Preparation method and application of humic acid-based carbon material loaded bimetallic catalyst

Abstract

The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method and application of a humic acid-based carbon material supported bimetallic catalyst. The catalyst is prepared from 0.1 weight percent to 10 weight percent of Pt, 0.4 weight percent to 10 weight percent of second metal (Fe, Ni, Co or Mo) and 80 weight percent to 99.5 weight percent of a humic acid-based carbon material carrier. The preparation method comprises the following steps: grinding humic acid and an accelerant, roasting at high temperature to obtain a humic acid-based carbon material, and loading the second metal (Fe, Ni, Co or Mo) and Pt on the surface of the humic acid-based carbon material by a step-by-step impregnation loading method. The catalyst can efficiently catalyze hydrogenation of 5-hydroxymethylfurfural (5-HMF) in a tetrahydrofuran solvent to prepare 2, 5-dimethylfuran (2, 5-DMF). The humic acid-based carbon material is used as a carrier, the catalyst is simple in preparation process, low in cost and high in catalytic activity, efficient conversion of the biomass-based platform compound 5-HMF can be achieved under mild reaction conditions, and the catalyst has remarkable industrial application value.

Description

Technical Field

[0001] The present invention belongs to the field of catalyst preparation, and particularly relates to a preparation method and application of a bimetallic catalyst supported on a humic acid-based carbon material, specifically to a preparation method of a bimetallic catalyst such as Pt-Mo, Co, Fe or Ni supported on a humic acid-based carbon material and its application in the hydrogenation of 5-HMF. Background Art

[0002] 5-Hydroxymethylfurfural (5-HMF) is an important biomass-based platform compound, which can be obtained from various biomass materials and is considered as a bridge connecting biomass resources and chemicals due to the versatility of its groups. Among its numerous derivatives, 2,5-dimethylfuran (2,5-DMF) is a high-quality new liquid fuel, and it can also be used to produce pharmaceutical intermediates, spices and p-xylene with important industrial application value. The catalytic hydrogenation of 5-HMF to 2,5-DMF involves multiple reaction processes such as the hydrogenation of aldehyde groups to the corresponding alcohols and the selective hydrogenolysis of alcohol hydroxyl groups.

[0003] The catalysts commonly used for the hydrogenation of 5-HMF to prepare 2,5-DMF are divided into non-precious metals and precious metals. Non-precious metal catalysts have the advantages of low price and wide source, but these catalysts have problems such as harsh reaction conditions and poor selectivity of target products. Precious metal catalysts have the advantages of high hydrogenation activity and good stability, but they have high costs and are prone to over-hydrogenation processes. In summary, the catalysts for catalytic hydrogenation of 5-HMF to prepare 2,5-DMF in the prior art have problems such as poor selectivity of target products, harsh reaction conditions and high catalyst costs. Therefore, it is of great significance to develop a 5-HMF hydrogenation catalyst with low cost, high activity and high selectivity. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a preparation method and application of a bimetallic catalyst supported on a humic acid-based carbon material, which is used to solve the problems such as high preparation cost of 5-HMF hydrogenation catalyst, poor selectivity of 2,5-DMF and harsh reaction conditions in the prior art.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A bimetallic catalyst supported on a humic acid-based carbon material, characterized in that: the catalyst is composed of 0.1 wt% - 10 wt% of Pt, 0.4 wt% - 10 wt% of Co, Fe, Ni or Mo and 80 wt% - 99.5 wt% of a humic acid-based carbon material carrier.

[0007] A preparation method of a bimetallic catalyst supported on a humic acid-based carbon material:

[0008] 1) Grind and mix humic acid and accelerator as raw materials, and then heat them to 300-800°C in a tube furnace under inert gas protection for 2-10 hours to obtain a black solid. Then treat it at 500-1000°C for 1-5 hours under vacuum conditions, and cool it to obtain a humic acid-based carbon material for standby use;

[0009] 2) Take 0.2-1g of humic acid-based carbon material and disperse it in an aqueous solution containing 0.02-0.2g of Co, Fe, Ni or Mo precursor, add a certain amount of polyacrylamide, and stir for 1-24 hours; after drying, calcine the obtained solid in an inert gas atmosphere; the calcination temperature is 300-800°C, the insulation time is 1-8 hours, and after calcination, it is cooled to room temperature to obtain MOx / C (M represents Co, Fe, Ni or Mo).

