Rate of Homogeneous Reactions

The progress of this category of reactions is expected to depend on the composition of the materials within the phase as well as the temperature and pressure of the system. The rate of homogeneous reaction should not be affected by the shape of the container, the surface properties of the solid materials in contact with the phase, and the diffusion characteristics of the fluid. Thus the rate of reaction of component i may be expressed as... 

Effect of Microwaves on the Rates of Homogeneous Reactions in Open Vessels 1123... 

The theory of premixed flames essentially consists of an analysis of factors such as mass diffusion, heat diffusion, and the reaction mechanisms as they affect the rate of homogeneous reactions taking place. Inasmuch as the primary mixing processes of fuel and oxidizer appear to dominate the burning processes in diffusion flames, the theories emphasize the rates of mixing (diffusion) in deriving the characteristics of such flames. 

Christian Reichardt, Solvent effects on the rate of homogeneous reactions in solvents and solvent effects in organic chemistry, 2nd ed., Wiley-VCH Verlag GMBH Co. Wiley-VCH Publishers, New York,... 

The rates of homogeneous reactions (radical or chain) are then computed taking into account the concentration of radicals generated in the initiation step. Usually from the steady-state approximation applied to chain reactions, the initiation rate is equal to the termination rate. An example of a termination reaction given below... 

A honeycomb shape has been considered as the most desirable structure for the combustion catalyst due to a small pressure drop across the channel and a large surface-to-volume ratio. Stable combustion can be attained with laminar flow of gas mixture along the channel of the honeycomb, whereas turbulent flow and back-mixing are operative for the conventional flame combustion. The temperature at the honeycomb wall rises rapidly with fuel contact. The rate of homogeneous reaction depends on the fuel concentration and temperature therefore, the non-catalytic gas-phase reaction initiates from this hot wall where the temperature is raised by catalytic combustion. Once this catalytically initiated gas-phase reaction started, the reaction propagates rapidly toward the center of the channel. Then the high combustion efficiency can be attained. ... 

Tritium labelled compounds can also be used as true tracers for following the rates of homogeneous reactions. Thus, in the reaction of amines with epoxides, one can label the amine and by taking samples at fixed time intervals, quenching and subjecting them to radio-HPLC one can follow the disappearance of amine, the increase in the formation of a 1 1 complex and in some cases, the appearance of further complexes until reaction is complete (Fig. With so much information becoming available it is... 

Rate of Homogeneous Reactions in Ideal Isothermal Reactors... 

Discuss the influence of gas pressure, temperature, and concentrations of reactants in solid state reactions. In what way do the kinetics of reactions involving solids differ from the rates of homogeneous reactions between molecules ... 

Let us now consider the contribution of diffusion to the maximum rates of homogeneous reactions involving associations as a first step in the interactions of proteins with both small and large substrates. In the present context association to form a specific complex does not include any covalent bond formation. Three events are involved in the approach to equilibrium collision, alignment to correct mutual orientation and for some processes separation after the event. These events depend on translational diffusion for approach and separation and on rotational diffusion for alignment. Earlier in this section the diffusion constant was defined using the principle of random Brownian motion and this will now be used in equations which have been derived to evaluate maximum collision rates. 

Approach curve (SECM) — A current-distance curve recorded as an ultramicro electrode (tip) approaches a surface in scanning electrochemical microscopy. On a surface where the reverse of the tip reaction occurs on the substrate surface the current increases as the distance between the tip and substrate, d, decreases (positive feedback). On an insulator surface the tip current decreases with decreasing d (negative feedback). The approach curve is useful in determining the absolute magnitude of d and can provide information about the heterogeneous electron transfer kinetics on the substrate and the rates of homogeneous reactions that occur in the gap between tip and substrate. 

Rvi represents the rates of homogeneous reactions in the pit, expressed as moles of i generated per time per volume of the solution. If the solution is very dilute, the species flux N/ is... 

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