Although the field of gas-phase kinetics remains hill of challenges it has reached a certain degree of maturity. Many of the fiindamental concepts of kinetics, in general take a particularly clear and rigorous fonn in gas-phase kinetics. The relation between fiindamental quantum dynamical theory, empirical kinetic treatments, and experimental measurements, for example of combustion processes [72], is most clearly established in gas-phase kmetics. It is the aim of this article to review some of these most basic aspects. Details can be found in the sections on applications as well as in the literature cited. [Pg.794]

The key to experimental gas-phase kinetics arises from the measurement of time, concentration, and temperature. Chemical kinetics is closely linked to time-dependent observation of concentration or amount of substance. Temperature is the most important single statistical parameter influencing the rates of chemical reactions (see chapter A3.4 for definitions and fiindamentals). [Pg.2114]

Hippier H and Troe J 1989 Advances in Gas Phase Photochemistry and Kinetics ed M N R Ashfold and J E Baggett (London Royal Society of Chemistry) pp 209-62 [Pg.1084]

Bohme D K and Raksit A B 1984 Gas phase measurements of the influence of stepwise soivation on the kinetics of nucieophiiic dispiacement reactions with CHjCi and CHjBr at room temperature J. Am. Ghem. Soc. 106 3447-52 [Pg.827]

Seeley J V, Jayne J T and Molina M J 1993 Fligh pressure fast-flow teohnique for gas phase kinetios studies Int. J. Chem. Kinet. 25 571-94 [Pg.826]

Howard M J and Smith I W M 1983 The kinetics of radical-radical processes in the gas phase Prog. Reaction Kin. 12 57-200 [Pg.1084]

An important example for the application of general first-order kinetics in gas-phase reactions is the master equation treatment of the fall-off range of themial unimolecular reactions to describe non-equilibrium effects in the weak collision limit when activation and deactivation cross sections (equation (A3.4.125)) are to be retained in detail [ ]. [Pg.791]

ESI Hydrogen/deuterium exchange, rapid monitoring of the exchange kinetics, gas phase Rajabi [335] [Pg.97]

RIchtsmeler S C, Parks E K, Liu K, Polo L G and Riley S J 1985 Gas phase reaction of Iron clusters with hydrogen. I. Kinetics J. Chem. Rhys. 82 3659 [Pg.2403]

Important aspects of all the models include limestone-S02 kinetics, combustion kinetics and other gas-solids reaction kinetics, gas phase material balances, solid phase material balances, gas exchange between the bubble and emulsion phases, heat transfer, and bubble hydrodynamics. [Pg.95]

Collisional energy transfer in molecules is a field in itself and is of relevance for kinetic theory (chapter A3.1). gas phase kmetics (chapter A3.4). RRKM theory (chapter A3.12). the theory of unimolecular reactions in general, [Pg.1053]

The foundations of the modem tireory of elementary gas-phase reactions lie in the time-dependent molecular quantum dynamics and molecular scattering theory, which provides the link between time-dependent quantum dynamics and chemical kinetics (see also chapter A3.11). A brief outline of the steps hr the development is as follows [27], [Pg.772]

However, a note of caution should be added. In many multiphase reaction systems, rates of mass transfer between different phases can be just as important or more important than reaction kinetics in determining the reactor volume. Mass transfer rates are generally higher in gas-phase than liquid-phase systems. In such situations, it is not so easy to judge whether gas or liquid phase is preferred. [Pg.45]

Reaction (5) proceeds mostly heterogeneously, reaction (6) mostly homogeneously. This mechanism can be integrated with simplifying assumptions to demonstrate the main features of gas-phase explosion kinetics [8] [Pg.792]

At the limit of extremely low particle densities, for example under the conditions prevalent in interstellar space, ion-molecule reactions become important (see chapter A3.51. At very high pressures gas-phase kinetics approach the limit of condensed phase kinetics where elementary reactions are less clearly defined due to the large number of particles involved (see chapter A3.6). [Pg.759]

Within physical chemistry, the long-lasting interest in IR spectroscopy lies in structural and dynamical characterization. Fligh resolution vibration-rotation spectroscopy in the gas phase reveals bond lengths, bond angles, molecular symmetry and force constants. Time-resolved IR spectroscopy characterizes reaction kinetics, vibrational lifetimes and relaxation processes. [Pg.1150]

Flere, we shall concentrate on basic approaches which lie at the foundations of the most widely used models. Simplified collision theories for bimolecular reactions are frequently used for the interpretation of experimental gas-phase kinetic data. The general transition state theory of elementary reactions fomis the starting point of many more elaborate versions of quasi-equilibrium theories of chemical reaction kinetics [27, M, 37 and 38]. [Pg.774]

Formic acid can decompose either by dehydration, HCOOH — H2O + CO (AG° = —30.1 kJ/mol AH° = 10.5 kJ/mol) or by dehydrogenation, HCOOH H2 + CO2 (AG° = —58.6 kJ/mol AH° = —31.0 kJ/mol). The kinetics of these reactions have been extensively studied (19). In the gas phase metallic catalysts favor dehydrogenation, whereas oxide catalysts favor dehydration. Dehydration is the predominant mode of decomposition ia the Hquid phase, and is cataly2ed by strong acids. The mechanism is beheved to be as follows (19) [Pg.504]

Perturbation or relaxation techniques are applied to chemical reaction systems with a well-defined equilibrium. An instantaneous change of one or several state fiinctions causes the system to relax into its new equilibrium [29]. In gas-phase kmetics, the perturbations typically exploit the temperature (r-jump) and pressure (P-jump) dependence of chemical equilibria [6]. The relaxation kinetics are monitored by spectroscopic methods. [Pg.2118]

Generalized first-order kinetics have been extensively reviewed in relation to teclmical chemical applications [59] and have been discussed in the context of copolymerization [53]. From a theoretical point of view, the general class of coupled kinetic equation (A3.4.138) and equation (A3.4.139) is important, because it allows for a general closed-fomi solution (in matrix fomi) [49]. Important applications include the Pauli master equation for statistical mechanical systems (in particular gas-phase statistical mechanical kinetics) [48] and the investigation of certain simple reaction systems [49, ]. It is the basis of the many-level treatment of [Pg.789]

A general limitation of the relaxation teclmiques with small perturbations from equilibrium discussed in the previous section arises from the restriction to systems starting at or near equilibrium under the conditions used. This limitation is overcome by teclmiques with large perturbations. The most important representative of this class of relaxation techniques in gas-phase kinetics is the shock-tube method, which achieves J-jumps of some 1000 K (accompanied by corresponding P-jumps) [30, and 53]. Shock hibes are particularly [Pg.2123]

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