Dissertation > Excellent graduate degree dissertation topics show

Chloromethane Transformation to Light Olefins over Molecular Sieve Catalyst and Reaction Mechanism

Author: ZhangDaZhi
Tutor: LiuZhongMin
School: Dalian Institute of Chemical Physics
Course: Industrial Catalysis
Keywords: chloromethane molecular sieve light olefin SAPO-34 MeASPO-34 magnesium modify reaction mechanism induction period
CLC: O643.32
Type: PhD thesis
Year: 2007
Downloads: 414
Quote: 8
Read: Download Dissertation

Abstract


Light olefins production from nature gas is an attractive subject considering the shortage of petroleum in the world. Among the processes for natural gas utilization, methane transformation to light olefins via chloromethane as intermediate is a potential and an alternative route, which could be realized under mild condition and in less steps. In the present study, we try to develop catalyst for chloromethane transformation to light olefins and investigate the possible mechanism of this reaction.Various zeolites and SAPO catalysts with difference channel structure and acidity have been employed in the chloromethane transformation. The acidity and channel structure of the catalysts affect the activity and selectivity. SAPO-34 molecular sieve presents high selectivity for light olefins production and good conversion, proving its application potential in chloromethane transformation. Silicon incorporation is the key for acid site generation of SAPO molecular sieves. The acidity and reaction behavior could be modified by varying the Si content of SAPO-34. When using SAPO-34 with different Si incorporation in chloromethane transformation, we find the conversion and product distribution varied with Si content. Isomorphous substituted MeAPSO-34 was synthesized by hydrothermal method. The incorporation of Metal into SAPO-34 can vary the selectivity to light olefins. For better catalytic performance, two methods of metalincorporated, isomorphous substitution and impregnation, are farther investigated in details. With hydrothermal method, a series of MgAPSO-34 are synthesized. Isomorphous Mg substitution of Al is proved. Chloromethane conversion over MgAPSO-34 showed improved C2=-C3=0 selectivity. Mg/SAPO-34, prepared with Mg impregnation, present higher initial selectivity to light olefins than SAPO-34.Differential pulse reaction equipment is used to investigate the reaction mechanism of chloromethane conversion. For the first time, the induction period of chloromethane conversion is proved. Cyclo-organic surface species, forming in induction period and behaving as reaction center for light olefins assembly, are determined by mass spectra and FT-IR. Those observation allow us to propose a realistic reaction mechanism—“Hydrocarbon pool”mechanism.

Related Dissertations

  1. Containing pyridyl group metal complexes Synthesis and Structure,O627
  2. Epoxidation of olefins with high activity cobalt zeolite catalysts,O643.32
  3. N-heptane HCCI combustion process temperature thermodynamics and kinetics theory,O643.21
  4. Synthesis and Modification of SAPO-34 Molecular Sieve Catalyst for Methanol-to-Olefin Reaction,TQ221.2
  5. Research on Adsorption of PH3 from Producing Sodium Hypophosphite by Phosphorus Sludge,X78
  6. Synthesis Mesoporous Molecular Sieve MCM-41 with Iron Ore Tailings,TQ424.25
  7. Kinetics of Catalysis Hydrolytic Depolym Erization of Poly (ethylene Terephthalate) Under Microwave Irradiation,O631.3
  8. The Mechanism of the Degradation of DNS and Its Kinetics,O643.12
  9. Fabrication of Oriented Molecular Sieve Layers,O643.36
  10. Synthesis and Characterization of SAPO-34,O643.36
  11. Preparation of Aluminumphosphate Molecular Sieves and Their Application to Preferential Oxidation of CO to H2-Rich Gases,O614.31
  12. Mechanism Study on Mercury Homogeneous and Heterogeneous Reaction,O643.12
  13. Oxidation of arsenic-containing copper sulfide concentrate roasting,TF811
  14. Study on Forming Mechanism of the Fe-Al2O3-FeAl2O4 Composite Coating by Reactive Plasma Spraying,TG174.442
  15. Process and Properties Research of the SiO2f/SiO2-BN Composites by Urea Route,TB332
  16. The Preparation and Commercial Application of Catalyst CC-20D,TE624.91
  17. Reinforcing and Flame-retardant Effects of Mesoporous Molecular Sieve on Polydicyclopentadiene,O632
  18. Studies on New Adsorbents for N2/CH4 and CO2/CH4 Seperation,TQ424.1
  19. Theoretical Studies on the Mechanism of CO Catalytic Oxidation on Au Surfaces,O643.32
  20. The Study on Reaction Mechanism and Dynamics of MgO Preparation with Molten Salt,O614.22
  21. Study on Calcium Removal in Seawater by Electrosorption,P747

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