Gas-Phase Reactions: Kinetics and Mechanisms

ISBN-13: 9783642676109 / Angielski / Miękka / 2011 / 242 str.

V. N. Kondratiev; E. E. Nikitin

Opis

The present monograph appears after the death of Professor V. N. Kondratiev, one of those scientists who have greatly contributed to the foundation of contem porary gas kinetics. The most fundamental idea of chemical kinetics, put for ward at the beginning of the twentieth century and connected with names such as W. Nernst, M. Bodenstein, N. N. Semenov, and C. N. Hinshelwood, was that the complex chemical reactions are in fact a manifestation of a set of simpler elementary reactions involving but a small number of species. V. N. Kondratiev was one of the first to adopt this idea and to start investigations on the elementary chemical reactions proper. These investigations revealed explicitly that every elementary reaction in turn consisted of many elementary events usually referred to as elementary processes. It took some time to realize that an elementary reaction, represented in a very simple way by a macroscopic kinetic equation, can be described on a microscopic level by a generalized Boltzmann equation. Neverheless, up to the middle of the twentieth century, gas kinetics was mainly concerned with the interpretation of complex chemical reactions via a set of elementary reactions. But later on, the situation changed drastically. First, the conditions for reducing microscopic cquations to macroscopic ones were clearly set up. These are essentially based on the fact that the small perturbations of the Maxwell-Boltzmann distribution are caused by the reaction proper."

