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CN-122006696-A - Phosphorus-tungsten/molybdenum synergistic modified supported catalyst and preparation method and application thereof

CN122006696ACN 122006696 ACN122006696 ACN 122006696ACN-122006696-A

Abstract

The invention discloses a phosphorus-tungsten/molybdenum synergistic modified supported catalyst and a preparation method and application thereof, and belongs to the technical field of catalysis. The catalyst takes gamma-Al 2 O 3 as a carrier and takes transition metal oxide and/or phosphide as an active component. Is prepared by precursor impregnation, drying at 80-120 ℃ and calcining at 300-500 ℃, and utilizes the synergistic effect of phosphorus, tungsten and molybdenum to not only increase acid sites but also enhance acid strength and inhibit active component agglomeration. The catalyst provided by the invention has excellent catalytic performance, has higher reaction activity under the pressure of 0.5Mpa, is far lower than the pressure provided in the prior art, and has the characteristics of high target product yield, good catalyst stability, simple preparation process and low production cost.

Inventors

  • CHAI YONGMING
  • LI XUQIANG
  • YU YINGMIN
  • LIU BIN
  • SUN YAWEI
  • WANG NANNAN
  • ZHENG SIYU
  • TIAN FENGYU
  • DONG BIN

Assignees

  • 中国石油大学(华东)

Dates

Publication Date
20260512
Application Date
20260109

Claims (10)

  1. 1. A supported catalyst with synergistic modification of phosphorus, tungsten and molybdenum is characterized by comprising a carrier and an active component, wherein the active component comprises transition metal oxide and/or phosphide, the carrier is gamma-Al 2 O 3 , and the active component accounts for 1-36% of the total mass of the catalyst.
  2. 2. The phosphotungstic/molybdenum co-modified supported catalyst of claim 1, wherein the transition metal oxide is WO 3 or MoO 3 , and when the transition metal oxide is WO 3 , WO 3 is 4% -36% by weight of the support, and when the transition metal oxide is MoO 3 , moO 3 is 1% -12% by weight of the support.
  3. 3. The supported catalyst of claim 2, wherein the phosphide is phosphate, and the phosphate accounts for 1% -5% of the mass of the carrier in terms of phosphorus element.
  4. 4. The supported catalyst for synergistic modification of phosphorus and tungsten/molybdenum according to claim 3, wherein the mass ratio of tungsten element to phosphorus element in the active component is 1:0.5-1:4.
  5. 5. A method for preparing the phosphotungstic/molybdenum synergic modified supported catalyst according to any one of claims 1-4, comprising the following steps: step one, dissolving an active component precursor in a solvent to prepare an impregnating solution; And secondly, contacting the carrier with impregnating solution for impregnation, and drying and calcining to obtain the catalyst.
  6. 6. The preparation method of the phosphotungstic/molybdenum synergic modified supported catalyst according to claim 5, wherein in step two, the mass ratio of the active component in the impregnating solution to the carrier is 1:40-100, the carrier is impregnated at least once in the impregnating solution, and the impregnation and calcination processes are repeated 1-10 times.
  7. 7. The method for preparing the supported catalyst with the synergistic modification of phosphorus and tungsten and molybdenum according to claim 5, wherein in the second step, the impregnation temperature is normal temperature, the impregnation time is 1-24 hours, the drying temperature is 80-120 ℃, the drying time is 1-12 hours, the calcination temperature is 300-500 ℃, and the calcination time is 1-12 hours.
  8. 8. A process for preparing aniline by amination of phenol is characterized in that a raw material containing phenol is mixed with ammonia gas and is contacted and reacted with a phosphotungstic/molybdenum synergistic modified supported catalyst according to any one of claims 1-4 or a catalyst prepared by a method according to any one of claims 5-7 under a reaction condition to obtain aniline, wherein the reaction condition comprises a reaction temperature of 320-400 ℃, a reaction pressure of 0.5MPa and a liquid hourly space velocity of 0.6h -1 .
  9. 9. The process for preparing aniline by direct amination of phenol according to claim 8, wherein the raw material containing phenol is a mixed solution of phenol and a solvent, the solvent is at least one selected from toluene, methylnaphthalene, paraxylene and metaxylene, and the mass ratio of phenol to solvent is 1:1.5-1:19.
  10. 10. The process for preparing aniline by amination of phenol according to claim 8, wherein the molar ratio of phenol to ammonia is 1:5-1:20, the reaction pressure is 0.1-0.7 mpa, and the liquid hourly space velocity of the reaction is 0.6-6 h -1 .

