Dissertation > Excellent graduate degree dissertation topics show

Studies on Friedel-Crafts Reation of Anisole Catalyzed by Zeolites

Author: ZuoHaiYang
Tutor: BaiGuoYi
School: Hebei University
Course: Applied Chemistry
Keywords: Friedel-Crafts reaction Acylation Hydroxyalkylation Zeolites Modification
CLC: O643.32
Type: Master's thesis
Year: 2010
Downloads: 71
Quote: 1
Read: Download Dissertation

Abstract


Friedel-Crafts reaction is one of the most important methods for the production of aromatic compounds. Friedel-Crafts reaction is carried out commercially using Lewis acids, such as AlCl3, or Br?nsted acids, typically H2SO4 or HF. However, these traditional catalysts have limitations such as environmental pollution hazards arising from the disposal of potential toxic wastes, reactor corrosion and difficulty in handling. Furthermore, the catalyst amount to be employed is more than the stoichiometric quantity required. In recent years, zeolite is being more and more regarded as an environmentally friendly catalyst instead of traditional catalysts for Friedel-Crafts reaction.p-Methoxyacetophenone was synthesized by Friedel-Crafts acylation of anisole and acetic anhydride over Cr-doped Hβzeolite in this paper. The conversion of acetic anhydride and selectivity to p-methoxyacetophenone are both over 99.0% under the optimized reaction conditions. This is attributed to the increase of weak and moderately-strong acid sites, caused by the Cr addition. The formation of carbonaceous materials and their coating of the acid sites are believed to be the reasons for the deactivation of the reused Cr-doped Hβzeolite, as indicated by BET, SEM, XPS and NH3-TPD measurement results. The catalyst activity can be recovered effectively by a subsequent calcination. Meanwhile, the effect of phosphoric acid modiffition on catalytic performance of Hβzeolite for acylation of anisole is presented. Effect of phosphoric acid modification was studied based on XRD and NH3-TPD characterization. The influence of the reaction temperature, the catalyst amount and the reaction time on the acetic anhydride conversion were investigated and optimized. The conversion of acetic anhydride and the selectivity to p-methoxyacetophenone are both higher than 99.0% in four runs catalyzed by the recycled catalysts under the optimum reaction conditions, while the reaction temperature is 120℃, the catalyst amount is 2.0 g and the reaction time is 2 h.On the other hand, oxalic acid modified Hβ(OA-Hβ) zeolite is found to have better catalytic performance than Hβzeolite in the Friedel-Crafts hydroxyalkylation of anisole with chloral. This is attributed to the increase of weak and moderately-strong acid sites, caused by oxalic acid modification. Furthermore, it is believed that the carbonaceous deposits on the acid sites and the blockage of the pores, together with poisoning by chlorinated materials, are responsible for the deactivation of OA-Hβzeolite, as indicated by XPS, XRD, NH3-TPD, BET, SEM, Py-IR and TG measurement results. Moreover, partial regeneration of OA-Hβzeolite can be achieved via subsequent calcination.

Related Dissertations

  1. Optimizition of Compositions and Processing Parameters and Wear Properties of Cemented Carbides YG11R Modified by Nanosized Rare Earth,TG135.5
  2. Research of High Speed Image Pre-processing System Based on FPGA,TP391.41
  3. Preparation and Characterization of the OCS/PLLA Composite Film for Biomedical Materials,R318.08
  4. First- principles calculations of doped anatase titanium dioxide photocatalytic properties,O643.36
  5. Synthesis of Polysulfones and Modification for Epoxy Adhesives,TQ433.437
  6. Synthesis and Performance Study of Bisphenol AP-based Polybenzoxazines,TQ320.1
  7. Preparation of Crop Stalk-Based Sorption Materials with High Performances and Their Applications for Pah Removal from Water,X712
  8. Synthesis and Biocompatibility of different types of hydrophilic surface - modified polyurethane,R318.08
  9. Hydrophilic structure of different types of surface -modified polyurethane material and coagulation 12 factor nine peptide fragments,and fibrinogen P1 fragment of computer simulation of the interaction,O631.3
  10. Research on the Interface Modification of Epoxy Resin/Metallic Substrates and Epoxy Resin/Pigment,TQ630.1
  11. The Effects of Exposure to Bisphenol-a between Adolescence and Early Adulthood on Behaviors in Mice and Its Molecular Mechanism,R965
  12. Selenium Modification of Astragalus Polysaccharide and Its Antioxidant Activity in Vitro,R284.1
  13. Physical Modification of the Soybean Protein Concentrate by Alcohol Extraction,TS201.21
  14. Effect of Single and Double Mutations of Yeast H3K79L、H4K20L on the Function of ELP3 and Expression of SSA3,Q75
  15. Research on the Modified Methods of Fly Ash for Ammonia-nitrogen Wastewater Treatment,X703
  16. Polyaniline / short fiber reinforced natural rubber properties,TQ330.1
  17. Phosphate modification of nano- TiO 2 Photoelectrochemical Properties of the,TB383.1
  18. Multi-dimensional charge transport group modify iridium complex design, synthesis and optical properties,O627.8
  19. Modification of SEBS Rubber Via Living Radical Polymerization,TQ330.6
  20. Bioinformatics Analysis of Ubiquitination and Pupylation,Q51
  21. Modification of Thermosetting Resins by Polyetherimide,TQ323.7

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