Dissertation > Excellent graduate degree dissertation topics show

Study on Cr-based Catalysts for Vapor-phase Fluorination to Synthesis CF4 and Preparation of β-AlF3 with High Surface Area

Author: JiaWenZhi
Tutor: LuoMengFei
School: Zhejiang Normal University
Course: Physical and chemical
Keywords: Cl / F exchange reaction Cr- based catalysts CF4 Lewis acid Carbon hard template A high specific surface area of the β-AlF3
CLC: O643.32
Type: Master's thesis
Year: 2011
Downloads: 33
Quote: 0
Read: Download Dissertation

Abstract


Due to the serious damage to the atmospheric ozone layer, chlorofluorocarbons (CFCs), international environmental organizations to develop Montreal Protocol to limit the use of ozone-depleting substances (ODS), chlorofluorocarbons (CFCs). CFCs elimination technology CFCs conversion and utilization or development of CFCs alternatives is a very meaningful work. CCl2F (CFC-12) has been widely used in household and industrial propellants, refrigerants, is destroying the ozone layer. How can tetrafluoromethane (CF4) transformed into a high value-added CCl2F2 one of the objectives of this study. C1 / F exchange reaction CCl2F2 transformed CF4 gas phase in the Cr-based catalyst CCl2F2 fluoride reaction to synthetic. The goal of our research is carried out a detailed study of Cr-based catalysts, catalyst phase structure and surface chromium species were characterized using a variety of characterization techniques. Catalytic C1 / F exchange reaction catalyst used in Cr/AlF3 A1F3 carrier has a great influence on the performance of the Cr-based catalyst; the A1F3 carrier wherein the high specific surface area is possible to improve the performance of the Cr-based catalyst; paper uses a novel carbon hard template prepared by a high specific surface area A1F3 A1F3 has more number of Lewis acid sites, the C1 / F exchange reaction has a strong catalytic activity; related to the characterization and materials prepared. The papers on the following three aspects to a series of work: 1, using deposition precipitation prepared a series of different calcination temperature CrOx-Y2O3 catalyst for the gas-phase the fluoride CCl2F2 synthesis CF4. Fluorination reaction CCl2F2 and CClF3 as the raw materials to participate comparative study, the researchers found that the process CCl2F2 two-step continuous fluoride from CCl2F2 into CClF3 occur relatively fast, however from CClF3 transformed for CF4 is the rate-determining step. Calcined at 600 ℃ CrOx-Y2O3 catalyst after the fluorination catalyst has a very good activity, the tetrafluoromethane the yield in the reaction is maintained at about 95% within 10 hours. Characterization results and found that the activity of the catalyst and catalyst Cr species and the Lewis acid sites related. 2, deposition of Cr2O3-AlF3 catalysts were prepared by different content of Cr203, used for the gas fluoride CCl2F2 synthesis of CF4 reaction. The experiment found that the activity of the catalyst The a Cr203 content was 61.2% Cr2O3-AlF3 best, 94% of the yield of CF4 at 400 ℃. Characterized by XRD and Raman spectroscopy showed that the presence of crystalline phases Cr203 and a-AlF3 catalyst. NH3-temperature programmed desorption and adsorption of pyridine infrared spectroscopy characterization of the catalyst surface and the presence of strong Lewis acidity. Cr2O3-AlF3 catalyst of Cr species and Lewis acids, respectively, as the active centers of the catalytic CC12F2 hydrofluorination reaction (reaction with HF) and disproportionation reactions. This shows that the Cr2O3-AlF3 catalyst is a dual-function catalyst of the fluorination and the disproportionation reaction. 3, through a novel carbonaceous hard template SYSTEM prepared by a high specific surface area of ??the β-AlF3-. Pores of carbon charged into the porous type of γ-A1203, and then formed by vapor-phase fluorination of carbon-containing AlF3-carbon templating agent is removed by burning method, to obtain a specific surface area of ??114 m2g-1 of β-AlF3-. Fluoride and carbon combustion temperature on the phase state of the sample preparation and the specific surface area of. A high specific surface area of ??the B-AIF3 for CCl2F2 Cl / F exchange reaction, and exhibits a high activity, which is attributed to a number of more Lewis acid centers.

Related Dissertations

  1. Cross Method Research of the Impaction on Etch Rate and No-uniformity of SiO2 and Photo Resist during Plasma Etching,TN405
  2. Study on Stereocontrol in Photopolymerization of Methyl Methacrylate,O631.3
  3. Novel Regioselective Nitration of Chlorobenzene in Presence of Lewis Acid Catalysts,TQ246.1
  4. AlCl3 Participated in Nucleophilic Substitution Reactions of Aryl Methaol Derivatives,O643.32
  5. Studies on Resorcinol Selective Hydrogenation to Prepare 1,3-cyclohexanedione,TQ234.21
  6. Selective Hydrogenation of Crotonaldehyde over Pt Catalysts,TQ203.2
  7. Study on the Diastereoselective Aza-Diels-Alder Reaction and Intramolecular Hydroalkoxylation Catalyzed by Lanthanide Compounds,O643.32
  8. Studies on the Application of Metal Triflates and Ioinc Liquids in Organic Synthesis,O621.25
  9. The Study on What Function Inorganic Salt Accelerates the Reaction between Tert-Amyl Alcohol and Sodium,O643.1
  10. Aminolalcohol-Zinc Promoted Highly Enantioselectieve Alkynylation of N-phosphinoylimine with Terminal Alkynes,O643.32
  11. Studies on the Total Synthesis of Maistemonine,R284.1
  12. The mesoporous electrode material and its super capacitor performance,TM53
  13. Functional organic antimony compounds Synthesis, Characterization and Catalytic Applications,O621.2
  14. Selective hydrogenation of crotonaldehyde over Pt catalysts,O643.32
  15. Stereocontrol during the Radical Polymerization with Combined Lewis Acids （AlCl3-FeCl2）,O631.3
  16. A Study on Synthesis of Polychloromethylated Aromatic Compounds and Their Derivatives,O643.32
  17. Niobium pentachloride as a Lewis acid catalyst in organic synthesis,O621.3
  18. Lewis acid-catalyzed carbohydrate Preparation of 5 - (hydroxymethyl) furfural,TQ251.11
  19. No Reduction Activity of Al2O3 Influenced by Lewis Acid Sites and the C2H2-SCR over Ce-Al2O3,O643.36
  20. Transition Metal-catalyzed Synthesis of Heterocyclic Compounds,O643.36

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