Spis treści

I. General Kinetic Rules for Chemical Reactions.- 1. Kinetic Equations. Rate Constants.- 2. Kinetic Classification of Reactions. Simple and Complex Reactions.- 2.1 Kinetic Types of Simple Reactions.- 2.2 Consecutive Reactions.- 2.3 Steady-State Method.- 2.4 Parallel Reactions.- 2.5 Coupled Reactions. Chemical Induction.- 2.6 Homogeneous Catalysis.- 2.7 Catalysis by Products (Autocatalysis).- 3. Chemical Equilibrium.- II. Mechanisms of Chemical Reactions.- 4. Macroscopic Manifestation of a Complex Reaction Mechanism.- 5. Intermediates.- 6. Atomic Reactions.- 6.1 Reactions in Highly-Rarefied and Diffusion Flames Reaction M + X2.- 6.2 Reaction M + RX and Other Reactions.- 6.3 Atomic Hydrogen Reactions.- 6.4 Atomic Oxygen Reactions.- 6.5 Reactions of Atomic Halogens.- 6.6 Atomic Nitrogen Reactions.- 7. Radical Reactions.- 7.1 Production of Radicals.- 7.2 Reactions of Certain Radicals.- III. Theory of Elementary Processes.- 8. Microscopic Formulation of Reaction Kinetics.- 8.1 Cross Sections, Transition Probabilities and Rate Constants of Elementary Processes.- 8.2 Kinetic Equations for Unreactive Processes.- 8.3 Translational, Rotational and Vibrational Relaxation.- 8.4 Kinetics of Reactive Processes.- 8.5 Relation Between Rate Constants of Forward and Reverse Non-Equilibrium Reactions.- 9. Dynamics of Elementary Processes.- 9.1 Adiabatic Approximation.- 9.2 Probabilities of Electronically Adiabatic Processes.- 9.3 Probabilities of Electronically Non-Adiabatic Processes.- 10. Various Types of Potential Energy Surfaces.- 10.1 Rectangular and Skewed Coordinates.- 10.2 Unreactive Interactions A + BC.- 10.3 Reactive Interactions A + BC.- 11. Equilibrium Rate Constants. Transition-State Method.- 11.1 Assumptions and Derivation of the Basic Transition-State Method Expressions.- 11.2 Activation Energy and Pre-Exponential Factors in the Reaction Rate Constant Expression.- IV. Energy Exchange in Molecular Collisions.- 12. Experimental Methods of Studying Vibrational Relaxation.- 12.1 Dispersion and Absorption of Ultrasounds.- 12.2 The Shock-Wave Method.- 12.3 Spectroscopic Methods.- 12.4 Molecular Beams.- 13. Transfer of Translational and Rotational Energy.- 13.1 Translational-Translational (TT) Energy Transfer.- 13.2 Rotational-Translational (RT) Energy Transfer.- 14. Transfer of Vibrational Energy.- 14.1 Exchange of Translational and Vibrational Energy (VT Process).- 14.2 Exchange of Rotational and Vibrational Energy (VR and VRT Processes).- 14.3 Effect of Non-Adiabatic Coupling on Vibrational Energy Transfer.- 14.4 Vibrational Relaxation via Long-Lived Complexes and in Symmetric Exchange Reactions.- 14.5 Intermolecular Quasi-Resonant Vibrational Energy Exchange (Intermolecular VV Process).- 14.6 Intramolecular Quasi-Resonant Vibrational Energy Exchange (Intramolecular VV Process).- 15. Kinetics of the Vibrational Relaxation of Diatomic Molecules.- 16. Energy Exchange with Electronically Excited Molecules.- 16.1 VRT Energy Transfer.- 16.2 Electronic Energy Transfer.- V. Unimolecular Reactions.- 17. The Theory of Unimolecular Reactions.- 17.1 Definition of Unimolecular Reactions.- 17.2 Molecular Activation and Deactivation.- 17.3 Unimolecular Conversion.- 17.4 Pressure Dependence of Rate-Constant of Polyatomic Molecules.- 17.5 Thermal Dissociation of Diatomic Molecules.- 18. Experimental.- 18.1 Pre-Exponential Factor in the k? Expression.- 18.2 Pre-Exponential Factor in the k0 Expression.- 18.3 Energy Exchange in Unimolecular Reactions.- 18.4 Activation Energy for Unimolecular Reactions.- 18.5 Boundary between High-and Low-Pressure Domains (p1/2) (Fall-Off Pressure).- VI. Combination Reactions.- 19. Atomic and Radical Recombination and Addition Reactions.- 19.1 Radiative Stabilization.- 19.1.1 Recombination on a Repulsive Potential Curve.- 19.1.2 Recombination on an Attractive Potential Curve.- 19.1.3 Recombination via Inverse Predissociation.- 19.2 Collisional Stabilization.- 20. Termolecular Reactions.- 20.1 Number of Three-Body Collisions.- VII. Bimolecular Exchange Reactions.- 21. Theory of Bimolecular Exchange Reactions.- 21.1 Classification of Exchange Reactions.- 21.2 Cross Sections of Exchange Reactions.