[0010] 3) After adding H2PtCl6 aqueous solution to MOx / C and stirring for 0.1-0.5h, add 8-hydroxyquinoline acetone aqueous solution and stir for 0.5-2h, then put the solid-liquid mixture into a tube furnace and reduce it at 150-500℃ for 0.5-5h, cool it to room temperature and set it aside.

[0011] The humic acid source in step 1) is coal-based humic acid or plant-based humic acid.

[0012] The promoter in step 1) is calcium acetate, glucose or boric acid.

[0013] In step 1), the mass ratio of humic acid to accelerator is 1:0.1-1:5.

[0014] Step 2) The Co, Fe, Ni and Mo precursors are Co(NO3)2·6H2O, Fe(NO3)3·9H2O, Ni(NO3)2·6H2O and H24Mo7N6O24·4H2O.

[0015] Step 2) The mass ratio of the humic acid-based carbon material to the Co, Fe, Ni or Mo precursor is 5:1-15:1.

[0016] Step 2) The mass ratio of the polyacrylamide to the metal M (M = Co, Fe, Ni or Mo) is 0.5:1-10:1.

[0017] Step 3) The mass ratio of 8-hydroxyquinoline to metal Pt is 0.5:1-10:1.

[0018] A use of a humic acid-based carbon material-supported bimetallic catalyst: the catalyst is used to carry out a 5-HMF hydrogenation reaction in tetrahydrofuran to prepare a 2,5-DMF compound.

[0019] A method for preparing 2,5-DMF compound, adding 5-HMF, the supported catalyst, and tetrahydrofuran into a batch high-pressure reactor, sealing it and filling it with 2-5 MPa of hydrogen, reacting at 100-220 °C, after reacting for 3-15 hours, cooling to room temperature, filtering the reaction solution, and obtaining the 2,5-DMF compound; wherein, the dosage of the supported catalyst is 1%-100% of the weight of 5-HMF.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The bimetallic catalyst supported on the humic acid-based carbon material of the present invention is prepared by using chloroplatinic acid and salts of a second metal (Fe, Co, Mo or Ni) as metal precursor substances and the humic acid-based carbon material as a carrier through a simple step-by-step impregnation method. The catalyst preparation process is simple and the cost is low; the prepared catalyst has high activity and can efficiently catalyze the hydrogenation of 5-HMF to prepare 2,5-DMF under mild reaction conditions, having significant industrial application value. Specific embodiments

[0021] In order to more clearly illustrate the present invention, the present invention will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the specific content described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0022] As an aspect of the present invention, a preparation method of a bimetallic catalyst supported on a humic acid-based carbon material of the present invention includes the following steps:

[0023] 1) Preparation of humic acid-based carbon material Weigh 1-5 g of humic acid and 0.2-4 g of promoter, grind them evenly, place them in a tubular furnace, keep them at 300-800 °C for 2-10 h under a nitrogen atmosphere, cool down and wash and dry, and then put them into a vacuum tubular furnace for high-temperature treatment to obtain a humic acid-based carbon material carrier.

[0024] 2) Addition of Co, Fe, Mo or Ni metal Weigh 0.02-0.20 g of Co, Fe, Mo or Ni precursor, add deionized water and dissolve it by ultrasonic, slowly add 0.2-1 g of humic acid-based carbon carrier, then add polyacrylamide, stir for 1-24 h, dry it and calcine it at 300-800 °C for 1-8 h in a nitrogen atmosphere to obtain an MOx / C monometallic catalyst;

[0025] 3) Addition of Pt active metal After adding 0.5 - 5 mL of aqueous H2PtCl6 solution to MOx / C and stirring for 0.1 - 0.5 h, add an aqueous solution of 8 - hydroxyquinoline acetone and stir for 0.5 - 2 h. Then, place the solid - liquid mixture in a tubular furnace and reduce it at 150 - 500 °C for 0.5 - 5 h, and cool to obtain a bimetallic catalyst supported on a humic - acid - based carbon material.

