Dissertation > Excellent graduate degree dissertation topics show

Gas Phase Reaction Mechanism of ZrO+ with CS2、NbS+ with H2O and N2O with H2 Cyclically Catalyzed by Ir+

Author: HuDongBao
Tutor: XieXiaoGuang
School: Yunnan University
Course: Physical and chemical
Keywords: Density functional theory (DFT) Coupled cluster theory (CCSD (T)) Transition metal cations Reaction Mechanism Potential energy surfaces crossing
CLC: O643.12
Type: Master's thesis
Year: 2010
Downloads: 19
Quote: 0
Read: Download Dissertation

Abstract


At present, the transition metal chemistry has been a very active area of ??experimental and theoretical studies. In industry, the transition metal oxide is used in many ways to do a versatile catalyst, but their activity is too high some of the reactions not expected product. Instead, transition metal sulfide as the activity of the catalyst reaction is low, does not easily poisoned shows high selectivity. Transition metal sulfides in biochemistry also plays a special role, because different metal sulfides formed active centers in metalloenzymes. In addition, transition metal ions are involved in the reaction often involves the reaction of the two-state potential energy surface crossing, theoretical chemists have also done a lot of this type of reaction theory. In this paper, based on molecular orbital theory, transition state theory and quantum mechanics theory, density functional theory DFT and coupled cluster theory CCSD (T) and a detailed study of the reaction mechanism of the three reaction system. In the first reaction system, we use B3LYP/6-311 G * and CCSD (T) / the SDD 6-311 G * are two ways to study the transition metal oxide cations ZrO with small molecules CS 2 reaction mechanism. According to theoretical calculations, we raised about the three product ZrS ZrS / sub> . and ZrOS possible reaction channels and reaction mechanism. Study found generate ZrS to , ZrS 2 reaction experienced with a four-ring transition state of the O / S exchange reaction steps, namely intermediates IM2 is formed through the transition state TS12. IM2 In addition to the direct solution off generate ZrS product, there is a molecular rearrangement reaction and to generate product ZrS 2 . Proposed molecular rearrangement reaction mechanism is reasonably explained no reaction after ZrS intermediates generated the product ZrS 2 phenomenon. The product generated ZrOS find two parallel reaction channels (Path A and B). Path B is an insertion - elimination reaction mechanism, this channel needs to overcome the reaction of 25.0 kJ / mol energy barrier. Path A is a sulfur atom transfer reaction, but the reaction (174.5 kJ / mol), the energy barrier is high only in the high-energy reaction conditions Path A fishes resulting product ZrOS there contribution. In the second reaction system, we B3LYP/6-311 G ** method the NbS (3Σ-1Γ) and H 2 O reaction theoretical calculation study, we found that the reaction is carried out through two reaction mechanisms: an oxygen-sulfur exchange reaction: NbS O atom in the S atoms with H 2 O mutual exchange and get the product NbO ; another off of the molecular H 2 (accompanied by the dissociation of a H atom and generate adverse NbOSH) and while give the product NbOS . For the process of de-H 2 molecule, the reaction is conducted in the most favorable way is 3NbS (3σ) H 2 O → 1NbOS -2 (1A ') H 2 . The reaction involves two states, there is the potential energy surface crossing phenomenon. The calculated results reasonably explain the experimentally observed phenomenon. In the third reaction system, we studied on a theoretical level, CCSD (T) / [SDD 6-311 G ** / / B3LYP / [SDD TZVP] loop catalytic reaction of transition metal ions Ir N 2 OH 2 → N 2 H 2 O ((1) N 2 O Ir → IrO N 2 (2) IrO H 2 → Ir H 2 O). The results show that: the whole reaction after a two-step process, the first step is to the Ir N 2 O win the O atoms generation of IrO and H 2 process, is the rate-determining step of the reaction need to overcome a 42.8kJ/mol energy barrier; second step of IrO generated and H reduction the generate a Ir and H 2 O process, this process does not require energy barrier. This two-step reaction is spin allowed reaction, there is no potential energy surfaces crossing. Both reactions are exothermic process.

Related Dissertations

  1. Containing pyridyl group metal complexes Synthesis and Structure,O627
  2. N-heptane HCCI combustion process temperature thermodynamics and kinetics theory,O643.21
  3. A Density Functional Theory Study for Wn C0,± （n=1-6） Clusters,O641.1
  4. A Study for Structure and Properties of OsnN0, ± （n=1-6） Clusters,O641.1
  5. Kinetics of Catalysis Hydrolytic Depolym Erization of Poly (ethylene Terephthalate) Under Microwave Irradiation,O631.3
  6. The Mechanism of the Degradation of DNS and Its Kinetics,O643.12
  7. Mechanism Study on Mercury Homogeneous and Heterogeneous Reaction,O643.12
  8. Study on Forming Mechanism of the Fe-Al2O3-FeAl2O4 Composite Coating by Reactive Plasma Spraying,TG174.442
  9. Preparation and Properties Research of New Type Nano-Porphyrin,TB383.1
  10. Process and Properties Research of the SiO2f/SiO2-BN Composites by Urea Route,TB332
  11. A DFT Study on Partial Process in Catalytic Purification of Auto Exhaust over Pd, Pt, Rh and Their Alloy Catalysts,U491.92
  12. Preliminary Research on the Reaction Mechanism and Application of Aryl Diazonium Acid,O621.25
  13. Theoretical Study on A Seriers of Crown Ethers Metal Complexes and Molecular Switch,O641.4
  14. The Theorical Study on the Formation about β-CD-Styrene Oxide and β-CD-N-Tosyl-2-Phenyl-Aziridine, and HBr-Induced Ring Opening of Styrene Oxide in the Presence of β-CD,O621.13
  15. Theoretical Study About Primary Particles of BTO Unit Cell Adsorption on Si(001) Surface,O469
  16. Theoretical Study of Activation C-H Bond of Methane by Ti, Zr, Hf in the Gas Phase,O641.1
  17. Multiple Condensation new barbiturate derivative Theoretical Study of the Reaction Mechanism,O643.11
  18. Study on Reaction Mechanism of Hydrogen Production Via Catalytic Steam Reforming of Bio-oil Model Compounds,TK6
  19. Theoretical Research of kemp Elimination Reaction and Its Mechanism,O643.12
  20. Catalytic Wet Air Oxidation (CWPO) Experimental study of the treatment of dye wastewater,X703

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