- 21.3 Energy Requirements.- 21.4 Energy Disposal.- 21.5 Temperature Dependence of Rate Constants of Equilibrium Bimolecular Reactions.- 21.6 Non-Equilibrium Effects in Thermal Bimolecular Reactions.- 22. Certain Types of Bimolecular Exchange Reactions.- 22.1 Abstraction of Atoms and Radicals.- 22.2 Isotope Exchange Reactions.- 22.3 Reactions between Atoms, Radicals and Unsaturated Molecules.- 23. Bimolecular Reaction Rates as a Function of Molecular Structure.- 23.1 Reactions of Atomic Sodium with Halogenated Hydrocarbons.- 23.2 Reactions of Hydrogen and Chlorine Atoms, and of Hydroxyl and Methyl Radicals with Hydrocarbons.- 23.3 Bimolecular Reactions of Electronically Excited Species.- VIII. Photochemical Reactions.- 24. Photochemical Activation of Molecules.- 24.1 The Lambert-Beer Law.- 24.2 Primary Photochemical Step. Quantum Yield.- 24.3 Quantum Yield a as Function of the Wavelength.- 24.4 The Nature of Primary Centers of a Photochemical Reaction.- 24.5 Hot Particles.- 25. Secondary Processes in Photochemical Reactions.- 25.1 Secondary Processes Involving Atoms and Radicals.- 25.2 Secondary Processes Involving Excited Molecules.- 25.3 Fluorescence. Metastable Molecules.- 25.4 Fluorescence Quenching.- 26. Photochemical Sensitization.- 26.1 Photosensitization with Halogens.- 26.2 Photosensitization with Mercury.- 27. Temperature Dependence and Photochemical Reaction Mechanisms.- 27.1 Temperature Coefficient.- 27.2 Formation of Hydrogen Bromide from Hydrogen and Bromine Molecules.- 27.3 The Photochemical Reaction Limit.- IX. Chemical Reactions in Electric Discharge.- 28. Activation in Electric Discharge.- 28.1 Excitation of Atoms and Molecules by Electron Impact. The Excitation Function.- 28.2 Excitation of Molecular Vibrations and Rotations by Electron Impact.- 29. Types of Electric Discharge. Low-Temperature Plasma.- 30. Certain Reactions in Electric Discharge and Their Yields.- 30.1 Ozone Production.- 30.2 Ammonia Synthesis from Nitrogen and Hydrogen.- 30.3 Acetylene Production from Methane.- X. Radiation Chemical Reactions.- 31. Primary Processes.- 31.1 Electron Impact Ionization. Generation of Positive Ions.- 31.2 Generation of Negative Ions.- 32. Secondary Processes Specific of Radiation Chemistry.- 32.1 Ion-Molecule Reactions.- 32.2 Recombination of Charged Species.- 32.3 Reactions Involving Highly-Excited Neutral Particles. Hot Atoms.- 33. The Sequence of Elementary Processes in Gas Radiolysis.- 33.1 Examples of Complex Reactions.- 33.2 Radiolysis of Hydrocarbons.- 33.3 Ammonia Radiolysis.- 33.4 Radiolysis of Nitrogen — Oxygen Mixtures.- XI. Chain Reactions.- 34. Non-chain and Chain Reactions.- 35. Stationary Chain Reactions.- 35.1 Mean Chain Length.- 35.2 Time Dependence of Chain Propagation.- 36. Chain Generation.- 36.1 Thermal Gas-Phase Generation of Active Centers.- 36.2 Gas-Phase Generation of Active Centers as a Result of Chemical Interactions.- 36.3 Chain Generation at the Wall.- 37. Chain Termination.- 37.1 Homogeneous Chain Termination.- 37.2 Heterogeneous Chain Termination. Diffusion and Kinetic Regions.- 37.3 Stationary Chain Reaction Rates.- 38. Branched Chains.- 38.1 Limiting Phenomena. Self-Ignition Peninsula.- 38.2 Temperature Dependence of the Chain Reaction Rates.- 38.3 The Role of Impurities in Chain Reactions.- 39. Hydrogen Combustion as Model Reaction.- 39.1 Reaction Mechanism.- 39.2 Low-Pressure Reaction Kinetics.- 39.3 Upper and Lower Ignition Limits.- 39.4 Induction Period.- 39.5 General Solution of Kinetic Problems.- 40. Hydrocarbon Oxidation and Combustion Mechanisms.- 40.1 Combustion Reactions.- 40.2 Slow Oxidations.- 41. Fluorination Reactions.- 42. Radiation-Chemical Initiation of Chain Reactions.- XII. Combustion Processes.- 43. Self-Ignition.- 43.1 Chain Explosion.- 43.2 Two-Stage Self-Ignition.- 43.3 Adiabatie Explosion.- 43.4 Account for Incomplete Combustion.- 44. Non-Premixed Flames.- 44.1 Highly Rarefied Flames.- 44.2 Hot Diffusion Flames.- 45. Premixed Flames.- 45.1 Rarefied Flames.- 45.2 Hot Flames.- 45.3 Cool Flames.- 46. Flame Propagation.- 46.1 Normal Burning Rate.- 46.2 Diffusion Flame Propagation.- 46.3 Thermal Flame Propagation.- 46.4 Flammability Limits.- 47. Detonation.- References.