Description

Phosphorus-tungsten/molybdenum synergistic modified supported catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of catalyst preparation, in particular to a phosphorus-tungsten/molybdenum synergistic modified supported catalyst, and a preparation method and application thereof. Background Aniline is one of aromatic amines and is widely used in polyurethane synthesis, rubber, medicine, dye and other fields. In addition, aniline can be used as a solvent and other chemical raw materials, and the application is very wide. However, the current main flow synthesis process of aniline still highly depends on benzene derived from fossil resources, and adopts a two-step method of benzene nitration-nitrobenzene hydrogenation reduction, wherein benzene is firstly taken as a raw material, nitration reaction is carried out under the action of a large amount of sulfuric acid and nitric acid to generate nitrobenzene, then the nitrobenzene is heated and vaporized and then mixed with excessive hydrogen, and hydrogenation reduction is carried out under the specific catalysis conditions at 260-285 ℃ to obtain aniline. The process has the obvious defects that on one hand, massive acid wastewater can be generated by using a large amount of strong acid, the nitrogen oxides released in the nitration process can cause serious air pollution and outstanding environmental protection pressure, and on the other hand, the reaction process is complex, the multi-step separation, dehydration and rectification procedures are involved, and the energy consumption and the production cost are high. In order to solve the problems of environmental protection and energy consumption of the traditional process, the direct amination method of phenol gradually becomes a research hot spot. According to the method, phenol is used as a raw material to replace benzene, aniline is generated by directly reacting with ammonia, the atomic utilization rate can reach 84%, the reaction byproducts are water only, the method is environment-friendly, the subsequent separation and purification process is simple, the hazard source and pollution problems caused by the nitration step are fundamentally eliminated, and the method has remarkable technical advantages. However, the existing phenol direct amination process and the matched catalyst still have technical bottlenecks to be broken through: The catalyst disclosed in the related patent (such as US 4987260) takes gamma-Al 2O3 with a specific aperture as a core, and can realize the phenol conversion rate of 99.8 percent, but the reaction pressure is required to be maintained at 1.5MPa, and the high-pressure condition has strict requirements on the pressure resistance of reaction equipment, so that the equipment investment cost is increased, the safety risk in industrial production is also improved, and the large-scale popularization of the process is limited. The catalyst is prepared by adopting fluoride to treat gamma-Al 2O3 in another patent-EP 0434771B1, and toxic substances are easily released by the fluoride in the high-temperature calcination process, so that the fluoride not only pollutes the environment, but also brings potential safety hazards to production operation, and meanwhile, the subsequent environmental protection cost of wastewater treatment and the like is increased. In addition, the catalyst is difficult to combine high conversion rate and high selectivity under low pressure conditions, and partial catalyst has the problems of agglomeration and low dispersity of active components, so that the active sites are underexposed, and the reaction efficiency is further affected. Disclosure of Invention Based on the prior research and the existing problems, the invention provides a phosphorus-tungsten/molybdenum synergic modified supported catalyst, a preparation method and application thereof after further research and analysis, and the catalyst modified by nonmetallic elements of phosphorus, transition metal molybdenum and tungsten can obviously improve the conversion rate of the reaction and simultaneously maintain higher selectivity of aniline. In order to achieve the above purpose, the present invention provides the following technical solutions: A supported catalyst with synergistic modification of phosphorus, tungsten and molybdenum comprises a carrier and an active component, wherein the active component comprises transition metal oxide and/or phosphide, the carrier is gamma-Al 2O3, and the active component accounts for 1-36% of the total mass of the catalyst. Preferably, the transition metal oxide is WO 3 or MoO 3, and when the transition metal oxide is WO 3, the weight of WO 3 accounts for 4-36% of the weight of the carrier, and when the transition metal oxide is MoO 3, the weight of MO 3 accounts for 1-12% of the weight of the carrier. Preferably, the phosphide is phosphate, and the phosphate accounts for 1% -5% of the mass of the