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CN-122006779-A - Composite catalyst for preparing furan by using furfural and preparation method thereof

CN122006779ACN 122006779 ACN122006779 ACN 122006779ACN-122006779-A

Abstract

The application relates to the technical field of catalysts, in particular to a composite catalyst for preparing furan by using furfural and a preparation method thereof. The preparation method comprises the following steps of 1) uniformly mixing chitosan and glacial acetic acid in water, then adding soluble nickel salt, soluble cerium salt and soluble ruthenium salt, carrying out a mixing reaction, 2) dropwise adding a phytic acid solution into a system obtained after the mixing reaction in the step 1), uniformly mixing, then adjusting the pH value to be 6.2-6.7, standing and aging to obtain hydrogel, 3) freezing the hydrogel obtained in the step 2) by liquid nitrogen, then freeze-drying to obtain aerogel, and 4) carrying out heat preservation on the aerogel obtained in the step 3) for 2.5-3.5h at 420-460 ℃ under a protective atmosphere, and then carrying out heat preservation on the aerogel for 3-5h at 530-580 ℃ under a hydrogen-containing atmosphere. The catalyst prepared by the application has good catalytic performance and strong stability, and the purity of the prepared furan is higher.

Inventors

  • LIU LIQIANG
  • ZHANG AN
  • LIU HUI
  • GU FENGQIANG
  • WANG BING
  • YANG HUA

Assignees

  • 陕西蒲城万德科技有限公司

Dates

Publication Date
20260512
Application Date
20260408

Claims (9)

  1. 1. The preparation method of the composite catalyst for preparing furan by using furfural is characterized by comprising the following steps: 1) Uniformly mixing chitosan and glacial acetic acid in water, and then adding soluble nickel salt, soluble cerium salt and soluble ruthenium salt for mixing reaction; 2) Dropwise adding a phytic acid solution into the system after the mixed reaction in the step 1), uniformly mixing, then adopting a potassium hydroxide solution to adjust the pH to 6.2-6.7, standing and aging to obtain hydrogel; 3) Freezing the hydrogel obtained in the step 2) by liquid nitrogen, and then freeze-drying to obtain aerogel; 4) And (3) preserving the heat of the aerogel obtained in the step (3) for 2.5-3.5 hours at 420-460 ℃ under the protective atmosphere, and then preserving the heat of the aerogel for 3-5 hours at 530-580 ℃ under the hydrogen-containing atmosphere.
  2. 2. The method for preparing the composite catalyst for preparing furan by utilizing furfural according to claim 1, wherein the mass ratio of chitosan to glacial acetic acid in the step 1) is 4-5:1.5-2.5.
  3. 3. The method for preparing a composite catalyst for preparing furan by utilizing furfural according to claim 1, wherein the soluble ruthenium salt in the step 1) is any one of ruthenium nitrate, ruthenium chloride and ruthenium acetate.
  4. 4. The method for preparing a composite catalyst for furan production using furfural as claimed in claim 3, wherein the soluble ruthenium salt in step 1) is ruthenium chloride trihydrate.
  5. 5. The method for preparing the composite catalyst for preparing furan by utilizing furfural according to claim 1, wherein the mass ratio of the soluble nickel salt to the soluble cerium salt in the step 1) is 7-18:3-9.
  6. 6. The method for preparing a composite catalyst for preparing furan by utilizing furfural according to claim 5, wherein the mass ratio of the soluble nickel salt to the soluble ruthenium salt in the step 1) is 7-18:0.02-0.08.
  7. 7. The method for preparing a composite catalyst for furan production by furfural according to claim 1, wherein the mass fraction of the phytic acid solution in step 2) is 40% -60%.
  8. 8. The method for preparing the composite catalyst for preparing furan by utilizing furfural according to claim 1, wherein the hydrogen-containing atmosphere in the step 4) is a mixed gas atmosphere of hydrogen and argon, and the volume ratio of the hydrogen to the argon is 1-2:8-9.
  9. 9. A composite catalyst for preparing furan by using furfural, which is prepared by the preparation method according to any one of claims 1 to 7.