[0026] In some embodiments, in step 1), the humic acid is selected from coal - based humic acid or plant - based humic acid; preferably, the humic acid is plant - based humic acid.

[0027] In some embodiments, in step 1), the promoter is calcium acetate, glucose or boric acid, preferably, the promoter is calcium acetate.

[0028] In some embodiments, in step 1), the mass ratio of the humic acid to the promoter is 1:0.1 - 1:5, preferably, the mass ratio of the humic acid to the promoter is 1:0.2 - 1:2.

[0029] In some preferred embodiments, in step 1), the heat - preservation temperature under vacuum conditions is 500 - 1000 °C, preferably, the heat - preservation temperature is 600 - 800 °C.

[0030] In some embodiments, in step 2), it is calcined at 300 - 800 °C for 1 - 8 h in a nitrogen atmosphere, preferably, the calcination time is 2 - 6 h.

[0031] In some embodiments, in step 2), the Co, Fe, Mo or Ni precursor is Co(NO3)2·6H2O, Fe(NO3)3·9H2O, H24Mo7N6O24·4H2O and Ni(NO3)2·6H2O.

[0032] In some embodiments, in step 3), the mass ratio of 8 - hydroxyquinoline to Pt metal is 0.5:1 - 10:1.

[0033] In some embodiments, in step 3), the mass ratio of polyacrylamide to metal M (M = Co, Fe, Ni or Mo) is 0.5:1 - 10:1.

[0034] As another aspect of the present invention, the present invention also provides an application of the bimetallic catalyst obtained by the above - mentioned preparation method in the hydrogenation of 5 - HMF to prepare 2,5 - DMF.

[0035] Example 1 Weigh 1 g of humic acid and 2 g of calcium acetate promoter, grind them evenly, place them in a tubular furnace, keep them at 450 °C for 4 h in a nitrogen atmosphere, cool down, wash and dry, then place them in a vacuum tubular furnace and treat them at 700 °C for 1 h, and cool to obtain a humic - acid - based carbon material. Weigh 0.04 g of Co(NO3)2·6H2O, ultrasonically dissolve it with deionized water. After slowly adding 0.5 g of the carrier, add polyacrylamide, stir for 5 h, dry at 120 °C for 2 h, and then calcine it in a nitrogen atmosphere at 550 °C for 4 h to obtain the CoOx / C single-metal catalyst. After adding an aqueous solution of H2PtCl6 with a concentration of 0.006 mol / L to CoOx / C and stirring for 10 min, add an aqueous solution of 8-hydroxyquinoline acetone, stir for 1 h, then put the solid-liquid mixture into a tubular furnace and reduce it with hydrogen at 300 °C for 1 h, and cool to obtain the Pt-Co-1 bimetallic catalyst supported on the humic acid-based carbon material. React the above catalyst under the conditions of 200 °C, 50 mL of tetrahydrofuran, 3.0 MPa H2, and a mass ratio of the catalyst to 5-HMF of 1:1.3 for 8 hours. The conversion rate of 5-HMF is 100%, and the selectivity of 2,5-DMF is 92.0%.

