3MPa, and the reactor was sealed. The mechanical stirring (600rpm) was turned on, and the reactor was heated to 160°C in 45min, and the timing reaction was started. The reaction time was 10h. The yield of 2,5-dimethylfuran was 31.1%. The reaction conditions and results are shown in Table 2.

[0066] Table 2

[0067]

[0068] Reactants: fructose 0.3g; catalyst 0.1g + C-SO3H (0.05g); solvent: 1,4-dioxane 22.5mL + deionized water 2.5mL; reaction temperature: 160℃; H2 pressure: 3MPa; reaction time: 10h; stirring speed: 600rpm. The reaction results of Examples 5-9 show that after adding the deoxygenation catalyst, the yield of 2,5-dimethylfuran increased significantly and the fructose direct hydrogenation product mannitol decreased, and the 5Pt5Fe / C catalyst had the best effect. At the same time, the reaction results of the 5Pt / C catalyst and other bimetallic hydrogenation catalysts were compared, indicating that the acidic bimetallic catalyst can promote the occurrence of the deoxygenation reaction and promote the further reaction of the intermediate product, thereby obtaining more 2,5-dimethylfuran.

[0069] Examples 10-13

[0070] Catalyst preparation: The catalyst 5Pt5Fe / C and C-SO3H obtained in Example 6 were used to carry out fructose hydrodeoxygenation reaction at different catalyst ratios.

[0071] Experimental evaluation of high-pressure reactor: Take different masses of 5Pt5Fe / C catalyst and C-SO3H catalyst, 0.3g fructose, 22.5mL 1,4-dioxane, and 2.5mL deionized water into a 50mL high-pressure reactor, replace the air in the reactor with N2 4 times, pressurize to 1MPa, and seal the reactor. Turn on the mechanical stirring (600rpm), heat the reactor to 160℃ in 45min, start the deoxygenation reaction, and the deoxygenation reaction time is 2h. After the deoxygenation reaction is completed, wait for the reactor to cool to room temperature, fill the reactor with H2 to a pressure of 4MPa, heat the reactor to 180℃ in 50min, start the hydrogenation reaction, and the hydrogenation reaction time is 10h. The reaction conditions and results are shown in Table 3.

[0072] Table 3

[0073]

[0074] Reactants: fructose 0.3g; solvent: 1,4-dioxane 22.5mL + deionized water 2.5mL; deoxygenation reaction: temperature: 160℃; N2 pressure: 1MPa; reaction time: 2h; hydrogenation reaction: temperature: 180℃; H2 pressure: 3MPa; reaction time: 10h; stirring speed: 600rpm.

[0075] Examples 14-26

[0076] Catalyst preparation: The catalyst 5Pt5Fe / C obtained in Example 6 and C-SO3H were used to carry out fructose hydrodeoxygenation reaction with different reaction times, different reaction temperatures and different fructose qualities, and the high-pressure reactor experiment was similar to that described in Examples 10-13. The reaction results are shown in Table 4:

[0077] Table 4

[0078]

[0079] Reactant: fructose; solvent: 1,4-dioxane 22.5 mL + deionized water, 2.5 mL; deoxygenation reaction: N2 pressure: 1 MPa; reaction time: 2 h; hydrogenation reaction: H2 pressure: 3 MPa; stirring speed: 600 rpm.