Description

Composite catalyst for preparing furan by using furfural and preparation method thereof Technical Field The application relates to the technical field of catalysts, in particular to a composite catalyst for preparing furan by using furfural and a preparation method thereof. Background Furfural is used as a biomass-derived platform compound with great potential, and the catalytic decarbonylation of the furfural is used for preparing furan, which has important application in the aspect of converting agricultural wastes into high-added-value fine chemical products (such as polytetrahydrofuran, medical intermediates and the like). Furan is very demanded in the global market and is increasing every year, but existing gas phase decarbonylation processes are generally faced with the problem of short catalyst life in continuous operation. This can directly lead to forced shut down of the production line due to catalyst conversion and selectivity drop, which severely affects production continuity, resulting in serious equipment depreciation and energy loss. At present, the gas-phase decarbonylation of furfural mainly depends on two types of catalysts, namely a noble metal catalyst such as palladium (Pd), which has high initial activity but extremely high cost and is sensitive to impurity poison, and a transition metal catalyst represented by nickel (Ni), which is usually alumina or phosphate as a carrier. The phosphate carrier has certain heat stability and adjustable acid-base property, so that the latter catalyst becomes the main direction for replacing noble metal routes. However, the existing phosphate-based nickel catalyst encounters a bottleneck in practical application that the furfural conversion rate is rapidly reduced after 50-100 hours of operation, and the catalyst is characterized in that the pressure drop of a catalyst bed is rapidly increased, the proportion of byproducts (such as methyl furan and polymers) in a reaction product is obviously increased, and the purity of the product is greatly reduced. The main reasons for the problems are that two mutually coupled microscopic mechanisms are out of control, namely carbon deposition is inactivated, the surface of a traditional phosphate carrier is rich in P-OH bonds, the Bronsted acid sites have extremely strong chemical adsorption capacity on electron-rich furan rings, so that furan and intermediate products undergo deep polymerization reaction on the surface of a catalyst to generate coated amorphous carbon, the other is active site sintering, and under the reaction temperature of 250-400 ℃ and the local exothermic polarization condition, the metal-carrier strong interaction between nickel nano particles formed by physical loading or simple coprecipitation and a phosphate substrate is insufficient, so that nickel atoms with higher surface energy undergo Oswald Ripening (Ostwald Ripening) to gradually aggregate into large particles, and the catalytic active area is rapidly lost. Therefore, development of a composite catalyst with a strong metal-carrier anchoring effect is needed, so that carbon deposition and sintering problems in the decarbonylation process of furfural are reduced, the catalytic performance of the catalyst is improved, and the purity of catalytic reaction products is improved. Disclosure of Invention In order to improve the performance of the catalyst and the purity of a catalytic reaction product, the application provides a composite catalyst for preparing furan from furfural and a preparation method thereof. In a first aspect, the preparation method of the composite catalyst for preparing furan by using furfural adopts the following technical scheme: A preparation method of a composite catalyst for preparing furan by using furfural comprises the following steps: 1) Uniformly mixing chitosan and glacial acetic acid in water, and then adding soluble nickel salt, soluble cerium salt and soluble ruthenium salt for mixing reaction; 2) Dropwise adding a phytic acid solution into the system after the mixed reaction in the step 1), uniformly mixing, then adopting a potassium hydroxide solution to adjust the pH to 6.2-6.7, standing and aging to obtain hydrogel; 3) Freezing the hydrogel obtained in the step 2) by liquid nitrogen, and then freeze-drying to obtain aerogel; 4) And (3) preserving the heat of the aerogel obtained in the step (3) for 2.5-3.5 hours at 420-460 ℃ under the protective atmosphere, and then preserving the heat of the aerogel for 3-5 hours at 530-580 ℃ under the hydrogen-containing atmosphere. According to the application, chitosan and phytic acid are introduced, the chitosan contains rich amino and hydroxyl, and the phytic acid contains six phosphoric acid groups, so that acid-base neutralization and multiple hydrogen bond crosslinking can be performed, and high-strength macromolecular hydrogel is formed. During gelation, nickel, cerium, potassium ions in the added salt can be uniformly locked in the molecular-level netw