[0036] Example 2 Weigh 1 g of humic acid and 0.2 g of glucose promoter, grind them evenly, place them in a tubular furnace, keep them at 450 °C for 4 h in a nitrogen atmosphere, wash and dry after cooling, and then place them in a vacuum tubular furnace and treat them at 700 °C for 1 h, and cool to obtain the humic acid-based carbon material. Weigh 0.04 g of Co(NO3)2·6H2O, ultrasonically dissolve it with deionized water. After slowly adding 0.5 g of the carrier, add polyacrylamide, stir for 5 h, dry at 120 °C for 2 h, and then calcine it in a nitrogen atmosphere at 550 °C for 4 h to obtain the CoOx / C single-metal catalyst; After adding an aqueous solution of H2PtCl6 with a concentration of 0.006 mol / L to CoOx / C and stirring for 10 min, add an aqueous solution of 8-hydroxyquinoline acetone, stir for 1 h, then put the solid-liquid mixture into a tubular furnace and reduce it with hydrogen at 300 °C for 1 h, and cool to obtain the Pt-Co-2 bimetallic catalyst supported on the humic acid-based carbon material. React the above catalyst under the conditions of 200 °C, 50 mL of tetrahydrofuran, 3.0 MPa H2, and a mass ratio of the catalyst to 5-HMF of 1:1.3 for 8 hours. The conversion rate of 5-HMF is 100%, and the selectivity of 2,5-DMF is 85.2%.

[0037] Example 3 Weigh 1 g of humic acid and 0.2 g of boric acid promoter, grind them evenly, place them in a tubular furnace, keep them at 450 °C for 4 h in a nitrogen atmosphere, wash and dry after cooling, and then place them in a vacuum tubular furnace and treat them at 700 °C for 1 h, and cool to obtain the humic acid-based carbon material. Weigh 0.04 g of Co(NO3)2·6H2O, ultrasonically dissolve it with deionized water, slowly add it to 0.5 g of the carrier, then add polyacrylamide, stir for 5 h, dry at 120 °C for 2 h, and then calcine it in a nitrogen atmosphere at 550 °C for 4 h to obtain the CoOx / C single-metal catalyst. After adding an aqueous solution of H2PtCl6 with a concentration of 0.006 mol / L to CoOx / C and stirring for 10 min, add an aqueous solution of 8-hydroxyquinoline acetone, stir for 1 h, then place the solid-liquid mixture in a tube furnace and reduce it with hydrogen at 300 °C for 1 h, and cool to obtain the Pt-Co-3 bimetallic catalyst supported on the humic acid-based carbon material. React the above catalyst under the conditions of 200 °C, 50 mL of tetrahydrofuran, 3.0 MPa H2, and a mass ratio of the catalyst to 5-HMF of 1:1.3 for 8 hours. The conversion rate of 5-HMF is 100%, and the selectivity of 2,5-DMF is 82.0%.

[0038] Example 4 Weigh 1 g of humic acid and 2 g of calcium acetate promoter, grind them evenly, place them in a tube furnace, keep them at 450 °C for 4 h in a nitrogen atmosphere, cool down, wash and dry, and then place them in a vacuum tube furnace and treat them at 700 °C for 1 h, and cool to obtain the humic acid-based carbon material. Weigh 0.04 g of Co(NO3)2·6H2O, ultrasonically dissolve it with deionized water, slowly add 0.5 g of the carrier, then add polyacrylamide, stir for 5 h, dry at 120 °C for 2 h, and then calcine it in a nitrogen atmosphere at 550 °C for 4 h to obtain the CoOx / C single-metal catalyst. After adding an aqueous solution of H2PtCl6 with a concentration of 0.006 mol / L to CoOx / C and stirring for 10 min, add an aqueous solution of 8-hydroxyquinoline acetone, stir for 1 h, then place the solid-liquid mixture in a tube furnace and reduce it with hydrogen at 200 °C for 1 h, and cool to obtain the Pt-Co-4 bimetallic catalyst supported on the humic acid-based carbon material. React the above catalyst under the conditions of 200 °C, 50 mL of tetrahydrofuran, 3.0 MPa H2, and a mass ratio of the catalyst to 5-HMF of 1:1.3 for 8 hours. The conversion rate of 5-HMF is 100%, and the selectivity of 2,5-DMF is 87.5%.

