Dissertation > Excellent graduate degree dissertation topics show

Catalytic Hydrogention of2,3,5-Trimethylbenzoquinone Over Pd Nanoparticles Confined in the Cages of MIL-101(Cr)

Author: ZhaoXiaoMin
Tutor: ZhangFuMin
School: Zhejiang Normal University
Course: Physical and chemical
Keywords: metal-organic frameworks Pd/MIL-101(Cr) catalyst 2,3,5-trimethylbenzoquinone 2,3,5-trimethylhydroquinone catalytic hydrogenation
CLC: O643.32
Type: Master's thesis
Year: 2013
Downloads: 52
Quote: 0
Read: Download Dissertation

Abstract


Vitamin-E (VE) that has recently become a major concern is not only widely used in the pharmaceutical, health-product, food, and cosmetic industry but also used as an industrially most important antioxidant.2,3,5-Trimethylhydroquinone (TMHQ) TMHQ is an important intermediate for VE production. The quality of VE varies, depending on that of TMHQ as the starting chemical. Thus, from a product quality as well as an economic point of view, TMHQ is required to have a high purity. TMHQ can be synthesized via the hydrogenation of2,3,5-trimethylquinone (TMBQ). This method for TMHQ production has several merits such as high-quality product, low cost, and a high degree of automation. However, the catalysts used for the hydrogenation of TMBQ by some domestic companies currently have some characteristics as low activity and low stability, resulting in a high manufacturing cost.Metal-organic frameworks (MOFs) are porous crystalline hybrid organic-inorganic materials constructed by metal ions coordinated to multidentate organic ligands leading to three-dimensional extended networks having channels and cages. Besides the well demonstrated catalytic activity of pure MOFs, in the field of heterogeneous catalysis, these materials themselves are also effective candidates as catalyst supports due to their unique physicochemical properties. Indeed, MOFs have been used as host matrixes to accommodate noble metal catalysts, because their large surface area and narrow pore size distribution facilitate the dispersion of metallic nanoparticles, which is of great importance for improving catalytic activities. The main results are summarized as follows:A5.0wt.%Pd/C catalyst was prepared by impregnation using activated carbon as support and noble metal Pd as active component. The obtained catalyst was characterized by N2adsorption and TEM techniques. TMHQ, as an important intermediate for VE production, can be obtained by hydrogenation of TMBQ. The kinetics of catalytic hydrogenation of TMBQ to TMHQ was studied in the temperature ranging from313to353K over5.0wt.%Pd/C in a high-pressure batch reactor. The result shows that the order of reaction with respect to TMBQ is found to be first order, and the activation energy is47.7kJ·mol-1, when the internal and external diffusion limitations are excluded. By further verification, it is found that the predicted results by the kinetics equation are well agreement with the experimental data.A series of Pd@MIL-101(Cr) catalysts were prepared by incorporating Pd nanoparticles into the highly porous and hydrothermally stable metal-organic framework MIL-101(Cr) via an incipient-wetness impregnation method, and characterized by XRD, N2adsorption, CO chemisorption, XPS, TEM techniques as well as by the elemental analysis. These prepared catalysts were applied in the catalytic hydrogenation of2,3,5-trimethylbenzoquinone (TMBQ) to2,3,5-trimethylhydroquinone (TMHQ) in a high-pressure batch reactor. The results reveal that Pd nanoparticles mainly within a range of2-3nm in diameter were identified to be confined in the mesoporous cages of MIL-101(Cr) for2.0wt.%Pd/MIL-101(Cr) catalyst, which are stable and rule out the possibility of Pd agglomeration due to the fact that the cages can confine Pd nanoparticles and restrict their growth, leading to a high catalytic activity, selectivity, and excellent reusability without Pd leaching in the catalytic hydrogenation of TMBQ to TMHQ, much superior than activated carbon supported Pd catalysts.

Related Dissertations

  1. Study on Using Sepiolite As Supported Catalysts in Selective Hydrogenation of Cinnamaldehyde to Cinnamyl Alcohol,O643.32
  2. Preparation and Catalysis of Supported Nano-platinum Catalysts,O643.36
  3. Synthesis, Characterizations and Catalysis of Mesoporous Carbon Material Supported Metal Catalysts,O643.36
  4. Syntheses, Structures and Properties of Microporous Metal-Organic Frameworks,O641.4
  5. Study of Assembled PT-Fe Nano-Catalyst for the Selectivity Hydrogenation,TE624.93
  6. Metal-Organic Frameworks of Tetrazolyl Derivative Ligands: Syntheses, Structures, and Properties,O621.13
  7. Study on the Controlled Synthesis of Palladium Nanoparticles and Their Catalytic Properties,TB383.1
  8. Catalytic hydrogenation reaction of hydroquinone,TQ243.12
  9. Liquid Phase Hydrogenation of Halogenated Nitrobenzene over Amorphous Alloy Catalysts,O643.32
  10. Palladium-Chitosan Complex Supported on Molecular Sieve for Kinetic Study on Hydrogenation of Aromatic Aldehyde and Ketone,O643.12
  11. Molecular Simulation Study of Natural Gas Purification in Metal-Organic Frameworks and the Synthesis and Catalytic Properties of Cu-BTC,O643.36
  12. CO2 Adsorbents: Synthesis, Characterization, and Their Adsorption Properties,O647.33
  13. Polymer hollow microspheres synthesis and catalytic reaction,O643.36
  14. Study on the Synthesis of Solvent-Stabilized Palladium Nanoparticles and Their Catalytic Activity,TB383.1
  15. Synthesis and Catalytic Performance of Metal-Organic Framework Cu-MOF and ZIFs,O643.36
  16. Ru Nanoparticles Entrapped in Mesopolymers for Efficient Catalytic Hydrogenation,O643.36
  17. Preparation of Noble Metal Colloids and Their Catalytic Properties for Hydrogenation of Ortho-chloronitrobenzene,TB383.1
  18. Study of the Adsorption Preparation for Eggshell-Type Pd、Pt Nano-Catalyst and Application,O643.36
  19. CO_2 Hydrogenation of direct synthesis of DME,TQ223.24
  20. The Preparation of Doped Palladium Catalysts Supported on Active Carbon and Study of Their Properties in Hydrogenation,O643.36
  21. Upgrading Research of Bio-oil,TE667

CLC: > Mathematical sciences and chemical > Chemistry > Physical Chemistry ( theoretical chemistry ),chemical physics > Chemical kinetics,catalysis > Catalytic > Catalytic reaction
© 2012 www.DissertationTopic.Net  Mobile