[0080] Examples 14-16 are reactions at different deoxygenation temperatures. The results show that the reaction is incomplete when the deoxygenation reaction temperature is low, but the reaction is prone to coking when the temperature is high, which will lead to a decrease in the yield of 2,5-dimethylfuran. Therefore, the deoxygenation reaction temperature is 160 degrees. Examples 17-19 are reactions at different hydrogenation temperatures. The results show that when the hydrogenation reaction temperature is low, more intermediate products such as 5-hydroxymethylfurfural and 5-methylfurfuryl alcohol are generated and the reaction is incomplete; when the hydrogenation reaction temperature is high, an over-hydrogenation product 2,5-dimethyltetrahydrofuran is produced. According to the reaction results, the hydrogenation reaction temperature is 180 degrees. Examples 20-23 are reactions at different hydrogenation reaction times. The results show that the yield is best at 10h, the shorter the reaction time, the more intermediate products, and the longer the reaction time, the further over-hydrogenation products are generated. Examples 24-26 are reactions with different substrate masses. The results show that good yields are obtained at 0.15g and 0.3g substrates, but when the mass rises to 0.4 and 0.5g, the excess fructose is easy to aggregate and coke, resulting in a decrease in yield. To this end, the preferred reaction conditions finally selected were: 0.3 g fructose, 0.1 g deoxygenation catalyst + 0.1 g 5Pt5Fe / C, deoxygenation reaction: 160 °C for 2 h under N2 pressure 1 MPa, hydrogenation reaction: 180 °C for 10 h under H2 pressure 3 MPa to obtain 56.4% 2,5-dimethylfuran.

Claims

1. A method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose, characterized in that: The catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose comprises a deoxygenation catalyst and a hydrogenation catalyst; The preparation method of the deoxygenation catalyst comprises: grinding the dried vinasse to obtain vinasse powder; adding the vinasse powder to a sulfuric acid solution, stirring it fully, and washing it with deionized water until the pH value of the filtrate is neutral; drying and grinding the washed vinasse powder to obtain a deoxygenation catalyst; The preparation method of the hydrogenation catalyst comprises: adding activated carbon to a nitric acid solution, stirring it fully, and then washing it with deionized water until the pH value of the filtrate is neutral; drying and grinding the washed activated carbon, and calcining it in a nitrogen muffle furnace to obtain an activated carbon precursor; adding the activated carbon precursor to a metal salt solution and stirring it fully, then placing it in a magnetic stirrer, stirring it under high temperature conditions until it is dry, and continuing to dry it to obtain activated carbon impregnated with a metal salt; grinding the activated carbon impregnated with a metal salt into powder, and calcining it in a nitrogen muffle furnace to obtain a hydrogenation catalyst.

2. The method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose according to claim 1, characterized in that: The mass ratio of the deoxygenation catalyst to the hydrogenation catalyst is 0~3:1~3.

3. The method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose according to claim 1, characterized in that: The supported metal of the hydrogenation catalyst is one or two of Pt, Ni, W, Fe, Cu, Mo and Co.

4. The method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose according to claim 1, characterized in that: The concentration of the metal salt solution is calculated based on the mass of metal ions and is 1-5% of the total mass of the activated carbon precursor.

5. The method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose according to claim 1, characterized in that: Add activated carbon to the nitric acid solution and stir at 70-90°C on a magnetic stirrer for 3-5 hours.

6. The method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose according to claim 1, characterized in that: The calcination temperature in a muffle furnace with nitrogen is 350~450℃, and the calcination time is 2~4h.

7. The method for preparing a catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose according to claim 1, characterized in that: The stirring to dryness under high temperature conditions comprises: adding the activated carbon precursor to the metal salt solution, stirring it fully with a glass rod, placing it in a magnetic stirrer, and drying it at 70-90° C. During the drying process, stirring it with a glass rod regularly until it is dry.

8. A catalyst for preparing 2,5-dimethylfuran by hydrodeoxygenation of fructose, characterized in that: Prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the catalyst according to claim 8 in the preparation of 2,5-dimethylfuran, characterized in that: Biomass fructose is used as a raw material, the catalyst described in claim 7 is added, and a deoxygenation reaction is carried out in a high-pressure reactor filled with nitrogen. After the deoxygenation reaction is completed, hydrogen is filled into the high-pressure reactor, and 2,5-dimethylfuran is obtained after the dehydrogenation reaction is completed.

10. The use according to claim 9, characterized in that: The deoxygenation reaction temperature is 140~180℃, the deoxygenation reaction time is 1~3h, and the nitrogen pressure is 0.5~2MPa; the hydrogenation reaction temperature is 160~220℃, the hydrogenation reaction time is 4-12h, and the hydrogen pressure is 0.5-5.0MPa.

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