[0039] Example 5 Weigh 1 g of humic acid and 2 g of calcium acetate promoter, grind them evenly, place them in a tube furnace, keep them at 450 °C for 4 h in a nitrogen atmosphere, cool down, wash and dry, and then place them in a vacuum tube furnace and treat them at 700 °C for 1 h, and cool to obtain the humic acid-based carbon material. Weigh 0.058 g of Fe(NO3)3·9H2O, dissolve it by ultrasonic treatment with deionized water. After slowly adding 0.5 g of the carrier, add polyacrylamide, stir for 5 h, dry at 120 °C for 2 h, and then calcine it in a nitrogen atmosphere at 550 °C for 4 h to obtain the FeOx / C monometallic catalyst. After adding an aqueous solution of H2PtCl6 with a concentration of 0.006 mol / L to FeOx / C and stirring for 10 min, add an aqueous solution of 8-hydroxyquinoline acetone, stir for 1 h, then place the solid-liquid mixture in a tube furnace and reduce it with hydrogen at 300 °C for 1 h, and cool to obtain the Pt-Fe-1 bimetallic catalyst supported on the humic acid-based carbon material. React the above catalyst under the conditions of 200 °C, 50 mL of tetrahydrofuran, 3.0 MPa H2, and a mass ratio of the catalyst to 5-HMF of 1:1.3 for 8 h. The conversion rate of 5-HMF is 100%, and the selectivity of 2,5-DMF is 88.3%.

[0040] Example 6 Weigh 1 g of humic acid and 2 g of calcium acetate promoter, grind them evenly, place them in a tube furnace, keep them at 450 °C for 4 h under a nitrogen atmosphere, cool down, wash and dry, and then place them in a vacuum tube furnace for treatment at 700 °C for 1 h, and cool to obtain the humic acid-based carbon material. Weigh 0.040 g of Ni(NO3)2·6H2O, dissolve it by ultrasonic treatment with deionized water. After slowly adding it to 0.5 g of the carrier, add polyacrylamide, stir for 5 h, dry at 120 °C for 2 h, and then calcine it in a nitrogen atmosphere at 550 °C for 4 h to obtain the NiOx / C monometallic catalyst. After adding an aqueous solution of H2PtCl6 with a concentration of 0.006 mol / L to NiOx / C and stirring for 10 min, add an aqueous solution of 8-hydroxyquinoline acetone, stir for 1 h, then place the solid-liquid mixture in a tube furnace and reduce it with hydrogen at 300 °C for 1 h, and cool to obtain the Pt-Ni-1 bimetallic catalyst supported on the humic acid-based carbon material. React the above catalyst under the conditions of 200 °C, 50 mL of tetrahydrofuran, 3.0 MPa H2, and a mass ratio of the catalyst to 5-HMF of 1:1.3 for 8 h. The conversion rate of 5-HMF is 100%, and the selectivity of 2,5-DMF is 81.4%.

[0041] Example 7 Weigh 1 g of humic acid and 2 g of calcium acetate promoter, grind them evenly, place them in a tube furnace, keep them at 450 °C for 4 h under a nitrogen atmosphere, cool down, wash and dry, and then place them in a vacuum tube furnace for treatment at 700 °C for 1 h, and cool to obtain the humic acid-based carbon material. Weigh 0.040 g of Co(NO3)2·6H2O, dissolve it by ultrasonic treatment with deionized water, slowly add it to 0.5 g of the support, then add polyacrylamide, stir for 5 h, dry it at 120 °C for 2 h, and then calcine it in a nitrogen atmosphere at 550 °C for 4 h to obtain the CoOx / C single-metal catalyst; After adding an aqueous solution of H2PtCl6 with a concentration of 0.01 mol / L to CoOx / C and stirring for 10 min, add an aqueous solution of 8-hydroxyquinoline acetone, stir for 1 h, then place the solid-liquid mixture in a tubular furnace and reduce it with hydrogen at 300 °C for 1 h, and cool to obtain the Pt-Co-5 bimetallic catalyst supported on the humic acid-based carbon material. React the above catalyst under the conditions of 200 °C, 50 mL of tetrahydrofuran, 3.0 MPa H2, and a mass ratio of the catalyst to 5-HMF of 1:1.3 for 8 hours. The conversion rate of 5-HMF is 100%, and the selectivity of 2,5-DMF is 90.1%.

[0042] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention. Table 1 Test results of catalysts prepared under different conditions

Claims

1. A bimetallic catalyst supported on a humic acid-based carbon material, characterized in that: The catalyst is composed of 0.1 wt% - 10 wt% of Pt, 0.4 wt% - 10 wt% of Co, Fe, Ni or Mo, and 80 wt% - 99.5 wt% of a humic acid-based carbon material support.

2. The preparation method of the bimetallic catalyst supported on the humic acid-based carbon material according to claim 1, wherein: 1) Using humic acid and a promoter as raw materials, grind and mix them thoroughly and evenly, then heat them in a tubular furnace under the protection of an inert gas to 300 - 800 °C, keep the temperature for 2 - 10 hours to obtain a black solid, and then treat it at 500 - 1000 °C under vacuum conditions for 1 - 5 hours. After cooling, a humic acid-based carbon material is obtained for use. 2) Take 0.2 - 1 g of the humic acid-based carbon material and disperse it in an aqueous solution containing 0.02 - 0.2 g of a Co, Fe, Ni or Mo precursor. Add a certain amount of polyacrylamide and stir for 1 - 24 hours; after drying, calcine the obtained solid in an inert gas atmosphere; the calcination temperature is 300 - 800 °C, and the heat preservation time is 1 - 8 hours. After calcination, cool it to room temperature to obtain MOx / C (M represents Co, Fe, Ni or Mo). 3) Add an aqueous solution of H2PtCl6 to MOx / C and stir for 0.1 - 0.5 h, then add an aqueous solution of 8-hydroxyquinoline acetone and stir for 0.5 - 2 h. Then put the solid-liquid mixture into a tubular furnace and reduce it with hydrogen at 150 - 500 °C for 0.5 - 5 h. After cooling to room temperature, it is for use.

3. The preparation method of the humic acid-based carbon material supported bimetallic catalyst according to claim 2, characterized in that: The source of the humic acid is coal-based humic acid or plant-based humic acid.

4. The preparation method of the humic acid-based carbon material supported bimetallic catalyst according to claim 2, wherein: The promoter is calcium acetate or glucose or boric acid.

5. The preparation method of the bimetallic catalyst supported on the humic acid-based carbon material according to claim 2, wherein: The Co, Fe, Ni and Mo precursors are Co(NO3)2·6H2O, Fe(NO3)3·9H2O, Ni(NO3)2·6H2O and H24Mo7N6O24·4H2O.

6. The preparation method of the humic acid-based carbon material supported bimetallic catalyst according to claim 2, characterized in that: The mass ratio of humic acid to the promoter is 1:0.1 - 1:

5.

7. The preparation method of the humic acid-based carbon material supported bimetallic catalyst according to claim 2, characterized in that: In the step 2), the mass ratio of the humic acid-based carbon material to the Co, Fe, Ni or Mo precursor is 5:1 - 15:1; the mass ratio of polyacrylamide to metal M (M = Co, Fe, Ni or Mo) is 0.5:1 - 10:

1.

8. The preparation method of the bimetallic catalyst supported on the humic acid-based carbon material according to claim 2, wherein: In the step 3), the mass ratio of 8-hydroxyquinoline to metal Pt is 0.5:1 - 10:

1.

9. Use of the humic acid-based carbon material supported bimetallic catalyst according to claim 1, characterized in that: The catalyst is used for the 5-HMF hydrogenation reaction in tetrahydrofuran to prepare 2,5-DMF compounds.

10. A method for preparing 2,5-DMF compound, characterized in that: Add 5-HMF, the supported catalyst, and tetrahydrofuran into a reactor. After sealing, fill it with 2 - 7 MPa of hydrogen and react at 100 - 240 °C. After reacting for 3 - 15 hours, cool it to room temperature and filter the reaction solution to obtain 2,5-DMF compounds; wherein, the dosage of the supported catalyst is 1% - 100% of the weight of 5-HMF.

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